P IANC

DRY

FOREWORD

During the l8th Meeting held on 8th October 1984 in

Brussels, the PIANC Council decided that the mandate of

the Commission for the Study of Locks, Dry Docks and .

Shiplifts be given to a new commission. Jn matters con­

cerning Dry Docks the new commission would function

within the framework of the Permanent Technical Com­

mittee No. II and the date fixed for the receipt of the

report on Dry Docks was to be not later than the end of

1987.

It was proposed in June 1985 that Mr G.P. Martin,

Senior Partner of T.F. Burns & Partners, Consulting Engin­

eers in the United Kingdom, should be appointed General

Reporter on the subject of Dry Docks. The proposal was

duly ratified by the Permanent International Commission.

1. CONTENTS OF REPORT

The report is concerned with the planning and design

of dry docks and a study of modern trends. In this respect

an attempt has been made to record information about

docks built since 1950, the results of which are shown in

the Appendix 'A'. The list is unfortunately not complete,

but nevertheless indicates general statistical information.

Clrap.t:u 1 consists of definitions of dimensions and

size of docks in order to achiern standardisation of infor­

mation.

Clrap.t:u 2 is concerned with the planning of Dry

Docks, including their size, siting and arrangement of

facilities, serdces and equipment.

Clrap.t:u 3 deals with the choice of o\·erall structural

design of a Dry Dock, the final decision ha\·ing a profound

effect on constructional costs of the project.

Clrap.t:u 4 sets out notes on the design of Yarious

types of Dry Dock floors that may be adopJed following a

P.l.A.N.C. • A.l.P.C.N.

REPORT on

DOCKS

decision being made on the o\·erall design philosophy con­

sidered in Chapter 3.

Clrap.t:u S sets out notes in a similar way to Chapter

4 on rnrious types of Dry Dock walls.

Clrap.t:u 6 deals with dewatering of Dry Docks in a

general way.

Clrap.t:u 7 deals with filling of Dry Docks.

Clrap.t:u g describes the factors affecting the choice

of Dock Gates and is followed by a description of the

main choices a\·ailable, together with their ad\·antages and

disad\·antage�.

Clrap.t:u 9 describes some of the major items of Dry

Dock equipment.

The Appendix 'A' is preceded by a simple statistical

analysis of dock floor and gate designs.

2. MEMBERS OF THE COMMISSION

The members of the new commission as related to

Dry Docks are a follows :

PRESIDENT :

Professor R . KUHN, Dr. -Ing . , Rhein-Main-Donau A . G . , Prokurist i. r. , Munich, F.R. Germany

GENERAL REPORTER :

Mr G . P . MARTIN, BSc FICE, Senior Partner, T.F. Burns and Partner s , Consulting Engineers, l1nited llingdom

SECRETARY :

Mr A. LEFEBVRE, Engineer of Highways Department, Ministry of Public Works , Brussels , Bel.giua

BULLETIN 1 988 - N° 63

MEMBERS

AUSTRIA Mr W. ROEHLE1 Dipl. Ing. , Director, Osterreichischen Donaukraftwerke A . G . , Wien

BELGIOM Mr. P. LAGROU, Director General of Central Supply Office, Ministry of Public Works, Brussels

Mr C. ROTHILDE, Engineer in Chief-Director, Administration of Waterways, Ministry of Public Works, Brussels

Mr J. SEIVERT, Inspector General, Administration of Waterways, Ministry of Public Works, Brussels

CAR&DA Mr D . J . GORMLEY, Marine Works and Transportation Division, Engineering & Architecture Parks, Ottawa

FRARCE Mr MONADIER, Chief Engineer of Highways Department, Compiegne

ITALY Mr G . DELLA LUNA, Ingegnere Direttore, Canale Milano-Cremona-Po, Cremona

REI'BERLARDS Mr VAN DER HORST, M.Sc. Senior Engineer, B.v. Aannemingsbedrijf NBM, The Hague

Mr F.A. VAN TOL, Ministry of Transport, Public Works, The Hague

Mr. F . C . DE WEGER, B.I. Consulting Engineer, Rorterdam

POLA!ID Professor MAZURKIEW!CZ, University of Gdansk

PORTUGAL Mr D . PINTO DA SILVA, Engenheire Chefe de Divisao CPE, Porto

FEDERAL REPUBLIC OF GEl!MAHY Mr H . D. CLASMEIER, Dipl. Ing. Niedersachsisches Hafenamt, Emden

Mr D . P . BERTLIN, M .Eng FICE, Redhill

Mr P . LACEY, FICE, Ove Arup & Partners, London

u.s.A. Mr J . DAVIS, Consulting Engineer, Washington D . C .

Mr . YACHNIS, D.Sc. Chief Engineer, Department of the Navy, Facilities Engineering Command, Alexandria, Virginia

u.s.s.R. Professor V .M. SELEZNEV, River Fleet Ministry, Leningrad .

2 P.l .A.N.C. • A.l.P.C.N. - BULLETIN 1988 - N° 63

C O N T E N T S

1. GENERAL 1.1 Introduction l.2 Terminology and assessment of dock 1.3 Entrance width 1.4 Dock barrel width l.5 Effective length of dry dock l.6 Effective depth of dry dock

2. PLANNING OF DRY DOCKS 2.1 Introduction

size

2.2 Clearances between ship and dry dock 2.3 Dock size 2.4 Level of dry dock cope 2.5 Depth of dry dock 2.6 Si ting of dry docks 2.7 Subsoil conditions 2.8 Navigational approach 2.9 Anchorages and quays 2.10 Availability of services 2. ll Prevailing wind 2.12 Tidal flow, currents and waves 2.13 Position with respect to buildings, workshops, etc. 2.14 Arrangement at dry dock copes 2.15 Access to dry dock floor 2.16 Area surrounding dry dock

3.

3.1

3.2

3.3

3.4

3.5.

3.6

3.7

3.8

3.9

3.10

4.

4-.l

4.2

4.3

4.4

4.5

lt.6

4.7

4.8

4.9

4.10

4.11

4.12

4.13

OVERALL STRUCTURAL DESIGN OF DRY DOCK Introduction The influence of the location The influence of the available space and execution time The influence of soil condition and groundwater situ­ation Making a decision Possible dock structures Overall structural design method Factor of safety of dry dock against flotation Structural analysis by finite element method Analysis in seismic areas

DESIGN OF DRY DOCK FLOORS

Introduction Gravity dry dock floors Under-drained dry dock floors Tied dry dock floors Dry dock floors bearing directly on the ground Dry dock floors supported on piling Ground improvement Dock floors constructed under water Longitudinal slope of dry dock floor Drainage of dry dock floor Cleaning of dry dock floor Services on dry dock floor Joints in dry dock floor

P.IAN.C. - A.l.P.C.N.

4.14 Loading on dry dock floor 4.15 Structural analysis of dry dock floor

5. DESIGN OF DRY DOCK WALLS 5.1 Introduction 5.2 Mass concrete dry dock walls 5.3

5.4

5.5

5.6

6.

6.1

6.2

6.3

6.4

6.5

6.6

7.

7.1

7.2

7.3

8.

8.1

Reinforced concrete dry dock walls Sheet piled dry dock walls Caissons formfog dry dock walls Dry docks without walls

DEWATERING OF DRY DOCKS Introduction Dewatering time for a dry dock Location of pumphouse Dry dock main dewatering pumps Dry dock drainage pumps Design of dry dock pumphouse

FILLING OF DRY DOCK Introduction Filling time for a dry dock Types of filling valves used

DRY DOCK GA TES Introduction

8.2 Width of entrance 8.3

8.4

8.5

8.6

8.7

8.8

8.9

8.10

8.11

8.12

8.13

8.14

8.15

8.16

8.17

8.18

8.19

8.20

Head of water to be retained Speed of operation Cost of operation Ability to open against a head Depth available outside dock Parking space availability Ease of maintenance Labour force required to operate gate Provision of power Access across top of gate Methods of construction Free floating gate (ship type caisson) Hinged floating gate Sliding caisson gate Mitre gate Flap gate Strutted flap gate Cantilever flap gate

8.21 Other gate designs

9. DRY DOCK EQUIPMENT 9.1 Keel and Bilge Blocks 9.2 Dock Arms 9.3

A B

Shiphauling systems

APPENDICES World dry docks built since 1950

Structural analysis of gravity dry docks by the Finite Element Method

BULLETIN 1 988 3

4

Dock Arm

D

( Neap tides ) Dock quoins

Depth of dock Clause 1.6 Width of Barrel

Clause 1.4 Dock sill

Dock floor

DOCK NO PROJECTING ALTARS

Width of entrance Cl ause 1. 3

Width of Barrel

Cl ause 1.4 Dock sill

Dock floor • �-· . 1

DRY DOCK PROJECTING ALTARS

Width of entrance Clause 1.3

Clause 1.4

Dock sill

Dock floor

DRY DOCK STEPPED ALTARS

Width of entrance Clause 1.3

Width of Barrel Clause 1.4

Dock sill

DRY DOCK WITH TRAPEZOIDAL GATE

Altars

Figs 1.3, 1.4, 1 .6 - Diagrammatic cross section of dry docks showing defined dimensions

P.l.A.N.C. • A.1.P.C.N. BULLETIN 1 988 - N° 63

1. GENERAL

1.1. INTRODUCTION

This is a 'state of the art' report concerned with the planning and design of dry docks and is restricted to the engineering aspects of their construction and operation. No detailed consideration is gi\·en to Electrical Systems, Fire Protection, Cranes, Railroad tracks, Capstans etc. Floating docks are not included in this report. Other structures and installations which are inrnh·ed with the functions of launching ships or remo\·ing ships from the water, such as

mechanical lift docks (sometimes referred to as shiplifts), marine railways and slipways, are also excluded from this report.

t.2. TERMINOLOGY AND ASSESSMENT OF DOCK SIZE

The leading dimensions and brief construction details of worldwide dry docks built since 1950 are gh·en in

Dock Gate

-

Appendix A. An attempt has been made to standardise the method of measurement of the leading d imensions in accordance with the ,·arious definitions gi\·en below. The estimated capacity of the dry dock in terms of the dead­weight tonnage (dwt) of the largest tanker or bulk carrier that can be accommodated has not been giYen since i t is felt that this may be misleading for this purpose. HoweYer, it is recognised that dry dock owners often refer .to this figure for commercial adYertising purposes and is useful as a general guide.

1.3. ENTRANCE. WIDTH

The entrance width is defined as the clear distance between the permanent dock fenders or structure at the dock entrance. Some dock entrances are trapezoidal in elerntion and are often cur,·ed at the junction of the side wall and sill. In this case the entrance width is defined as the distance between the bottoms of the battered sides at the tangent points of the cur\·es if this is less than the distance between permanent fenders.

Depth if keel block s below sill

Depth if keel blocks above sill

Dock -Gate

Clause 1.6 Clause 1.6

DRY DOCK WITH LEVEL

Effect�".'._e length (with ste ed end wall Clause 1.5 O utline �- �'.2�- __ --- - --

I ..... ....

,---""" , I : Al l_;:-J_\ll

c. •

Dock cope (us u ally level)

Depth at entrance

Clause 1.6 Slope

- - - - - �� t_h_

Depth at head

often conforms Clause ..sbip_ - - -

Slope down us ually about 1:300

DRY DOCK WITH SLOPING

Figs 1. 5 and 1. 6

I I

/

Diagrammatic longitudinal sections of dry docks showing defined dimensions

P.l.A.N.C. - A.l.P.C.N. BULLETIN 1 988 - No 63 5

l.IJ. DOCK BARREL WIDTH

The dry dock barrel width is defined as the maximum clear distance between the faces of the ·dock walls or altars at or above keel block leYel. The dry dock barrel width is normally greater than the width of the dry dock entrance.

I.5. EFFECTIVE LENGTH OF DRY DOCK

The length of a dry dock js defined as the minimum horizontal distance measured on the centre line of the dock between the face of the head wall or the furthest projecting fender thereon and the furthest internally pro­jecting part or fender of the dock gate. If the head wall is . stepped, the length should be measured to the Yertical face of the step at keel block leYel. It should be noted that some dock gates are supported by internal inclined struts which may restrict the effective length of the dock and measurement should then be taken to the appropriate point on the strutting system.

1.6. EFFECTIVE DEPTH OF DRY DOCK

The depth of a dry dock is defined as the depth of water measured to the sill or keel block at the entrance, whichever is the higher at mean high water neaps.

2. PLANNING OF DRY DOCKS

2.1. INTRODUCTION

Dry docks ln the world haYe widely different dimen­sions due to the large number of factors influencing the choice of size, type and operation. Dry docks can be di\"ided into two broad categories, namely shipbuilding and ship repair docks, but some docks are used for both. The requirements of the dry dock owner, dock size, siting, ground conditions and environmental conditions will all ha\·e a great effect on the planning of a dry dock. An increas­ing number of dry docks are co\·ered which are used for both shipbuilding and shiprepair.

2.2. CLEARANCES BETWEEN SHIP AND DRY DOCK

The clearances for working space will need to be assessed in relation to the maximum size of vessel to be docked when deciding the leading dimensions of a dry dock.

The clearance under a ship will normally be go\·erned by the height of the keel blocks, and it is often considered desirable that personnel can walk upright under the ship. In general, the height of blocks is a matter for the indh·idual yard and the techniques used for repair and construction. The recent use of mechanical equipment on wheeled vehicles to clean and paint the underside of ships has required higher clearances and a minimum keel block height

of 1.8 m is recommended if this type of equipment is to be adopted. Sonar domes and other protuberances below the fore part of the keel of modem warships often require higller blocks or alternatively pits in the dock floor of sufficient dimensions to facilitate remo\'al.

The width at the dock entrance will normally control the maximum beam of ship able to enter the dock. Due allowance must be made for the clearance required which will yary according to wind and tidal conditions, ship hand­ling facilities aYailable and type of ship to be docked.

It is normal when planning new dry docks to allow about 1 m clearance on each side of the maximum width ship to be docked. This may be reduced to about 0.5 m clearance if horizontal wheel fenders are proYided to ease the ship into the dock. I t should be noted that when a ship enters a dry dock the rnlume of water displaced by the ship flows out of the dock through the clearance gaps between the ship and the entrance walls and sill and too tight a clearance is therefore undesirable. The speed of approach is an important factor in this respect.

The width of the dock barrel is norm ally greater than that of the dock entrance. The extra width is required as working space to carry out work on the side of the ship, possibly using dock arms in more modern installations. In older docks the dock walls were generally constructed as a series of steps or altars which gave economy of construc­tion, facilitated the positioning of side shores (or struts) to keep the ship vertical and suited the more flared sides of the ships. Modern docks are generally provided with \"ertical walls to suit the vertical sides of modern ships and because side shores are now rarely required.

The clearance in the dock barrel at the sides of a ship should not normally be less than 1.5 m or 2.5 m if dock arms are used and some authorities recommend between 3 m and 6 m on each side. Additional clearances may be required for certain types of ships for the remoYal of stabilizers although many stabilizers are now being de­signed to be removed internally. The remO\·aJ of tail shafts often requires an extra length of dock and due allowance should be made for this process.

2.3. DOCK SIZE

The size of a new dry dock will generally be im·esti­gated at the preliminary planning stage when initial feasi­bility studies are carried out. Such studies would include a comparison of the effects of increased dock size and con­struction cost with the likely increased re\·enue accruing from handling bigger ships. The investment strategy may also need to take account of national policy, for example, a desire to be able to maintain the biggest ships in the national fleet.

Some of the largest dry docks in the world were sized on the basis of an anticipated increase in ship size, which it was considered might rise to J,000,000 dwt. It now appears unlikely that ships of this size will eYer be. built.

6 P.!AN.C. A.LP.C.N. - BULLETIN 1 988 - N° 63

HE l80A LANG l0,00 HDll 2,52

! dnt Jf\n\ pill" l.AJ;iS,S(H l:IM 1t.U_-U h"'Jth,. 1�00

A TYPICAL SH\PBUlLDlNG DR.Y [)OCK

: . .

FIG.·Z·J(o..)

. . . . . . . . . . . . .

_A_ TYPICAL REPA.IR. 'DR.'( t>OCI". FIG 2.·I (b)

P.l.A.N.C. • A.l.P.C.N. BULLETIN 1988 N° 63

10

7

I I IJ

E 0

� HEATING

ASSEMBLING ARE A

WORKSHOPS

I .J

11 [; IJ

! .L

\ I : i 11

__ [ :'·:· ;----- · ··•

IJ

JS.SO m• M.S.L.

2 OVERHEAD

E � N

I SOI I TOTAL LIFTING CAPACITY 200 I

OOCKSHEO 150 •SO m

SOI SI

COMMISSIONING QUAY L.OOm•M.S.l. I_ 3.SOm•M.S.LfF

:=;;�����="'="'="'=c;�ts�������=::§:� -: ! r,=�=====<--

M.H.W 0.9m• ... ';';rn:;'.'.�;. :;;:.;:;-m:;:_ :'.::l �- --.----- ----+<--H--

: E ORYOOCK 1l.5·30•t0 m : -H-----1+--· -+- 5? - --·---- Jiil._-1-

7.00m-H.S.L

8

1 : \ ;

...... __ ____ __,__ _______________ ...... ' 6.00m-M.S.L

Fig, 2. 1 ( c ) - Covered docks

P.l.A.N.C. - A.l.P.C.N. - BULLETIN 1988 - N° 63

Min. clearance

l.5m if no dock

arms

Bilge

blocks

Keel

blocks

Bilge

blocks

Dock

Arm

Min. clearance 2.5m

if dock arms used

Min. clearance

l.8m if mechanical

cleaning equipment

used

Fig. 2.2 - Cross section showing minimum clearances

Stern Section Completed Ship

Intermediate

Gate

Closed

Main Dock -----Gate

Open

Fig. 2.3 - Shipbuilding dock with intermediate gate

Dry docks may be designed to accommodate more

than one vessel at a time. Some are divided by an inter­

mediate gate to convert the dock into a shipbullding dock

and a secondary shipbuilding area so that stern sections of

ships can be assembled simultaneously. Assembly of the

stern section may take twice as Jong as construction of

the rest of the ship and its prefabrication in the smaller

secondary area and subsequent transfer to t!ie main dock

area for the remainder of the ship to be added, is a very efficient use of dock space. The intermediate gate in such

a dock can be sited in various positions to permit

variations in the sizes of completed ships and stern

sections. The construction of each ship has to be

programmed so that each section of the dock can be

flooded at the appropriate time for launching completed

ships.

P.J.A.N.C. - A.l. P.C.N. - BULLETIN 1988 9

2.1+. LEVEL OF DRY DOCK COPE

The level of the cope should be assessed taking into account the following :

(a) The highest water le,·el likely to be attained outside the dock entrance taking into account tidal levels, surge and wa,·e action.

(b) The highest water level ·likely to be attained in the dock. In some cases it may be desirable to raise the water Je,·el in the dock higher than the water Je,·el outside. In this case th� gate would need to be designed for re,·erse head capability.

(c) The provision of external sen-ices and possible open galleries near the dock cope and the necessity or otherwise for them to remain in the dry when the dock is filled.

(d) The pro\·ision of rails for dock arms or ship leading equipment below cope le\·el which normally should remain in the dry.

(e) The general Je,·el of the ground surrounding the dock and the ad,·antage of maintaining the cope level similar to the ground level.

2.5. DEPTH OF DRY DOCK

The depth of water o\·er the sill will, in most cases, control the draft of the ship able to enter the dock. It may be possible to accommodate ships of greater draft by timing docking and undocking operations at or near spring tides.

In considering depth, due account should be taken of the longitudinal inclination of the dock floor and/or keel blocks as this could in some cases be limiting. In general, unloaded ships will ha,·e a deeper draft at the stern due to the weight of the engines and other machinery. If a longitudinally inclined floor is prodded, it is normal to slope the floor up from the gate end of the dock which then suits docking 'bow first', assists drainage, and gives economy of construction towards the head of the dock. It should be noted that there may be operational factors in farnur of 'stern first' docking and it would then be normal to pro,·ide a horizontal floor. This solution has the advan­tage that the stern of the ship may be closer to the centre of the shipyard, thereby reducing the time for transporting material and personnel to the part of the ship requiring most work to be carried out.

Consideration may also need to be giYen to the inter­relationship between the depth of the dry dock, the draught of the ship, the time taken to position the ship over the blocks, the height and rate of fall of the tide and the characteristics of the dock gate. The dock gate should normally be closed and water pumped out of the dock to seat the ship on the blocks before the tide level drops to produce re\·erse head conditions across the dock gate. In areas of high tidal range consideration may need to be given to designing the gate for rernrse head conditions to overcome this problem.

Repair docks may be used by damaged ships which may ha Ye some compartments flooded and· be out of normal docking trim. It may be possible to reduce this effect by floodiQg appropriate compartments to balance the ship but damaged ships may nevertheless require a depth of water over the sill greater than would be required under normal docking conditions.

It is difficult to predict the likely frequency of visits by damaged ships to a dry dock and the additional depth required. It is thus a matter of commercial judgment as to the economic Yiability of pro\·iding additional depth. It should be noted that the additional capital cost of proYiding additional depth may vary depending on the type of design adopted.

2.6. SITING OF DRY DOCKS

The siting of a new dry dock within an existing ship­yard is often determined by the constraints imposed by the existing layout and aYailability of land and water frontage. The siting of· a dry dock in a new shipyard is more likely to be affected by other factors and may in itself be a major factor in determining the choice of site for the whole shipyard. The siting of shipyards is outside the scope of this report.

2.7. SUBSOIL CON DITIONS

The soil type and strength will greatly influence the choice of dock structure which, in turn, will influence the construction method and time as well as the cost. It is therefore essential that an accurate sun·ey of the subsoil conditions for the chosen site or sites should be available so that the dry dock can be positioned to best advantage.

The presence of rock at floor Je,·el may lead to a very economic floor design and whilst exca\·ation in rock for the dock barrel may be expensive, no temporary works to support the sides of the exca\'ation are required and it may be possible simply to provide dressed rock walls, thereby eliminating the cost of concrete walls. The possi­billty of horizontal fissures in rock containing water under pressure should be considered. The danger may be elimin­ated by draining, grouting, or anchoring.

The presence of suitable imperYious substrata at dock floor le\·eJ or at a leYel into which a cut-off can be formed may lead to a drained floor design being adopted. The cost of pumping water from under a dock floor of this type to preYent the build up of hydrostatic pressure is normally cheaper than the provision of a gra,·ity or tied down structure even though it will be necessary t o continue pumping throughout the life of the dock. If the water carrying layers (aquefers) · cannot be closed off, the de

.­

watering of the em·ironment by the necessary drainage may be of deciding importance.

An adequate depth of water at the dock entrance and associated quays is clearly essential finally, but due con-

10 P.l.A.N.C. · A.l.P.C.N. - BULLETIN 1 988 - N° 63

Dry Dock Cope Original Ground Line

Dock Gate

r Dry Dockfloor___________ -----

Dock Sill Remove by Dredging

Fig. 2.7 - Longitudinal section of dry dock showing temporary eofferdam

sideration should be given to the necessity of providing temporary cofferdams during construction which are cheaper to form in shallow water. Dredging will normally be re-quired to remove bunded cofferdams (dykes) and the dredging can then be extended to form the necessary depths for the dock entrance without great extra expense. However, dredging in rock is extremely expensive and time consuming and should be minimized by suitable positioning of the dock and other structures.

The final position of the dock is normally a matter of compromise and judgment and the necessity of an accurate subsoil investigation by qualified specialists together with land and bathymetric surveys cannot be over emphasized.

2.8. NA VIGA TI ON AL APPROACH

Dry docks should be sited to provide an easy navi­gational approach, if possible. At building docks ships will generally only be required to leave the dry docks. This may be before completion of the ship's engines and it would then be necessary to manoeuvre the ship from the dock to the fitting out berth using only tugs. At repair docks ships will be required to approach to and depart from the dry dock. It should be borne in mind that vessels at these times, although usually under control of tugs, may have no power from the ship' s engines. Lead-in structures such as jetties or dolphins may be required. in some lo­cations.

2.9. ANCHORAGES AND QUAYS

A sheltered anchorage and/or mooring facility should be provided as there ·may be a delay between the arrival time of the ship and the time of docking. Docking is usually carried out at slack water usually near high tide. Work may be required to be carried out afloat before or after docking and this should normally be carried out at a

fitting out quay. Modern practice generally dlt:tates that at least two repair/fitting out quays should be provided for each dry dock. Sufficient depth of water will be required at all states of the tide at anchorages and quays.

2.10. AVAILABILITY OF SERVICES

The availability and routing of electric power, fresh water and other services should be considered when the position of the dry dock within the shipyard is determined.

2.11. PREVAILING WIND

The wind direction is generally a minor factor in the choice of the position of dry docks due to the importance of the other factors involved. However, the centre line of a dry dock should be aligned as close as possible to the direction of the prevailing wind. This greatly assists the docking operation since manoeuvring large ships in an un­loaded condition in a cross wind even with tug assistance is very difficult. This is more relevant to shiprepair docks where ships may be expected to enter and leave the dock more frequently than shipbuilding docks.

2.12. TIDAL FLOW, CURRENTS AND W AVES

Consideration should be given to the effect of tidal streams if the dock is to be located on an exposed coast or on a tidal river. Docking and undocking is generally carried out near high water but the tidal streams before and after high water should be checked to confirm that there is sufficient time for the docking operations to be carried out before an unacceptable velocity develops.

Currents resulting from river flow do not normally affect the operation of a dry dock except by modifying the effect of the tidal conditions. The possibility of sil­tation or scouring at the dock entrance and its effect on the dock gate and gate recess may need to be considered.

P.l.A.N.C. - A.l.P.C.N. - BULLETIN 1 988 - N° 63 1 1

Main ho1sl Slewing radius: m 80

:!. Bollards � Arch lenders n Cyhndncal fenders qi Wheel fenders c Capstans a F1lhn9 valves '* Lighting lowers II 10 I winch

12

.

Flap; gate'.

