mathcad - 1000 kl tank1

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CONTENTS

1. GENERAL

1.1 Outline of Structure

1.2 Unit of Measurement1.3 Computer Software

1.4 Codes & Standards

1.5 Used Material & Allowable Stress

1.6 Other Requirement Data

2. PRELIMINARY

2.1 Layout

2.2 Dimension

3. LOADING DATA

3.1 Dead Load

3.2 Equipment Load

3.3 Wind Load

3.4 Seismic Load

3.5 Load Combination

4. FOUNDATION DESIGN

4.1 Bearing Capacity

4.2 Settlement

4.3 Sliding Check

4.4 Overturning Check

4.5 Check Tension

5. FOUNDATION REINFORCEMENT

ATTACHMENT

1. Loading Data 4. AWWA standard 2005 Reference2. Soil Data 5. Circumferential Reference3. Engineering Drawing 6. Immediate sett lement (Bowles) Reference

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1. GENERAL

1.1 Outline of Structure

Project : PONDASI TANGKI SUMBAGUT

Client : PT. PERTAMINA (Persero)

Location : TBBM Dumai, Riau Kepulauan, Indonesia

Equipment : Oil TankFoundation Type: Ring Beam Foundation (Shallow)

1.2 Unit of Measurement

Unit of measurement in design shall be in metric system.

1.3 Computer Software

Computer software used in design analysis are as follows :

- MathCad

1.4 Codes & Standards

- ACI 318 1999

Building COde for Structural Concrete

- SNI 02-1726-2002

Earthquake Resistant Code for Building in Indonesia

- Soil Investigation Report & Recommendation

1.5 Used Material & Allowable Stress

Compressive concrete strength : fc 250 kg cm2

Yield strength of rebar : fy 4000 kg cm2

Unit weight of reinf. concrete : c 2400 kg m3

Unit weight of soil : soil 1600 kg m3

Unit weight of sand /filler : filler 1800 kg m3

Unit weight of water : w 1000 kg m

3

Unit weight of gravel : gravel 1800 kg m3

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1.6 Other Requirement Data

Based on soil investigation report :

Ground water table : 8.4 m below ground level

Allowable Bearing Capacity : qall 72.5 tonne m2

Elev 7.00( ) BH 06

Based on site condition after excavation there is andesite rock at elevation +7.00

Assume bearing capacity : qall 72.5 tonne m 2

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2. PRELIMINARY

2.1 Layout

2.2 Dimension

Height of Tank H 10.97 m

Diameter of Tank D 11.64 m

Diameter of Bolt location db D 0.1 m db 11.74 m

Inner diameter of Ring Wall di D 400 mm di 11.24 m

Outer diameter of Ring Wall do D 500 mm do 12.14 m

Inner Diameter of Foundation dfi D 1500 mm dfi 10.14 m

Outer Diameter of Foundation dfo D 1500 mm dfo 13.14 m

Height of Ring Wall (h pad) hw 0.8 m hw 0.8 m

Thickness of Foundation hf 0.5 m

Base Fdn Area ( Empty) Ate 0.25 dfo2

dfi2 Ate 54.852 m 2

Base Fdn Area (Operational) Ato 0.25 dfo2 Ato 135.607 m 2

Perimeter of Fdn : kt dfo kt 41.281 m

Height soil hs 1 m

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3. LOADING DATA

3.1 Dead Load

Ring beam : Wbr 0.25 do2 di2 hw c Wbr 31.731 tonne

Footing : Wf 0.25 dfo2 dfi2 hf c Wf 65.823 tonne

Filler inside : Ws1 0.25 di2 16.8 m( )2 filler hw hf ( ) Ws1 286.522 tonne

Filler outside : Ws2 0.25 20.8 m( )2

do2 hw hf ( ) filler Ws2 524.261 tonne

Weight of Foundation : Wf Wbr Wf Ws1 Ws2 Wf 335.291 tonne

3.2 Equipment Load

weight of roof Wr 5 tonne

weight of wall of tank Ws 42 tonne

Self weight of tank (erection weight) We Wr Ws We 47 tonne

Test weight (exclude tank weight) Wt 1170 tonne

Operational weight (exclude tank weight) Wo 1125 tonne

3.3 Wind Load

Base on ANSI (Wind velocity 120 MPH)

