3.1- CALCULATION FOR - FOUNDATION 3.1.1- COMPUTER MODEL A "plate on elastic foundation" model is set up in STAAD-Pro. The soil spring applies on are the corresponding contrib bases.The forces applied on the model are basically the reactions of relavant STAAD-Pro model for corresponding struct typical mat foundation for Pipe rack is given below 3D RENDERED VIEW FOR FOUNDATION General - Item No. - Service - Type Ref Doc. Note: Loading data is taken form this sheet Foundation drawing - Refer to Dwg.No. Elevation - Top of Foundation Ele EL + 98.500 (m) - Unit Elevation GH=+ 100.000 (m) (LPP EL) - Ground water table GWL - (m) Foundation Geomatry Length (X-Dir. 7 (m) Width (Y-Dir.) 7 (m) Thickness 1.5 (m) Col. Size (X) 750 (mm) Col. Size (Y) 750 (mm) Col ht abv gr 300 (mm) Socket Thickness 0 (mm) Gap b/w Socket and Col. 0 (mm)
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Order no : 25173Doc No : 1334001Date: 04/21/2023
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3.1- CALCULATION FOR - FOUNDATION
3.1.1- COMPUTER MODEL
A "plate on elastic foundation" model is set up in STAAD-Pro. The soil spring applies on are the corresponding contributry area bases.The forces applied on the model are basically the reactions of relavant STAAD-Pro model for corresponding structure. The typical mat foundation for Pipe rack is given below
3D RENDERED VIEW FOR FOUNDATION
General
- Item No.- Service- Type
Ref Doc. Note: Loading data is taken form this sheet
Foundation drawing- Refer to Dwg.No.
Elevation
- Top of Foundation Elev. EL + 98.500 (m)
- Unit Elevation GH=+ 100.000 (m) (LPP EL)- Ground water table GWL - (m)
Socket Thickness 0 (mm)Gap b/w Socket and Col. 0 (mm)
Order no : 25173Doc No : 1334001Date: 04/21/2023
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ELEMENT NUMBERS IN STAAD
PLATE NUMBER
Column Strip Column StripMiddle Strip
Order no : 25173Doc No : 1334001Date: 04/21/2023
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3.1.1.1- DETRMINATION OF SOIL SPRING
For limiting soil settlement to the required 30mm, the estimated allowable bearing pressure given for this particular raft foundation for 10m width is given as 400kN/m2.(For Transient loading condition, the bearing pressure can be increased by 33%.)
modulus of subgrade reaction for soil is 40000 kN/m3 (Soil report)
3.1.2- STABILITY CHECKS
3.1.2.1- BEARING CHECK
Max support reaction
Fy kN Node L/CMax Fy 52.25 31 1 LC 1000
STAAD GLOBAL AXIS
Max bearning pressure from STAAD
Pr N/mm2 Node L/CMax 0.243 1 1 LC 1000
Allowable Bearing Capacity shear failure is 400 (kN/m2)
The corresponding area for this spring 0.25 (m2)
The bearing pressure for this maximum load is 209 (kN/m2)
The bearing pressure from staad 243 (kN/m2)
OK
3.1.2.2- SETTLEMENT CHECK
y mm Node L/CMax y 5.846 1 1 LC 1000 5.846
Min y -6.07 2 1 LC 1000 6.07
Allowable Settlement 30 mmActual settlement 6.07 mm
OK
3.1.2.3- SLIDING CHECK
FX kN Fz kN Fy L/CMax Fx 330 334 1000 (Combining horz loads of all columns)
Min Fx -245 334 1300Max Fz 325 334 1200Min Fz -325 334 1600
Coefficeint of friction 0.4 FOS (Normal Condition) 1.50Height of overburden soil 1.00 (m)
Soil density 18.00
Concrete density 24.00Overburden weight on foundation 882.00 (kN)Foundation Self wt. 1764.00 (kN)
Sliding Force 463.17 (kN)Resisting Force 1192 (kN)FOS: Factor of saftey 2.57 OK
3.1.2.4- OVERTURNING CHECK
Moment w.r.t one corner of footing FOS (Normal Condition) 1.50Overturning moment from column loads
Overturning moment -3990.64 (kN)Resisting moment 12117.561 (kN)FOS: Factor of saftey 3.04 OK
(kN / m3)
(kN / m3)
Moment horz loads
(kNm)
Moment vert loads
(kNm)
y
X
Z
Order no : 25173Doc No : 1334001Date: 04/21/2023
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3.1.3- REINFORCMENT DESIGN OF MAT FOUNDATION
3.1.3.1- Flexure Reinforcement
A- Plate Maximum Moment Results (kNm)
North Side Foundation X-Direction Y-Direction Plate L/C Column Strip Middle Strip Column Strip Middle Strip Bottom Top Bottom Top Bottom Top Bottom Top
The maximum moment along transverse direction is found to occur near the column location and so on. So the foundation is divided into three strips. Two strips are column strips and the third is middle strip. The reinforcement in the each strip will be
NO STIRRUPS REQUIRED PROVIDE D12 @1573mm cross ties
Instead of cross ties, mid layer reinforcement is provided
Punching shear stress (N/mm2)
Allowable Punching shear stress (N/mm2)
(N/mm2) (N/mm2) (mm) (mm)
N/mm2
N/mm2
N/mm2
fAvFyd/(Vu-fVc) fAvFyd/(Vu-fVc)
f =
Vu-fVc= Vu-fVc=
y
X
Z
8474L-015-CN-1732-161 OP Center Job No. 0- 3952-20
OP Center Doc. No. C-015-1323-161
3.1- CALCULATION FOR - FOUNDATION
3.1.1- COMPUTER MODEL
A "plate on elastic foundation" model is set up in STAAD-Pro. The soil spring applies on are the corresponding contributry area bases.The forces applied on the model are basically the reactions of relavant STAAD-Pro model for corresponding structure. The typical mat foundation for Pipe rack is given below
3D RENDERED VIEW FOR FOUNDATION
General
- Item No.- Service- Type
Ref Doc. Note: Loading data is taken form this sheet
Foundation drawing- Refer to Dwg.No.