Dredged lo - 9-0 m MSL : (-7·4 m COJ

Scale of melres

Pump \ chamber '

J_ I

Scaic ol meires Sub-floor drainage system

10 m gauge and roadway

Collector trench

3·6 m

- 9·0 m dredged level

Fig. 2.9 (a) - A typical repair dry dock with two associated quays

P.1.A.N.C. • A.l.P.C.N. - BULLETIN 1988 - N° 63

Soulh quay

Dredged 10

Jetting discharge pipe

Control room

Substation

Overall length ol dock 301 70 m

Keel block heigh! 1 ·8 m

Substation ,,,

-9-0 MSL (- 7..C CO) 1

-.!11!1'. -· -·-·-·-·

Dredged 10 - 9-0 MSL (- 7·4 COi

/I I"� -:::J �o� I p�·-·-t � 70 60 50 27 Slewing radius

t. Bollards 111J Capstan �i: l19htrng lower .. Cyhndrtcal !ender • Arch fender � Filling valve !'. Crane Jacking and

anchorage points • Access tower position

Hau1tng-1n winch Winch conlrol tower

-·-·- l -· --

+ 1·2 mMHWS --.- ±00 m MSL

,,..r-

r:;:, -> 52 m clear width •

ol dock l I ,--L- ----- - - --...1-.,

: Travelling : 1 dock arms 1 • Hauhng-in·track

·-t::�rfr..d!:...,"r;;,!!�' services walkway

- 9·8 m at head

I

- 1 ·2-5 m MLWS --------------'

Scale ol metres .____, 0 10

Sub-floor drainage system

Fig. 2.9 (b) - A typical repair dry dock

P.l.A.N.C. - A.!.P.C.N. - BULLETIN 1988 - No 63 13

Currents in the sea are unlikely to have a great direct effect on a dry dock which is normally within the protection of a harbour, but consideration may need to be given to anchorages associated with operation of a dry dock.

In cases where a current in the sea or river is con­sistent and parallel to the shoreline it may be advantageous to orient the dry dock in a slanted position.

The effect of waves is not normally of great import­ance except with respect to the dock gate and mooring conditions at associated quays and achorages.

2.1 3. POSITION WITH RESPECT TO BUILDINGS, WORK­SHOPS, ETC.

In a new shipyard the position of buildings and work­shops can normally be arranged to suit the chosen position of the dry dock. In existing shipyards, it may be advisable to move existing buildings so that a new dry dock can be positioned to best advantage.

2.14. ARRANGEMENT AT DRY DOCK COPES

Modem dry docks are generally provided with vertical or near vertical walls and the arrangement at the top of the dock wall or dock cope will be influenced by a number of factors. The following features may need to be accom­modated and incorporated into the overall structural arrangement :

(a) Crane rails - for jib cranes on the side of the dock and/or goliath cranes spanning across the dock and, sometimes, the ships assembly area.

(b) Ship hauling-in track. (c) Track for dock arms. (d) Capstans, possibly with snatch blocks.

E1ectrical Services Duct

Dockside Crane Rai 1

\

Handrail

Services to Dock Floor

(e) Bollards. (f) Fairleads for capstans and bollards. (g) Fendering. (h) Access steps, possibly with access hatches (or man­

"1oles) . (j) Handrails, possibly removable type. (k) Services of all types, complete with connection points

including : {i) electrical pick up to dock cranes, and dock arms (ii) electricity supply to power points, ship and

dock lighting and lighting generally (iii) ballast water main (iv) drinking water main (v) fire water main (vi) oxygen and acetylene supplies (vii) high pressure water facility (viii) compressed air main (ix) steam main (x) drainage (xi) sewage oil waste

The service galleries may be of open or closed con­struction depending upon the climatic conditions or local rules governing such structures. If the gallery is closed, an open walkway may be of great advantage, the level of which should be higher than the highest water level that can occur inside the dock, or, alternatively, the walkway should be protected by a wall. In the case of a closed gallery, both pipes and cables may be contained therein except oxygen and gas pipes which should always be in the open.

Doors may be provided between the closed gallery and the open walkway for security and/or weather protection purposes. Arrangements must be such that pipes, hoses and cables may be Jed to the dock floor or to the ship's deck without interference to the dockside cranes or dock arms.

The provision of dock arms will greatly influence the shape of the dock wall coping.

For covered dry docks additional con­sideration must be given to the arrangement of columns to support the building structure. In order to avoid an excessive span for the roof of the building, the columns are usually placed only a small distance behind the dock cope. This arrangement is often ac­ceptable since cranage is usually provided by Electric Overhead Cranes spanning across the dock and running on longitudinal crane guides supported by the columns.

2.15. ACCESS TO DRY DOCK FLOOR

Fig. 2.14 (a) - Typical arrangement of dry dock cope

Access to and from the dock flqor may be by staircase, ladder, elevator or ramp. Cranes are generally used for hand­ling materials.

1 4 P.l.A.N.C. - A.l.P.C.N. - BULLETIN 1 988 N° 63

LI!_,

i ..:.. _25 50

I .

;_QL:

li)S --· �p5 __

;, .

I hondrail 2 cable in let 3 ckcuic: connection -1 brid,&ing sl.:i.b 1500 x �00 x 250 mm S h:.Hch SOO x �OCX> mm 6 mastic joint filler 7 inlet bush 8 cable :a:nd pipe cuhen 9 !>en ice Slllcry

10 \lOoJcn fender 2�0 "' :<00 mm II �a1crstop 11 columns XIO • �00 mm •n .i.1 m Clrs Ll anchor 80 mm dia. ai JO m �trs

..

F ig. 2.14 (b) - Typical arrangement of dry dock cope and wall

Access steps are often provided at the four corners

of the dock for personnel access between the cope level

and dock floor. Additional steps may be provided in wall

recesses at intervals along the dock walls for very long

docks. Access steps are generally situated on the face of

the dock wall or in recesses where the general arrangement

of the dock permits. It is recommended that fibreglass

staircases should be considered. Alternatively, they may be

positioned in tunnels behind the dock wall but in this case

provision needs to be made for removing silt and other

debris.

Suitable access for stretcher carrying wounded from

the dock floor is required by some authorities.

Ladders are provided for emergency access only and

are recessed into the walls of the dock at about 25 m

centres. These are generally of galvanised steel and may

require frequent maintenance.

Access steps are usually arranged so that free access

to service galleries and tunnels is not possible. Entry to

these areas is generally via a locked door, hatch or man­

hole.

Lifts are not normally provided in modern dry docks

due to the difficulty in maintaining them in operation in

the very aggressive conditions.

Ramps have been provided at many of the dry docks

constructed recently for vehicular access to the dock floor.

Ramps are usually provided at the head of the dock. Ramps

typically have a slope of 1:10 with transition curves, are

about 5 m wide and are flooded with the dock. The centre

P.l.A.N.C. - A.l.P.C.N. - BULLETIN 1988 - N° 63 15

16

-4�����·�-=2�50'--��-. 2

250 ----

1

I hauling carriage track 2 crane rail 3 electric-cable pipe 4 bollard 0.15 MN 5 safety ladder

6 3 x 5 compressed air pipes 7 ballast-water valve S steering board for movable bilge

blocks 9 electricity cables

10 propane main 11 oxygen main 12 drinking-water main 13 COfI!pressed-air main 14 sea-water main

15 fluorescent tubes 16 electric-cable pipe 17. air escape·of the drainage system 18 lighting of ship's side 19 timber fender 20 handrail 21 eyehook 0.15 MN

Fig, 2.14 (c) - Typical arrangement of dry dock cope showing services in open

P.1.A.N.C. - A.l.P.C.N. - BULLETIN 1 988

11 II \I

I I I I

I I

I I I I I I

WALL COPE

.................... -- ....... ,,....,,,. - .... _ ..,-

\� .. _::'.!

.--------JI I ' � l I I I I I

I I

F'IG. 2.14-d) -TYPICAL PIPE AND CABLE CROSSINGS • I

FIG. 2.14-e) WALKWAY CLEARANCES

P.l.A.N.C. • A.l.P.C.N. BULLETIN 1988 - N° 63 17

SWITCH BOX

£=--

BALL VALVE

18

12"

2"

2"

6"

6"

6"

.. . . . . . -· .

OXYGEN

PROPANE

COMPRESSED AIR

DRINKING WATER

FIRE FIGHTING

SERVICES IN OPEN SUBWAY

HAULING IN CARRIAGE

Fig. 2.14(;f')

P.l.A.N.C. • A.l.P.C.N. BULLETIN 1 988 - N° 63

� N

Fig. 2.15 (a) - Typical stairs to dock floor

··--·-L---·--·----·- ______ _JQQ.,JL _____________________ _ ' ... :pJj

• ..11 I '1 I I ' : l1 I ·1 ;'. 1:.1 Iii ll 1\ !1 11\ l;I i1 u � � � u u uJ

73. S.57 = 71..21 ; 5 19 ,,.1.0

Fig. 2.15 (b) - Typical ramp to dock floor

section of the ramp often takes the form of a tunnel

whereas the top and bottom sections are unroofed. Ramps

are used for transporting to the dock floor, materials of

all types, dock cleaning equipment, truck mounted hoists,

etc.

Advantage may be taken of the ramp during construc­

tion of the dock for access to the dock floor by the civil

contractor' s plant.

Ramps have also been added to existing dry docks to

improve efficiency and reduce the work load on the dock

cranes.

2.16 AREA SURROUNDING DRY DOCK

The area immediately surrounding a dry dock is often

used for short term storage of ship parts or sections,

vehicular access and, in the older shipyards where space

was at a premium, by workshops. In modern shipbuilding

yards considerable space is required adjacent to the dry

dock for prefabricated ship sections to be offloaded prior

to their incorporation in the ship. This area may be covered

by a large goliath (or Gantry) crane which also straddles

the dock. Jib cranes may also be used to position pre­

fabricated sections in the ship sometimes working in

tandem.

Ship repair docks require less storage space at the

sides of the dry docks. Where two repair docks are built

near to each other they may be situated close together so

that one crane running on rails between the docks may

serve both docks.

The areas surrounding a dry dock are usually paved

either with concrete interlocking blockwork or asphalt to

P.l.A.N.C . • A.LP.C.N. - BULLETIN 1988 - N° 63 19

I i i i i t

I t

I i t

ir=====-----i i i i i •

k

20

Fig 3. 2( a)

P.1.A.N.C. A.l.P.C N . . - BULLETIN 1988 - N°63

lam

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FIG. 3.2-b) •

P.1.A.N.C . • A.l.P.C.N. BULLETIN 1 988 - N° 63 21

-llq. 1

22

35.0

.f·� 10.0 l�

l8.0 ."f'q. 120 ·I

3 -:;: ____ ... -..,.,:.=-:.:: =-----:.-:�!' ....... ... --""' �-

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1

1 coff erdam 6 cellular cofferdam 2 sheet wall 7 coral sediments 3 existing ground surface 8 diabase fill 4 dewatering 9 coral 5 excavation slope 10 diabase

Fig. 3.2 (o)

P.l.A.N.C. - A.l.P.C.N. - BULLETIN 1 988 - No 63

9

9

I �

i: " \i !iu .. _,,.t.!?.

L---

\ \ \

+

8 1� �\

·,1 " ·•

+ :: I\ I\ 11 l\ \1 11

8 + -+- +

FIG. 3.2-d) - LocatioL h·.n:.. docks in a ship yard.

��-.. /1L \ � J\ � ,,,,,,,, :

� ' .,.,.,.,,, 1•1•1•\1111'1'1'1'\'1' :

-----:::::=:: '/'/'/ \tl'''f'/ \'\' '- ..-.- •

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r-------�dY�-� I I L _ - - - - - -�-1-.ll.J'i;.;.,;;;..;.;.:;,;;,;.;i,i,;;....""'-'-'""'"'=-'"""""'-'-......_--'-...,....._"'-'-'='

Ill V £ R t A 0 US

I \.,

P.l.A.N.C. - A.l.P.C.N. - BULLETIN 1 988 - N° 63

D

23

�

accept the heavy vehicle and

plant loads to which they will

be subjected.

3. OVERALL STRUCTURAL

DESIGN OF ORY DOCK

3.1 . INTRODUCTION

The dimensions of the

dock will be determined by

the requirements of the ship­

yard and by some of the

physical conditions, such as

tidal heights and range.

The type of dock struc­

ture may be influenced by :

the location in relation to

the waterfront

- the available space

the execution time

- the soil conditions

- the groundwater situation

the loads of ships, cranes,

etc.

the economic evaluation,

3.2. THE INFLUENCE OF THE

LOCATION

The location in respect

to the waterfront will lead to

different building pits, which

will in their turn lead to dif­

ferent types of structure.

The building pit can be

- in land

closed of.f from the water­

front by a cofferdam

- surrounded by dikes

surrounded by structural

elements, such as a cellular

cofferdam formed of straight

web steel sheet piling.

When the pit is ·surrounded

by dikes and major dredging

must be executed it is, for

example, easy to make a

ground improvement which

could widen the choice of

structural possibilities. Figure

3.2 (a) gives an example of a

building pit surrounded by dikes

for a double dock.

Building pits in themselves

are already large and im-

24

I l phase

phase 3

phase 4

phase 5 Fig. 3,3 - Construction phases of a dry dock

P.LA.N.C. • A.l.P.C.N. - BULLETIN 1 988

PHASE OF STUDY

0 Inventory and Interpreta-tion of Existing data

0 Investigation of the Extreme Situations

0 Provisional Design of the Dewateiing

CV Conclusions

CV Additional Investi-gations

C0 Decisions

.

AVAILABLE DATA

Boring logs Cone penetrations Literature

Permeabilities

Geographic situation Boundary conditions -Bay River

Data existing winninBS Original potentials

tge :L1 .. n.mn;;u

r--v

r---. i..-

!"'---.. ..........

SUB-DIVISIONS OF THE STUDY

Geological profile

-w Geo-hydrological

profile I

w . . Calculation model

�___L� ------ � -

"'-&..--"'

------No infiltration Only infiltration from river from river

. \V w Dewatering capacity De.watering capacity Drawdowns Drawdowns

-.....

'I/ I Most likely situation !

w \Dewatering capacity Drawdowns I

'7 Report:

Technical description

w Conclusions I

H7 I 'f

Additional testsl �

Pumping tests l

I

Borings

I Organization � 1::!S

w Decisions about building pit ......., and drainage dock . ._

Fig. 3,4 (a) - Dewatering - Schematic summary of the study

I

'7

I

portant maritime civil engineering

structures. Sometimes it is p0ssible to

incorporate substantial parts of the pit

as permanent features. Figures 3.2 (b)

and (c) give an example of using the

ring of circular sheetpiling as quay

walls.

3.3. THE INFLUENCE OF THE A Y AIL­

ABLE SPACE AND EXECUTION

TIME

It may happen . that there is not

enough space in the shipyard to make

a building pit with slopes. Making the

dock walls of the sheetpile type can

then bring about the solution. This

kind of narrowed building pit can also

be dictated by a limited execution

time. Figure 3.3 gives an example of

the execution of a dock between

sheet piling.

3.4. THE INFLUENCE OF SOIL CON-

DITION AND GROUNDWATER

SITUATION

The most i mportant items influ­

encing the type of dock structure are

the quality of the soil and the ground­

water situation. Sufficient data about

these items must be known to answer

the important questions :

Can the dock be built in the dry or

must it be constructed totally or

partially under water ? - Can a drainage dock be provided or

must the uplift be compensated by

anchoring or gravity ? The designer will make an inven­

tory of the existing data about the

subsoil before proceeding. In any case

he must have sufficient insight of the

quality and continuity of the different

layers. The designer will study the

dewatering possibilities more or less

along the scheme as given in figure

3.4 (a).

Sometimes it is clear from the

beginning what type of structure for a

certain situation is the best. Further

investigation will then be done to

confirm the assumptions.

f 300 N E u ..... "' -" 200 1------..;.....-----'· � w u z � "' 1001----�!-:;.L-.:; Vl w a: w z 0 u 2 3 l\g / cm2 -

4 5 6

Graph �hawing 1hc rdf!tionship bc:tween cone rc,ist ancc, local friction and �oil type:

C O N E B E A R I N G C A P A C I T Y ( k g tc m2 1

00 100 200 300 0 F R I C T I O N R AT I 0 { 0/o) S O I L 2 4 6 B l N T E R P ( TATION

:r .... 0.. w 0 0 z :r < "' ,_ 3::

:z: a: <( w w ..I "' u z

.... 20 !-----+----+-----< w 0 w w ... :z: O r Z <

<(..I ..,,u

SAN � . >- 0 < z ..J < u "' >- ,... 0 w z >-< <( "' _J

u

1--.:'.'.=:t::::::.:::::=l:====::::l::===--l soFT CLAY

L C L A Y · S A N O M I X T U R ( A N.0 S I l T S

0 S O F T R O CK

llr;uh• nf :\ pc-nr!rati<>n lt«I prdnrmrcl hr Pmf,.smr Srhmrrlm;mn

Fig. 3 . 4 (b)

w z 0 I-"' w l: ..J

In many cases however, a decision on the structural

type can only be taken after a thorough and extensive

study. The first thing to do after studying the available

data, is to draw a geological profile of the site. Extra

borings and penetration tests may have to be made to

have more information about the continuity of the different

26 P.l.A.N.C. A.l.P.C.N. - BULLETIN 1 988 N° 63

.. •

JC u .. x •

o • 0 ..

----------. .......... _ _ _ _ _ ---

• •

coarse Gand

. ..

- / ,/' / G<'.01.(X;CAl l'ROFllE lt<Gf!UOIOIU.t. SECTIC>l 11 - 11

-s I I I I ,/ . I I . . © (j) © 0 · · © -.- .

�<D j__ j ,H• 30m i.. H . 2500 m'ldcy

: · · I . .

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. cqui!..r

• . . • . .

9>(<)<�,<0>&'95�99.S� RECH ARGE SOURCES:

Q) Rtehcr9t' from rivtr

(D R.chor9" throu;ih oquifrr {D RethO!'Qt from infitlrc lion

© RH horQ• from Boy of Gcfon�k

;m�rvious bO:�

Fig. 3.4 (o)

P.l.A.N.C. A.l.P.C.N. - BULLETIN 1 988 - N° 63

Geohydrol ogicol model

0 20

27

....

1 Comparison of models.

I · ell ;4 c: l')}<> � <7'P -:;() 1"'3;'hc - • Y' t : • \,,.� · - ""' '°' '-""- 1 t.. · �.- .�' .. "'""

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----- · - - _w·

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35.CXlm

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B

Fig. 3 . 4 {d)

CROSS SECTION 2 - 2

!- -- - - - - ·-· LT ---------< !_,o .0 __ .._.,. .• --· .... ......_.CiQ___ -+---5G_ ---t I . I

I BI I R2 Rl

I nfluence of boundary conditions.

..

,.. .

OUAY WALLS WITH P R E PAKT FLOOR

f!NIStUHG \U(R TQ �A.Sf Jk l1'1t OAY h--.. --c-"""""r"<--.-

PLASln: F'Oll.., �PR [ PAl<l CONClitlC WITH GR>.VH Fill

flOOR lMICKM( S S )$• Al PR(PAKT CONCRr'J( Wilt' GllAV(l rlLl flOOR TklCJ<ktSS lt·r J.:J Pfi:(PAi<T COHCRr:lE Wilti fH.l OF' l[AD StJ.G$

C O NC RETE CAIS S O N S WITH PR EPAKT FLOOR

SIJlt.OING Pff 750' DR: 710' W}0£

WAllS ANO 'J#ISHtNG l.l.Y£R ]_0 CAS'f IN l�£ oi:n

111111tl11111111 i po£P••t coi<•m l1 1 t ! l 1 1 '.Ill P'<.ASl K::; fOt� J"ENSlON BARS �ITH ca�AVE\. 141..

HOOR 1HICXN(SS JG ,t..T P f<EPAKl C ONC Rtlt WllH GR.tv(l rn.1 HOOR ltil(�N(SS 1l' •l fiR(PAKl tONCR(T(. WITH nu. or u: ... o S l J. G $

Cons tructi ons cons i d e r e d in the wet .

GRAVITY TYPE OF DOCK

. . eun.OINC PIT UO' WlD[

Constructions consi dered in the dry.

P R E PAKT FLOOR WITH WALLS CAST IN THE DRY

. . . . .... If ...... ._. GUllOINO Pr! .. u OR 5J<l' WlOt .. . ( ' WA.US ANO F'IH!StUWG lA'r(R

J_O C.15.l lH 1H£ OR\'

1111111111111111

fLOl)ft lHICKN£SS ll" 141. fREP•J<1 CO�CAt:lt WITH GRAV(I. Ffll HOOR tH1C••irss n· 14 PRt,4KI CO•CAtlE Wr!H fill or U:•D SLAGS

CELLULAR STRUCTURE WITH PREPAKT FLOOR

9UILOIMO Prt 7W • 'W!O[

DfU,ttO.Q[ O.PH11NO� flHiStllHG l.ll[A 1Q t1:

,..tJ..Sl IN 'ht( 0-RY

llllllllllll1ill P R C PAKl t;ONCRtt£..- ._PL;..S11C rot. Wlltt GRAVtl F�U

1111111111111111

fLOOR lHICXHESS. H-" At P R t PAKT (0HCRt:1£ Wl!H GR.&Y[L fltL FLOOR lHICf(.N(SS :zs· AI PR CPAKT C0t<CR£1£ WllH: f tLt or l[J.0 SlAGS

SAND F'll.l �··1 ��

C O NC RE T E CAIS S O N S

SUll O!NG Pn U o' WlO[

F'lNIS�ING U.YER 10 EE .1.so m ... CASl ,,.. lHE. ORY

,..OR £0Glt¥:G Uk(

T°R.P. .:r

f11.l or t£ AD SLAGS.., ,_nooA ANO w�u.s OfSIGN:(t>

AS CONCRt 'ft r ".tSSOhS

DOCK WITH T E N S I O N ANCHORS

,., ,ButLOIHG PIT 'l7 0 ' WIO� .

,..txCAUTtow LNE

Lson. tKPRCVEHENf

DOCK WITH T E N S I O N AND COMPR E SSION PILES

.... ....

A.S C H O $E N

f\,OOR 1tUCKH£SS to• A! R[IHFORC[D t:O.,:C-R£Tt FLOOR tttW:.ttHtSS 10' JJ U�t1£RWAl'£R CONCR(lt

Fig. 3 . 5 (a) - Constructions considered partly in the wet and partly in the dry

6

d.

� 11 II 11 11 11 II I

/

! Af= �����t::::,,...,..�����/IF

I dredged >lope 2 �lling 3 canh fill 4 reinforced c.onae!e topping placed in

the dry 5 grout inlru,(ion conctclc placed under

water

e.

a caisson floated over prepared bed sunk by water ballast

b caisson filled with soil by conveyor

6 stone filling i culvert for electrical St:rvia:s 8 kvel keel block strip 9 piped �crviccs

JO sub�station l I crane beam and trnHey channel

c.

f.

e floor grouted, over-height of front wall of caisson demolished, backfill continued from land

c partial backfill behind caisson by barge d floor stone placed, further backfill and

f floor topping laid, crane track piles and beam constructed

subway construction started

n II Ii 11 1, Ii

\ • " II II 1 ,, /I

3 �--·r I " .i 11 tl ii tl 11 "

9

n "

F'IG . 3 - 5-b )

4 n " "

10 I - 10 50 � 11 20

- 1700 "18.00

working platform on floating oil drums

5 gr6uting pipe driven through stone by light compressed air hammer

9 top or ungrouted stone 10 shoe for driving

2 grouting point 3 lengths of grouting pipes removed as

pipes are l ifted 4 grout supply line

6 floating service platform travels. forward approx. 3 m in every 12 h

7 pipe to be extracted 8 top of grout intrusion concrete

I J grouting completed 12 next area to be grouted 13 parallelogram area being grouted 14 pipe lifted immediately after grouting

just clear of grout

layers. It is recommended to limit the number of borings

to a\·oid making too many holes in watertight layers. It is

known that penetration tests can give information about

the soil type. If done with the Dutch penetration cone

with adhesion-jacket the ratio between local friction and

cone penetration will be constant for a certain soil type

(sec figure 3.4 (b)).

By indicating the aquifer and the boundary condi tions

and by adding rnlues for permeability and transmissivity

the geological profile will be developed into a geohy­

drological model. See fi gures 3.4 (c) and (d) as examples.

Usually a pumping test is an important part of the

investigation. It gi\·es information about the aquifer coef­

ficients (transmissibility and storage coefficients). With

measuring after stopping information can be obtained about

the water flow direction.

The end result will be a reliable schematization of

the site, with which the different dewatering and drainage

systems can be calculated.

During the inrnstigation the designer will obtain infor­

mation about the consequences of dewatering for the en­

,-i ronment. These consequences can lead to situations where

dcwatering, although technically possible, is not allowed or

only to a l i mited degree.

3.5. MAKING A DECISION

Now, haying sufficient information about the soil and

the groundwater situation the designer can list the ,-arlous

structural possibilities and compare them technically and

economically.

Sec figure 3.5 (a) for a comparison and a choice. In

this case it was only allowed to lower the groundwater

le,·cJ around the dock by a few metres. As a closing off

of the water carrying layers was not possible and bringing

the water back into the ground by way of infiltration

wells did not work well in the related soil type, the dock

had to be l;luilt partly under water.

Fi gure 3.5 (b) gives an example where the building pit

could not be pumped dry and where the dock floor had to

be built under water.

3.6. POSSIBLE DOCK STRUCTURES

The following pages show a procedure for de\·elopment

of possible basic dock structures starting from an indication

of the soil type or types and the geological and hydro­

geological cond itions appertaining.

3.7. OVERALL STRUCTURAL DESIGN METHOD.

Ha\'ing made the decision as to the basic dock struc­

ture to be proYided, consideration must be gi\·en to the

method of design of the structure and whether it can be

treated in its separate parts i.e. floor and walls (chapters

P.l.A.N.C. A.l.P.C.N .

4 an d 5 ) o r whether an o\·erall treatment must first b e

adopted.

3.8. FACTOR OF SAFETY OF DRY DOCK AGAINST

FLOTATION

Dry docks designed as gra\"ity or anchored structures

must have an adequate safety margin against flotation. The

calculations should assume the highest possible leYel for

the ground water and the lowest expected density for con­

crete with no ship or other loading on the dock floor. It

i s also usual when comparing the downward weight of the

dock with the ground water uplift forces to introduce a

factor of safety which is often taken 1. i.

The upward load calculated to be resisted by pre­

stressed ground anchors or anchored piles is usually in­

creased by a factor greater than that for gra\·ity docks

and a figure of the order of 1.3 is often used in the

design of each anchor, sui table allowances having been

made for corrosion ·and creep etc.

It should be also noted that the design should take

account of any local regulations which m ight apply to such

structures.

An alternatiYe approach to safety of graYity and

anchored docks has been recently suggested. The principle

i s to ensure that the downward weight or applied load of

the structure is in excess of the hydrostatic uplift by an

amount proportional to the area of the structure and not

as a factor of the loads i m·olved. This surcharge weight or

load has been suggested as 600 kg per square metre of

dock structure.

3.9. STRUCTURAL

METHOD

ANALYSIS BY FINITE ELEMENT

Structural analysis of the whole dry dock structure

may be undertaken by computer using the finite elei:nent

method. Care must be taken to include appropriate para­

meters and the results should be ,-erified by experienced

engineers in this field. Appendi x ' B' consists of a technical

paper describing the process i nvoked.

3.10. ANALYSIS IN SEISMIC AREAS

The finite element method may assist in consideration

of seismic loads since such loading can Yery easily be

incorporated i n the computer model and the subsequent

deflection and other effects noted. A range of loading

cases with seismic loads added should be considered.