Kz 0.85 Kzt 1 V 120km

hr I 1

Q 0.613 Kz KztV s

m

2

IN

m2

Q 578.944N

m2

G 0.85 C 0.7 A 0.5 D H A 200.576 m

2

Wind load : Pw Q G C A Pw 7045.514 kg

Moment at tank base due to wind load : Mw PwH

2Mw 38.645 tonne m

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3.4 Seismic Load

Seismic parameter (Zone 4, Hard soil) : C 0.6 SDS C

Sai SDS I 1.5 R 3 (AWWA table 24 and table 28)

Ai SaiI

1.4 R Ai 0.214 Ac Ai

Based on ANSI / AWWA 2005 (section 13.5.2) : (see attachment 4)

overturning m oment at the bottom of shell do e to seismic:

the design overturning moment at the bottom of the shell caused by horizontal design acceleration isthe SRSS combination of the impulsive and convective components and shall be determined by theeqation:

Ms1 Ai Ws Xs Wr Hr Wi Xi( )[ ]2

Ac Wc Xc( )2

Xs

for D/H >1.33Wt 62.4 G H

D2

4

Wt 3457.7 tonne

Wi tanh 0.866D

H

Wt

0.866D

H

Wi 2263 tonne

Wc 0.230D

Htanh 3.67

H

D

Wt Wc 1199 tonne

Ws 92594 lb Xs1H

2 Xs1 20.227 ft

Wr 11023 lb Hr1 H Hr1 40.453 ft

Xi1 0.375 HWi 4988118 lb Xi1 15.17 ft

Wc 2643104 lb Xc1 1.0

cosh 3.67H

D

1

3.67H

Dsinh 3.67

H

D

HXc1 26.383 ft

Ms1 Ai Ws Xs1 Wr Hr1 Wi Xi1( )[ ]2

Ac Wc Xc1( )2

Ms1 3099 tonne m

Moment for Operational Condition at bottom of shell doe to seismic:

Mo1 Ms1 Mo1 3099 tonne m

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overturning moment at the bottom of footing doe to seismic

the design overturning moment at the bottom of footing caused by horizontal design acceleration is theSRSS combination of the impulsive and convective components and shall be determined by theeqation:

Ms2 Ai Ws Xs Wr Hr Wi Xi Wf Xf ( )[ ]2

Ac Wc Xc( )2

Xs

for D/H >1.33 Wt 62.4 G H D24

Wt 3457.7 tonne

Wi tanh 0.866D

H

Wt

0.866D

H

Wi 2263 tonne

Wc 0.230D

Htanh 3.67

H

D

Wt Wc 1199 tonne

Xs2H

2hw hf ( ) Xs2 24.492 ftWs 180779 lb

Hr2 H hw hf ( ) Hr2 44.718 ftWr 22046 lb

Xi2 0.375 H hw hf ( )Wi 4988118 lb Xi2 19.435 ft

Wc 2643104 lb Xc2 1.0

cosh 3.67H

D

1

3.67H

Dsinh 3.67

H

D

H hw hf ( ) Xc2 30.648 f

Wf 739191 lb Xf hw hf ( )

2Xf 2.133 ft

Ms2 Ai Ws Xs2 Wr Hr2 Wi Xi2 Wf Xf ( )[ ]2

Ac Wc Xc2( )2

Ms2 3904 tonne m

Moment for Operational Condition at bottom of footing doe to seismic

Mo2 Ms2 Mo2 3904 tonne m

Soil Pressure for Seismic Condition

friction angle : 16.4 deg

surcharge load : q 1.00 tonne m2

Cohession : c 2.4 tonne m2

height of soil : hs 1m

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Coefficient of earth pressure at rest : Ko 1 sin ( ) Ko 0.718

Earth pressure due to surcharge in Ground level

P1 q Ko( ) P1 0.718 tonne m2

Earth pressure from the back fill

P2 soil Ko hs( ) P2 1.148 tonne m2 (assumed: c is neglected)

The earth pressure during seismic is calculated as follow :

During seismic load (internal friction angle of soil) = 0, Kp = 1, and the pressure in ultimatecondition. The nominal pressure = Ultimate pressure / Reduction factor

R 1.6 (reduction factor)

Earth pressure due to seismic in Ground level

P31

KoP1 P3 1 tonne m

2

Mo3 P3 hw hf ( ) 0.5 dohw hf ( )

2Mo3 16.114 tonne m

P41

KoP2 P4 1.6 tonne m

2

Mo4 0.5 P4 hw hf ( ) 0.5 dohw hf ( )

3Mo4 8.594 tonne m

3.5 Load Combination

1. 1.0 (Empty Condition)

2. 0.75 (Empty Condition+Wind Condition)

