Staad foundation tank ringwall calculation STIRRUP DESIGN

Tank Foundation Ringwall Design

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Tank Foundation Ringwall Design
API 650
Input Parameters
Footing Geometry
Footing Centreline Diameter (Fd) : 348.960 ft
Minimum Ringwall Width (Fwmin): 1.000 ft
Maximum Ringwall Width (Fwmax): 20.000 ft
Ringwall Height (Fh): 5.000 ft
Compacted Granular Fill (Ds): 3.000 ft
Width Dimension Increment (widinc): 3.000 in
Distance from Tank Shell to Inside Edge of Ringwall (L): 0.600 ft
Bottom of Footing Elevation (BOF): 100.000 ft

Tank Properties
Internal Tank Diameter (Di) : 29.000 ft
Height of Tank Shell (Hs): 16.080 ft
Average Thickness of Tank (Tavg): 1.000 in
Thickness of Tank Bottom (Tbot): 0.310 in
Thickness of Tank Roof (Trf): 0.500 in
Yield Strength of Bottom Plate (Fby): 36.000 ksi
Elastic Modulus of Tank Shell (Es): 29000.000 ksi
Insulation Thickness (Tins): 0.300 in

Fluid Properties
Nominal Product Volume (Voltest) : 11159.000 ft3
Operating Product Volume (Voloper): 11159.000 ft3
Specific Gravity of Liquid Stored (SG): 0.800

Miscellaneous Loading
Internal Operating Pressure (

) : 0.000 psi

oper

Internal Test Pressure (

test):

0.000 psi

Minimum Roof Snow Load (Snow): 0.000 kip/ft2
Snow Importance Factor (Isnow): 0.000
Miscellaneous Dead Load (Misc): 0.000 kip/ft2
Miscellaneous Live Load (Live): 0.000 kip/ft2
% Miscellaneous Weight for Attachments (Misc_wt): 5.000 kip

Wind Load

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Tank Foundation Ringwall Design

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Wind Speed (V) : 80.000 mph
Wind Directional Factor (Kd): 0.950
Wind Exposure (Exp): C
Exposure Case (Case): Case 2
Topographical Factor (Kzt): 1.000
Importance Factor (Iw): 1.150
Gust Wind Effect Factor (G): 0.850
Net Force Coefficient (Cf): 0.800
Partial Wind Case (W%): 50.000

Seismic Load
Spectral Response Acceleration at Short Periods (Ss) : 2.599
Spectral Response Acceleration at Period of 1 sec (S1): 1.073
Factor to adjust 5% damping to 1/2% damping (K): 1.500
Long-Period Transition Period (TL): 12.000 sec
Seismic Use Group (SUG): I
Site Class (Class): A
Impulsive Response Modification Factor (Rwi): 3.500
Convective Response Modification Factor (Rwc): 2.000
Importance Factor (Ieq): 1.000

Design Parameters
Soil Properties
Allowable Bearing Pressure (SBC) : 2.000 kip/ft2
Soil Density (Ysoil): 110.000 lb/ft3
Coefficient of Friction (): 0.400
Soil Bearing Multiplication Factor for Wind and Siesmic Load Case
1.330
(SBF):

Lateral Earth Pressure Coefficient (k_lateral): 0.500
Overturning Safety Ratio (OTR): 1.500
Sliding Safety Ratio (SLR): 2.000

Material Properties
Concrete Compressive Strength (fc) : 4.000 ksi
Concrete Density (Yc): 150.000 lb/ft3
Concrete Cover (cc): 3.000 in
Yield Strength of Rebar (fy): 60.000
Minimum Rebar Size : #8
Maximum Rebar Size : #10
Minimum Stirrup Size : #8
Maximum Stirrup Size : #10

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Tank Foundation Ringwall Design

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Minimum Stirrup Spacing : 6.000 in
Strirrup Spacing Increment : 2.000 in

Calculations
External Diameter of Tank (D) = Di + 2.Tavg : 29.167 ft
Top of Ringwall to Top of Berm (e) = Fd - D : -0.087 ft
Miscellaneous attachment weight is considered for Weight of Tank Shell and Roof

