PILECAP DESIGN CALCULATIONS
Project Name : s
Client Name : s
Engineer Name : s
Design File : D:\Working\RCDC\Documentation\ACI Pilecap 2014\PC ACI 318M-14 -5&6.rcdx
Analysis File : C:\Users\Sudeep.PM\OneDrive - Bentley Systems, Inc\Desktop\RCDC -SampleFiles\Staad-Samples\STAAD Sample file new\RCC Wall - RCDC STAAD Demo.std
Analysis Last Modified : 22-Apr-21 12:57:14 PM
Definitions:
1. α = Coefficient of Thermal Expansion
2. ρact = Percentage steel provided
3. A1 = Area of Base for Load Transfer in 'sqm'
4. A2 = Area of Bearing under column in 'sqm'
5. AsfrPrv = Area of face reinforcement provided in 'sqmm'
6. AsfrReq = Area of face reinforcement required in 'sqmm'
7. AstPrv = Area of tensile reinforcement provided in 'sqmm/m'
8. AstReq = Area of tensile reinforcement required in 'sqmm/m'
9. AsvPrv = Area of shear reinforcement provided in 'sqmm/m'
10. AsvReq = Area of shear reinforcement required in 'sqmm/m'
11. Av = Location of section of shear-check from Pile Center
12. Beff = Effective Width for design for bending and shear in 'mm'
13. Beffsfr = Effective Width for design for Face Reinforcement in 'mm'
14. BMux = Factored Design Bending Moment for pile-cap along column D in 'kNm'
15. BMuy = Factored Design Bending Moment for pile-cap along column B in 'kNm'
16. Cx = Width of column in 'mm'
17. Cy = Length of column in 'mm'
18. D = Depth of Pilecap in 'mm'
19. Deff = Effective Depth of Pilecap in 'mm'
20. DfCol = Distance of Pile center to face of column in 'm'
21. Icr = Moment of Inertia of concrete crack section in 'mm4'
22. Mcr = Cracking Moment
23. Mx = Bending Moment in column along Column D (from analysis) in 'kNm'
24. My = Bending Moment in column along Column B (from analysis) in 'kNm'
25. P = Axial load in pile due to Ptotal in 'kN'
26. Pcomb = Axial load in column for a load combination in 'kN'
27. Ppile = Axial Load on pile in 'kN'
28. Ptotal = Total vertical load on pile-cap for a load combination in 'kN'
29. Pmx = Axial load on pile due to moment Mx in 'kN'
30. Pmy = Axial load on pile due to moment My in 'kN'
31. sp = Spacing Between bars at outer most layer in 'mm'
32. Temp1 = Peak Hydration temperature in Degree
33. Temp2 = Seasonal Temperature Variations in Degree
34. Vc = Nominal shear strength provided by concrete in 'kN'
35. Vs Capacity = Shear strength capacity of provided shear reinforcement 'kN'
36. Vu = Design shear force in 'kN'
37. Vus = Design shear force for stirrups in 'kN'
38. Vs = Nominal shear strength provided by shear reinforcement, in 'kN'
39. Vx = Shear in Column along major axis (from analysis) in 'kN'
40. Vy = Shear in Column along minor axis (from analysis) in 'kN'
41. y = Neutral axis depth in 'mm'
42. φ = Strength reduction factor in shear
43. φ1 = Strength reduction factor in concrete bearing
44. Φ1Pnb = Bearing strength of column in 'kN'
 
Code References:
ACI 318M - 14
1. Ptmax : 7.3.3.1, 8.3.3.1, 9.3.3.1
2. Ptmin : 7.6.1.1 & 8.6.1.1/7.7.2.3
3. Vc : 22.6.5
4. Vcper : 22.5.5, 22.5.6
5. AvReq : 22.5.10.5 & 22.6.7
6. Min Shear Reinf : 7.6.3, 9.6.3 & 10.6.2
7. Max Stirrup Spacing : 9.7.6 & 10.7.6
8. One Way Shear Criteria : 13.2 & 13.4
9. Load transfer : 22.8
10. fs,perm : 24.3.2.1
11. fc,perm : 22.2.2.4.1
12. Wcr : Eq 4.2(a)
 
BS 8007 (For Early / Initial Thermal Cracking)
1. Surface Zone for suspended slab : Figure A.1
2. Surface Zone for ground slab : Figure A.2
3. Factors for the calculation of minimum reinforcement : Table A.1



 
Design Code : ACI 318M - 14  
Pilecap No : PC5  
Column No : C5 (700 mm X 700 mm)
Member Ref. No : 401  
       
Concrete Grade : C20  
Steel Grade : Fy420  
Clear Cover : 50 mm
Top of pile-cap below ground : 2.12 m
       
Density of Soil = 18 kN/cum
Founding Depth = 4 m
Pile Capacity in Compression = 2000 kN
Pile Capacity in Tension = 500 kN
Pile Capacity in Shear = 200 kN
Pile Capacity Reduction = 0 %
Pile Overloading = 5 %
Pile Group Overloading = 5 %
Pile Capacity Increase for EQ = 0 %
Pile Capacity Increase for Wind = 0 %
Live Load Reduction = 0 %
       
Consider Capacity Design : Yes  
Consider Overburden Pressure : Yes  
       
No. of Piles = 5  
Pile Diameter = 600 mm
Pile Spacing = 2.5 x Ø
Pilecap Size = 2154 mm (edge)
Pilecap Depth = 1875 mm
Pilecap Offset = 150 mm
Soil Wt. + Pile-cap Wt. = 660.7 kN
       
       
 