4. DESIGN OF DRY DOCK FLOORS

4.1. INTRODUCTION

Dock floors are now almost im·ariably constructed of

concrete. There are three main types of dock floor

BULLETIN 1 988 - N° 63 3 1

SOIL IND ICAT ION

If ll is too high for cut off or Car infl uence of lower lnycr on <lock s true tu re

then

CEO LOGICAL

I . Dock bedded in :

l . l Closed rock l . 2 Cons o l id ated clay l . J l'ervious rock

1 . 4 Rock w i th water c<lrrying s l i ts . Pos s ib i l i ty to c l o se? :

--��- Y N

2 . or nhova :

2 . l Closed rock 2 . 2 Cons o l id a ted clay

2 . J rci:viou:; rock

2 . 4 Rock wi th wnter carrying s l i t s . l'o s s i b i l i t y to clos e? :

y N

3 . Dock i n wntcr lncGcd s:11Hiy dcposi ts (homogeneous or w i t h sma l l enclosure s ) :

Bearing capacity s u f f i cien t :

3 . 1 . I Sil ty

J . 1 . 2 Medi um

J. I . J Coarse

J . 2 Bearing capacity no t s u f f i c i en t : Improving possibl e ? :

y N ) � - If drainage dock ·

pos s ib l e :

D EWATEl\ING mm.DING PIT

JlYDRO-CEOLOG lCAL'

Y/N

1•11ss1111.1•. TYPES Of CONSTRUCTION (llUILDING !'ITS Ill l'ARENTUESIS)

l:l(Al\UlG CJ\l'AC11'Y

CASE SUl!l:'ICIENT I NOT SUfi'ICIENT

Impervious Impervious Moderate

pcrmc:i.b i l i ty llii:;h

permeab i l i ty

> Excessive permeabil i ty

Impervious Ilnpc1·vious

Moderate pcrmcabili ty

lligh perme a bi l i ty

;>- Exces sive permeabil i ty

Low permeab i l i t y

Hoder a t e permcabil i ty

l::xccssivc permeab i l i ty

Y Y D l ( B l ) D2 ( 1l2 ) Y Y D l ( B l )

Y Y D4 ( ll l )

\--�I Y N A l ( B l ) AL I (D3)

N N GWI CW3 ( ll5 ) GW5 ( 1l7 )

ffi>-< y y D l D J ( ll l , B I O ) ll'N y DL I ( BJ )

� y y DJ D4 ( B 1 , B I O) .YN y D L l ( llJ )

y N A l A2 ( 1l l , B l 0 ) AL l (BJ , ll4 )

@--4 N N GWl GWJ(ll5) Gw5 (B7 )

®------7:sl I Y Y D5 ( 1l9) DLJ ( ll l 6)

1 2 � Y N AJ(l!9 ) A5 A6 A7 ( D9 , ll l 0 ) AL2 ( Il i 6 ) AL4 AL5 AL6 ( l! l 6 , ll l 7 )

I J N N /\Wl ( ll l 5 ) Gli2 Gll4 ( ll6) GW7.( 1l l 5)

a<l<l supporting piles Low

� tension and suppor t ing p i l e s

permeabil i ty

Moderate permeabi l i ty

Excess ive permeab i l i ty

@---------�

Fig. 3 . 6 (a) - Dewatering building pit

y y D l l ( ll9) DL8 ( U l u·

y N 118 ( !!9 , ll ! O) AL5 /\L6(JJ l 6 , ll l 7

�l":>) N N AWl (ll l 5)

The indication N also comprises the situation where dewatering is technically possible, but not allowe d , i . e . expected damage to enviroment.

* N is open dewatering - see building pit B17

SOIL INDIC/\TlON GEOLOGIC/\L

DEW/\TERING · l'lltl DING PIT Dll/\TN/\Gl> DOCK

SlllLE l"Yl'ES 01' CONST!tUCTION ·�· · · · .. · � .

m'.DRO-C!WLOG IC/\L' ILDING PITS IN P/\RENTllllSIS) �������+-������������-+-������-+����1--'--'-i

4 . Dock in water l oi;&ed snndy deposits al ternated with clay layer s .

4 . 1 llcnrinr. capac i ty suffi cient

4 . l . l Hor. s t ratif ication with many thin clay l ayer._s_

4 , l , 2 One cl;il h;!'.cr:

o Cluy bycr wi th bo t tom low enough to ;:ivoid upli£ t

o llot tom cl;:iy layer too high t o avoid upl i f t fo r :

- buildinc p i t alone

- drain;:ir;c dock

4 . 1 , 3 More clay layers : o Bottom upper clay

layer too hii;b; Cut off to lower clay layers :

Clay layers closed and wi th low perm.

D i f f ci·encc be tween hor. nnd ver t . pcnncnbi l i ty

Sand layer I : - modcr;:itc

pcrmc;:ibi l i ty - excessive

permeabi l i ty

Sand layer 2 :

- mod .. perm. hich perm.

- h ir;ll perm. - mod. perm.

possible --1 ------;o ... ------- impossible

4 . 2 llc adni; capacity rio t ::>ufficicn t :

Improvinr; possibl e? : y N _,.._)

c;: usa richt column of

CASE

Y/N

y y N y y N

@-- Y y

®-- <tN y N N

� y y

I N N

2 � y y y N

11111\lt INC C1\l' AC ITY SUl'l!ICIENT

D & ( ll 1 4 ) DL4 ( ll l J) DL4 (Ill 7 ) /\6 A 7 /\S(ll9)

/\LS /\LG ( ll l &)

D7 D3(1l l 0) DL5(1ll 7 , ll l !))

DL5 ( 1l l 7 ) /\Wl ( ll l 5 )

D 7 DB ( ll l l ) DL5 ( 1ll 6)

AW! ( B I S )

D9 (1ll l ) DL6 ( ll l 8) 115 /\6 /\7 /\8 ( 3 1 1 )

/\L4 /\LS AL6 ( B l 8 )

NOT SUFTICltNT

D l 2 ( ll l 4 ) DL9 ( ll 1 J) DL9 ( 11 1 7 ) A8 ( U9) ALG ( B I G)

DI 1 ( 1110) DLS(lll 7 , .

DLB ( l H7) t31t/)

AWi (11) 5 )

D I l ( ll l 1 ) DLB ( ll l 6)

AW! (ll15)

D l l ( ll l l ) DL8(ll 1 8) A8 ( n l I )

/\LS AL6 ( B l 8 )

®- Y Y D ! O(lll l ) DL7 (1ll 8 ) D l 2 ( lll l ) DL9 (ll 1 8)

t possible con:.;t:ructions -i---------1------1---1--.,_-----------1---�

N,ll. If a <lrainai;e dock is possibla we can add supporting p i l es in the case of insufficient bearing. capaci ty ; (solutions :

D I ! , D l 2 1 DLB, DL9) !Jut it can be more economical to use tens ion-supporting piles and n o t to use the Y for dra inage .

F ig. 3 . 6 (b) - Dewatering building p it

sUn'lCIENT llE/\l\ING C/\P/\CITY

NOT SUl'FlClliNT llEARING CAP/\CITY

The indication N also comprises the situation where dewatering is technically poss ible , but not allowe d , i.e . expected damage to enviroment .

* N is open dewatering - see building p it B17

P.J.A.N.C. - A.l.P.C.N. BULLETIN 1 988 33

D • • DRAINAGE-DOCKS

vertical drains

34 P.1.A.N.C . • A.l.P.C.N. - BULLETIN 1 988

· DL • •

l imited building pit

_,·; .�. �;�·.: ·�:��:�·�:� .�...:, .-:f'-::qP� � t='?°-?i ;�L . "' .

�, .. ' '· �

� .:.< � . �

re.inforce.d concrete -under-wate.r concrete. --+

ANCHORED DOCKS

0::yf}/ � ... . .

. ·�· .. ::.· ........ _._ •.• _""" . ..,....,.-i....,..., .... ,�)0.·:.: .. ��- ', . • \ " 4 ·"

• " (.. . '· ' . . .. .. · . . �

8 -.-,--_-!-.-.-

Fig 3 . 6 ( D J P.l.A.N.C. - A.l.P.C.N. - BULLETIN 1 988 - N° 63

AL • •

t, - • '\. . ..

' . ,

35

G • • GRAVITY DOCKS GW • •

.....ro--c-�--e ( .

.. .. ...

. .

M�:' �� l'' < :x ��� .......... �1. •.�11!" .. ��:·.'�.' ... �. :: ..

.

·: ..

36

.. .... • • - .. • • • , *� .. ' t •� • ·� ' t • • • 1" i '

. .. -• ,. • .. I C' ,. • f t i:' ,. . ;, •• I ,• • r �°':.. ..•

�. , ': � �· . .... . "

Fig . 3 . 6 ( E )

P.1.A.N.C. A.l.P.C.N. - BULLETIN 1 988 - N° 63

B • •

BI

B3

:����f l\��h'·��\i,�\�t� :'.'

B7

BUILDING PIT

B4

("\ r - - -o if·�-:-.-. -. �

I

B • •

l imi ted build ing pit

- - - - -l

P.1.A.N.C. • A.l.P.C.N. - BULLETIN 1 988 - N° 63

B I S

37

38

---·�--··-- - _____ )�--· .

anchor-pi l e s

HHWS.� H�W_gl.JL

(� ��� '·D I

__ -.e� -- -

Fig. 3 . 6 (g) - Considered constructions for a dock

\

ANCHORED DOCK

DRAINAGE DOCK

DOCK WITH TENSION-SUPPORT I PILES

From the study for a certain building dock about the structural shape, resulted the possibilities as shown above . In the tender the contractors were asked to price the bills of quantities for all possibilities. The d ifference in cost appeared to be small. As the client wished a rigid floor without settlements , the construction with the dock with tension-supporting piles was chosen.

P.l.A.N.C. - A.l.P.C.N. BULLETIN 1 988

depending on the method used to

counteract the effects of buoyancy

when the dock is empty, i.e. gravity

design, under-drained design (fully re­

lieved or partially relieved) and anchored

design. These are discussed in paragraphs

l:f.2 to It.It. There are two main methods of

carrying the concentrated loading from

ships, i.e. bearing directly on the ground

or supported on piling. These are dis­

cussed in paragraphs l:f.5 to 4.6. In some

cases it may be possible to improve the

ground and this is discussed in paragraph

l:f.7.

l:f.2. GRAVITY DRY DOCK FLOORS

Traditionally most dry docks were

of gravity design with the floor and

dock walls having sufficient mass to

overcome the upwards pressure of the

ground water acting on the underside

of the dock f loor with the dry dock

empty. This was acceptable at the end

of the l 9th century when docks were

not wider than about 20 m and heavy

altarcd walls were provided. Before the

advent of reinforced concrete, brick arch

and stone block floors were provided

both for structural strength and mass,

and dock floors were often about 4 m

thick.

Modern dry docks are often much

wider and although reinforced concrete

floors can be designed to span across

between the walls to assist resistance

to uplift, a thick floor is usually also

required. Under-drained or tied floors

are therefore to be preferred if ground

conditions permit, but several dry docks

have been built in recent years using

gravity design.

Modern designs of gravity docks

often provide a wide floor slab which

extends past the dock walls, thus pro­

viding heels to the walls. The backfill

behind the dock walls bears on the

heels at each side of the dock and this

additional mass can be used to help

resist the uplift water pressure.

4.3. UN DER-DRAINED

FLOORS

DRY DOCK

Under-drained dock floors have been

provided to· more than half of the dry

a.

b.

c.

_J ]_ S? I I

Ill 1 1\\ll ! lll

1 /

/l]j � . : ..... 2 : ·: ·: -----

-2 l s:ttdrovc:r 2 uav•l

. · • • 3 PVC pipe 200 mm dia 4 JOCktt S gavel 6 �nd

. . .

a drainage: layer and c:olketin£ pires b drainarc pipes in the drainacc hf)·c:r c draina,gc: pipe in rhe dock f\oor slab J cont"rclc blocls O.� k 0.3 x O.S m a.I

0.6 m Cln 2 macadam J6 lo 64 mm 3 F�"d 0 to 64 mm 4 conc1clc pipe } m tdia. I -= 80 mm 5 P\'C pi;< 90 x S.3 mm 6 PVC pipe 315 x 9.2 mm 7 pa\'cl 3 to 6 mm i PVC pi)'< 400 mm 9 PVC ripe: 200 mm

m >1oe1 srid J1 m�:c.ad;am l6 10 � mm 1:2 tfl\'cl 0 10 64 mm 13 .shin£it 2 to & mm

Fig. 4 . 3 ( a) - Details of under-drained dock floors

P.l.A.N.C. - A. l.P.C.N. - BULLETIN 1988 39

� t 1200 3010 lOt& UOtl 4,ii

---- ----

iv: sheet p i les �� � 11

!• The two sand layers are connec ted by ver t i ca l sand drains because !i l: the b o t tom of the upper clay layer is too high to avoid upl i f t by !!

(E' r '

11\

layer

- sand layer

:l the water pressure under that layer . ::

�hzzv_zzzzl777_2ZZ727ZZ?Zzmzzzz:zz7zt?zzL

�· • relie fvalves �

� H' ...

flow d i rec tion in the f i l te r

reliefval ve

-· --0

inspection channel

Fig. 4 . 3 (b) - Drainage system

is maintained under the fle<;>r to

prevent any drying out of the soils

involving shrinkage which has the

added advantage of further reducing

the quantity of water to be pumped.

lf the dock is designed to be divided

into compartments by means of an

intermediate gate, it is essential that

the drainage system be separated

from the normal dewatering of the

dock.

If the dock floor has a con­

siderable longitudinal slope the drain­

age system may have to be divided

into sections to ensure that the

filter layer remains charged with

water.

Fig. 4 . 3 ( c ) - Drainage system for floor with longitudinal slope

If the dock is to be flooded

for an extensive period it is possible

to cease underfloor pum pfng but this

should be restarted well before sub­

sequently dewatering the dock in

order to prevent uplift conditions

developing.

I II III IV v VI VII VIII

Perforated drain tubes Collecting and inspection overflows Discharge channels Non return flap Transport channel in sill Pump room Air vents

channels

docks built during the last 40 years. This type of floor has

generally been found to be the most economic where ground

conditions permit the ground water below the dock floor to

be pumped away so that no uplift pressure develops.

In order to collect and pump away the under-floor

ground water, a drainage layer of no-fines concrete (i.e.

porous concrete) or gravel is usually provided immediately

below the dock floor with a series of porous pipes and

drainage culverts to lead the water to a sump in the

pumphouse. Pumping is usually arranged to be intermittent

with the pump commencing operation when the sump fills

up and cutting out when the sump has been emptied.

Pumping is required to be carried out throughout the life

of the dry dock. Regular monitoring of the pumped water

should be, carried out to confirm that no fine grained

material is being extracted from the soil.

Under-drained floors are generally designed to be

much thinner than gravity floors since a large mass to

resist uplift is not required and the floor may be sized

from structural considerations only. On a sound rock foun­

dation, the floor thickness may be reduced to less than

0.5 m thick.

It is normally preferable for the underfloor drainage

system to remain in operation whether the dock is flooded

or empty. The underfloor pumping system is thus indepen­

dent of the main. dock pumping system and should be

designed accordingly. If the principle of continuous pumping

is adopted there will be a minimum of ground water

movement and the ground water regime will be as stable

as possible. lt is also preferable that a small static head

It is essential to introduce

simple fail-safe pressure relief valves

into the system to prevent an unexpected pressure devel­

oping under the floor. These are sometimes provided by

heavy manhole covers being introduced in the underfl oor

culverts which then lift if an underside pressure develops

and allow discharge into the dock.

It is important to recognise that in some ground con­

ditions under-drained floors cannot be permitted. A perma­

nent lowering of the water table can sometimes cause

consolidation of clays and silts with the result that unac­

ceptable settlements of surrounding buildings, roads and

other structures are produced. It is also possible that the

water supply of the district can be affected either by a

reduction in the yield of wells or by enforced contamination

by sea water.

In some highly sensitive areas even temporary ground

water lowering cannot be undertaken and special , measures

of construction may be necessary. These may consist of

forming a complete cut off surrounding the site by sheet

piling or diaphragm walling or alternatively by constructing

the dock structure unqer water. Piezometers are rec­

ommended to be installed in fully or partially relieved dry

docks to ensure that pressure relief is being maintained.

4.4. ANCHORED DRY DOCK FLOORS

Anchored dock floors may be provided, if suitable

ground conditions permit, in conditions where an under­

drained floor is not feasible for the reasons discussed

above, or due to high ground permeability. In this type of

floor the uplift forces resulting from the upward pressure

P.l.A.N.C. · A.1.P.C.N. - BULLETIN 1 988 41

CROSS SECTION

•ump

SOLUTION A

3 2 1 main gate

intermedia t e got cs

Q s OLUTION B

3 2 1 main gotc

"'- i n \ crmedia\c gates

I I l s I I I ON C

3 2 1 main gotc

' ' "'- i n t ermediate gotes

d iame ter of perforation in d�ains is 2 mm

I� "]--- "'° -t---it!lt+l-H-+---+t!-l-t+-l·--1-7-'J_ : H·+·+-t-HJ-� -�

. \ .... � ":- ; l � \J \ IN1"-n""'t¥An LA"i'C.fl

I �

pre.ssur e val ve

Three separated compartments under the dockfloor, with three sumps � No drainage under the dock sections which arc f il led w i th water .

do ck f"lcer

No separations under the dock.floor . rcrmanent drainage: under the dock sections which arc fi l led with water.

Three scp-ar<Jlcd compartments under the dockfloor. There i s only one sump. The discharge channels f rom the three compartu,cnts arc separated. Only in emergency cases when a f i l l ed sections is l eaking very much , the valve in the d ischarse channel is closed to scpar:itc the concerned compartmc:ot .

Fig. 4 . 3 ( d ) - Drainage system with separated compartments

of the ground water on the underside of the dock floor

are resisted by piles or ties anchored at depth below the

dock floor. This solution, if appropriate, is likely to be

considerably cheaper than an alternative gravity floor,

particularly for large docks.

Anchors may be of many different types including

steel strand or bar attached to anchor blocks or grouted

steel H piles, or reinforced concrete piles. In the case of

anchor piles, the tension forces may be transmitted via

friction from the piles to the adjacent ground.

G reat care must be taken with the design of anchored

floors and in particular with ties themseh'es.

There is considerable structural ad\·antage in the use

of prestressed ties by which the floor is held down on the

ground with a force greater than that due to the upward

water pressure. With this arrangement the movement of

the floor under varying conditions i.e. dock full, dock

empty etc, is negligible and the stress in the prestressing

ties remains virtually constant.

High tensile steel in the form of strands or cables

are often used and special precautions must be taken to

satisfy the design conditions, particularly since unbonded

(free slidi ng) tendons are ' normally required to produce and

maintain the necessary prestressing forces. Stress corrosion

of the high tensile steel is a seri ous risk and measures

must be taken to aYoid this phenomenon. It is now gener­

ally accepted that the stress in the steel under these

onerous conditions should be limited to considerably below

that commonly used for prestressing. 50 % of the yield

stress is considered by some authorities to be a safe stress

for most steels in order to aYoid stress corrosion but an

even lower stress may be recommended in some cases

depending upon the method of manufacture of the steel. It

should be appreci ated that the stress corrosion is most

likely to be hydrogen embrittlement which is initiated by

free hydrogen as a .by-product of ordinary electro chemical

corrosion. It follows that measures to arnid ordinary cor­

rosion should'

be of the highest order. High tensile steel

rods (st 52} are considered by some authorities as preferable

to cables but sim ilar precautions against corrosion are

essential.

Steel ' H' piles or q:inforced concrete piles may be

used as ties in suitable ground conditions but it must be

recognised that unless special design arrangements are

made, the piles will be subject to tension and compression

alternately during their life. When the dock is filled, the

uplift water pressure will be counterbalanced and the piles

will be supporting the mass of the dock structure and thus

be in compression. This re\"ersal of stress can, in some soil

conditions, cause a breakdown of the adhesion or friction

between the pile and the ground with resulting failure of

the floor. Tests to reproduce these conditions should be

carried out on the piles prior to incorporation in the final

dock construction.

Where in-situ reinforced concrete piles are used with

mild steel (St 37) the design stress in the steel should be

limited to 100 N/mm2, ln-situ piles with enlarged toes

produce a satisfactory solution in suitable soil conditions.

Many Yariations of anchors for dry dock floors ha\'e

been used which take into account particular ground con­

dit ions. Steel ties anchored into rock at some distance

below the floor girn a positi\'e solution and can readily be

tested. Drilled and grouted anchors ha\·e been successfully

used but precautions against corrosion must be taken.

4.5. DRY DOCK FLOORS BEARING DIRECTLY ON T H E

GROUND

Most dry docks bear directly on the underlying ground

and the dock floor is designed to spread the concentrated

loads from the ship to the ground. Gravity floors will

almost certainly be sufficiently strong to spread the load

of the ship to the ground and many of the thinner floors

associated with under-drained or anchored designs may also

be sufficiently strong · if the ground conditions are good.

4.6. DRY DOCK FLOORS SUPPORTED ON PILING

If the strata immediately below dock floor leYel are

not suitable to support the concentrated loads from a ship

then piling may be pro\·ided. This may be under the whole

of the dock including the walls or merely under areas of

high load at the centre of the dock. W hen tension piles

ha\·e been used they may also be used to support down­

ward loads. If these are not sufficient, extra piles should

be proYided which may be of different length to the tension

piles. Underdrained floors may also require bearing piles i n

some ground conditions.

4.7. GROUND IMPROVEMENT

Poor ground conditions may be i mproved by rnrious

methods and have been successfully used, although in some

cases it tends to be both expensive and time consuming.

Ground i mpro\·ement may be carried out by replacing

weak or compressible soil by a granular material which can

be well consolidated by rolling or vibration. The granular

material will then ham the dual function of spreading the

ship loads and acting as a drainage layer for a pressure

relie\·ed floor.

Where the dock is to be constructed in reclaimed

land and dykes are required around the building pit, the

weak soil may be excavated and used for the temporary

construction of the dykes. Good granular soil can then be

used for the area under the floor without great extra cost

im·oked.

Grout injection may be used to strengthen the u nder­

lying soils provided that they are of a suitable nature to

accept the grout. This process will ha\·e the additional

adYantage that the permeability will be reduced and that

the rnlume of underground water ultimately to be pumped

for a drainage dock will be reduced. The life performance

P.1.A.N.C. • A.l.P.C.N. - BULLETIN 1988 - N° 63 43

of chemical grouts should be confirmed before use.

Vibratory compaction may be used in some soils in­

cluding the introduction of stone or sand i:iiles.

Timber or concrete displacement piles are sometimes

used to consolidate and generally strengthen the ground

without using the piles for direct bearing. Such a design

can be used satisfactorily combined with an under floor

drainage system.

4.8. DOCK FLOORS CONSTRU�TED UNDER WATER

It may be necessary to construct the dock floor under

water particularly if it is not possible to dewater the site

due to high permeability of the underlying ground or the

.danger of lowering the water table surrounding the building

pit is too high.

4.9. LONGITUDINAL SLOPE OF DRY DOCK FLOOR

Dry docks used for shipbuilding are normally con­

structed without longitudinal slope since it is easier to

construct a ship if the keel is horizontal. Ship repair docks

are often proYided with a longitudinal fall of about l :300

towards the dock entrance to facilitate drainage of the

dock during dewatering. This inclination is generally in line

with a Yessel being of deeper draft at the stern and

entering a dock bow first.

/t.10. DRAINAGE OF DRY DOCK FLOOR

Drainage of the dock floor is desirable so that water

from rainfall, ship cleaning and water discharged from the

ship may be remo,·ed. It also assists in remo,·ing water

from the dock when dewatering is almost complete.

Drainage is usually by falls in the dock floor to

drainage channels at the perimeter of the dock. ConYen­

tional surface water drainage using gulleys drained by pipes

in the dock floor is i mpracticable since a system of this

type would block up with debris from shotblasting and

shipcleaning processes.

Drainage mar be by longitudinal fall only usually from

the head towards the dock entrance but with no lateral or

cross fall. One of the adrnntages of haying no cross fall

is that, for flat bottomed ships, bilge blocks need not to

be altered in height when adjusting their position laterally

to suit different ship sizes.

Cross falls may alternath'ely be provided in the dock

floor to assist drainage and in this case, it is normal to

proYide a fall from the centre of the dock towards the

dock walls where a longitudinal drainage channel is pro­

Yided. Some docks are provided with both longitudinal and

cross . falls.

Longitudinal drainage channels are often provided at

the edge of the dock floor adjacent to the dock walls.

One channel discharges direct into a sump in the pumphouse

44 P.l.A.N.C. - A.l.P.C.N.

and a trans,·erse channel or cukert is .provided to link the

other channel to the pumphouse sump. This transverse

channel is often located adjacent to the dock sill.

4.1 1. CLEANING OF DRY DOCK FLOOR

Large quantities of debris may accumulate on the

dock floor due to shotblasting and ship cleaning operations.

Some of the smaller debris may be washed into the pump­

house sump although this is not desirable since it ma)•

cause damage to the dewatering pumps. Screens are usually

employed to prevent larger debris from entering the pump­

house.

Debris may be cleared from the dock using small

rubber tyred dozers. These may enter the dock by the

ramp or be placed in the dock by crane. Debris may be

placed in special skips by the dozer for remoYal from the

dock by lorry or crane.

t+.12. SE&V!CES ON DRY DOCK FLOOR

Services are not normally pro\·ided on the dock floor

since they are likely to interfere with the placing of the

keel and bilge blocks. Manholes for under floor drainage

may be required and very heavy duty flush cm·ers are

usually prO\'ided and located away from the centre line of

the dock so that interference with the blocks is minimized.

Provision of seryices to the dock floor is usually

achieved using flexible pipes and cables connected into

suitable points in the sen·ices gallery situated in the dock

walls at high level. These may be positioned and remoyed

as required. I f ser\'ices are required at dock floor leYel

they are generally located in recesses in the dock walls.

4 . 1 3. JOINTS IN DRY DOCK FLOOR

Joints may be required i n the dock floor to provide

hinges as part of the o\·erall structural design of the dock.

Joints may also be required to cater for expansion and

shrinkage. Construction joints will also be required. Joints

may be provided with water bars, joggles, dowel bars and

sealers, as approprla te.

Expansion joints are rarely used in dry dock floors

since the temperature of the floor slab tends to be

goYerned by the temperature of the underlying ground

water, which is generally fairly constant.

Shrinkage joints are often pro\·ided in floors concreted

in the dry to reduce the effect of the shrinkage as the

floor hardens. It ls normal to cast the floors i n alternate

bays or to lea\·e shrinkage gaps.