Weight of Tank Shell (Ws): 63.089 kip
Weight of Tank Roof (Wr): 14.345 kip
Weight of Tank Floor (Wf): 8.470 kip
Snow Load (Wsnow): 0.000 kip
Live Load (Wlive): 0.000 kip
Tank Empty Weight (Wempty) = Ws + Wr + Wf : 85.904 kip
Density of Fluid (Y1) = SG.Ywater : 0.04977 kip/ft3
Nominal Fluid Weight (Fluidtest)= Voltest.Y1 : 555.343 kip
Operating Level Fluid Weight (FluidOper)= Voloper.Y1 : 555.343 kip
Tank Test Load (Wtest) = Wempty + Fluidtest : 641.247 kip
Tank Operating Load (Woper) = Wempty + Fluidoper : 641.247 kip

Wind Load Calculations
Wind Load Calculation per ASCE 7-05
Wind Speed : 80.000 mph
Wind Directionality Factor (Kd) : 0.950. . . . per ASCE 7-05 Table 6-4
Topographic Factor (Kzt) : 1.000. . . . per ASCE 7-05 Fig. 6-4
Exposure Case : Case2. . . . per ASCE 6.5.6
Exposure Factor : C. . . . . . . per ASCE 6.5.6
Importance Factor (I) : 1.150. . . . per ASCE 7-05 Table 6-1
Gust Effect Factor (G) : 0.850. . . . per ASCE 7-05 6.5.8
Net Force Coefficient (Cf) : 0.800. . . . per ASCE 7-05 Fig. 6-20 & Fig. 6-21
Partial Wind Percentage : 50.000 %
Design Wind Pressure (P) = 0.00256 Kd.Kz.Kzt.v2.I.G.Cf psf - per ASCE7-05 6.5.10 & 6.5.15
Elevation

Kz

Pressure

Width

ft

-

kip/ft2

ft

Area
ft

2

Shear

Moment

kip

kip-ft

0.000

0.849

15.195

29.167

0.000

0.000

0.000

15.000

0.849

15.195

29.167

437.500

4.520

33.903

16.080

0.861

15.419

29.167

31.500

0.330

5.132

=4.851

=39.035

Seismic Load Calculations
Design Spectral Response Acc. Parameter at Short Period (SDS) : 1.386. . . . per ASCE 7-05 11.4.1

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Tank Foundation Ringwall Design

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Design Spectral Response Acc. Parameter at 1 sec (SD1) : 0.572. . . . per ASCE 7-05 11.4.1
TO : 0.083 s. . . . per ASCE 7-05 Table 15.4-2
TS : 0.413 s. . . . per ASCE 7-05 11.5.1
DH : 1.746. . . . Ratio of Diameter to Liquid Height

0.588. . . . Per API 650 E.4.5.2-c

5.717 s. . . . Convective Period API 650 E4.5.2-b
0.396 . . . . Impulsive Spectral Acceleration Parameter API 650

E.4.6.1-1

0.075 . . . . Convective Spectral Acceleration Parameter API 650
E.4.6.1-1

Seismic Load Calculation per API 650 Section E
Parameter

Operating Condition

Test Condition

Unit

Impulsive Product
Seismic Weight (Wi)

384.731

384.731

kip

Convectve Product
Seismic Weight (Wc)

249.973

249.973

kip

Impulsive Component
Base Shear (Vi)

186.393

186.393

kip

Convective
Component Base
Shear (Vc)

18.771

18.771

kip

Total Design Base
Shear (V)

187.336

187.336

kip

Impulsive Fluid Force
Height (Xi)

6.263

6.263

ft

Convective Fluid
Force Height (Xc)

10.486

10.486

ft

Ringwall Moment
(Mrw)

1262.012

1262.012

kip-ft

Overturning Effect of Seismic Forces (Slab Moment Calculation)
Overtuning Seismic Forces per API 650 Section E
Parameter

Operating Condition

Test Condition

Unit

Slab Moment
Impulsive Fluid
Height (Xis)

11.830

11.830

ft

Slab Moment
Convective Fluid
Height (Xcs)

10.486

10.486

ft

Slab Moment (Ms)

2103.968

2103.968

kip-ft

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Tank Foundation Ringwall Design

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Vertical Seismic Force Coefficient
0.265