Check for Maximum Load on One Pile:
Critical Load Combination : [6] : (LOAD 1: LOAD CASE 1) +0.75 (LOAD 2: LOAD CASE 2) +0.525 (LOAD 3: LOAD CASE 3 EQ-X)
Pcomb = 1199.31 kN
Ptotal = Pcomb + (1 x Soil Wt.) + (1 x Pilecap Wt.)
  = 1860.01 kN
Mx = 85.88 kNm
My = -22.85 kNm
P = Ptotal/ No. of Piles
  = 372 kN
Pmx = 21.78 kN
Pmy = 4.21 kN
       
Maximum load on pile = 397.99 kN
Allowable load on pile = 2000 x 1.05
  = 2100 kN
 
Check for Maximum Load on Pile Group:
Critical Load Combination : [2] : (LOAD 1: LOAD CASE 1) +(LOAD 2: LOAD CASE 2)
Pcomb = 1181.81 kN
Ptotal = Pcomb + (1 x Soil Wt.) + (1 x Pilecap Wt.)
  = 1842.51 kN
Mx = 23.42 kNm
My = -22.11 kNm
       
Maximum load on pile group = 1842.51 kN
Allowable load on pile group = 5 x 2000 x 1.05
  = 10500 kN
 
Check for Maximum shear on Pile Group:
Critical Load Combination : [3] : (LOAD 1: LOAD CASE 1) +0.7 (LOAD 3: LOAD CASE 3 EQ-X)
Pcomb = 1114.89 kN
Ptotal = Pcomb + (1 x Soil Wt.) + (1 x Pilecap Wt.)
  = 1775.59 kN
Mx = 106.19 kNm
My = -21.87 kNm
Vx = 13.85 kN
Vy = 41.81 kN
Maximum shear on pile group = sqrt(13.852 + 41.812)
= 44.05 kN
Shear capacity of pile group = 5 x 200 x 1 x 1
  = 1000 kN
 
Check for Uplift Load on Pile:
No uplift in any pile
 
Design for Bending:
Bottom Reinforcement Along Parallel Edge
Ppile = Capacity of pile
  = 2000 x 1.5
  = 3000 kN
       
Deff = 1795 mm
Beff = 900 mm
DfCol = 0.86 m
BMux = Ppile X DfCol
  = 2590.58 kNm
PtReq = 0.24 %
AstReq (BM) = 4374 sqmm/m
AstPrv = #25 @ 115 C/C
  = 4406.17 sqmm/m
 
Top Reinforcement Along Parallel Edge
D = 1875 mm
AstReq = 3375 sqmm/m
AstPrv = #25 @ 150 C/C
  = 3378.07 sqmm/m
 
Bottom Reinforcement Along Perpendicular Edge
Ppile = Capacity of pile
  = 2000 x 1.5
  = 3000 kN
       
Deff = 1815 mm
Beff = 900 mm
DfCol = 0.93 m
BMuy = Ppile X DfCol
  = 2777.93 kNm
PtReq = 0.26 %
AstReq (BM) = 4646 sqmm/m
AstPrv = #25 @ 105 C/C
  = 4825.81 sqmm/m
 
Top Reinforcement Along Perpendicular Edge
D = 1875 mm
AstReq = 3375 sqmm/m
AstPrv = #25 @ 150 C/C
  = 3378.07 sqmm/m
       
Design for One Way Shear:
Along Parallel Edge
Ppile = Capacity of pile
  = 2000 x 1.5
  = 3000 kN
       
Location of critical section is at d/2 from face of column
Section Location from column center = 1247.5 mm
       
Data for Piles      
Pile No Load (kN) % covered Shear (kN)
P1 3000 0 0
P2 3000 55.66 1330.13
P3 3000 55.66 1330.13
P4 3000 0 0
P5 3000 0 0
 
Design Shear Force (Vu) = Max. of (Shear due to P2+P4, P3+P5, Max. of (P2, P3))
  = 1330.13 kN
Deff = 1795 mm
Beff = 1883.21 mm
φVc = 1910.89 kN
Vu < φVc,  Hence Shear Reinforcement is not required
 
Along Perpendicular Edge
Ppile = Capacity of pile
  = 2000 x 1.5  
  = 3000  
       
Location of critical section is at d/2 from face of column
Section Location from column center = 1257.5 mm
       
Data for Piles      
Pile No Load (kN) % covered Shear (kN)
P1 3000 46.92 1592.38
P2 3000 0 0
P3 3000 0 0
P4 3000 87.54 373.93
P5 3000 87.54 373.93
 
Design Shear Force (Vu) = Max. of (Shear due to P1+P2+P3, P4+P5)
  = 1592.38 kN
Deff = 1815 mm
Beff = 1582.03 mm
φVc = 1634.66 kN
Vu < φ Vc, Hence Shear Reinforcement is not required
 
Design of Face Reinforcement:
AsfrReq = SFR % X D X Beffsfr
= 0.05 X 1875 X 500 / 100
= 469 sqmm
Asfr Prv = 7-#10
= 496 sqmm
 
Check for Load Transfer from Column to PileCap
Critical Load Combination : [20] : 1.2 (LOAD 1: LOAD CASE 1) +(LOAD 2: LOAD CASE 2) -(LOAD 4: LOAD CASE 4 EQ-Y)
P = 1502.89 kN
A2 = 0.49 sqm
A1 = 7.98 sqm
Base Area = 7.98 sqm
A1 < Base Area  
Modification Factor = SquareRoot(A1/A2) < = 2
SquareRoot(A1/A2) = 4.04  
Thus, Modification Factor = 2  
Φ1Pnb = Φ1 x 0.85 x Modification Factor x A2 x Fck x 1000
  = 0.65 x 0.85 x 0.49 x 2 x 20 x 1000
  = 10829 kN
Φ1Pnb > P, Hence Safe.