3. 1.0 (Operational Condition)

4. 0.75 (Operational+Seismic Condition)

5. 0.83 (Test Condition)

4. FOUNDATION DESIGN

4.1 Bearing Capacity

Vertical load on ring beam:

- vertical load due to tank & roof

qt We qt 47 tonne

- vertical load due to water

qw 0.25 D( )2

D 0.2 m( )2

H w qw 72.824 tonne

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Width of Ring beam Bpdo di( )

2Bp 0.45 m

Area of Foundation Ap Ate Ap 54.852 m2

Pressured on bottom of foundation

empty condition qp1qt Wf

Apqp1 6.969 tonne m

2

operational condition qp2qt qw Wf

Apqp2 8.297 tonne m

2

Modulus of Base Tank :

Statis Moment Ze dfo

4dfi

4 32 dfo( )

Ze 143747 L

4.1.1 Empty Tank Condition

a). Bottom of Shell:

Self Weight Tank

qem1aWe

Ateqem1a 0.857 tonne m

2

Status "Fdn Ok" qem1a( ) qallif

"Fdn Not ok" otherwiseStatus "Fdn Ok"

Self Weight Tank + Wind Load

qem2a 0.75We

Ate

Pw H

Ze

qem2a 1.096 tonne m2

Status "Fdn Ok" qem2a( ) qallif "Fdn Not Ok" otherwise Status "Fdn Ok"

b). Bottom of Found ation :

Self Weight Tank

qem1bWe

Ate

Wf

Ap

qem1b 6.969 tonne m2

Status "Fdn Ok" qem1b( ) qallif

"Fdn Not ok" otherwiseStatus "Fdn Ok"

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Self Weight Tank + Wind Load

qem2b 0.75We

Ate

Pw hw hf ( )

Ze

Wf

Apqem2b 5.275 tonne m

2

Status "Fdn Ok" qem2b( ) qallif

"Fdn Not Ok" otherwise Status "Fdn Ok"

4.1.2 Operational Condition


Operational Weight of Tank

qop1aWo We

Ato

qop1a 8.643 tonne m2

Status "Fdn Ok" qop1a qallif

"Fdn Not OK" otherwise Status "Fdn Ok"

Operational weight + Seismic Load

qop2a 0.75Wo We

Ato

Mo1

Ze

qop2a 22.653 tonne m2

Status "Fdn Ok" qop2a qallif


b). Bottom of Found ation :

Operational Weight of Tank

qop1bWo We Wf

Ato

qop1b 11.115 tonne m2

Status "Fdn Ok" qop1b qallif

"Fdn Not OK" otherwise Status "Fdn Ok"

Operational weight + Seismic Load

qop2b 0.75Wo We Wf

Ato

Mo2 Mo3 Mo4

Ze

qop2b 28.834 tonne m

2

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Status "Fdn Ok" qop2b qallif


4.1.3 Testing Condition


Test Weight

qosa 0.83We Wt

Atoqosa 21.451 tonne m

2

Status "Fdn Ok" qosa qallif


b). Bottom of Found ation:

Test Weight

qosb 0.83 We Wt Wf Ato

qosb 23.503 tonne m 2

Status "Fdn Ok" qosb qallif


Maximum soil pressure happen at Operasional condition

qof max qem1a qem1b qem2a qem2b qop1a qop2a qop2a qop2b qosa qosb( )

qof 28.834 tonne m2

Status "Fdn Ok" qof qallif


NOTES :

The requirement bearing capacity at bottom of tank

Qrequirement at bottom of shell: qop2a 22.653 tonne m2

The requirement bearing capacity at bottom of footing

Qrequirement at bottom of foundation: qop2b 28.834 tonne m2

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4.2 Settlement

4.2.1 Immediate Settlement

Assume : -Based on Teory Elasticity, Timoshenko and Goodier (1951)

-Modified by Bowles (1987)

-fleksible bottom of tank

convert from circle area to square area

B Ato0.5

B 11.645 m

assume average value of poisson ratio 0.33

average elastic ity modulus Es 81100 tonne m2

center point of tank side point of tank

qcpWe Wo( )

0.25 di2

qst qp2

qst 8.297 tonne m2

qcp 11.812 tonne m2

H hs H 1 m H 1 m

Bc 0.5 B Bc 5.823 m Bs B Bs 11.645 m

M 1 M 1

Es 81100 tonne m2

Es 81100 tonne m2

H

Bc0.172

H

Bs0.086

mc 4 ms 2

I1 0.028 I1s 0.009

I2 0.061 I2s 0.041

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qst 8.297 tonne m2

qst 8.137 10 4 N m2

qcp 11.812 tonne m2

qcp 1.1583 10 5 N m2

qs max qst qcp( )