It is modern practice to proYide water bars at j oints

in the floors of dry docks, particularly if the floor is

underdrained. If the floor ·foundation is directly on rock,

water bars may sometimes be omitted. Reinforcement is

usually continued through construction joints. The concrete

sides of a construction or shrinkage joint is either mechan-

BULLETIN 1 988 - N° 63

ically roughened prior to casting the adjacent or infill sec­tion, or alternatiYely joggled joints pro\·ided.

4. 1 4. LOADING ON DRY DOCK FLOOR

Loading on the dock .floor can be di\·ided into three categories as follows

(i) Upward reaction from the ground and ground water pressure. Loading transmitted from the dock walls should also be considered.

(ii) Loading from water in the dock with the dock full of water,

(iii) Loading from the ship or ships including tank testing loads and isolated loads from jacking etc.

Loading from (i) and ( i i) abo\·e can be estimated fairly simply depending on the ground conditions and the general arrangement of the dock. The loading from the ship or ships cannot be determined with any precision, Dry docks will normally be required to accommodate a large range of different sized ships up to the limits of the dock dimensions. Ships will normally be in a ' light' condition but this wi1l not always be the case, particularly for repair docks where damaged ships may be docked.

The procedure normally followed is first to assess the docking weight of the biggest ship that can be accommo­dated in the dock by reference to Lloyds or other lists gi\·ing \·essel statistics. The proportion of load carried by the keel block and bilge blocks respectiYely must then be estimated. For flat bottomed ships such as tankers it is of ten assumed that 50 % of the mass of the ship is sup­ported by the keel blocks and 50 % by the bilge blocks. For ships with finer lines a greater proportion of the mass of the ship will be carried on the keel blocks. Raking shores may be used instead of bilge blocks, particularly for warships, and in this case the whole mass of the ship will be carried on the keel blocks. The aYerage loading on the keel blocks · is thus assessed and is usuall�· expressed in tonnes per metre run.

Loading at the ends of a ship, particularly at the stern, may be higher than the a\·erage loading and these sections of the dock are often designed for a keel block loading 50 % higher than the a,·erage loading. The effect of sew loading due to Yessels being docked out of trim may also need to be considered.

Bilge blocks are usually arranged in rows parallel with the keel blocks. The rows may be positioned anywhere from close to the dock wall to close to the keel blocks. Bilge blocks are usually designed to carry 50 % of the mass of the ship but in some circumstances the loading may be higher. Bilge blocks may be widely spaced longi­tudinally and indh·idual blocks may therefore carry a similar load to the keel blocks.

In shipbuilding docks, it is common for ships to be built off centre. In wide docks two or more vessels may be constructed side by side. The dock may also be used

for the construction of . drilling rigs, floating dry docks, floating cranes etc. In these cases it may be preferable to e\·oke a set of line loads and point loads to be considered at any position on the dock floor.

The loading from other sources such as mobile cranes, scaffolding and materials, is generally small compared with the bilge block loading. Jacking loads ·may be considerable and of the same order as the bilge block loads.

4 . 1 5. STRUCT.URAL AN ALYSIS .OF DRY DOCK FLOOR

As noted in 3.7 structural analysis of the dock floor is sometimes initially carried out in conjunction with the design of the dock walls and other elements of the dock. Notwithstanding this, a separate and detailed design of the floor is almost always required. The loading parameters and alternatiYe loading conditions are applied as appropriate. The design of the dock floor is usually carried out to elastic principles. The floor slabs may need to be designed as slabs on elastic foundations, the modulus of elasticity of the underlying strata being used to calculate the bending moments and shear forces in the floor slab. In docks with thin floors subjected to a hea\·y keel block loading, the floor is sometimes thickened at the centre of the d.ock to increase· load spread and reduce reinforcement quantities.

In dew of the uncertainty attached to the loading and ground parameters it is not always appropriate to carry out the designs to great accuracy and simple hand calculations may be preferred initially and then checked by computer finally.

5. DESIGN OF DRY DOCK WALLS

5.1. INTRODUCTION

Dry dock walls are usually designed in conjunction with the dock floor. In addition to the loads transmitted through the dock floor, the dock walls are designed for a \'ariety of loadings and load combinations, including earth pressure and surcharge, ground water pressure, seawater pressure from inside the dock and loading from equipment and fittings including quay cranes, mobile cranes, ship hauling gear, dock arms, bollards, shores, strong points and sen·ices. In some locations it is necessary to consider earthquake loading which should conform with the local regulations in force for retaining walls. Layout of the dock walls is co-ordinated with the serYices gallery required at the cope. There are many different types of dry dock walls as outlined hereafter.

5.2. MASS CONCRETE DOCK WALLS

Dry dock walls prior to the first part of the 20th century were generally of massive construction, usually with stepped altars on the front face. This wall profile was conYenient for supporting horizontal shores to the sides

P.!.A.N.C. - A.l.P.C.N. - BULLETIN 1 988 45

C anti l ever / __ Anchorages

Dock F l oor Dock F l oor

Fig. 5 . 3 - Alternative dock wall construction i n reinforced concrete

of ships and at the same time followed the line of thrust

from the earth pressure. The back of the wall was also

sometimes stepped to economize in material. Mass concrete

may still be used economically for wall construction in

some circumstances although It is not common in modern

practice. The weight and thickness of the wall is primarilr

designed to resist the o\·erturning moments due to horizon­

tal earth and ground water pressure. The economy can be

shown if the weight of the wall can be arranged to be

added to the floor weight to resist the upward ground

water pressure on the whole dock.

5.3. REINFORCED CONCRETE DRY DOCK WALLS

About 50 % of the dry docks built since about 1950

Dry Doc k F l o o r

Stee l Sheet P i l i ng

Underfl oo r Dr a i n a g e L ayer wi t h Por o u s D ra i n s

Underf l o or Dra i n a g e C u l vert

ha\'e been constructed with reinforced concrete walls. Re­

inforced concrete walls \·ary greatlr in their arrangement.

The following types are the most common :

(a} L shape

(b) inYerted T shape

(c) counterfort.

Where ground conditions permit, walls may be tied

down to increase their resistance to oYerturning.

5.4. SHEET PILED DRY DOCK WALLS

Steel sheet piling has been successfully used for drr

dock walls although they are less common than reinforced

concrete walls. The following factors must be taken into

r Anchorage

Ti e Rod s

Fig. 5 , q (a) • Sheet piled dry dock wall (with drained dock floor)

46 P.l.A.N.C . • A.l.P.C.N. - BULLETIN 1 988 - N° 63

1:r.o I 255 IY.>5 335 255 175 --·-·4---=-+-------'-'"'------+-��--t---�r-

rod M �· , root i...,

sh u t pHin9 : dou bt• PSp SOO s lrng t h • 21.00 m.

w i t h inltrmedi>!a pilu PZ 1' s l•ngth = l7,00 m. stulqu�l i t y : St. Sp. S min. yield trus = 3600 kgt/cm.2

slop1 o5 "!.

"pull ing •r•

I I

reinforced concrete

: : ( tor s. t t 1 l pHt i ) !. '

Fig. 5 . 4 (b} - Sheet piled dry dock wall with floor on tension-supporting piles

P. l .'A.N.C. - AJ.P.C.N. - BULLETIN 1 988 - N° 63 47

account in the design :

i} An allowance in the thickness of steel proYided should

be made for corrosion or adequate protection of the

steel be giYen. The amount of corrosion is found to

\·ary considerably with different soils and the type of

protection should be carefully considered for the par­

ticular conditions existing. Cathodic protection is not

normally considered appropriate.

i i) The abi lity of steel sheet piles to carry high Yertical

loads from cranes or from stanchions in co\·ered docks

should be considered.

i i i) The clutches of some sheet piling sections allow water

penetration and consideration must be gi\·en to caulking

or welding up the clutches exposed in the dock barrel.

Sheet pil ing may be required as part of the temporary

works for the excarntion of a dry dock, particularly where

the space for construction is restricted. In this case it

may be economical to incorporate the piling in the perma­

nent works.

Sheet piling is also used where a cut-off is required

into an impen·ious layer below dock f loor le\·el so that an

under drained floor can be pro\·ided with a reduced quantity

of water to be pumped.

Sheet piling may also be used with great ad\·antage if

a ground water cut off is required to make possible an

efficient under-drained dock. In this case the piling forming

the dock walls may be extended downwards and terminate

in an i mpen·i ous layer some distance below the dock floor,

thus reducing the quantity of water to be continuously

pumped.

Facing of the steel piling in concrete has been used

to increase the structural strength of the wall and to im­

proYe the aesthetic effect.

5.5. CAISSONS FORMING DRY DOCK WALLS

Floating caissons may be used for constructing the

walls of dry docks which are to be constructed in land

reclaimed from the sea. Caissons mar also be used in ,·ery

Water Level

Underv1ater/ Concrete F.lo.Qr.

... ..... (�

F i g . 5 . 5

Cai sson Sunk on Rock Bed

per,·ious ground where it may be easier to exca\"ate the

complete area of the dock by dredger rather than attempt

to dewater the ground to construct the dock in the dr}'•

5.6. DRY DOCKS WITHOUT WALLS

Dry docks ha\·e been constructed with sloping sides

instead of con\"entional walls. This type of construction

may be particularly appropriate to dry docks for the con­

struction of drilling rigs.

6. DEWATERING OF DRY DOCKS

6.1. INTRODUCTION

The arrangements for dewatering a drr dock are

crucial to its efficient operation and consultations with the

dock owner concerning its future usage are essential before

the design of the dewatering system is undertaken.

6.2. DEW A TERING TIME FOR A DRY DOCK

The dewatering time for a dry dock i s normally

specified as being the time taken to empty the dock from

high water {spring t ides) without a ship in dock.

Docks used for shiprepairing normally require fast

pumping and the time specified is usually between l t and

4 hours.

Docks used for shipbuilding ca11 normally accept a

longer time and may rangE: between 4 and 12 hours or

e\·en longer i n some special instances.

Shiprepairing docks often require one ship to Jeaye

and another to enter during a high tide period and it may

be necessary to ensure that the water in the dock is

maintained below the sea level after the gate i s closed to

aYoid a reverse head on the gate. Fast pumping may be

essential in these conditions.

On the other hand, having floated a new ship out of

a shipbuilding dock there may be an acceptable delay

before work is started on a further ship in the dock and

the pumping time is thus not critical. In some cases

ad,·antage may be taken of a falling tide to reduce the

amount of pumping to be undertaken.

6.3. LOCATION OF PUMPHOUSE

Pumphouses are usually located near the dock entrance

for a number of reasons.

Ad,·antage can be taken of any longitudinal fall of

the dock floor which, when provided, is normally towards

the dock gate. Location near the dock entrance normally

results in the shortest discharge culYert system with cost

and efficiency ad\·antages. The control of the gate and the

pumping which are related to each other can b e housed in

close proxi mity with obYious ad\"antages.

48 P.l.A.N.C. - A.J.P.C.N. - BULLETIN 1 988

t:

�-

o�C!!&::liii!�ta=�======j'ioo.,.,... - ... - -

Fig, 6.4 - Pumphouses using syphonio discharge

P.l.A.N.C. • A.l.P.C.N. - BULLETIN 1 988 - N° 63

In some instances

pumphouses have been

placed centrally in the dock

where. the floor i s horizon­

tal and the discharge cul­

\'erts can be short, but

these conditions are rare

and central pumphouses are

not normally recommended.

In the case of double

or twin docks the pum p­

house may normally be

located between the en­

trances. In some dockyards,

notably na\·al yards, a s ingle

pumphouse is used for mul­

tiple docks. In such cases

the cukert S}'Stems are

complex in\'Oh'i ng a num ber

of expensi\·e sluice vah·es.

6.1/.. DRY DOCK MAIN DE­

W A TERING PUMPS

Dry dock main de­

watering pumps may ha\·e

horizontal or ,·ertical

spindles. Horizontal spindle

pumps are usually centrifu­

gal and haYe advantage in

easy maintenance but due

to space requi rements and

extra ci\'il engineering costs

they are not commonly

used in modern installations.

Vertical spindle pumps

are normally axial or m i xed

flow and haYe great advan­

tage in that the motors

can be positioned high in

the pumphouse and gener­

ally the pumping installation

with these pumps takes up

less space in the pum p­

house.

may

The

be

final

decided

selection

on

considerations with

cost

the

pump manufacturer choosing

the pump design to suit

the specification prov ided

by the user.

The number of main

pumps used normally ranges

between two and fh·e.

Single pumps are rarely

used since a breakdown

will put the dock out of

action.

49

Pumps are usual!�· arranged to be able to start when

the water leYel in the dock is low and each should be

able to generate sufficient head to prime the syphon

(where syphonic discharge is incorporated).

Pumps are commonly designed to cut out in sequence

as the water level in the dock falls and the rate of flow

into the dock sump reduces.

6.5. DRY DOCK DRAINAGE PUMPS

Drainage pumps with their suction in the dry dock

main sumps are required to deal with the water remaining

i n the dock after the last of the main pumps ha,·e cut

out. These pumps should ha\·e adequate capacity to deal

with the maximum ' run off' from the dock floor in the

shortest possible time and at the same time remoYe the

rain water and any leakage from the gate, floor and walls.

6.6. DESIGN OF DRY DOCK PUMPHOUSE

The design of the pumphouse for a dry dock should

mir DISCKU&{

mrm SYfHD•S

DISCHARGE

CULVERT

- - - - - "l I

.. ,, .. ':-� .,.

be such that the equipment contained therein can be easily

installed, operated and maintained.

Provision for increase in required capacity should be

considered such as the possible installation of extra pumps

if the duty of the dock was to be changed say from ship­

building to shiprepair. A change from · single to . multiple

usage of the pumphouse would normally only be possible if

the original design had taken this into account and pro- · ,·ision for the necessary \·akes and cuh"erts had been made

initially.

Arrangements for the remoYal and replacement of all

the major equipment should be incorporated in the design

such as the proYision of removable panels in the roof

which would normally be within the reach of the dockside

cranes.

Some pumphouses are equipped with an oYerhead crane

which is able to rnO\'e the equipment to a suitable place

for maintenance or to a position from which i t can be

remo,·ed from the pumphouse using the dockside crane.

UL UST rm )WI HUI

f!RE JOtrEY mm

hlDD '/.

I

-t:<l .. ri:";.i--=�=<] . ., : . • .

�­·r l . I • • . . . .

-��l

S(LWATCR 1n hlOO 'l• J 2 100 ·1 •

··-f ( t J

HOUS{ o�mm

PUHtS

2,100 .,. hlnO '/,

SUHr �=-�������-::-'--�����_..::·��-!_'====�! 11111 D£W1i'[ RIXI mirs

h�D '/, l ( h ll '/,Jj

DOC! DUIUtE

tUHPS li1DO '/, ]

1 1 . 100 ·1.1

HY. 8 �

-l<l-

l mmL ru1-1r mvc ISQl!TlkG � SOlBOID GHHHD YAlYE m-HlURI

m ·nu1sE nm VALVE

Fig. 6 . 6

50 P.1.A.N.C. - A.l.P.C.N. - BULLETIN 1988 - N° 63

rvKflXC uurmm1

A

Fig. 7 , 3 (a) - Pumphouse with butterfly valves

P.l .A.N.C. • A.l.P.C.N. - BULLETIN 1 988 - N° 63

o so too ctn -=- ..::.-=-� 0 '$ lll' m

5 1

Pro\"ision should be made for venti­

lation of and heat extraction from

the pumphouse.

The main dock sump is usually

located under the pumphouse and

below the suction of the main

pumps. The ducts leading from the

dock floor to the sump should be

large to enable the flow to be as fast and smooth as possible to pre­

rnnt starvation of the pumps

towards the end of the dewatering

operation.

Model testing of the layout is

often done to optimize the shapes

proYided and to study the possible

interaction between pumps in a

common sump. This phenomenon can

usually be o\·ercome by suitably

placed baffles.

7. FILLING OF DRY DOCKS

7.1. INTRODUCTION

The filling of a dry dock is

normally by gra\'ity directly from

the sea. It may be supplemented by

pumping if the operation is required

to be particularly fast or if some

impounding of water abon� tide

Je,·eJ is needed.

7.2. FILLING TIME FOR A DRY

DOCK

The filling time for a dry dock

is normally considered to be the

time taken to fill the dock with

the outside water le,·el at Mean

High Water Springs and without a

ship in dock. The fiJJing time is

usually specified to be between

and 2 hours.

7.3. TYPES OF FILLING VALVES

USED

Equilibrium filling YalYes are

commonly used and consist of a

large rnrtical cylinder set in Yerti­

cal guides in a compartment with

direct access to the sea. The top

Fig. 7 , 3 (b) -> Dry docks using equilibrium valves

52

-+

P.l.A.N.C. - A.l.P.C.N. - BULLETIN 1 988 - N° 63

' li'LOW GLI Dr� .PA�.NJ.;L

of the C)'linder is abo\·e sea leYel and the bottom consists of a seal set oYer a culvert leading directly to the dock. To open, the cylinder ls rai sed a small distance allowing water to flow radially into the cuh-ert and thence into the dock. The weight of the cyli nder is often counterbalanced so that the force required to open the yal\'e is \·ery small and can be done by hand, operating a simple screw. Altemath·ely they may be motorized with remote control from the pumphouse.

Sluice Yalrns for dry dock filling are large, power operated and expensirn. Where impounding of the dock is not required, single faced penstocks may be used which are cheaper than double faced ,·akes but must still be power operated.

Butterfly val\·es are often used when the filling of the dock is carried out through the dock gate. Normally a number of such ,·alves are used which can be either hand or power operated. The number of \·aJves used permit regular maintenance to be carried out so that the system can be generally reliable.

&. DRY DOCK GA TES

8.1. INTRODUCTION

Dry dock gates are highly 1·ariable in principle and design, the choice being goYerned by the different features which may be required and the different conditions under which the gates must operate. The factors affecting the choice are coYered by subsequent paragraphs followed by a more detailed description of alternath·e choices of gates together with their adYantages and disadrnntages. The final choice may depend upon judgment and commercial consider­ations.

8.2. WIDTH OF ENTRANCE

The width of entrance will ham profound influence on the type of gate chosen and on the structural solution deYeloped. Whilst there are no absolute l i m i tations, there may, for instance, be a practical limit to the length of gate which is required to span horizontally across an entrance.

8.3. HEAD OF WATER TO BE RETAINED

The maximum head of water, its direction and its relationship to sill and cope lernls will influence the choice of gate type.

The maximum height of water to be retained by a gate facing the sea should be related to the highest re­corded tide le\·el at the gate location or the highest astro­nomic t ide (HAT) plus an allowance to include for surges and other exceptional water conditions. Wa\·e conditions should be considered separately as an addition to high water le\·eJ.

For some dry docks there may be a requirement for the dock to impound so that the gate in that case must be capable of retaining a reverse head. This may occur when there is a l arge tidal variation and. the ship in dock is required to remain afloat during a tidal cycle.

In dry docks which have the capability for pumped i mpounding, precautions should be taken against oYer fill ing by designing the gate accordingly, by pro,·iding an overflow facility or some other safety feature.

8.4. SPEED OF OPERATION

The speed of operation required for the opening and closing of a gate will depend on the use of the faci lity which is protected by the gate.

For shiprepairing dry docks fast opening and closing times are normally considered essential, especially when there is a large tidal rnriation. An operating time of the order of 10 m inutes is often considered appropriate.

For shipbuilding dry docks slower operating times of the order of 30 minutes are usually acceptable since the operations occur infrequently •.

8.5. COST OF CONSTRUCTION

The o\·erall 'Cos t of provision of the gate should in­clude the cost of the associated c ivil engineering works and the operating mechanism. The ch·il engineering works form a major part of the total cost of some designs w h ich is referred to in the descriptions of the various types of gate. The cost of the operating mechanism also \'aries widely with different gate designs.

8.6. ABILITY TO OPEN AGAINST A HEAD

In gates requiring a fast opening speed there may be a great ad,·antage in the gate being able to open before the water level on the ' low' side has reached the water level on the ' h igh' side. It may be noted that when a dry dock i s filled by gra\·ity, the speed of filling falls greatly as the water le\·els approach equality and this is accentu­ated if the operation is carried out before high tide. The ability of a gate to open against a head of the order of 50 mm to 100 mm is worth achieYing and greater figures will shorten the o\·erall operating time still further. Hy­draulic rams are sometimes used for this purpose.

8.7. DEPTH AVAILABLE OUTSIDE DOCK

The natural depth of water arnilable outside the dock entrance will greatly affect the choice of gate. If a recess below the general bed le\·el is required to house the open gate there may be a problem of s i ltation.

P.l .A.N.C. - A.l.P.C.N. - BULLETIN 1 988 - N° 63 53

8.8. PARKING SPACE AVAILABILITY

The availability of quay space to accommodate a free

floating or side hinged gate is an important consideration.

The parked gate should be protected against damage by

ships entering or leaving dock which may involve fendering

systems and extra ci vii engineering costs.

8.9. EASE OF MAINTENANCE

Consideration should be given to the ease of mainten­

ance of the gate. Preference should be given to those

types of gate which permit maintenance being carried out

with the gate in operation. The use of spare gates being

placed in outer ' stops' so as to allow the working gate to

be fully dried out is an expensive possibility but becomes

more acceptable if one spare can be used for a number of

similar gate entrances.

8.10 LABOUR FORCE REQUIRED TO OPERATE GATE

The number of personnel required to operate the gate

can vary between one man controlling a single winch to a

considerable number of men forming mooring gangs com­

bined with tug crews.

8.1 1 . PROVISION OF POWER

Whilst the total power consumed in one

operation of a mechanised gate will not be

large, the provision of suitable power sources

in the form of electric, diesel or hydraulic

motors may involve a considerable capital

cost affecting the choice of gate. An

emergency standby power facility is usually

provided for gates.

8.12. ACCESS ACROSS TOP OF GATE

· ' I ' I , I ,{ :

ditions is most desirable from the point of view of accu­

racy and workmanship and mass production of identical

units' may show considerable saving.

Erection of the . gate by joining the units may be

undertaken behind a temporary cofferdam on the dock floor

and the gate floated into position when the construction

site can be flooded. Erection may alternatively be under­

taken on a slipway or in an existing dry dock and the

completed gate floated to the site. Erection of the gate

on the sill, so that the dock construction site need not be

prematurely flooded is also possible, but may produce some

practical difficulties depending on the details of design.

8.11;. FREE FLOATING GATE (SHIP-TYPE CAISSON)

The free floating gate is one capable of becoming

buoyant by pumping out or otherwise discharging sufficient

water ballast. The cross-sectional shape of the gate may

be either rectangular or ship-shaped .or be shaped to con­

form with the structural and operational requirements of

the gate. The elevational shape of the gate may be rec­

tangular or, in cases where the gate is required to be

located in a close fitting groove in the dock walls and

dock sill, it may be trapezoidal.

The hydrostatic design usually involves the gate being

divided into separate compartments consisting of air tanks,

Dock Si l l Level

ELEVATION CROSS SECTION

FREE

FLOODfNG

Water

Level

In some shipyards, vehicular access

across the top of the gate is a feature,

essential to the operational efficiency of the

yard. High wheel loads from fork lift trucks

and trailers may be required to be carried

by the gate. In other shipyards, only ped­

estrian . _?ccess may be required across the

gate, which may be elevated on stilts above

the main structure of the gate if required

to be at cope level. ,� : I �� I I

8 .13. METHODS OF CONSTRUCTION

The facilities available for fabrication

and erection of the gate should be con­

sidered when choosing the design. Prefabri­

cation of units of the gate in factory con-

I Gate Si l l ! 1 l-------- ---�-----J · ·,,,·�.;s·· ,,.� *' ��·,. · ' .. . ,,, ·t·; · ' ,,, ' v•»;;'-'

ELEVATION CROSS SEC TI ON

Fig. 8 . 1 4 - Typical free floating gates

Top : Trapezoidal gate - Bottom : Rectangular gate

54 P.l.AN.C. • A.1.P.C.N. - BULLETIN 1 988 - N° 63

ballast tanks and free flooding tanks. Trim­

ming tanks can also be provided for both

longitudinal and tra.nsverse stability. In some

designs small baUast tanks are located above

sea level which are filled by pumping and

discharged by gravity when the gate is re­

quired to float. Compressed air may be used

to ' unstick' floating gates as dock filling

nears completion.

The structural design of the floating gate

may vary in principle.

(a) The gate may be designed to span between

the quoins possibly taking advantage of the

support of the sill.

(b) The gate may be arranged with the upper

part being a horizontal beam and the lower

part spanning vertically between the beam

and the sill.

(c) The gate may be designed as a gravity

structure supported on its base in which

case it will normally be necessary for the

gate to be fllled with ballast water and

for water pressure to be excluded from its

underside as the dock is pumped dry.

Floating gates can be designed as re­

versible and advantage should be taken of this

feature where possible to enable mai ntenance

to be carried out to both faces of the gate.

In some gates, complete maintenance of the

outside of the gate is possible including the

underside and seals.

(a) The gate can be constructed remote from the site and

towed into position for immediate use.

(b) The gate can be reversed and easily maintained.

(c) Entrance civil engineering works are usually simple.

(d) Can accept a wide heavy roadway if required.

(e) Can accept reversal of water pressure if required.

(f) Does not require extra depth of water to operate.

(a) Requires mooring gangs and possibly a tug to operate.

(b) Takes considerable time to operate.

(c) Operation may be delayed in moderately poor weather

conditions.

(d) Operation may require careful monitoring of pumps and

water levels.

8.15. HINGED FLOATING GATES

A modification of the free floating gate can be made

by introducing a loose hinge or hinges on one side. The

gate may be - opened and closed by means of wire ropes or

chains operated by a winch. An alternative method is by a

P.JAN.C. • A.l.P.C.N.

Dock Gate Cl osed

DOCK

Dock Si 1 1

Dock Entrance

H i nge

PLAN

' ! Hi nge

! l I I

I ! L ___ J_���-����--�----J ELEVATION ON XX

Out l i ne of Gate

CROSS SECTION

Fig. 8 . 1 5 (a) - Hinged floating gate.

Water

Level

connecting boom pushing or pulling direct on the gate

normally operated by an hydraulic ram. As a further

alternative it is possible to swing .the gate by means of

equipment similar to a ship' s bow thruster at . the end,

of

the gate remote from the hinge. This incidentally has the

added advantage of assisting the dewatering of the dock.

The hydrostatic principles of the gate are similar to the

free floating gate. It is possible to maintain the gate at a

constant level with a slight upward pressure against the

hinges (in this case two in number). The effect of tidal

difference being kept low by using free flooding tanks. The

extra stability provided by the hinges may allow a re­

duction in width of gate and thus a cost advantage.

The structural principles of the gate are similar to

the free floating gate except that it is difficult to arrange

for the gate to be located in a groove and thus reverse

head conditions cannot normally be accommodated.

(a) Can be constructed remote from site.

(b) Can be reversed for maintenance.

(c) Civil engineering works simple.

(d) Can accept a wide roadway.

(e) Does not require extra depth of water.

