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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 -:;: ____ ... -..,.,:.=-:.:: =-----:.-:�!' ....... ... --""' �-
1.8.0 .f·�.10.0 I
�1-8=.0�1�·��2��0,,__ __ -+--· ��·-��--���� -�---t--"-'--�
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 . .
· · >.. c 1 10o-2soom
. 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.. · �.- .�' .. "'""
, 5pacing 1 5rr! .
----- · - - _w·
CllOSS S£CTI0!4 l - I
35.CXlm
""--.L·_·s.._·__,.--1"·-··��w . .
I
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