Status "Over Consolidation" qs Pcif

"Normal Consolidation" otherwise Status "Over Consolidation"

Sc 0 m

Total Settlement (St) = Immediate Settlement (Hs) + Consolidation Settlement (Sc)

St Hc Sc

St 0.0001781982 m

4.3 Sliding Check

P6

qop2

P4P1h1

bp

h2

hh

P2

P3

bb

P5

7P3h

B

h1 300 mm

h2 hf hw h1 h3 h2 hf h2 1 m h3 0.5 m

h h1 h2 h 1.3 m

r 0.5 D( ) 0.175 m r 9.625 m

Assume dimension based on Principles of Foundation Engineering Fourth Edition Braja M. Daspage 389 (not applicable with this case)

bp min = 0.3 m

bb = (0.45 - 0.7) x h

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dimension that shall be usebp 0.45 m

bb 1.5m

Friction angle of soil : 16.4 deg

Reffer to Rankine

Coefisien of active soil Ka tan 45deg

2

2

Ka 0.56

Coefisien of passive soil Kp tan 45deg

2

2

Kp 1.787

Active soil pressure

P1 0.5Ka h12

soil P1 0.04 tonne m1

P2 Ka h12


P3 0.5 Ka h22


P4 qop2a Ka h P4 16.481 tonne m1

Ta 1.7 P1 P2 P3 P4( ) r [ ] Ta 278.975 tonne

Passive soil pressure

c 2.4 tonne m2

P5h2 0.3m( )

2

2 soil w( ) Kp w[ ] 2 c Kp h2 0.3m( )P5 4.999 tonne m

1

Tp 1.7 P5 r ( ) Tp 81.797 tonne

EMPTY CONDITIONFriction between base of tank and soil (gravel) below is :

tan 0.67 ( ) 0.194

c 2.4 tonne m2

Horizontal load

Based on ANSI / AWWA 2005 (section 13.5.3) :

Design shear at the bottom of the foundation. The design shear at the bottom of the foundation doe tohorizontal design acceleration is the SRSS combination of the impulsive and convective component andshall be determined by equation:

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Vf Ai Ws Wr Wf ( )[ ]2

Vf 91.562 tonne empty( )

Ph Vf Ph 91.562 tonne

Vertical load

Pv We Wf Pv 382.291 tonne

Capacity of shearing force

Fce c Ate

Fce 131.645 tonne Cohesion Force

d 1.2tonne

m3

Passive force :

Fpph2 0.3m( )

2

2 soil w( ) Kp w[ ]

dfo

22 c Kp

2do h2 0.3m( )

Fpp 96.127 tonne

Pr Pv Fce Fpp Pr 301.999 tonne

Safety factor

SFsPr

PhSFs 3.298

Status "Fdn Ok, SFs > 1.5" 1.5 SFsif

"Fdn Not Ok" otherwise Status "Fdn Ok, SFs > 1.5"

FULL CONDITION

Horizontal load


Design shear at the bottom of the foundation. The design shear at the bottom of the foundation doe tohorizontal design acceleration is the SRSS combination of the impulsive and convective component andshall be determined by equation:

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Vf Ai Ws Wr Wi Wf ( )[ ]2

Ac Wc( )2

Vf 631.06 tonne full( )

Ph Vf Pw Ph 638.105 tonne

Vertical load

Pv We Wo Wf Pv 1507 tonne

Capacity of shearing force

Fco c Ato

Fco 325 tonne Cohesion Force

Fpp 96.127 tonne Passive Forces

Pr Pv Fpp Fco Pr 714 tonne

Safety factor

SFsPr

PhSFs 1.119

Status "Fdn Ok, SFs > 1.5" 1.5 SFsif

"Fdn Not Ok" otherwiseStatus "Fdn Not Ok"

4.4 Overturning Check

Distance from side of tank

Lr 0.5 do Lr 6.07 m

EMPTY CONDITION

Total vertical load =

wL We Wf wL 382.291 tonne

Moment againts overturning

Mr wL Lr Mr 2321 tonne m


Design overturning moment at the bottom of the foundation for tanks supported by ring beam foundation

shall include the effects of varying bottom pressures and shall be determine by the equation:

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Ms Ai Ws Xs2 Wr Hr2 Wf Xf ( )[ ]2