Vertical Seismic per API E.6.1.3

Freeboard Check
-0.622 ft

Available Freeboard Height,

Vertical Seismic per API E.6.1.3

Af = 0.105

per API650 E.7.2-2, E.7.2-3, E.7.2-4 & E.7.2-5

1.532 ft
Freeboard Requirement,

per API650 E.7.2-1

1.073 ft

FB< FR, Hence Freeboard Requirement Is Not Satisfied

Internal Pressure Calculation
Total upward force due to internal pressure :
= 0.000 kip

= 0.000 kip

Internal pressure around the perimeter :
= 0.000 kip/ft

= 0.000 kip/ft

Load Combination

Allowable Stress Design Factors (Service Loads)
Empty

Operating

Test

0.00

0.00
1.00
0.00
1.00
0.00
0.00
0.00
1.00
1.00
0.00
0.00
0.00
0.00

1.00
0.00
0.00
1.00
0.00
1.00
1.00
1.00
0.00
0.00
1.00
1.00
1.00
1.00

0.00

1.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

Internal
Pressure
0.00
0.00
0.00
0.00
0.40
0.40
0.40
0.40
1.00
1.00
1.00
1.00
0.00
0.00

External
Pressure
1.00
0.00
0.40
0.40
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.40
0.00

Test
Pressure
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

0.00
0.00
0.00
0.00

Snow

Live

Wind

Earthquake

0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.00
0.00
0.40
0.00
0.40
0.10
0.10

0.00
0.00

0.00
0.00
0.00
0.00
1.00
0.00
0.40
0.00
0.40
0.00
0.00
0.00

0.00
0.00
1.00
1.00
1.00
1.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

0.00
0.00

0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.00
1.00

Snow

Live

Wind

Earthquake

0.00

0.00

0.00

0.00

Ultimate Stress Design Factors

Empty

Operating

Test

0.00

1.00

0.00

Internal
Pressure
0.00

External
Pressure
1.00

Test
Pressure
0.00

file://C:\foundation\Source 5.2\Bin\Debug\CalcXsl\Tank.xml

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Tank Foundation Ringwall Design

0.00
1.00
0.00
1.00
0.00
0.00
0.00
1.00
1.00
0.00
0.00
0.00
0.00

0.00
0.00
1.00
0.00
1.00
1.00
1.00
0.00
0.00
1.00
1.00
1.00
1.00

1.00

0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

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0.00
0.00
0.00
0.40
0.40
0.40
0.40
1.00
1.00
1.00
1.00
0.00
0.00

0.00

0.40
0.40
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.40
0.00

0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

0.00
0.00
0.00

0.00
0.00
0.00
1.00
0.00
0.40
0.00
0.40
0.10
0.10

0.00
0.00
0.00
0.00
0.00
1.00
0.00
0.40
0.00
0.40
0.00
0.00
0.00

0.00
1.00
1.00
1.00
1.00

0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00

0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.00
1.00

Applied Loads At Top of Ringwall- Service Stress Level
Axial
(kip)
-641.247
-641.247
-85.904
-641.247

-85.904
-641.247
-641.247
-641.247
-85.904
-85.904
-641.247
-641.247
-471.092
-471.092

LC
1
2
3
4
5
6
7
8
9
10
11
12
13
14

Shear
(kip)
0.000

0.000
4.851
4.851
4.851
4.851
0.000
0.000
0.000
0.000
0.000
0.000
187.336
187.336

Moment
(kip-ft)
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
1262.012
1262.012

Applied Loads At Top of Ringwall- Strength Level
LC
15
16
17
18
19
20
21
22
23
24
25
26
27
28

Axial
(kip)
-641.247
-641.247
-85.904
-641.247
-85.904
-641.247
-641.247
-641.247
-85.904
-85.904

-641.247
-641.247
-471.092
-471.092

Shear
(kip)
0.000
0.000
4.851
4.851
4.851
4.851
0.000
0.000
0.000
0.000
0.000
0.000
187.336
187.336

Moment
(kip-ft)
0.000
0.000
0.000
0.000
0.000
0.000

0.000
0.000
0.000
0.000
0.000
0.000
1262.012
1262.012

Design Calculations
Tank Stability
Effective Specific Gravity of Liquid,

file://C:\foundation\Source 5.2\Bin\Debug\CalcXsl\Tank.xml

0.04448 kip/ft^3

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Tank Foundation Ringwall Design