Elevation
- Top of Foundation Elev. EL + 98.500 (m)
- Unit Elevation GH=+ 100.000 (m) (LPP EL)- Ground water table GWL - (m)
8474L-015-CN-1732-161 OP Center Job No. 0- 3952-20
OP Center Doc. No. C-015-1323-161
3.1.1.1- DETRMINATION OF SOIL SPRING
For limiting soil settlement to the required 10mm, the estimated allowable bearing pressure given for this particular raft foundation for 10m width is given as 400kN/m2.(For Transient loading condition, the bearing pressure can be increased by 33%.)
modulus of subgrade reaction for soil is 40000 kN/m3 (Soil report)
Note: Considering the Coupling effect, the exterior edge springs are doubled in the model as per ACI-336.2.
3.1.2- STABILITY CHECKS
3.1.2.1- BEARING CHECK STAAD GLOBAL AXIS
Max support reaction
Fy kN Node L/CMax Fy 52.25 31 1 LC 1000
Max bearning pressure from STAAD
Pr N/mm2 Node L/CMax 0.243 1 1 LC 1000
Allowable Bearing Capacity shear failure is 400 (kN/m2)
The corresponding area for this spring 0.25 (m2)
The bearing pressure for this maximum load is 209 (kN/m2)
The bearing pressure from staad 243 (kN/m2)
OK
3.1.2.2- SETTLEMENT CHECK
y mm Node L/CMax y 5.846 1 1 LC 1000 5.846
Min y -6.07 2 1 LC 1000 6.07
Allowable Settlement 30 mmActual settlement 6.07 mm
OK
3.1.2.3- SLIDING CHECK
FX kN Fz kN Fy L/CMax Fx 330 334 1000 (Combining horz loads of all columns)
Min Fx -245 334 1300Max Fz 325 334 1200Min Fz -325 334 1600
Coefficeint of friction 0.4 FOS (Normal Condition) 1.50Height of overburden soil 1.00 (m)
Soil density 18.00
Concrete density 24.00Overburden weight on foundation 882.00 (kN)Foundation Self wt. 1764.00 (kN)
Sliding Force 463.17 (kN)Resisting Force 1192 (kN)FOS: Factor of saftey 2.57 OK
3.1.2.4- OVERTURNING CHECK
Moment w.r.t one corner of footing FOS (Normal Condition) 1.50Overturning moment from column loads
8474L-015-CN-1732-161 OP Center Job No. 0- 3952-20
OP Center Doc. No. C-015-1323-161
Resisting moment 12117.561 (kN)FOS: Factor of saftey 3.04 OK
8474L-015-CN-1732-161 OP Center Job No. 0- 3952-20
OP Center Doc. No. C-015-1323-161
3.1.3- REINFORCMENT DESIGN OF MAT FOUNDATION
3.1.3.1- Flexure Reinforcement
A- Plate Maximum Moment Results (kNm)
North Side Foundation X-Direction Y-Direction Plate L/C Column Strip Middle Strip Column Strip Middle Strip Bottom Top Bottom Top Bottom Top Bottom Top
The maximum moment along transverse direction is found to occur near the column location and so on. So the foundation is divided into three strips. Two strips are column strips and the third is middle strip. The reinforcement in the each strip will be
fy 460 = 1000 (mm)
fc' 40 = 1000 (mm)
75 mm h = 1500 (mm)
75 mm
Limits for Re-bar ratio areMinimum p1 = 0.0018*( h/d ) (ACI 318 Sec 7.12.2) PLATE LOCAL AXIS