Ms 207 tonne m Empty( )

Mo1 Ms Mo1 207 tonne m

Safety Factor

SFmMr

Mo1SFm 11.206

Status "Fdn Ok, SFm > 1.5" 1.5 SFmif

"Fdn Not Ok" otherwiseStatus "Fdn Ok, SFm > 1.5"

FULL CONDITION

Total vertical load =

wL Wf Wo We wL 1507 tonne

Moment againts overturning

Mr wL Lr Mr 9149 tonne m


Design overturning moment at the bottom of the foundation for tanks supported by ring beam foundationshall include the effects of varying bottom pressures and shall be determine by the equation:

Ms Ai Ws Xs2 Wr Hr2 Wi Xi2 Wf Xf ( )[ ]2 Ac Wc Xc2( )2

Mo2 Ms Mo2 3904 tonne m

Safety Factor

SFmMr

Mo2SFm 2.344

Status "Fdn Ok, SFm > 1.5" 1.5 SFmif

"Fdn Not Ok" otherwise Status "Fdn Ok, SFm > 1.5"

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4.5 Check tension

Circumferential reinforcing s teel must be provided in the concrete ringwall to develop the hoopstress produce by lateral soil pressure within the ringwall. The required area As, of circumferentialsteel is determined by:

Tr 31.2 Ka H D d g (see attachment 5)

As1.7Tr ( )

0.9 fy

Tr = ringwall tension, lbKa = lateral earth-pressure coeffic ientd = ringwall height, ftH = shell height, ftD = tank diameter, ftg = spesific gravityfy = rebar yield stress

Tr 31.2 Ka H D d g

Tr 1.868 10 5 lb Tr 84734 kg

Required area (As) of circumferential steel:

As1.7 Tr ( )

0.9 fy As 4001 mm

2

5. FOUNDATION REINFORCEMENT

Ring Wall Re-bar

Required of rebar Area caused by lateral soil pressure within the ringwall (circumferential

rebar) :

As1.7 Tr

0.9 fy As 4001 mm2

Use D25 @ 150

Asteel

422 mm( )

2 2 hw

150 mm Asteel 4055 mm

2

Status "Asteel=>Aps ---- > rebar ok" Asteel Asif

"Change rebar dimension" otherwise Status "Asteel=>Aps ---- > rebar ok"

( inside & outside rebar) D22 @ 150

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Comp ression rebar :

ApvWe 0.2 m D H w( )

0.85fy Apv 5689 mm

2

Use D13@200

Asteel

4

1 mm( )2 2 D( )

200 mm

Asteel 466 mm2

Status "Asteel => Apv -----> rebar OK" Asteel Apvif

"Change rebar" otherwise

Status "Change rebar"

Horizontal Re-bar

min 0.0018

As min Bp hw 0.5 As 0.000324 m2

NAsteel As

132 mm2

NAsteel 2.455 Use 4 D 13

Concrete Bearin g Check

Check :

0.7

Pu 1.7 0.25 D( )2 D 0.2 m( )

2 H w We Pu 204 tonne

P nw 0.85 fc( ) 0.25 D( )2 D 0.2 m( )2 P nw 8785 tonne

Status "OK" P nw Puif

"NOT OK" otherwiseStatus "OK"

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Footing reinforcement

Earth pressure, q

qmax qof

qult 1.4 qmax qult 40.368 tonne m2

Moment at the pedestal face (critical section)

Ldfo do( )

2L 0.5 m

Mz 1.4 0.5 qult L2

m Mz 7.064 tonne m

Diameter of rebar shall be used : dia 13mm

Concrete cover : cover 75mm

Effective depth : d 0.5 m cover 1

2dia d 41.85 cm

Effective width : b 1 m b 1 m

- Ultimate moment :

Mult Mz Mult 7.064 tonne m

Calculations :

RnMult

0.9 b d2

Rn 44.816 tonne m2

0.85 fc

fy1 1

2 Rn

0.85 fc

0.001132

min 0.0018 minif

min minif 0.0018

Area of rebar required : As req b d As req 7.533 cm2

Section of rebar : Asteel 0.25 dia2 Asteel 1.327 cm 2

Number of rebar : nos As req

Asteelnos 5.675

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For Practical used : nos ceil nos( ) nos 6

Distance between rebar : sb

nos 1s 200 mm

For practical Use : Use D-13 @ 200

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ATTACHMENT 6

IMMEDIATE SETTLEMENT (BOWLES) REFERENCE

mathcad - 1000 kl tank1

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