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Wa- Resisting force of tank contents
per unit length of shell circumference
that may be used to resist the shell
overturning moment

12.666 kip/ft

Tank Shell and Roof Weight Per Unit
Length,

0.845 kip/ft

Snow load per unit length,

0.000 kip/ft

per API650 E.6.2.1.1-1b

Governing Load Case No for Tank Stability Check: 0
Liquid Weight on Tank Floor : 0.831 kip/ft^2
Internal Pressure : 0.000 kip/ft^2
Liquid Density per unit Length : 0.000 kip/ft
Factored Ring wall moment,

1262.012 kip-ft

0.111

Anchorage Ratio,
J<=1.54 , Tank is stable

Internal Soil Bearing Check
(Below Tank Floor)
Maximum Internal soil bearing check (below tank bottom plate) for dead load case
0.003 kip/ft^2
Maximum Internal soil bearing check (below tank bottom plate) for seismic load case

0.002 kip/ft^2

Governing Internal Soil Bearing
SBint = max(SBint_dl,SBint_eq) = 0.003 kip/ft^2
SBint < SBC, Hence Internal Soil Bearing is OK

Ringwall Soil Bearing
Governing Load Case For Ringwall Soil Bearing Check: 1

Allowable Ring Wall Soil Bearing Check: 2.000 kip/ft^2
Maximum Ring Wall Soil Bearing : 1.962 kip/ft^2

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Tank Foundation Ringwall Design

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SBring < SBC, Hence Ringwall Soil Bearing is OK
Ringwall Dimension After Soil Bearing Check
Footing Width (FW) : 3.250 ft
Footing Depth (Fh) : 5.000 ft
Entire Foundation Self Weight
Wfdn_total : 223.960 kip

Overturning Check

Governing Load Case for Overturning Check: 1
Governing Overturning Moment (Ms) 2103.968 kip-ft
5.040
Overturning Safety Ratio =
Tank Foundation Passes Overturning Check

Sliding Check
Governing Load Case For Sliding Check : 1
Total Shear

: 187.336 kip
1.224

Tank Foundation Fails In Sliding Check

Reinforcement Calculations
Hoop Steel
Governing Load Case : 1
Unfactored Hoop Tension : 80.659 kip

per PIP STE03020 5.6.3.3

Area of Hoop steel
required :

= 5.850 in2

Per PIP STE03020 5.6.3.4
and API 650 B.4.2.3

Twist Steel
Governing Load Case : 1
As_Twist : 7.800 in2
Twist Moment Lever Arms
z_1 : 0.080 ft
z_2 : 0.853 ft
PT = Total Load on Tank
WP = Product load on Tank Bottom
E = Linear Earthquake Load on Ringwall
L = Distance from tank shell to inside edge of ringwall
Twist Moment in Ringwall
per PIP STE03020 4.6.5.6 per Section 10.9 of Roark's Formulas
for Stress and Strain and per PIP STE03020 4.6.5.6

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Tank Foundation Ringwall Design

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Mu : 51.945 kip-ft
Mimimum Rebar Size : #8
Maximum Rebar Size : #10
Minimum Stirrup Size : #8
Maximum Stirrup Size : #10
Governing Load Case : 1
:

:

4.614 ft

7.800 in2

0.070 kip/ft
:
0.000
:

:

7.800 in2

: : 13.650 in2

Total Area of Reinfocement Required

Stirrup Design
:3.510 in2

Minimum stirrup requirement :
Minimum Strirrup Spacing : 6.000 in
Maximum Stirrup requirement : 18.000 in
Reinforcement distribution is based on Temperature
and Shrinkage steel requirement per API650 B4.2.3
and per ACI 318 14.3
Vertical Steel Requirement :

7.020 in2
11.700 in2

Horizontal Steel Requirement :
Provide #8 - 10

Reinforcement Bars Along The Section of
Ringwall

Provide #9 @ 6.00

in o.c. Two Legged Stirrups
Print Calculation Sheet

file://C:\foundation\Source 5.2\Bin\Debug\CalcXsl\Tank.xml

9/24/2010