BULLETIN 1 988 - N° 63 55

?���, .. I ,,; ,, : !�-��� r---- -'�,::, _ _ _ _ u, "�.�� I '-, I ·�����-.l!--:..� ' I I I ' I

r- - .. - - - --, I I 1 support 1 I I � -- - - - - --�

river side dock s ide sealing under gate

I temporary sheet p i l ing for main tenance of sealing flaps

/

CAI S SON GATE

the gate is capab le o f retaining a reverse head

I I I I I I I I I I I I

r - -·"' - - , I I 1 s up port 1 I I L _ _ _ _ _ _ J '

I I I I

I.- - - - - - - -...::;:.-- !

(a) Requires tug or extra machinery to operate.

(b) Medium time to operate.

Fig. 8 . 1 5 (b)

seal ing at gate bot tom ! dock s i de - .. · - --- ... .J

&.1 6. SLIDING CAISSON GATE

guiding p in

(c) Operation may be delayed by very poor weather con-

The sliding {or rolling) caisson gate is one which is

housed, when open, in a recess or ' camber' at the side of

a dock. To close, the gate moves across the entrance

under the action of a winch operating an endless chain or

wire rope • . Before movement, the gate may be deballasted

to become semi-buoyant and in some cases wheels are

designed to be jacked down under the gate to reduce

ditions.

(d) Some monitoring of water levels required.

(e) Cannot easily accept reversal of water pressure.

(f) Cannot operate against a head.

56 P:l.A.N.C. - A.l.P.C.N. - BULLETIN 1 988 - N° 63

Dock Entrance r Camber Cover Jacked up to a 1 1 ow Gate to Open

c:.-::;:::::: .. ";;.-.. ·.==-:.·..l-=:::::::.::-c::: .. --:::-:--� Wi nch

11, ;1G':..�di::::.r�-;;..£:;� ( Handrai 1 folded l 1,.,. «•t

Gate Cl osed \ j'' P ' J' Gate Open l f t i ------------------ I in Gate Camber 1 � ·.� .. � .. ,-�•.1·•····'7-,· ... ·

\. } 'I.

'· '•

'"' l: ,. .4 . .. ,.<t., '•1� '"i'T-:· :ir::-;�::-:-:--:.:::::;.�.,.: ..... i

Dock

ELEVATION ON AA

Temporary Stop logs for Gate Mai ntenance

PLAN

Gate Open i n C amber

A 1 T! DAL

AIR

(d) No extra dredging required.·

(e) Small number of operating

personnel required.

(f) Can accept a wide road­

way.

(g) Not affected by weather

conditions.

(h ) Suitable for locl<s and

docks.

(i) Can be floated out for

repair.

V.i..e.adva.nta.gu o' 4Ud.i.ng gahl :

(a) Very expensive ci vii engin­

eering work.

(b ) Mai ntenance possible but

difficult.

(c) M e c h a n i c a l maintenance

considerable.

(d) Gate structure and equip­

ment expensive.

(e) Camber requires consider­

able space.

&.1 7 MITRE GATES

Mitre gates consist of a

Fig. 8 . 1 6 - Typical sliding caisson gate pair of gates each with a

vertical hinge · at one side of

the .. entrance. The gates are

arranged to meet or • mitre'

further the tractive force required.

The cross section of the gate is usually rectangular

and it can be provided with meeting faces on both sides,

and thus be able to accept a reversed water pressure as

would be require? for impounded docks.

The track on which the gate travels can be provided

with a slope to enable the gate to be housed at a lower

level in the camber. This allows for a permanent roof over

the camber to be provided for general access at cope

level. This roof can be jacked up to allow the gate to be

moved and then lowered when the gate is either open or

closed. The gate may be .capable of becoming fully buoyant

for removal docking and maintenance purposes. An alterna­

tive arrangement may be made by sealing the end of the

camber with temporary stop logs and then dewatering the

camber completely, leaving the gate in the dry for main­

tenance.

(a) Can be fast operation.

(b) Can accept reversed head.

(c) Can operate .when under a small differential head.

on the centre Ii ne of the entrance thus giving mutual

support which, together with the two hinges, form a three

pinned arch structure. The sill is arranged to fit this con­

figuration so that the bottom edges of the gates are in ·

contact and form water-tight meeting faces. The gates are

usually constructed in steel with some buoyancy tanks to

limit load on the hinges when opening and dosing. The

buoyancy is usually provided below low water level with

tidal tanks above to maintain a constant hydrostatic con­

dition. The mechanism for operating and closing may be by

chain of steel wire rope or, now more commonly, by

hydraulic ram.

The gates are unable to withstand a reverse water

pressure and provision must be made for the operating

mechanism to be protected against an overload should a

reverse pressure on the gate tend to develop. The gates

require considerable precision in construction to maintain

their structural integrity and at the same time produce

water-tight seals. In this respect the sill should be de­

signed to accept a load from the gates, notwithstanding

the fact that the gates are designed to resist the full load

by arching.

P.l.A.N.C. • A.l.P.C.N. - BULLETIN 1 988 57

� Dock

ELEVATION ON AA

iDock

Dock Floor

Fig. 8 . 17 - Mitre gates

(a) Fast operation.

(b) No extra dredging required.

Gate Open

(c) Small number of personnel required to operate.

(a) Great precision of construction required in\"OlYing high

cost.

(b) Machinery maintenance required.

(c) Maintenance o f structure not easy.

(d) Space for recesses for gates in open position required

invoking high cost.

(e) Cannot accept rernrse loading.

(f) Cannot accept roadway.

(g) Watertightness difficult to maintain.

(h) Generally considered unsuitable for Yery large entrance

widths.

(i) Are susceptible to ' slam' .

8.18. FLAP GATE

A flap gate rotates about a horizontal axis on the

dock sill and remains horizontal when open to allow a ship

to pass o\·er i t to enter or lea,·e a dock. The whole of

58 P.l.A.N.C. • A.l.P.C.N.

the gate is therefore below sill le\•el when open and mar

require a recess in the dock apron. The gate i s usually

raised by a winch on one entrance pier pulli n g a steel

win� rope which passes over shea\·es on the gate and is

attached to a hold-fast on the opposite side of the en­

trance. The gate is arranged to be semi-buoyant to reduce

the load on the rope and is di\'ided into buoyancy and

ballast tanks as requireq.

To Wi nch

Fig. 8. 1 8 - Flap gate

An attempt should be made i n the design to mini mize

the extent of free flooding tanks so that corrosion and

silting can be aYoided in the tanks. The structural design

of the gate is greatly influenced by the shape of the

entrance, in particular the ratio of height and width. The

gate may be designed with the top portion for m i ng a deep

box girder spanning the width of the entrance with the

lower portion spanning \'ertically between the girder and

the sill. Alternath·ely, the gate may be designed as a grid

of beams with supports on three sides being the two

quoins and the sill. Consideration should also be given in

the design to the method of initial stepping and remo\"al

of the gate for maintenance. This can be done by adjusting

the contents of the buoyancy and ballast tanks. The flap

gate is thus easy to operate and can be built on site or

i n a remote location and towed to site.

(a) Relath·ely cheap structure.

(b} Simple construction work.

(c} Simple and cheap ciYil engineering works.

(d) Can be built on site or remote from si te.

(e) Fast operation.

(f) Operated by one man.

(g) Can accept a medium width roadway.

(h) Not susceptible to ' slam' •

(a) Requires extra depth of water outside s i ll.

(b) Cannot easily accept a reverse head.

BULLETIN 1 988 - N° 63

(c) Cannot be maintained in-situ. (d} Can open against only a small head.

8.19 STRUTTED FLAP GATE

The strutted flap gate is used where the width of the entrance is too large for a simple flap gate to span hori­zontally between the quoins without becoming too heavy and uneconomic. The gate is arranged to be hinged hori­zontally on the line of the sill in a similar manner to the flap gate previously described.

Dock Cope

Hi nge

Fig. 8 . 1 9 - Strutted flap gate

Gate Open

When closed, the gate is supported at intervals against the horizontal water load by a series of inclined struts which are pinned at the bottom and which arc usually raised by the gate when it is lifted by the winch mech­anism. The struts bear against a bracket on the face of the gate structure when in the raised position. The vertical component of the load in each strut is thus transferred to the gate structure and it may be transmitted to the sill through the hinges at the bottom of the gate or by some other device.

An alternative arrangement is involved in the C.J. Foster gate which provides for the vertical component of the load in each strut to be taken by tie rods which are hinged and anchored to the sill forming a series of • A' frames. In this case the gate structure simply transmits horizontal load to the • A' frames without being subjected to a vertical component. The tie rods and struts lie flat on the gate when it is open.

The operation of strutted flap gates may be by winch and wire rope using a multiple sheave system if the load is too great for a single rope. The gate is usually made semi-buoyant to reduce the lifting load.

(a) Can be used for very wide entrances. (b) Fast to operate. (c) Can be prefabricated remote from site.

(d} Can be erected in-situ. (e} Only one man required to operate. (f) Narrow roadway over top possible.

(a) High precision of manufacture and erection. (b} Maintenance not possible in-situ. (c) Requires extra depth of water outside slJI. (d) Civil engineering of medium high cost. (e) Removal �nd repair not easy. {f} Struts reduce useful length of dock. (g) Struts are potentially subject to damage.

8.20. CANTILEVER FLAP GA TE

The cantilever flap gate is used for entrances which are too wide for the gate structure to span horizontally. The gate is so arranged to cantilever from the sill where it is also hinged to rotate horizontally as it opens.

The gate can be operated by a winch system similar to the other flap gates or it can be operated by flotation with compressed air arranged to expel ballast water from the gate.

The gate requires a considerable extra depth of water outside the sill to accommodate the extension of the gate to form the cantilever anchorage and the remainder of the gate when it is open. Various methods have been devised to provide ' fixity' of the bottom of the gate when closed but all involved considerable extra civil engineering work.

Dock Cope

Fig. 8 . 20 (a) - Cantilever flap gate

(a) Can be used for very wide entrances. {b} Fast to operate. (c) Can be prefabricated remote from site. (d) Can be erected in-situ. (e) Only one man required to operate. (f) Narrow roadway on top possible.

P.1.A.N.C. • A.l.P.C.N. - BULLETIN 1988 - N° 63 59

Fig. 8.20 (b) - Cantilever flap gate

The door is moved by changing the water ballast in the door

(g) No obstruction by struts inside dock.

(h) Remornl and repairs possible with some designs.

(a) Maintenance not possible in-situ.

(b) Requires extra depth of water outside sil 1, (c) Cid! engineering high cost with some designs.

(d) Remoyal and repair not easy with some designs.

8.21. OTHER GATE DESIGNS

Other gate designs are numerous and are usually

deYeloped for special purposes where special conditions are

present. Gates l ifted out by a floating crane haYe been

adopted where a suitable crane is a\·ailable without a

prohibitiYe hire charge being required. Sectional gates lifted

into. position with joining seals to form immediate gates

for di\·ision of large dry docks are in common use in ship­

building yards.

9. DRY DOCK EQUIPMENT

9.1 . KEEL AND BILGE BLOCKS

Methods of supporting ships in dry docks haYe under­

gone yarious changes in recent years. A comm on system,

used for many years of docking, was to allow the keel of

the ship to be set down on a central row of cast iron or

timber keel blocks, the full weight of the ship thus being

carried on the centreline of the dock. Lateral support to

each side of the ship was pro\·ided by timber or steel

struts or shores placed horizontally between the ship and

the dock walls at interrnls along the length of the ship.

The outer ends of the shores usually rested on altars

formed on the dock walls. The shores were normally placed

in position and adjusted during the pumping process at the

t i me when the keel just touched the blocks and buoyancy

still proYided some stability. Additional blocks were some­

ti mes placed under the ship' s bilges for additional stability

after the dock was fully pumped out. These additional

blocks are usually referred to as bilge blocks.

60 P.l.A.N.C. - A.l.P.C.N. - BULLETIN 1 988 - N° 63

If the profile of the ship is accurately known, it is

often possible to set out on the dock floor, i n the dry, a

complete set of keel blocks and bilge blocks each adj•Jsted

to the correct height to suit the shape of the ship' s hull.

This method i s common in narnl rards where the shape of

the hulls is known and which sometimes inrnll:es consider­

able cun·ature.

Bilge blocks which are remotely adjustable both in

position and in height have been introduced into some dry

docks with Yarious degrees of success. Many such instal­

lations have become disused due to maintenance difficulties

in the harsh em·ironment of a working shiprepair yard.

Electrical, hydraulic and compressed air systems ha\·e been

used in addition to operation by chain.

More recently, the design of many ships has provided

for the hull to be flat-bottomed which has greatly simpli­

fied the dry docking problem. This has enabled sl)ipyards to

set out both keel and bilge blocks in one plane in position

to suit the loading condition with the ship being allowed

to settle as the water is lowered without any adjustment

or difficulty.

Keel blocks may be formed of hardwood, cast iron,

mild steel or concrete all of which are usually capped

with softwood to amid high concentrations of stress. Some

are also laid on timber to o\·ercome irregularities of the

concrete dock floor.

The remornl of blocks for repair purposes when under

load from the ship has always presented a problem. Sand

boxes on the top of the blocks with arrangement made for

the sand to be remo\·ed by water jet have been \•ery

successfully used.

Cast iron blocks were often formed in three wedged

shaped pieces which could be driYen apart when under load.

Rubber capping pieces ha\·e recently been introduced

to take the place of the soft timber which el iminates the

maintenance and regular replacement of t imber. A system

of jacking has been de\·eloped to enable such blocks to be

removed under load.

9.2. DOCK ARMS

A feature of modem ship repair docks has been the

introduction of dock arms. A dock arm can be described

as a mobile platform supported on an adjustable hinged

canti le\·er arm fitted to a carriage which runs on rails

fixed to the dock wall and cope. These ha\·e only become

possible with the elim ination of side shores.

High pressure water cleaning, shot blasting and paint­

ing of the ship' s hull can be performed from the dock arm

platform with considerable efficiency.

The dock arms may be electric or diesel powered.

The electric power can be supplied by pro\'iding collector

rails or flexible power cables but these must be so arranged

to not i nterfere with the other serdces on the dockside.

The supply of water to the dock arm has been o\·ercome

in Yarious ways including a permanently connected reeling

hose or regularly spaced automatic supply points filling a

tank carried on the dock arm carriage. Supplies of paint

and grit or shot must also be carried on the carriage.

Longitudinal movement of the carriage is preferably

arranged by driving the upper wheels which always remain

out of the water.

Raising, lowering and slewing of the arms is usuallr

undertaken by hydraulic ram operation, but other methods

such as wire rope on shea\·es ha\·e been used.

The design of the dock arms should be robust to suit

shipyard conditions and it is recommended that the

operators should be well trained to deal with this sophisti­

cated equipment.

9.3. SHIP HAULING SYSTEMS

Modern dry docks are now fitted with ship hauling

systems which control the entry and exit of the .ship.

There are many differing systems used but most are

based on self tensioning winches with ropes. attached to

trollies or mules running on rails on the dock cope. It is

essential to plan carefully the interaction between the

hauling system and the dock arms although fortunatelr the

two systems are not required to be used at the same t ime.

Provision must, howe\·er, be made for the parking of the

dock arms at the dock head and so they should be able to

pass the trollies at that point.

The systems differ considerably with respect to trollies

and the rope attachment. In some cases the hauling rope

i s attached to the trolley with a separate ' spring' rope

extending from the ship to a hook on the trolley. I n other

cases the hauling rope passes round a shea\·e on the

trolley and is attached directly to the ship.

In these cases the trollies are sometimes pro\·ided

with braking systems so that, when appl i ed, the trollies

can be used to centre the ship by hauling on the main

winches as appropriate.

In all cases there is angular pull on a trolley with a

high upward and outward component which must be resisted

by the trolley' s wheel srstem which requi res up to six

running surfaces.

P.l.A.N.C. - A.l.P.C.N. - BULLETIN 1988 - N° 63 6 1

APPENDIX "A"

WORLD DRY DOCKS CONSTRUCTED SINCE 1 950

The following pages show the data collected to date on modern

dry docks throughout the world with special reference to their size,

type of construction, type of gate and type and capacity of pumps.

It will be observed from the summary overleaf that the majority

of modern docks are of the under drained floor type. It will also be

noted that only the Netherlands and Germany P.R. have a majority of

other types, no doubt due to the ground conditions. Germany appears

to favour anchored docks whereas the Netherlands appear to favour

gravity docks.

The most common gate used appears to be the steel flap type,

closely followed by the steel hinged caisson. The mitre gate which was

once very popular appears to have lost favour as the widths of docks

have increased.

P.l.A.N.C. - A.1.P.C.N. - BULLETIN 1 968 - N° 63 A - 1

DOCK FLOOR DOCK GATE CONSTRUCTION

CONSTRUCTION

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AUSTRALI A 1 1 1 BELGIUM 7 6 1 - 1 2 4 BRAZIL 2 1 1 1 1 CUBA 1 1 1 CANADA 2 2 - 1 1 DENMARK 7 1 1 5 6 1 E GYPT 1 1 - 1 E IRE 1 1 1 FI NLAND 1 1 1 GERMANY FR 10 10 - 4 1 2 2 1 FRANCE 8 1 2 4 1 4 2 1 1 GREECE 2 1 1 - 1 GI BRALTAR 1 1 - 1 I ND I A 1 1 1 I TALY 4 2 2 2 2 J APAN 43 43 6 1 8 1 9 KENYA 1 1 1 MALAYSIA 1 1 MALTA 1 1 1 MEXI CO 2 1 1 - 2 MIDDLE E AST 4 4 1 3 NETHERLANDS A . 1 1 - 1 NETHERLANDS 1 3 1 0 3 3 8 2 NORWAY 3 3 2 1 PAKISTAN 2 2 - 2 POLAND 2 1 1 1 1 PORTUGAL 7 7 - 1 5 SI NGAPORE 8 5 3? 4? 4 1 SOUTH KOREA 6? 4 2 4? 2 SPAIN 2 1 1 - 2 SRI LANKA 1 1 - 1 SWEDEN 4 1 3 3 1 THAILAND 1 1 - 1 U . K . 16 5 8 3 - 2 2 11 1 U . S . A . 24 21 3 1 3 9 1

A - 2 P.l.A.N.C. - A.l.P.C.N. - BULLETIN 1 988 - N° 63

\!Oilil DRY JXX:KS BUILT SJN:E 19:0

:-0 s;: z 9

i'.': "O () �

CD c: r-r-m -l z (J) co co

z 0 "' 00

Ref No. !.ocaticn

ClllW)A

Saint John N.B.

Saint John N.B.

lENIWlK

Helsing.or

Nakshov

FrederiKshavn

Lindo

Lindo

Ccpenhagen

�en

Owner or Yartl

Saint Jchn

WJRUl DRY IXXl<S BUILT SIIO: 19:0

Year Use Entrance IXlck Ef'fectr- Depth Tidal Canstructicn in of Width Ba:r:rel i ve over range of Walls

coocrete caisscris stooe filled

1923 B/R 33.2 38.l 431. 8 12.8 8.5 Reinforced

Construction of Floor

- drained

Reinforced coocrete Shipb.rl.lcling Ltd extended coocrete slabs o. 91!'.:rn -

1983 3.lm thick 0.7621\ drai.ned and excavated Reinforced ccn:::rete rock face slab - drained en exte'!Sicn

Saint John 1942 R 18.3 21 .3 134.1 7.3 8.5 Ccncrete 3.an O::ncrete slabs Shipb.rl.lcling Ltd ttti.ck o.an thick ooder

keel strips -drained

B 21.9 146 7

Nakshov Shipyard 27.5 176 8.4 Reinforced Reinforced cmcrete coocrete - Drained

Frederickshavn R 26 176 Precast lhreinforced coocrete Vaerft og Tordok A/S coocrete - Drained

Odense Shipyard l 46 300 !'recast Reinforced ccncrete coocrete slabs O. 7!'.:rn max thicl<ness with anchors - Drained

Odense Shipyard 2 1969 83.9 415 8.7 Reinforced Reinforced ccncrete ccncrete 0.35- - Drained 0.73n thick

app. B/R 3'.).3 218 8.25 Chlcrete th:lerwater concrete 195,5 at HI/ caisscns 4-!'.:rn ttti.ck

5.::rn wide Gravity

Bunreister & Wain 38 240 6.5 Reinforced Reinforced cmcrete Shipyard cmcrete 1.0-1. !E thick

- Drained

Soil i;}'pe

rock

sandy clay rock

firm clay

firm clay

'fype of Gate

Steel caisson 1400 tens

Steel Mitre

sand over-lying l:imestcne

clays/ Steel Flap gravels

'fype of Mo:ir1

3 electric vertical spindle c�rtri� purps 11, lrot/f each

2 electric hori:ir-cntal centrifugal puips 382t/h each

8):i; 2 ancillary purps - 963t/h each. 1 SU!p J"fP 6S.8t/h

9 2 SU1P purps 132t/h each

2Y, 2

�

1%

(Jl

Ref !"·h . Locatim

Alexandria

D.Jblin

Ov.ner or Yard N3re

Year Use in of

Service Dock

1965 R

Pre '58

�.CIRl.D DRY 00'.YS BillLT SHT.E 19::0

Entrance Dock Effect- Depth Tidal C'.onstruction C'cristructirn Widtti Barrel ive over range of Walls of Floor

Width Sill DesiBJ1 Fhllosophy (m) (m) lml (m) (m)

39.6 42.0 2:B 10.8 Reinforced Reinforced c=rete ccncrete up to 2. 7m thick

with anchor ties in deep leyer or sandstcne

Soil Type of Type De- Renarl<s type Gate of Main (secondary

Furps ir..nps)

sand Steel floating 3 with caisscn shells

\>.QRill DRY o::x::KS BUILT SIN::E 19:0

)> O> Ref Year Use Entrance Dock Effect- D.:."'Ptil Tidal Ccnstructioo Ccnstructim Soil 'l'.',>pe of fype De- R�

No. Locatioo Owner or Yaro in of Widtil llarTel ive over range of Walls of Floor type Gate of Main Watering (secood-ory Nare Service Dock Widtil l/>.ngth Sill D.:.-'Sigp Fhlloscphy f\J1ps Time(hrs) prnps)

(m) (ml (m) (m) (m)

FEDERAL IU'-1'\ELIC OF G»ltlNY

Hu.sun Husumer 1974 B/R 22.0 25.0 120.0 4.10 3.50 Horizootal O:ncrete with anchor filled Mitre Gates 2 Schiffswerft at anchored steel steel piled bottcrn sand

M-!JS Sheet pile wall thickness l .CDn fine sand

H..1sun HJsurer 1900 B/R 22.0 25.0 150.0 5.20 3.:0 furizootal Coocrete with steel filled Mitre Gates 2 Schiffswerft at anchored steel piled bottcm sand

l'IH#5 sheet pile wall thickness = 1. ron fine :u sand £ z 0 Thyssen 1954 B/R �.o 32.0 218.0 8.20 Ccncrete U frane, thickness of walls Floating 3 l\b. electric 2.6 2 l\b. ancillary

l\brdseewerke at and botton = 2.0n. Botton anchored caisson vertical spindle purrps 360t/h each ;:: M-!JS against uplift with prestressed cable gate 294t centrifugal purps 2 No. arergency 'o anchors 7 .z:tJ t/h each pulps: 218t/h each 0 :z

Kiel HoJ/aldtswerl<:e 1976 B/R 88.4 88.4 426.0 10.0 Steel sheet Ccncrete with anchor sa'ld Floating co DeutcheWerft pile wall with steel pile bottcms in ex- caissoo c inclined steel thickness "' 1.3'.rn change gate .-.- pile anchors for silt m -! deposits z -<D CD CD

Brall"'..n llrerer Vulkan 1973 B/R 58.0 ee.2 331.6 8.6'.) 3.90 Left side - Ccncrete wi til anchor Support beam 2 No. electric 2 No. ancillary at angular cooc- piles system Franki with skin vertical spindle pl.llpS

z l<Th'IS rete retaining plate centrifugal purrps 5JJt/h each 0 "' wall . Ri,Pt elements 10. CXl)t/h e.ach "'

side - steel sheet pile wall as part of a cofferdam.

Bra:ner Vulkan 1979 B/R 25.0 25.8 170.0 8.� 3.90 Steel sheet thderwater coocrete Single leaf' 2 l\b. electric 3 3 l\b. ancillary at pile wall with thickness 1. Qn with wi til buoyancy vertical spindle puips 400t/h each

Mi\S inclined steel steel anchor piles charrbers borne centrifugal purrps Covered dock pile anchors a1d concrete coostn>ctioo in gudgecn & 5.0COt/h each w:i th hangar

floor l. Qn thick plintle bearing dim3nsioos 37x 190n hei,Pt of ridge over dock boti=rd 5Qn heigi't of ent-ranee over MilJ LIO. 7:'rn.

OJ c r ffi z ID CD CD

z 0

WJRID DRY J)'.X;l(S BUILT Sll'CE 1950

!Ref N::J. locaticn

Year Use Entrance Dock Effect-- Depth TidaJ Ccnstructicn o.ner or Yard in of Width Barrel ive over range of Walls

Name Service Dock Width Length Sill (m) (rn) (m) (rn) (ml

FEl:ERAL REPlllLTC OF GEl1Mi\N\' (Cm tin ood)

Constructicn Soil of Floor type

Desi@1 Fhiloocphy

Type of Gate

Papenburg Meyer Werft R 35.0 35.0 2:0.0 6.50 +.40 Hvrizcntal Concrete with anchor filled Steel flap

Kiel N::J.7 Howaldtswerke Dock Deutsche Werft

l'b.7 enlargement

Howaldtswerke Deutsche Werft

Papaiburg Meyer Werft

Pemo Wartsila

1953 B/R 38.0 38.0 260.0 6.63

1900 B 50.25 :0.25 310.10 6.63

1953 B/R M.00 44.00 285.0 6.63

mchored steel piles system Franki sand gate sheet pile wall

Angular remining concrete wall Widening:

( as above ( Leng'"J1ening: ( concrete wall ( en steel piles

Ps d<x;k l'b. 7

Ccncrete thickness = l . lQn with anchor piles System Franki

as above

filled Floating sand caisson

gate

as alxlve as above

1987 B/R 40.0 40.0 257.0 9.50 O.LIO Horizcntal Ccncrete with anchor piles system Franki

sand Steel flap gate at an:::hored

M3L steel sheet pile wall

1yPe of M3.in

Ptlrps

3 N::J. electric vertical spindle centrifugc!l purrps 11. OX>t/h each

De­Watering Time(hrs)

1

3

5

2 N::J. pu1ps

Covered cb::k. Cover 101. 8n x 265-n heigJ'lt ffin ridge . Entrance heig)1t 41m above MllL.

\l.ORlD DRY ro:::KS BUil.T SII>CE 19:0

)>

00 Ref Year Use Entrance Dock Effect- Depth Tidal Ccristruction Coostructim Soil Type of Type De- R61larl<s No. Location CN.ner or Yard in of Width Barrel ive (Jlfer range of Walls of Floor type Gate of i'l'ain Watering -· _ ,

!'are Service Dock Width Length Sill Desi!?)1 Ihllosoph,y PU!ps Tilre{hrs) {m) {m) (m) {m) {m)

FRAN:E

St J\l3Zaire Olantiers de l 'Atlantique B Inclined floor

Dunkerque Jlb.6 Dock 1978 :0 52 310 -5 Sheet piling Reinforced cmcrete fine Steel flap 3 1*>. purps 2 with ties at en filter layer sand 130'.l Kw 2 levels oo clay 3 x 8 rrr /s

Marseilles Jib. 7 or 8 Dock :0 320 Thick rein- Prestressed ccncrete forced concrete 5.5-n thick

� ;i..

M3rseilles Jlb.9 Dock '37 2:0 9 Reinforced cm- Reinforced ccncrete z 9 at LW crete app 5.an 4.3-4.7m thick

max thickn€ss

;:: 1l h Marseilles Jlb.10 Dock 1975 R 85 85 465 -11.0 Reinforced Reinforced cmcrete clay Prestressed 3 No. J'.lUTPS 3)4 3 dewatering ;.:: at lJil crncrete with l.O-l . 5n thick cmcrete 3 x 13 5ii' /s purps

relieving on filter layer caissoo CD platform c r 6 Brest No.2 Ccncessimnaire 1968 R 53 55 338 -7.3 Reinforced 5n thick anchored rock Caissoo 4 centrifugal 4 2 nfilntenance z 0::1 to rock purps purps �

4 x 15.crotf /h <O 00 00

z Brest N:>.3 1900 00 00 42) -7.4 Reinforced 1 .!':m thick en schist Prestressed 3 No. puips 1-3 3 pmps + 0 a:ncrete filter la,yec- ccncrete 40, o:xni' /h 3 dewatering (J) w caissoo plllpS

Bordeaux R 34 240 8.5 Mass coocrete Reinforced ccncrete marl � or 218? at lJil - Drained

Hellenic Shipyards 1970 R 53.3 335.3 9 . 25 Reck filled Gr=t :intrusicn coo- rock Steel flap gate O:xrpany coocrete Crete placed under resid-

caiSSCllS ..at.er �rox 7.5TI ual thick soils

Scar-� Hellenic Shipyards 1977 R 75 420 Reinforced Reinforced ccncrete resid- Steel cantilever O:xrpany cuicrete Lan thick ual gate

originally i'IDChored soils with prestressed

� piles rD# drained � (1986) z 0

� GlHW . .'fllR 'u h Gibraltar Shipngpa:ir Ltd 10Cl5 R 37.8 37.8 Z76 12.42 r.Ess Gravity Floating caissm z Refurbished cxncrete

1985

ID c r r m ::! INJ!A z � <O Visakhapatnam Hindustan <X> <X> Shipyard Ltd

z 0

� ITALY

Palerno 1979 68 370 11.3 Reinforced cco- Reinforced ccncrete Lime- Steel flap Dock bt.1il t :in crete caissms caisscns co piles/ stale/ gate twJ secticns

reinforced ccncrete alluvial 2. 5"n thick with ties clep:si ts

No.5 Dock 1962 38 38 2:il 9 Prestressed precast an:rete Silt caisscns assait>led co site and overlying 5U1k :in coe piece rock

Trieste Cantiere Navale !:',6 3:'D 8.5 Reinforced Re:infarced cax:rete Reck del Italccntieri coocrete tied to rock

foondaticn

Livano Crnsorzio Livomese 1S75 !:',6 3&) 10 Re:inforced Reinforced ccncrete mixed Steel flap 4 l'b. vert. 3.5 3 l'b. centrif.

)> Bacini Carena,ggi.o cco:::rete - Gravity (sea Gate prq:ieller @ 2,crot/h. 3 fb. bed) 27,COJt/h 200t/h

(0

\>.ORl.D DRY ro::KS B'JILT SIN::E 19:0

::t> Ref Year Use Eni:r'dl1Ce IX:ck Effect- Depth Tidal Ccnstructioo Ccnstructicn Soil 'fype of 'fype De- Re;arks

0 No. LoCaticn O.ner or Yard in of Width Barrel ive over range of Walls of Floor type Gate of �'.a:in Watering (secmdary Natre Service IX:ck Width Length Sill Design Phil ooophy fuJps Time(hrs) prnps)

(rn) (m) (m) (m) (m)

JAPAN

1 Aioi No.l ED Ishikawajima 1975 B ro ro 291. 5 11.3 7.9 Reinforced Reinforced Ccncrete rock Steel Caisson HariJra Heavy Calcrete on gravel layer & sand Industries Ltd Drained

2 Aioi No.l FID 1963 R 35.3 41.3 238.1 11.7 9.07 Plain Reinforced Ccr1erete rock Steel Caissoo ) Diagonal JJUTP 1.5 ) Cam= Concrete & sand l 24.cro ni' /au ) use

) } ) )

3 Aioi !'b. 2 RD 1963 R 21.2 30.0 152.14 9.27 6.42 Pla:in Reinforced Ccncrete rock Steel Caissoo ) s.cro ni' /2x2 1.0 ) 540 rri' /h Ccncrete & said ) )

:0 s;: 4 Aioi No.3 RD 1973 R 56.0 !Xl.O 340.0 11.0 8.0 Reinforced Reinforced Ccncrete sand Steel Flap Gate Diagoo;il JJUTP 2.5 Diagooal puip z Cc:ncrete oo gravel layer 24.cro ni' /M 7CO n? /h xl !."> Drained

� 5 Kure l'b. 2 ID 1969 B 65.0 65.7 339.65 10.15 6.81 Grav:ify Reinforced O:nc:rete rock Steel Caissoo "=' 10.0 Centrifugal. """""" �""" -- -i:::>""

'o 'fype x2 3COii' /h xl 0 Diagcnal Diagcnal � 700'.lli' /h xl 700i1' /h xl

en 6 Kure No.3 ED 1973 B 80.0 80.0 !003.2 12.5 8.91 Grav:ify Reinforced Concrete rock Steel Caisson Diagcnal 7.0 Diagcnal c 'fype en gravel layer & sand 2:). cmrr /h x3 lcmiT /h x2 r Drained r m -i z 7 Kure i'b.4 RD 1974 R 44.4 46.6 331 . 2 15.4 12.8 Plain Reinforced Ccncrete rock Steel Caissoo Diagonal 3.0 Diag::nal ...

Ccncx-ete 12.cmrr /h x2 :ooii' /h x2 <O "' 15.cro xl "' 19.CIXl x2

z 0 8 Tokyo No.2 RD 1962 R 24.0 30.0 100.0 9.9 7.25 Plain Reinforced Concrete sand Steel Caisson Centrif\igal 2.0 C'.entrifugal °' (.:> CcrlCrete 2. 7COi1' /h xl � 3.CXXJ xl 3.42:) xl

9 Yokohara RD 1966 R :x>.o 06.0 35'3.0 11.5 8.6 Sheet Reinforced Ccncrete sand Steel Flap Gate Diagcnal 4.0 Diagonal Pile 24.cmiT /h x2 240x2

10 Aichi ID 1984 B 92.0 92.0 518.0 13.0 9.62 Reinforced Reinforced Ca1Crete sand Steel Caisson )Diagcnal 10.0 )Diagcnal Ccncrete oo gravel layer )3'.l.CIXl x2 )10'.Xl x.l

Drained ) ) ) )

11 Aichi RD 1980 R 43.4 43.4 290.5 13.0 9.62 Reinforced Reinforced Ccricrete sand Steel Caisson )Centrifugal 5.0 )Turbin Concrete )6XXJ xl )200 xl

\l.ORW DRY DXKS BUILT SIN::E 19:0

Ref Yezr Use Entrance Dock Effect- Depth Tidal O::nstructicn C'.onstruction Soil Type of Type De- RE<Tm'ks !'b. l=ation o.ner or Yard in of Width Barrel ive over ra'1ge of Walls of Floor type Gate of 1"ain Watering (secoodary

Nare Service Dock Width Length Sill Desigp Fhiloscphy PLJrps Tilre(hrs) purps) (m) (m) (m) (m) (m)

JAPAN ( Ccntin.Jed) 12 Tsu J'b.IBD Nippcn Kokan K.K. 1969 B 75.0 75.0 348.3 7.9 2.1 Reinforced Reinforced Concrete sand Steel Caisson Electric vertical 4 Electric vertical

at Hl\IS Ccncrete 0.7$-2.0m thick with over Steel wt= mJ spindle miJ<ed flOH spindle nill<ed flOI> 0.75n thick Water cut off clay ton PUJP 39,CXXlt/h purp fD)t/h

Drained

13 Tsu l'b.2BD Nippcn Kol<an K.K. 1969 B/R 75.0 75.0 143.0 7.9 2.1 Reinforced Reinforced Concrete sand Steel Caissm *Carbined use 1 *Ca!bined use at tt.\15 Ccrr.,rete 0.7:m-2.0m thick with over Steel wt= mJ 2 i'b. electric 2lb electric

0.75n thick water cut off en clay ton vertical spindle vertical spindle gravel layer 4ffi.. 650 miJ<ed flOH purrps nill<ed flry,1 P'JlPS

� thick Drained 39,CXXlt/h each fD)t/h each }> z 9 14 Tsu Nippon Kokan K.K. 1970 R 75.0 75.0 500.0 10.2 2.1 Reinforced Reinforced Concrete sand Steep Flap 4

Repair Dock at tt.\15 Ccncrete 0.00-2.0m thick with over Steel wt= 900 ?:'.: 0.75n thick water cut off and clay ton 'u water relief well h system en gravel layer � 450-6:0 thick Drained

CD c 15 Kobe J'b.4 Kawasaki Heavy 1969 R 33.5 33 . 5 215.0 6.0 N/A Reinforced Reinforced Concrete sand- Steel Flap N/A 3Y, r-r- Industries Ltd Ccncrete Stene m -i z � (!) CD CD 16 Sakaide i'b.l 1967 B 62.0 62.0 300. 0 5.9 N/A Reinforced Reinforced Concrete clay Steel Flap N/A 5 Exclusively for

Concrete on gravel 50-4:0 thick and building offshore z Drained silt strucb.Jres 0 CJ) U>

17 Sakai de i'b. 2 1968 R 72.0 72.0 4:0.0 7.9 N/A Reinforced Reinforced Concrete clay Steel Flap N/A 3Y, Concrete on gravel layer 100- and

4:0 thick Drained silt

18 Sakaide i'b.3 1972 B 75.0 75.0 420.0 6.2 N/A Reinforced Reinforced Concrete clay Steel Flap N/A 5 Concrete en gravel layer and

100-4:0 thick silt Drained with water relief well system

)>

V.ORID DRY lXlCKS BUILT SIN:E 19::0

)>

..... Ref Year Use Entrance iX1ck Effect- Depth Tidal Coostructioo Constructicn Soil Type of Type De- Rema."'ks [\) N:>. L:x:aticn 0."1et' o:r Yan:l in of Width BarTel ive over ra.'1ge of Walls of Flooi- type Gate of !fain Watering (secoodary fl0re Ser-vice Dxk Width Length Sill Design Fhi.lascphy PU!ps Tilre(hrs) puips)

(m) (m) (m) (m) (m)

JAPAN (Q:ntimed)

19 Tamano N:i.1 Mitsui Zcsen O:>rp 1974 81 81 187 . 2 9 . 3 2.3 Reinforced Reinforced Ccocrete granite ffiXhi' /Hx9 9 . 5 �Tete etc.

al 01iba l'b. lA 1962 B 45.0 47.0 100.0 5.5 2.2 Reinforced Reinforced Ccncrete sand- Steel Flap 6.5 Ccncrete stcne

21 Qdba N:l.lB 1965 R 45.0 45.0 310. 0 5.5 2 . 2 Reinforced Reinforced Ccncrete sand- Steel FJ.l¥,l 114ffili' /Hx2 4 Ccncrete stcrie

� )> z 22 01iba !'b.2 1968 B 72.0 72.0 400. 0 7 . 7 2 . 2 Reinforced Reinforced Ccncrete sand- Steel Caisscn 19aX:lli' /Hx2 9 Ccncrete oo gravel lqyer stcrie

2C!)..,ll50 thick with

;:: water relief' well 'o system 0 ;z

23 Qrlba !'b.3 1973 B 72. 0 72.0 219.0 7.7 2 . 2 Reinf'orced Reinforced Ccocrete sand-

CD Ccncrete oo gravel layer' stone c ZX)...450 thick with r r water relief' well � system z � (j) Q) Q) 24 Yura N:i.l 1973 R 65.0 65.0 350.0 9.5 2 . 5 Reinforced Reinforced Ccncrete rock Steel Fl!:IP Electrical Vertical 2 . 5

Concrete oo gravel layei- Mixed Flow Putp z 0 3'.l.cx.xrr? /Ii x 3 °' CU

25 Yoko.suka Sumi tmo Heavy 1972 B/R m.o .m.o !:ro.O 9 . 2 2.0 Reinf'orced Reinfor-ced Ccncrete vecy Steel Floating � N/A Th.ial entrance Industries Ltd Ccncrete oo gravel layer- hard Q:ipalra Shipyan:l 21XJ-700 thick clay

Drained

26 Toyahaski l',ariazash.i 1977 B 66.0 66.0 380.0 10.7 2.4 Reinfon::ed Reinforced Concrete fine Aichi Zosen Ltd Ccncrete ro gravel layei- sand

Dmined

WORLD DRt rxx::KS BUILT SITO: 19::0

Ref Year Use fatrance Dock Effect- Depth Tidal Constructirn Constructicn Soil Type of fype De- R6!0l'.i<s No. Lccatirn O.i.ner or Yard in of Width Barrel ive aver range of Walls of Floor 1;ype Gate of Main (secondary

N3me Service Dock Width Sill Desigp Fhllcoopey furps prnps) (m) {m) (m) (m)

JAPAN ( Ccntir:ued) Z7 Tadotsu Hashihara 1975 B eo.o eo.o 38:).0 11. 5 3.5 Reinforced Reinforced O::ncrcte clqy

Kagawa Zosen Ltd Ccncrete en gravel l"llfer sand Drained

28 Oshirra Osaka 1975 B oo.o 00.0 53'3.0 13.0 3.3 Reinforced Reinforced Ccncrete rock Naga.51'.i Zosen Ltrl O:ncrete layer

29 � MU � 1976 B 56.0 56.0 375.0 10.15 3.3 Reinforced Reinforced Ccncrete rock Steel Flap Vertical spindle 2.5 2 No. VS::: purrps N::>. l Ccncrete o.an thick on axial flON purps lo:xni' /H

� 0.5n thick gravel layer 23CXXhi' /Hx3 ;r:. Drained z 0 21) Nagasaki 1965 R 56.0 :'6.0 375.0 10.15 3.3 - ditto- -ditto- rock -ditto- Purp in camon 2.5 in crom:n

f'b.2 with above dock with above

?:: 'o 31 � 1900 R 38.8 41. 0 276.6 9.33 3.3 Ccncrete Ccncrete 0.94m thick rock Steel caisscn Vertical spindle 4.0 1 [b. vs:: purrp 0 N::>. 3 l .2m thick oo gravel pU1p 48)if /H. Si.lb-� �

1 purrp Cl! l purrp roil' H c r-

32 Koyagi 1972 B 100.0 100.0 790.0 11 .65 3.3 Reinforced Reinforced Ccncrete rock Steel caisscn Vertical spindle r- 9 . 5 3 No. VSA purrJS !!l No.I crncrete 1 . 5n thick en axial flow PLJTPS lo:xni' /H z O. Sn thick gravel layer ro.cmrr /Hx3 � <O � thick Cl> Cl> Drained

z 33 Koyagi 1973 R 100.0 100.0 400.0 11 . 65 3.3 Reinforced -ditto- reek Steel flap Vertical spindle 3.5 2 No. VSA ptrnpS 0

ccncrete axial flow puips 2(XXhi' /H (l) U> O.Em thick 40. CXXhi' /Hx4

34 Konnuku �HI Yol<oharra 1003 R ::0.8 !'0.8 332.6 8.84 2.0 Reinforced Reinforced Ccncrete clqy Steel flap Vertical spindle 2.0 2 No. VSA pl.JlpS ccncrete 1.an thick oo gravel axial fl<M pu!pS lo:xni' /H 0.5n thick layer Drained

35 1003 R !:D.8 !:D.8 57.4 8.84 2.0 Reinforced Reinforced Ccncrete clay Gate in Purps in cam= 2.0 Purps in camon ccricrete 1. an thick on gravel cmm:n with with above with above a. Sn thick layer Drained above

)>

JAPAN ( c.:ntirued) :06 Homuku M:Il Yokoharra

31

38 K1.m31roto !'b. l Hitachi :&sa1 :u Prof Nagaik Corporaticn

;i. Ariak� z � ;i>- 39 No.2 'o 0 40 Sakai !'b.l Hitachi Zasen � Osaka Corporaticn

Osaka \llarl<s Ol c ....

41 !'b.2 .... m ::! z � "' Q) Q) 42 !'b.3

1 43

z 0 °' "' Innoshima Hitachi Z.OSen

Hi.rcsh:ima Carporatioo Jlb.3BD Innoshima Works

llEN'iA

1972 R ro.o

1005 R 30.0

1973 ? 85.0

1973 ? 85.0

1966 B/R !"X>.O

1972 B/R 62.0

1900 B/R 100.0

1965 B 45.0

ro.o

30.0

85.0

85.0

56.0

62.0

100.0

45.0

app 26

270.0 9.85

100.0 10.7

620.0 10.8

:ni.o 10.8

400.0 7.8

455.0 7.8

lZl.O 9.3

227.25 11.3

app 7.em

WJRlIJ DRY JXC'i<S BUILT srra: 1900

2.0 Reinfoixed Reinforced O:::ncrete ccn::rete l.Qn thick en

gravel layer

2.0 Steel sheet Reinforced Coocrete piles l. cm thick oo

gravel layer

4.7 Reinforced Reinforced Ccncrete 600-:nl 600-:nl on gravel thick and layer Drained steel sheet with water relief piles well system

4.7 -ditto- -ditto-

0.3 Reinforced Reinforced Coo::rete ccncrete an-2.an thick with 2.lrn thick gravel lqyer

Drained 0.3 -ditto- -ditto-

0.3 Slcping !'nrm asphalt en earth s:om. crushed

grenite 3.5 Re:infoixed Reinforced Ccncrete

en gravel en 12JO..-1300 thick Drained

3.&n Reinforced ccn-- Reinforced cxncrete crete 0.5-0.?m 0.&-0.9;n thick thick tied with tied with Macalloy M9callqy bars bars

clay Steel flap

cla.y Steel flap

clay Steel caisson

cla.y -ditto-

clay Steel flap

clay -ditto-

clay Steel caisson

silty ? clay & sand over dock

Ge-rented sands/coral over fine medl=e sandstcne

Purps in crnm:n 2.0 Purps in =m:n with above with above

Vertical sp:indle 2.0 1 No. VSA purp aidal fle>N purps l<XXlli' /H l!'lX'Oii' /Hx2 Electric vertical 10 flcm 3'.l. <XXlli' /HJ<2

-ditto- 6

Electric vertical 4 centrifugal 25. <XXlli' /HJ<2

Electric vertical 3

� )> z p � "O h ;z

OJ c r r m -I z ..... <O °' °'

z 0 "' "'

)> ...... (Jl

!Ref !lb. locaticn

Ml\LAYSIA

Johore Bahru

MALTA

Valletta N::>.6

r.rnrrro

CMner or Yard Nane

\\'alaysia Shipya..-U

fiEl ta Drydocks

Ciudad ltadero

Veracruz

MIIDIB EAST

Dubai Dubai Dry Dock Co. Dock No.l

Dubai Dubai Dry Ikx:k Co. Dock No.2

Dubai Dubai Dry Dock Co. Dock N::J.3

Bahrain f.sry

Year Use in of

Service Dock

R

B

R

R

R

�})Rill DR'I' rxx::KS BUILT SIN:E: 19:0

Entra.'1Ce Dock Effect- Depth Tidal Ccnstructioo Constructia; Soil 'fype of 'fype Re<narns Width Ba.""rel ive over t"dllge of Walls of F1oor type Gate of Main ( sc-ccndary

Width Sill Desigp Fhil�hy Purps pwps) (m) (m) (ml (m) (m)

8'.) 385 14 Flap gate

62 65 ?BJ 9.2 17 .46Jt/hx3 lcrot/hx2

'37 249 9.0 Anchored steel Reinforced ccoorete Floating at M5L sheet piling o.an thick i. 7m thick steel

and steel under keel strip caisson sheet piled - Drained caf'ferdam

36 36 269 5 . 7 M3!;s coocrete Gravity Floating 3 N::>. at MHW walls steel in line

caissa; sumersible

66 '370 2.28 Reinforced ccn- Reinforced ca;crete Rock l?rq)ped 5 No. vertical crete caissons 1. 511 thick steel mixed flow pUtpS

- Drained flap gate to serve all docks arranged in tv.o purplxA.lses

100 525 2.28 Reinforced cm- Reinforced coocrete Rock l?rq)ped crete caissons 1 .511 thick steel

- Drained flap gate

eo 415 2.28 Reinforced cm- Reinforced ccncrete Rock l?rq)ped crete caissons 1 .511 thick steel

- Drained flap g;ite

75 Reinforced Reinforced ccncrete concrete - Dra.ined

:J> .... Ref Year Use Entrance Dock Effect- Depth Tidal Constructioo Constructioo Soil Type of Type De- Renarks O'> l'b. Location e>.ner or Yard in of Width Barrel ive over range of Walls of Floor type Gate of M3.in Watering (secondary

Name Service Dock Width Sill Desigp fhlla;qIDy PL1!ps Till>3 (hrs) purps) (m) (ml (m) (m) (m)

ffi:JllERLAN) ANl'Il..llS

Curacao Curacao Dry Dock 1971 47.70 48 200 8.5 • 5 Reinforced Reinforced ccncrete weathered Hinged 3 l'b. vert • 3 Caip. Inc. ccncrete - Drained rock floating 12,crot/h

t£JlERLN'1[6

� Den Helder Dutch Royal Navy 1978 R 23 153 9 Reinforced Reinforced coocrete soil Hinged floating Covered dcrJ< )> coocrete - Gravity desilir! :iJlprove- caisson for frigates

z ment med

9 ) 3 !'b. vert. ) Purp r=n Sloe- Kon rt11 "De Schelde" 1961 R 24 25.3 175 6.5 3 Reinforced Reinforced concrete sand Steel flap

� Vlissingen Dock I ccncrete - Gravity d� ) spindle ) for

'u ) 10,crot/h ) 2 docks h Sloe- Kon "1Y ''De Schelde" 1961 R 29.5 29.00 215 7.6 3 Reinforced Reinforced coocrete sand Steel flap ) ) � Vlissingen Dock II ccncrete Gravity desigp. ) )

Vlissingen Kon �1Y ''De Schelde" 1975 B/R 22 22 2)4 5 Steel sheet Reinforced ccncrete mixed Hinged Covered dock to Navy dock piles with coocrete piles floating for frigates c: r caisson r

gi z Schiedam Dok-en Werf- 1955 R 28.35 31 . 5 211 9 . 5 3 Reinforced Reinforced ccncrete mixed ) 3 l'b. 2 ) Purp r=n � !10atschappij ccncrete - Gravity desigp ) horiz ) for <O "' Wilb::n-Fyenoord NI/ caisscn ) cmtrif. ) 2 docl<S "'

Dock 6 ) 12,cx:ot/h ) z ) ) " Schiedam Dok-en Werf- 1956 R 28.35 31. 5 216.4 9 . 5 3 Reinforced Reinforced c=rete mixed Hinged ) ) &l M:latschappij ccncrete - Gravity floating ) )

Wil b::n-Fyenoord NI/ caisson Dock 7

Schiedam Dok-en Werf- pre '66 R 47.3 tl9 305 9.4 3 Reinforced Reinforced concrete sand 3 l'b. puirps 2 M3atschappij coocrete 6. 211 thick ancrored and 25, roJ t/h each Wil in'l-Fijenoord with sheet to precast ccncrete gravel N.V. Dock 8 piled backing piles

RosenbJrg Verolmz- 199'3 B 43.5 297.0 app 3 Reinfon:;ed Reinforced coocrete Hinged floating (Scheur) l'b. 4 5.0 cmcr-ete 2.0-6.&n thick caissoo

at M3L min. wall - Gravity desilir! thickness 2. Qn

�JJRlD 00\I ro::l<S BUILT SIN:::E 1950

f Year Use Entrance Dock Effect- Depth Tidal Coostruction Coost:ruction Soil Type of Type Rerrarks !'b. 1=ation CMner or Yard in of Width Barrel ive over range of Walls of Floor type Gate of M3in (seccndary

Narre Service Dock Width length Sill DesillP Fhlloscphy Puaps pl.ITpS) (m) (m) (m) (m) (m)

Ml:'� ( Ccnt:inJej)

Rosenburg Verolme- 1962 R 36.0 230.0 app 3 Reinforced Reinforced cc:ncrete Hinged (Scheur) l'b.5 8.0 a:ncrete 4.0-6.0n thick floating

at MSL - Gravity desillP caisson

Verolme- 1962 R 41.0 274.0 app 3 Reinforced Reinforced concrete Hinged ll.O concrete 4. 0-6. On thick on floating

at MSL crnpression piles caisson - Gravity desillP

� Verollre- 1971 R 90.0 410.0 3 Reinforced Reinforced cc:ncrete Hinged ;i.. Rosenburg app z (Scheur) !'b. 7 12.0 crocrete app 3.0n thick steel floating 9 at MSL app 3.0n teision/carpressim caisson

thick piles

� 'o h Harlingen Frisian Dockyard 19:)7 B 30 30 145 6 2 Steel sheet Reinforced concrete sand � piles

OJ c Amsterdam Nether landsche Dock 1956 R 36.6 39.50 245 8.4 Reinforced Reinforced coocrete sand • en Scheepsba.!\\l- concrete app 5.0n thick •

m -i maatschappij - Gravity desillP z � '° 00 00

z 0 O> N:BJIM w

Stord Steel arch sliding g;ate

Kristiansand R 30.5 210 9 :?% Kristiansand R a:J.4 137 6.3 2

il.Olll.D DRY lXJCKS BUILT SIN:E 1900

)>

..... OJ Ref Year Use Entrance Dock Effect- Depth Tidal Constru::tim Constructicn &:>il Type of Type De- Renarns

!'b. Lcx:aticn Ov.ner or Yard in of Width Barrel ive over range of Walls of Flcxr type Gate of J\Bin Watering (secondary Name Service IJcck Width � Sill Design Fhilcscphy PUips Tirre(hrs) puips)

(m) (m) (m) (m)

P.AKISTAN

Karachi Pakistan Irrlustrial 1959 R 27.4 27.4 190.8 7.8 3.0 Reinforced Reinforced caicrete fine St.eel floating 3 !'b. propeller 2Y, 2 !'b. bilge DevelO[l'le'lt Corp. at ccncrete 1.2- l. 8n thick with sand caissm purps purps !'b.l IJcck MM 3.an thick prestressed anchors 6, 6Xl t/h each 3rot/h each

!'b.2 IJcck 1971 R 24.33 24.38 170.70 7.2 3.0 Reinforced Reinforced ccncrete fine Steel floating at M-111 o::ncrete min l . 511 thick with sand caisscn

prestressed anchors

� )> z 0

i:: 'o b

roLAJI[) � Gydnia Centroror'-lhl ted B/R 42.5 239.3 7.1 Reinforced Reinforced ccncrete sand/ Steel flap 2 !'b. purps 4

Shipyan:ls cooc:rete 2.8-4.an thick cley 7 ,200 t/h each CD 3.6m thick - Gravity c .-.-m -i Gydnia Centrarol'.'-lhi ted B 70 38'.) 7.1 Steel sheet Reinforced o::ncrete sand 8 l'b. puips 8 z Shipyards N:J. 2 IJcck piling with l. 7-2.411 thick 3,a::o t/h to .... "' relieving - Drained 6,100 t/h each 00 00 platform/

gallery z 0 "' "'

WJRlll DRY ro::KS BUILT SIN::E 199:>

Ref lib. Lxaticn 0...ner or

Name

f1:RlUll\L Lisbm Lisnave 1970 B 54.0 54.0 300 7.55 3,30 Reinforced Reinforced ccncrete miocenic Steel caisson 3 vertical spindle 4 2 filter purps Tagus f'b.10 Dock ccncrete floor slab 0.911 thick silt hinge:! self purps lfilXl nf /H estuary walls o,ron and keel beam; under'- clay prcpelle:l each

thickness floor drainage and r.ccric-rete gravity wall£ O,OOn thickness

:0 Lisbm Lisnave 1967 R 54.0 54.0 350 11.70 3.30 Reinforced Reinforced coricrete miocenic Steel flap 3 vertical spindle 2.5 2 filter purps )> Tag.is No.11 Dock o:ncrete floor slab .911 thick silt purps lfilXl nf /H z esruary gravity and keel beam; under clay each 9 walls LOO floor drainage

and 3.COOn

;::: thickness 'u h Lisbm Lisnave 1967 R 42.0 54.0 263 11.70 3 . 30 Reinforced Reinforced cmcrete miocenic Steel flap 2.5 2 filter p.rrps z TagL1s !lb.12 Dock ccncrete floor slab .911 thick silt

estuary gravity and keel beam; under clay Cl walls 1 . 00 floor drainage c and 3.00n r r thickness m -i z

Lisl:x:n Lisnave 1971 R oo.o 97.0 5.3:) 12.00 3.30 Reinforced Reinforced ccncrete miocenic Steel flap 3.0 2 centrifugal � "' Tagus [lb.13 Dock ccncrete floor slab . 9n thick silt filter purps "' "' estuary b.rttresses and keel l:ica-n; under clay 15'.X) nf /H each and meta.lies floor drainage

z gabicns 0 m VJ Setuba1 Setenave 1974 B 75.0 75.0 420 6.50 3.10 Reinforced Reinforced ccncrete hydraulic Re<rovable 3 SJRK vertical 2 KSB

Sado l'b.2:) Dock concrete slab and keel bo..an sand iretalics 2000 each estuary walls l .2:ln over reclalined area fill plus 2 KSB

and .70n (sand) purps l::a:J nf thickness each

Setubal Setenave 1974 R 75.0 75.0 4::0 6.::0 3.10 Reinforced Reinforced ccncrete hydraulic Steel flap 3 SORK vertical 2.5 2 !<SB PLl1PS Sada l'b.21 Dock (17) ccncrete slab and keel beam sand spindle purrps 2000 ii /H each estuary with over reclaimed area fill 3EOX> nf /H each plus 2 KSB

l:uttresses (sand) purps l:>:X> nf /H each

SeUJbal Setenave 1974 R 55.0 55.0 3::0 10.00 3.10 Reinforced Reinforced ccncrete hydraulic Steel flap 3 s:lRK vertical 2 KSB purps Sade l'b.22 Dock ocncrete slab and keel bean sarrl spindle purps 2000 nf /H each estuary with over reclaimed area fill 3SXXl nf /H each plus 2 KSB

buttresses (sand) purps l::a:J )> nf /H each ..... CJ:)

1/XlRl.D Dffi' OCCKS BUILT SIN::E 19&>

)> Ref Year Use Entrance Dock Effect- Depth Tidal Ccnstructicn Ccnstructicn Soil Type of Type De- Renarl<s I\) l'b. Locatiai Owner or Yard in of Width Barrel ive over range of Walls of Floor type Gate of M3:in Water:ing (seccndary 0 tare Service Dock Width J..ength Sill Desi!lTl Philosq:ihy PuJps Tlire(hrs) purps)

(m) (m) (m) (m) (m)

SilG\IUlE

Tuas Keppel Shipyard Ltd R 52 52 3)2 9 2.4 Reinforced ccn- Reinfol'Ced ca:icrete Steel 3 Jib. mixed flo.< 21; Tenasek Dock at MSL crete with 0.8-l .2m thick flap pu!pS z:m'.)t/h

ccunterforts - Drained gate eoch

Tuas Keppel Shipyard Ltd R 00 335 9.4 2.45 ReinfOl'Ced ccn- Reinforced ca:icrete dense Steel 3 lib. Rafiles Ib::k at �l:!JB crete 0.3-0.55 0.8-l .65n thick clayey flap

thick with - Drained silt gate ccunterforts

� Sanbawang Sarbawang Shipyard Ltd 1975 R 64 65 384 8.0 Reinforced Reinforced o:ncrete Steel Centrifugal )> Prenier Ib::k at ll'fMS z

ccncrete piled floip

p Serbawang Seibawang Shipyard Ltd 39.6 42. 5 � 13 ll'ass ll'ass caicrete Steel Centrifugal

� King George VI Ib::k at !II-MS o:ncrete caissm 'u b Singapore Slipwey 1982 R 20 20 lCO 3. 5 2.2 Sheet piled Reinfol'Ced ccncrete rrat"ine Steel 4 No. Flygt � ;z & Engineering Co (Pte) Ltd at MSL with relieving 0.92511 thick m clay flap sulmarsible puiµ;

platform steel piles - drained gate

OJ c: r r Tanjcng Hi tactii Zcxsa1 R 00 00 35 6.0 Efl.s:Dt/h totru a:mt/h total � Qil ROOin DockYard (Pte) Ltd at LIJil z -' Channel "' co co Mitsubishi Singapore R 00 00 300 9.0 Steel 35. crot/hx3 2Y, lcrot/hx:2

Heavy Industries ( Pte) Ltd flap z gate 0 °' (.:>

Jtll'.'CXlg JUl:"Q:lg Shipyard Ltd R � 56 3:0 5.64 39.9COt/h total at Ll.Jil

\\QRUJ DRY IX:CKS BUILT Sm::E 19:0

Ref Year Use Entrance Dock Effect- Depth Tidal O::nsb:uctioo Coos1nlctioo S:lil 'fype of' 'fype De- Ranarl<s l\b, Locatioo CJl..ner or Yard in of Width Barrel ive over range of Walls of Floor type Gate of Main Watering (seccndary

Narre Service Ilock Widlh Length Sill Design Fhilo;opcy Fl.Jrps Time(hrs) puips) (m) (m) (m) {m) (m)

IDJlH l«llEA

Okpo Da.."'VXJO Shipbuilding & B 131 131 529 Reinforced cm- Reinforced cmcrete rock Steel inverted 4 vertical mixed Heavy Machinery Ltd crete CDlll1ter- o.s-1.an thick 'T' floating flow puips

forts - Drained caisson

Daew:io Shipbuilding 1983 B/R 81 81 3!50 10 Reinforced coo- Reinforced ccncrete rock Steel inverted 4 & Heavy M3ch:inery Ltd at M:iL crete 0.45-0.fm 0.8- 'T' floating

thick with - Drained caisson OOJnterforts

Ulsan N:>.4 Hyundai Shipbuilding & B/R :B Ee 2SJ 8.0 4

� Heavy Industries Co Ltd

)> l\b.3 B/R 92 92 00'.) 8.7 40.o:Dt/h total !'kD'.)t/h total z

p

!'..'. 'o h z

SPAIN Ol cadiz 1975 R 55.6 386 12.0 Reinforced con- Reinforced coocrete Steel flap 4 No. c: r at M3L crete caissons - Drained gate 24,CX::O each r gj ( Strutte:l) z "' El Ferrol l\stilleros del 1969 B/R 36 :'>/.00 254 Chart D Reinforced con- Reinforced cmcrete sandy Steel flap Electric vertical CD

l\broeste SA -8.48 crete gravi t;y gravi t;y 5. ::on silt gate 3 side spil'.'dle centrifugal CD dam 4.0J:n with boulders slate bearing pt.rrpS

z " "' "'

ERI LAN<A

ColClltx) Colaitxl Dockyard 1985 R .a3 44 263 48.5 0.77 Reinforced cm- Reinforced ccncrete rock Steel flap 3 N:J. vertical <% Ltd at LW crete 0.5n thick 0.5-1 .lm thick gate mixed flOll purps

with counter'- - Drained 14,CXXl t/h each forts

\\ORl.D DRY DXKS BUILT Sil'O!: 19::0

)>

I\) I\) Ref Year Use Entrance Dock Effectr- Depth Tidal Ccnstructicn Ccnstructioo Soil Type of Type De- Re1Erl<s

lib. Locatioo Ol!.ner or Yard in of Width Barrel ive over range of Walls of Floor type Gate of !lain Watering (secoodary Nooe Service Dock Width Length Sill Desi!?}'l fhilcsophy fu!ps Tbre(hrs) purps)

(rn) (rn) (rn) (ml (rn)

�

Uddevalla lkldevallavaret AB 100 400 Rock with cm- Reinforced concrete i.=k Steel crete prctectioo 0.35n thick Floating

- Drained caissoo

Kockurs �ooiska 75 405 9 Steel sheet Reinforced concrete bculder Verl<smi« AB piling with o.an thick cley/

relieving Drained with grUJt rrerl platform injectioo belcm

� )> Gothenburg Aredal Shipyard z 9 � Gothenl:urg Eriksberg 65.2 381.9 Rock with thin - Drained reek

"1) concrete CJ coating z

CD c r-r-� z '.lHAILAN) .... co O:> Bang}<ok Royal Thai Navy 1981 22.5 118.3 Steel sheet c.oncrete Um thick Steel Flap gates 1Y, O:>

!Xlckyard piles with with anchors with buoyancy

z 2 l\b. Docks concrete t.q:J clarbers hinged 0 at floor a> ....,

� )> z p ;:: 'o h ;z

Ill c r r m -i z � (j) GO GO

z 0

°' "'

)> [\) (;)

Ref !'b.

1

2

3

4

5

6

7

8

9

U:>cati01

lM'lEJ KThtD'.ll! 1'bM:h Shields

Newcastle (Wallsend)

South Shields

Falm?uth

Inminghool

Jarrow

Hebbum

Greencck

Belfast

Year Use Owner or Yard in of

Naire Service Dock

Smith's Dock Co Ltd 1954 R No.8 Dock

Swan H..tnter and 1995 R Wigtiam Rich--mlson Ltd. lb.4 Dock

Brigtiam & Ccmar1 19"6 R

Fa.1.m:uth Dock and 1958 R Engineering Co Ltd

H..m:>er D:lck and 1960 R

Engineering Co Lt.cl

The �tarcantile Dry 1960 R D:lck Co Ltd

Vickers ._. ..... . 't> 1962 R (Sf>;'.'" '' ' -'�-::; Ltd l'b.2 Dock

.Firth of Clyde 1964 R Dry Dock Co Ltd

Harland & Wolff 1968 R

\\OOID DRY D:Xl<S BUILT SIN:,'E 19::0

Entrance Dock Effect- Depth TI.dal Ca:istructim Constructicn Seil 'fype of 'fype De- Remarks Width Barrel ive over range of Walls of Floor type Gate of Main Watering (secondary

Width Length Sill Desi@'I fhllosq>ey Purps Time(hrs) purps) (m) (m) (m) (rn) (m)

29.0 2-0.5 216.l 8.2 4.6 Sheet piled - Reinforced crncrete boulder Steel flap 2 No. electric horizontal 3 3 l'b. ancillary at slq:>e 20:1 1 .8 - 3.&n thick cley gate-190t spindle centrifugal p.mps p.mps 0.3m dia

!IHllS Gravity 10,00J t/h each 32.0 34.7 217.9 8.8 4.6 Reinforced Ccncrete 3.1 - 4.'.h boulder Steel flap 2 lb. electric horizontal 2Y, 3 l'b. ancillary

at concrete thick - Gravity clay/ gate spindle centrifugal purps puips 0.3m dia !IHllS 3.&n thick sand 14,400 t/h each

28.9 28.9 217.9 6.4 4.6 !'recast C01Crete Reinforced crocrete boulder Steel flap 2 lb . electric vertical 4Y, 2 lb. ancillary buttresses with 1 . 1-1.:ln thick with clay/ gate spindle centrifugal pLUpS purps 0.3TI dia insitu concrete H pile anchors soft 6,8XJ t/h each between - Tied sand

39.6 39.6 289.0 11.0 Reinforced cuic- Moss coocrete reek Steel flap 3 lb. double entry, single 2% at rete o.an thick awrox l.lm thick gate-s:::ot stage, split casing,

Mi.I'S with reek anchors - Vented vertical spindle, centrifugal purps 14,400 t/h each

27.4 29.9 182.9 6.7-* Reinforced ccnc- Coocrete 4.lm thick sand/ Steel flap 2 lib. h:rizootal split 3'i:i *�ding en level 8.2 rote 3.an thick reinforced under gravel gate casing centrifugal purps in >.et deck ccl:side

keel strip-Gravity 6,8Xl t/h each 3 1'b. • 3TI dia ancillary purps

25.9 28.3 182.9 7.2 4.6 Steel sheet liass concrete boulder Steel flap 2 No. horizontal split 3Y, 2 tb • • 3m dia at piling with 3.fm thick cley gate casing centri:fUgal puips ancillary pt.rrpS

!IHllS relieving Drained 6, 8X) t/h each platform

44.2 44.2 2!'B.1 10.7 4.6 'lied re:inforced Mass ccncrete cley Steel flap 3 Jib. vertical spindle 2Y, at cmcrete 1 . 7m 7.3m thick over gate axial flCM purrps

M-!IB thick Gravity sand 548t 18, 3::0 t/h each 44.2 44. 2 a:i4.8 8.2 3.1 Re:inforced crno- Ccncrete O.&n thick reek Steel flap 3 l'b. vertical prr,peller

at rete 3.lm thick l.lm thick under gp.te-5'Dt type 23,Z:O t/h each 2Y, MlllJS keel strip-Drained

:D.3 9'.l. 9 335 11.6 3.9 Steel sheet Reinforced ccncrete clay Steel flap 3 No. electric vertical 3� 3 !'b. ancillary llHiB piling with 3.l-\3.4n thick with gate-647t spindle axial DCM purrps purrps lcm t/h each

relieving grcund anchors and 28, Ero t/h each underfloor clra.inage platform pressure relief drains =54 t/h approx

!i.ORlll DRY J:)XKS BUILT SIN:E 19:0

)> f\) !Ref Yli>.ar Use Entrance Dock Effect- Depth Tidal Ccnstructirn Constructirn �il Type of Type De- R� .i::. l'b. I=atirn o...ner or Yard in of Width Barrel ive over range of Walls of Floor type Gate of Main Watering (secc:ndary

l'hre Service Ikx:k Width Length Sill Design Fhilceqol\)I Purps Ti!T>2(hrs) purps) (m) (m) (m) (m) (m)

UNITED KINGDOM (Continued)

10 Belfast Harland & Wolff 1969 B 93.0 93.0 556 8.38 3.9 Reinforced crnc- Reinforced ccncrete clay Steel 2 l'b. vertical spindle 12 2 lb. underfloor at rete L rn steel 1.8-2.311 fuick en caisscn electrically driven drainage pU1ps 135

Mi;/$ piles-Headwall drained broken mixed flCM pu1pS t/h each. 3 l'b. tied reinforced rock fi 11-Drained 20. 5'.Xl t/h each dock floor puips ccncrete HID t/h each

11 Nigg Bay Bro-.n & Root + 1974 B* 122 176 305 13.5 4.6 Slq:iing 1 :1 :5 Crushed granite sayj/ Concrete 4( +4 standby) 217 *far offshore George W:i.npey & bi tuiai sand sand- caisscn 2Xhrn Flygt pU1pS structure Co Ltd covered stale

:0 12 SUnderland Sunderland Ship- 1975 . B 49 :o.o 181 5.47 4.4 Precast crnc- Reinforced ccncrete lime- Steel 2 l'b. 24" vertical Covered deck

� builders Ltd at rete panels, 0.22511 thick stale caisscn axial flCM pu1pS z Pal.lien JIH>IS wal:ings and - Drained !:"> colums

- Drained � 13 Birl<.enhead Cannell Laird 1961 R 42.7 45.l 289.6 10.3 9.2 Rock (0.15-n thick ccno- sayj/ Sliding 2 l'b. harizcntal shaft ,, h (Shiprepairers) Ltd at (as excavated) rete with 0.45 thick stale steel centrifugal purrps � Princess Dry Dock llf'f;B keel strip caisscn 24,:oJt/h each

- Vented cn ciro-ular tra:k Ill c: r 14 Devooport Ministry of Defence 198J R* 21 147 approx Reinforced ccno- 'Ihin reinforced rock Steel flap 2 l'b. ** 4 * Sul::rnarine refit r m 14 Dock lQn rete 1.25-n cx:ncrete Drained gate (ll ,3:0t/h ea:h) ** l?\.IJpha.lse serves -i

z 15 Dock thick 1>.1 th 1=k up ties ( lOOt) both docks -(.0 ()) 15 Stmderland T W Greenwell & Co 1952 R 26.7 28.6 205.7 8.3 4.5 Reinforced cooo- Reinforced ccno- rock Steel flap furphcuse for l'b. 2 1% ()) Ltd. No.l Dry Dock at rete 1. 2-4. 3n rete 1.4-1. :rn gate deck used

z Mi\$ - Drained - Drained 0

"' <.:> 16 Swansea Duke of Edi.nbu:rWi 19$ R 28 2:)4 6.4 Reinforced cone- Reinforced ccno- cx:ncrete Caicrete (Siared p.npha.ise) 2Y, with ship Dry Dock at rete rete - Gravity caisscn in d::x;k

llORLD DRY DOCK BUILT SlllCE 1950

Count ry : U .S . A . Sheet l o f 3

REF YEAR USE ENTRANCE DOCK EFFECT- DEPTH TIDAL CONSTRUCT! ON C O!lSTRUCTI Oil SOIL TYPE OF TYPE OF DE- REHARKS NO. LOCATION OWNER OR YARD Ill OF WIDTH BARREL IVE OVER RANGE OF \/ALLS OF FLOOR TYPE GATE MAIN PtmPS WATERING ( SECO!IDARY)

NA.ME SERVICE DOCK WIDTH LENGTH SILL DESIGH PHILOSOPHY TIME PUl!PS) (m) (m) (m) (m) (m) (HRS)

l Bangor U . S . Navy 1981 R 32 .07 27 .43 2 18 . l 16 . 16 3 .05 Reinforced Concret e , Reinforced Concrete , Sand Floatill8 3-Electric Driven, 2 .75 2-Electric Washington TRIDENT \/EST Varies from 4 .87m 4 .87m to 5 . 79m, and Caisson, 54,000 GPM, Driven,

Refit Facility at Floor to 2 .74m Gravity Type , Gravel Rectall8ular Mixed Flow, 2 , 500 GPM at Service Gallery Soil Supported Box Type, Vertical

Steel

2 Charleston U . S . Navy Rebuilt R 32 .31 28.35 176 .8 1 1 . 46 l.07 Reinforced Concret e , Reinforced Concrete , Marl Floatill8 2-Electric Driven, 2 .75 2-Electric SC Charleston 1968 varies from 3 .28m l . 22m und er Keel, Caisson, 83 ,000 GP!l, Driven,

Naval Shipyard at Floor to 3 .20m Partially Relieved Rectall8ular 48" , 550 HP 2 , 000 GPf.!, DD#2 at Copill8 Soil Supported Box Type , 8 " , 250 HP

Steel

3 Charleston U . S . Navy 1964 R 40 .24 33 . 69 193 . 6 ll .28 l .07 Reinforced Concrete , Reinforced Concrete , Marl Floatill8 3-Electric Driven, 3 2-Electric SC Charleston 3 .35m 2 .74m under Keel, Caisson, 65 , 000 GPM, Driven,

Naval Shipyard Partially Relieved , Rectall8ular 42" , 700 HP 10 , 000 GPH, DD#5 Soil Supported Box Type , 14" , 150 HP

Steel

4 Norfolk U . S . N avy Rebuilt R 2 9.57 23 .28 148 .4 ll.37 0.85 Reinforced Concret e , Reinforced Concrete, Sand , Floatill8 1-Electric Driven, 2 .7 5 2-Electric Virginia Norfolk Naval 1966 Sloped , 5 .Sm at l . 06m und er Keel, Clay Caisson, 45 ,000 GPM, 42" , 600 HP , Driven,

Shipyard Floor to 4 .89m at Partially Relieved,. and Recta!J8ular 1-Electric Driven, 4 , 500 GPM, DD#2 Copill8 Pile Supported Shells Box Type , 50,000 GP!l, 42" , 600 lil' , 12 " , 125 HP

Steel 1-Electric Driven, 96 , 000 GPH, 42" , 800 lil'

5 Philad elphia U . S . Navy Rebuilt R 26 .04 23 .26 131.7 8 .41 l .70 Reinforced Concret e , Reinforced Concrete , Sandy Floatill8 2-Electric Driven, l . 5 2-Electric Pennsylvania Philad elphia 1956 0 .9lm et Floor, 0 .762m under Keel, Clay Caisson, 34 , 000 GPM, Driven,

Naval Shipyard 0.4lm above alter, Fully Relieved , Rectall8uler 36 " , 500 HP 7 , 500 GPf.!, DD#l 2. 9m et Copill8 Pile Supported Box Type, l6" , l25 HP

Steel

6 Kittery U . S . Navy Rebuilt R 23 .78 18 . 9 148.3 ll.28 2 . 44 Reinforced Concrete , Reinforced Concrete, Bedrock Floeti!J8 2-Electric Driven, 2 2-Electric Maine Portsmouth 1962 l . 92m 3 .54m, Gravity Type , Caisson, 30,000 GPM, Driven,

Naval Shipyard Rock end Pile Rectall8uler 36 " , 350 HP l , 500 GPM, DD#3 Supported Box Type, 8", 40 HP

Steel

7 Bremerton U . S . Navy 1962 R 5 2 . 5 9 5 4 . 88 35 1 .2 16.23 3 . 29 Reinforced Concrete , Reinforced Concret e , Sand Floetill8 4-Electric Driven, l . 5 3-Electric lleshill8ton Puget Sound Column Support ed , 2 . l3m, end Caisson, ll4,000 GPJ.I, Driven,

Naval Shipyard 3 .66 et Floor, Fully Relieved , Sandy Rectell8uler 54 " , 1 , 500 HP 15 , 000 GPM, DD#6 8 .84m et Copill8 Soil Supported Gravel Box Type, 20" , 400 HP

Steel ?. '!{O"t:i \:

8 Sturgeon Bey Ship- 1976 B/R 42 . 68 42 . 68 353 7 . 92 l .28 Reinforced Concrete , Reinforced Concrete, Coarse Hill8ed 2-Electric Driven, 7 . 5 2-Electric Bay, Wi s . buildill8 Corp. Sloped 0. 9lm to 0 .76m, Send Gate, 28 , 000 GPM, Driven,

0.305m Fully Relieved, and Steel Vertical 2 , 000 GP!-!, Soil Supported Gravel Vertical

Notes: B•Bui ldill8; R•Repeir ; B/R•Bui lding and Repair

This information is taken from existill8 documentation which is approved for Public Release end is in the Public Domain.

WORLD DRY DOCK BUILT SINCE 1950

C ountry : U .s .A . Sheet 2 of 3

YEAll USE EJITRANCE DOCK EF - DEPTH TI DAL C OIISTRUCTI O!i C ONSTRUCT I Oll SOIL TYPE OF TYPE OF DE- REMARKS LOCATI O!I OWNER OR YAllD Ill OF WI DTH BARREL I OVER RANGE OF WALLS OF FLOOR TYPE GATE MAll! PUMPS WATERil!G ( SECOllDARY )

NAME SERVICE DOCK WIJJ.l'H L SILL DESIGN PHILOSOPHY TH!E PUJ.IPS) (m) (m) ( (m) (m) (HRS)

9 Sparrows Bethlehem 1971 B - 45 . 43 329 . 5 7 . 36 0 . 335 · l . 67m Diame t e r , Reinforced Concrete , Unknown Floating 2-Electric Driven, 18 )-Electric Point , MD St eel Corp . Prestressed 1 . 22m, 17 , 800 GPM Driven ,

Cylind e r Fully Relieved , 1 � 3 . 50 0 GPH C oncrete "�� -:::;:;, Piles Soil Suppo rted Box Type ,

St eel

10 G roton DD#l, General 1963 B/R 2 1 . 03 22 . 17 1 5 9 . 6 10 . 15 0 . 914 Sheetpile C ells, Reinforced Concrete , Bedrock Hinged Gat e , 2-Electric Driven, 3 . 5 4-Electric Connecticut Dynamics , Filled with Sand 0 Steel 5 0 , 000 GPM, Driven,

Elect ric Boat and G ravel Fully Vertical 2 , 00 0 GPM, Division I Soil Supported Vertical

l l Groton DD#2 , General 1968 B/R 2 6 .85 2 9 . 167 190 .85 9 .75 0 . 914 C el l s , Reinforced Concrete , Bedrock Hinged G at e , 2-Electric Driven, 5 4-Electric C o nnecticut Dynamics, with Sand 0 . 914m Steel 3 0 , 000 GPM, Driven,

Electric Boat and G ravel Fully Relieved , Vertical 2 , 000 GPM, Division Soil Supported Vertical

1 2 G roton DD#5 , General 1977 B 3 3 . 91 2 9 .42 188 . 2 1 1 . 7 0 . 914 Sheet}'ile C ells Eart h , Floating Bed rock Floating 2-24" Air Lift 92 1-12" Air Connecticut Dynamic s , Cofferdams, Platform within Caisson, Pump s , 8000 GPM Lift Pump ,

Electric Boat 1 9 . 83m Diamet er, Super-st ructure Rectangular 640 GPM Division Filled with Sand Soil Support ed Box Type ,

and Gravel Steel

13 G eneral 1958 B 37 .4 3 8 . 3 2 264 . 2 4 . 87 2 .89 Sheetpile C ells Reinforced Concrete , Fine Hinged Gat e , 2-Electric Driven, 13 2-Electric Dynamic s with Sand and l .22m, Sand , Steel 12 , 000 GPH, Driven , Quincy Division Gravel Fill, and Fully Relieved , Trace Vertical 3 ,800 and DD#6 Steel Bulkh eads Soil Supported of Clay 2 , 000 GPH

14 Quincy General 1958 ll 44 .81 44 . 87 289 . 8 4 . 87 2 .8 9 Steel Eulkheads Reinforced Concre t e , :Fine l�!:;ed Gat e , 2-Electric Driven, 8 2-Elect ric Mass . I ""·-"-' "Q l . 22m, Sand , 12 , 000 GPM, Driven, , -, ! Quincy Division Fully Relieved , Trace Vertical 5 , 800 and

I DD#7 Soil Suppo rted of Clay 2 , 000 GPM

15 General 1958 B 38 . 2 3 8 . 2 2 264 . 9 4 . 87 2 .8 9 Sheetpile C ells Reinfo rced Concrete , Fine · Hinged Gat e , 2-Electric Driven, 13 2-Blectric Dynamics with Sand and l . 22m , Sand , St eel 12 , 000 GPM, Driven, Quincy Division Gravel Fill, and :Fully Relieved , Trace Vertical 3 , 80 0 and DD#S St eel Bulkhead Soil Supported of C lay 2 , 000 GPM

1 6 Quincy 1975 B 44 ,7 44 . 7 9 266 . 6 4 . 87 2 . 89 C ells Reinforced Concret e , Fine l�inged Gat e , 2-Electric Driven, 10 . 5 2-Elect ric Mass .

lfu�;, with and Fully Relieved , Send 5 0 , 000 GPM, Driven,

Division Grave l Fill So i l Suppo rt ed Vertical 2 , 000 GPM l

Notes : B=Building; R=Repair; B/R=Building and Repair

Thi s information is taken from existing documentation which is approved for Public Release and is in the Pub lic Domain.

REF no.

17

18

1 9

20

21

2 2

23

24

-

LOCATI OJI

Quincy Maas.

,, , 1 . iH"""""'_;,,..-<--

San l'o 1 H '<'!'n' -

Newport News Virginia

Newport News Vi rginia

N ewport News Vi rginia

Newport News Virginia

Tampa Florida

YEAR USE EJITRA!ICE O\niER OR YARD Ill OF ill llTH

NA.ME SERVICE DOCK (m)

General 1975 B 44 .7 Dyne.mice Quincy Division DD#l2

I nga lls 1972 }) 2 2 .7 4 Shipyard

National Steel 1976 ll 5 1 .2 5 Ship Building & Dry Dock C o . DD#l

Newport Neva Rebuilt il/R 35 . 97 Ship Buildiil8 1959 II: Dry Dock C o . DD#2

N ewport Jlews Rebuilt ll/R 1 9 . 93 Ship Building 1980 & Dry Dock C o . DD#3

Nevport News 1981 ll/R 2 1 . 7 Ship iluilding & Dry Dock C o . DD#4

N ewport l!ewa 1976 }) 7 5 , 3 Ship Builditl(!; II: Dry Dock C o . DD#l2

Tampa 1978 B/R 45 . 5 2 Shi pyard Inc .

DOCK EFFECT-ilARREL IVE Wl lY.l'H LENGTH

(m) (m)

44.79 266 .6

26.52 156 . 1

54.88 304.87

38.26 262 . 67

2 l .34 156 .4

22 .86 160 . l

7 6 . 2 2 491.77

45 . 5 2 276. 5

WORLD DRY DOCK BUILT SINCE 1950

DEPTH OVER SILL

(m)

4 . 87

1 0 . 5

6 .40

9 . 5 6

1 0 . 06

1 0 . 06

-- -TIDAL RAJlGE

(m)

2 . 89

0 .44

1 . 7 1

0 .798

0 .7 98

0 . 798

9 . 93 I 0 .798

7 . 87 0 .314

Count ry : U .S . A .

C Ol!STRUCTI Oll C O!ISTRUCTI OI! OF WALLS OF FLOOR

DESIGN PHILOSOPHY

Steel Sheetpile Reinforc ed Concret e , C ells vi t h Sand Fully Relieved , and Gravel Fill Soil Supported

Stoel Sheetpile Reinforced Concret e , C el l s , Filled l . 16m, with Sarni and Fully Relieved , Cravel Soil Supported

Steel Reinforced Concret e , Cells, 0 . 609m, with Sand and Fully Relieved, G rave l Soil Supported

Reinforced Reinforced Concrete, Concret e , 0 . 635m, Slant ed , Fully Relieved , Vari ea from O .83t Soi l Supported to l.70m

Steel Sheetpile Reinforced Concret e , aod Reinforced 0 . 915m, Concrete Fully Relieved ,

Soil Supported

1 . 67m Diamet er, Reinforced Concre t e , Prestreaaed o . 915m, Conc ret e , Fully Relieved , Cylind ri c a l Piles Soil Supported

l .67m Dirunet e r , Reinforc ed C oncrete , Prest reseed 0 . 915m, Concrete Fully Relieved , Cylind e r Piles Soil Supported

Steel Sheetpile Reinforced Concret e , Cells and Fully Reli eved , Reinforced Soil Supported C oncrete

Not e s : B•llui lding; R•Repair; ll/R•Building and Repair

SOIL T!PE 01' Tll'E OF TYPE GATE MAIN PUHPS

Fine Hinged Gate , 2-Electric Driven, Sand Steel 5 0 , 000 GPM,

Vertical

Silty Hinged Gat e , 2-Electric Driven, Sand Steel 30, 000 GPM each ,

Vertical

Soft Float ing 1-Elect ric Driven, to Gate, Not a 1,800 GPM, Firm C a isson Vertical Clay

Marl Fl oat i ng 2-Electric Driven, Cai aeon 115 , 000 GPM, 60", ::�� •a"!>" 600 HP Box

Marl Float ing 1-Electric Driven, Caisson, 60" and Rectangular 1-Electric Driven. :Box Type , 20· St eel

Marl Float ing 2-Electric Driven, Caisson 25 , OOO GPM, 36" Rectangular Mixed Flov, 200 HP ilox Type , Steel

Marl Floating 8-Electrie Driven , Caisson, 1 1 , 600 GPM, R ect angular Mixed Flow, 200 HP Box Type , Steel

lilij ""'" '" ..

4-Electric Driven, Steel 30,000 GPM

e

This information is taken from existing documentation which is spprovea for Public Release and is in the Public Domain .

Sheet 3 of 3

DE- RE!IARKS WATERillG (SEC OJ/DARY )

'.i'HIE PUJ.!PS ) (HRS)

1 0 . 5 2 -Elec tri c Drivenp 2 , 000 GPM

3-12 2-Electric Driven, 2 , 000 GPM

2 1 2-1000 GPM Vertical Turbine

1 . 5 I-Electric Driven, 2 0 " , 600 GPJ!, I-Electric

3 . 0 2-3" SubDe rsible

3 .78 2-Elect ric Driven, 2 , 000 16" f 25 HP

13 1-Electric Driven, 1 , 900 GPH, 100 HP

4 2-Electric

1 , 200

APPENDIX " B"

STRUCTURAL ANALYSIS OF GRAVING DRY DOCKS BY THE FINITE ELEMENT METHOD (*)

by M:tliuA: ff. Ml, Ge.o:tecluti.eal Engineui.ng s�. Na.vat faeU.l..t.i.u Enginee.Wlg

c_,m Headq�, AJ.vc.andtia., VA !f33f lU.c.had. YACllNlS, Ch.ie.6 Eng.br.e.e.t, Na.vat faei.Ut,i.u Engineui.ng

c_,m HeadqutVttM.6, AJ.�.ia. VA 22332 E-tnu.t fll. 8ROOKS, 'Rue.Mch Sta.66, Va.v.id Tayto.Jt Na.vat Skip 'RUe.Mch 8 De.11e.lo,,..e.n.t Ce.n.tM,

Bethuda., "" 20140

Graving drydock structural analysis by the finite element method is described . Structural and geotechnical parameters, which are important in setting up structural models are discussed. Loads include static load, the earthquake induced dynamic load, and the ship weight . The analytical method is useful for evaluation of drydock stability and in certifying the safety of drydooks.

INTRODUCTION

A structural analysis for gra\'ing drydocks has been

made using a NASTRAN finite element method (FEM) com­

puter program ( 1 ,2). The purpose of this analysis is to

e\-aluate the safety of drydocks which are subjected to

static soil and hydrostatic pressures, as well as the appli­

cable updated earthquake i nduced dynamic loads and \'arious

shi ps' weights. In the past, analysis was generally made

using concepts of elementary strength of materials and

simplified elasticity theories. Factors such as the soil/

structural interaction, the restraint from the surrounding

structures, and the rigidity and stress-strain characteristics

of the drydock were not fully included in the analysis.

Because of the complexity of the drydock structure, the

analysis should begin setting up structural models which

can accurately include structural and geotechnical para­

meters for finite element numerical analysis. The accuracy

of the results can then be checked through a comparison

of the different models used in the analysis. This paper

describes the analytical procedures for drydock stability

analysis, and includes examples of the results. The results

of the analysis are used in certifying the safety of dry­

docks.

l * J 4th lntvr.nati.ona.l. Con6M.e.nee. on AppUe.d NumeJt.lcal Mode-llng, Ve.c. 27-29, 1 984, T�, Ta.iwan, R.O.C.

PJAN.C. - A l.P.C.N.

STRUCTURAL TYPES OF DRYDOCK

The gra\'ing drydocks are constructed on the shoreline.

They are, generally, embedded in the ground to a depth of

50 to 70 ft, the width ranging from 100 f t to 1 60 ft and

the length from 800 to 1 200 ft. Since each case is different

in shape, size, and type of backfill soil and drydock struc­

ture, the formulation of the finite element model cannot

be standardized. The type of drydock used depends on what

is needed to neutralize the water pressure (3). The degree

to which the water pressun{

must be relieved determines

which of the following three types of drydock is used

(1) Full Hydrostatic - A drydock is classed as being fully

hydrostatic if there is no relief drainage system that

lowers the natural hydraulic head on the walls or floor.

The full buoyancy of the drydock must be resisted by

one or more of the following : (a) weight of concrete,

(b) weight of soil behind the dock and/or friction of

the earth on the sidewall; and (c) piles installed to

support the floor slab.

(2) Fullr Relie\·ed - A fully relie\'ed drydock is one which

has a drainage system to eliminate or reduce the

hydrostatic pressure on the floor and walls.

(3) Partially Relie\·ed - A partially relie\'ed drydock pro\·ides

relief for the floor only. Its use reduces the amount of

floor concrete and minimizes difficulty in the cofferdam

t o be used temporarily during construction. It features

the following : (a) cutoff wall to surround the floor

area only; (b) filter course under the floor; and (c)

holes in the floor for the water seepage flow into the

drydock chamber.

MODES CAUSING PROBABLE DRYDOCK FAILURE

Structural analysis of a drydock must include the

applicable earthquake induced seismic load as this load is

BULLETIN 1988 - N° 63 B - 1

critical to the stability of the drrdock. In general, there

are two types of drydock failure mopes which may be

caused by seismic loads ( 4) :

A. FLOAT AND TILT

The maximum uplift pressure under the floor slab

occurs when the dock is empty. The uplift stability of the

drydock mar reach a critical rnlue if the uplift pressure

during earthquakes exceeds static value due to increase in

pore pressure caused by the shaking. If pore pressure of

the backfill behind the wall were to increase to nearly the

total pressure, effective stresses and shear . strengths would

approach zero and soil liquefaction would occur. A net

uplift would result, causing the drrdock to float and/or

tilt. Howe,·er, if soil liquefaction is unlikely, then this type

of failure would not result.

B. OVERSTRESS AND/OR OVERTURN OF DRYDOCK WALL

Should an earthquake occur when the dock is e mpty,

the ultimate moment capacity of the drydock wall ma}· be

exceeded, causing overstressing and/or O\'erturning if the

wall is considered to be a "cantile,·ered" structure. This is

the usual assumption made, which calls for a construction

joint between the drydock wall and the floor slab. Obviously

the "cantilevered" structure approach is an o\·erly simplified

assumption.

STRUCTURAL AND GEOTECHNICAL PARAMETERS

Figures 1 and 2 show two examples of drydock cross­

sections which ha\·e been used in the analysis. Backfill soil

properties are also shown in Figure 2.

Prolws•·1loodi1>& 'llmod

rtilUy h!!!.. .... ll '!Unn<l

�&RT IA.\. �fCTION P-..llTIAL '!>eCTION n ,.,...,.., aoow,otW'aTt•..w:. � lflf wv .. 0•1•·nc •c&.,t.r w1.u.. ==:·;:.�=�="::C'ta.. f t'UIQPiN' ftfio&.T.

Figure 1 . An Ex1mpl e of • Drydock Cros s ·S�c tion

A. ST A TIC LOADS

1. La:teJtal Eiuth P.t�e.. To establish lateral earth

pressures acting against the walls, the follbwing assumptions

are made :

8 - 2 P.l.A.N.C. - A.l.P.C.N.

(a) Under the earthquake loading, one side o f t h e dock wall

will experience active earth pressure as well as earth­

quake induced pseudo-static pressure. These two pressures

may be assumed to be in- or out-of-phase;

(b) The opposi t e side wall will deYelop semi-passh·e earth

pressure, which · may be assumed to be equal to or

higher than the at-rest earth pressure;

(c) In the passi\·e side wall, a series of horizontal linear

springs can be modeled to simulate the lateral soil

stiffness induced by the earthquake; and

(d) In the static loading case, the drydock walls are subject

to at-rest earth pressure and the structure is in static

equilibrium.

2. flg�o.Jltat;ic P.t�e.. Since the drydock may be

either a full h>·drostatic type, a fully relieved type or a

partially relieved type, the uplift hrdrostatic pressure mar

or may not act at the floor slab even when the dock is

empty. · Figure 3 shows a fuli hydrostatic type with the

uplift force.

Typical Cross Sec tion

,.

· Granular Fil l . 0 to 36 ' deep · · · : Yt•l20 lb'/c . f . ; �30° ; c•O . . . . .

Figure 2. An Example of a Drydock Cross -Section and Backfill Soil Characteris tics

3. VJtgdock FloOJt SUbg.tade. Uodulu.4. The floor slab is

generally a reinforced concrete, high rigidity structure

supported by competent foundation soils. The ultimate

bearing capacity of the foundation soil can be est imated

by

BULLETIN 1 988 - N° 63

Ship in Dock (Mid s hip Lo a d ing) Wi thou t Ea r t hquake Load ing

,. ,.

I Yi- l\t 1Wt.f.

� E I h 37 ..,.,-.,7..,T, ._ ........ _..J....,,.-,...11 :...,,-.1-L _ _L _ _J__, __ 'J;"L/-''.J---',___-;:,.,.., ,.ur

Figure 3 . A S truc tural Model for Fini te Element Ana lysis • A Ful ly Hyd ros ta t i c Type

where

quit

c

Ne' y D

N q

ultimate bearing capacity

cohesion of the foundation soil

bearing capacity coefficients

effecti,-e weight of overburden

depth of the floor slab.

Deflection of a simulated elastic foundation which

support the floor slab is general ly not to exceed d=0.50

inch. Considering that a safety factor of F 5 is assigned to

the bearing capacity of the foundation soi l , then the sub­

grade modulus, K5 can be estimated by

B. EARTHQUAKE LOADS

I. Ea.U:hquak.e Ct.i.:t.e.tia.. The drydock shall be con­

sidered adequate' if it can resist w ithout collapse the forces

associated with an earthquake of magnitude such that there

is an 80 % probabil ity of not being exceeded in 50 years.

Because of the uncertainties inrnh-ed in seismlcity ernlu­

ation, and the difficulty and cost of upgrading existing

structures, remedial measures usually are not deemed

necessary if the structure' s capacity to resist the force of

an earthquake is equal to at least 75 % of the demand

associated with a postulated earthquake. This criterion is

adopted for the drydock stabi l ity analysis.

2. llla.U Invr.t.ia. tUld F.ti.d.ion Fo-tcu. An additional

horizontal load of the drydock wall generated by the

earthquake load is added to the wall stabil ity analysis. It

is the gravity force of the drydock wall times the horizon­

tal seismic coefficient. Applying the Coulomb earth pressure

theory and considering the euect of earthquake excitation,

the wall friction force for \'arious ground accelerations is

calculated by the following equation

F P tan.S I

where

F

p tano

Friction force adjusted for earthquake excitation

Resultant of the lateral soil pressure

soil/drydock wall friction earthquake force

Correction factor for earthquake force

ah Horizontal seismic coefficient

c A constant, use 1 0 to satisfy the following

1=1.0 for ah=O; l=O for ah=0.35

Note that .the P \'alue may be an acth·e force, an

at-rest force, or a passive force. From the abo\·e equation,

the earthquake versus drydock wall friction factor is as

follows :

ah(g)

o.o l .O

0.1 0 0.92

0.1 5 0.86

0.20 0.78

0.30 0.39

The F rnlues which represent the drydock wall friction

force, modified for earthquake load, are used in the finite

element analysis.

3. Soil lnvr.t.ia. Fo-tce. For earthquake conditions, an

equi\'alent pseudo-static loading was used to include the

dynamic loads. An effective horizontal surface acceleration

of Kh is selected for each of the loading cases. To calcu­

late the pseudo-static earthquake pressure acting against

the drydock wall, a computer program was deYeloped. The

method was adapted from NAVFAC DM-7.2 (5), Earthquake

Loading section. The dynamic earth pressure distribution

was modified to make the resultant force act at a point

two-thirds of the wall height up from the base.

C. CRANE RAIL SUPPORT AND CONCRETE TIE BEA M ·

RESTRAINT

Figure 4. Crane Track Found a tion and Concrete Tie Beam

Figure 4 shows the connection of crane track foun­

dation and concrete tie beam. The tie beam stiffness is

calculated by

P.l.A.N.C. • A.1.P.C.N. - BULLETIN 1 988 - N° 63 8 - 3

where

concrete tie beam stiffness

steel reinforcement cross section

Young' s modulus of the steel reinforcement

tie beam length

S tie beam spacing

These concrete tie beams are included in the analysis

because the beams would provide a restraint to the lateral

loads.

LOADING TO BE USED IN STRUCTURAL ANALYSIS

A. SHIP LOADING CONDITIONS

The ship types to be considered are a submarine,

destroyer, frigate, cruiser, or carrier, depending upon the

capacity of the drydock. The blocking loads are based on

the assumption that the largest ship that will fit in the

drydock will generate the heaviest loading per foot of dock.

The blocking loads for the earthquake case are determined

by applying a horizontal load of seismic coefficient (ah

)

multiplied by the ship displacement at the approximate

center of gravity of the vessel. The overall capacity of

the dock may range from 25,000 to 80,000 long tons.

B. CASE OF LOADING CONSIDERED

Generally, five to six cases of drydock loading con­

ditions are included in the analysis. The main loading con­

ditions considered are :

(a) empty drydock with an earthquake load;

(b) flooded dock with an earthquake load;

(c) ship in the dock without an earthquake load;

(d) ship in the dock with an earthquake load.

Loading condition (d) may include the case of the

ship on center or off center; aft keel line or aft quarter

loading; midship loading; or with a higher earthquake load.

STRUCTURAL NUMERICAL ANALYSIS - FINITE ELEMENT

METHOD

A. GENERAL DESCRIPTION

The drydocks are analyzed for different cases of

loading using the NASTRAN finite element structural

analysis computer program. Examples of load cases analyzed

are shown in Figure 5. This drydock consisting of concrete

and steel reinforcement, is modelled as a non-linear elastic

material having different properties in tension and com­

pression.

The soil foundation is modelled as a series of vertical,

linear springs using ELAS2 elements (scaler spring element).

140'

r.•7.6 1t1p1 i,-su 1t1p1ftt21tt i,•17.50 lr.lp•fft

Figure 5 . An Example of Finite toad Case

s.02 luf ) r,•t . 1 ltlp• Kt•14S kip• ff•

Element Model

The concrete tie beams at the top corners of the wall are

modelled by horizontal springs with a computed stiffness of

K8• For the earthquake load cases, the right side wall of

the backfill is modelled, in addition to the lateral resisting

pressure, by a series of horizontal ·springs. The lateral soil

pressures, wall friction force, hydrostatic uplift force, if

any, and ship line loadings for the various cases are input

as equivalent nodal loads which are determined using a

pre-processor.

To determine the friction force to be applied at

nodal points along the bottom, an initial analysis may be

performed with the friction force equal to zero. The

normal forces along the slab bottom are then determined

from the spring displacements determined by this analysis.

These net normal forces are multiplied by the coefficient

of friction to obtain the friction forces which are included

in the final analysis.

Output from the NASTRAN analysis is in the form of

displacements and local clement stresses (crxL

' cryL

' i:xyL

)

at the nodal points. The stresses were input into a post­

processor (ISOSTRS) which output the average stresses at

the nodal points in a global coordinate system ( crxg

' cry g'

i:xy ) along with the corresponding major and minor prin-g

cipal stresses and maximum shear stress. ISOSTRS also

flags all stresses which exceed prescribed values. A second

post-processor (PL TSTRS) is used to interactively generate

computer graphs of these six stresses versus positions along

essentially horizontal or vertical lines through the structure,

for example, the top of the dock floor slab or inface o f

the dock wall.

B. FORMULATION OF FINITE ELEMENT MESH

An example of finite element mesh developed for the

analysis is shown in Figure 6. This model consists of 966

IS2D8 elements (an iso-parametric, quadratic, plane stresses,

8 noded element) with 3215 node points.

The objective in modelling this structure is to generate

a fine mesh in areas where high stress gradients might

occur. A pre-processor (DCKMSH) is developed which allows

for the generation of a model requiring concentration of

elements in some areas while requiring less concentration

B - 4 P.l.A.N.C. - A.l.P.C.N. - BULLETIN 1 988 - N° 63

Figure 6 . An Exampl e of Fini te El ement Me s h Formula ted for Ana lys i s

in other areas. The use of DCKMSH involves dividing the

structure into quadrilateral sub-regions prompted by either

geometrical or element concentration considerations. One of

the important features of DCK MSH is the numbering

pattern for nodal points and elements. These _numbering

schemes facilitate plotting the output stresses and displace­

ments by computer.

C. MODE.LS OF FINITE ELEMENT ANALYSIS

Normally as many as six different loading models are

selected to evaluate the results of various critical loading

conditions using two-dimensional, static, and elastic finite

element analysis. The models chosen include a combination

of the following conditions : empty dock; ship in dock; with

or without earthquake load. The configurations of the utility

tunnel and discharging/flooding tunnels are both included in

the analysis.

Recent research indicates that while the location of

the resultant of the earthquake induced dynamic earth

pressure for an at-rest condition is near the two-thirds

point of the wall height measured from the base up, the

location of te resultant drops rapidly to the one third

point when the wall displacement is sufficient to approach

or achieve the conditions of the active state of the back­

fill. In the analysis, we apply the resultant of dynamic

lateral earth pressure at the two-thirds point of the wall

height. This is a conservative assumption.

D. RESULTS OF FINITE ELEMENT METHOD ANALYSIS

Figure 7 shows the exaggerated displacement of a

drydock under two loading cases. The maximum displace­

ment of the wall ranges from 0.3 to 0.7 inches, and the

floor slab ranges from 0.09 to 0.36 inches.

Normal stresses in tension and compression, shear

stresses, and major principal stresses for the two loading

conditions were plotted using the computer and are shown

in Figure 8.

Some nodal points, mainly at the center of the floor

slab, were chosen to summarize the results and compare

I I G It .. I

p ' I

(a) Maximum Displacement: 0 . 6 55 inches

1 (b) Maximum Disp lac emen t : 0 . 221 inc hes

F i gure 7 . Drydock Displacement Under Load ing (a) Wi th Ship Load , and Kh•O . JOg (b) Wi thout Ship Loa d , Kb•0 , 15g

-·10N'� lllhlC[ l f ! I Figure 8. Example o f Sigma·X S tresses Along

the Top of the Floor S lab

the displacement and stresses for the different models. The

results are reviewed to determine whether the tensile,

compressive, and shear stresses are within or beyond the

allowable limits.

SUMMARY AND CONCLUSIONS

Conclusions from the drydock structural analysis using

the finite element method- of analysis are as follows :

1. Geotechnical mechanics principles can be applied to

the structural analysis of a drydock. However, over-simpli­

fication of structural mechanics principles may lead to

unrealistic results. For example, the drydock wall can not

be considered to behave as a "cantilever" structure. The

use of the equilibrium of free body concepts should be avoided. The use of elementary strength of material con­

cepts, such as a simplified flexural equation of f=My/I

should not be adopted for the overall analysis.

P.LA.N.C. - A.l.P.C.N. - BULLETIN 1 988 - No 63 B - 5

2. The crane rail foundation and concrete tie beam does provide a restraint to the lateral movement. However, the passive resistance of the soil actually dissipates the unbalanced lateral force. Thus, a tie beam does not signifi­cantly reduce the stresses in the drydock.

3. The finite element models must be carefully developed to simulate the drydock structural properties and geotechnical loading conditions. The assigned values of sub­grade modulus, drydock wall and soil interactions, and soil ·lateral soil stiffness induced by the earthquake are signifi­cant to the results of analysis.

4. A two-dimensional finite element method for the entire drydock structural analysis provides satisfactory results. The structure may be considered to behave as a linear or non-linear material, depending on the effect of the steel reinforcement.

5. A well formulated finite element mesh with proper

numbering schemes would facilitate plotting of the stresses and displacements by computer.

6. The validity of the analytical results obtained by the finite element method must be checked by experienced structural and geotechnical engineers.

REFERENCES

[ 1 ] Naval Facilities Engineering Command, Structural Analysis , Drydock Nos. 1 and 2, Long Beach Naval Shipyard , California , August-November, 1 983.

[2] Naval Facilities Engineering Command , Structural Analysis, Drydock No. 5, Charleston Naval Shipyard, South Carolina, April , 1 984.

[3J NAVFAC DM-29 . 1 , Graving Drydock, May, 1982.

[4J Woodward-Clyde Consultants and Moffat & Nichol Engineers, Facilities Certification Report, Long Beach Naval Shipyard , Drydock No. 1 , April , 1 979 .

[5J NAVFAC DM-7 .2, Foundation and. Earth Structures, May, 1 982 • .

8 - 6 P.1.A.N.C. - A.l.P.C.N. - BULLETIN 1 988 - N° 63