FOOTING DESIGN CALCULATIONS

Project Name : sdgsdg

Client Name : dsgfsd
Engineer Name : asdas
Design File : E:\STAAD FILES\GERDY\2.26.24\footing.rcdx
Analysis File : E:\STAAD FILES\GERDY\2.26.24\2.26.24.STD
Analysis Last : 27/02/2024 9:17:02 am
Modified
Definitions:
1. A = Plan area of footing base in sqmm
2. Ast (min) = Area of longitudinal reinforcement as per code
cl. 7.12.2.1 in sqmm
3. Ast Prv = Area of tensile reinforcement provided in sqmm
4. Ast Rqd = Area of longitudinal reinforcement from bearing
moment and minimum % steel provided by user
and as per code cl 7.12.2.1 in sqmm
5. Av = Area of shear reinforcement required in sqmm
6. AvPrv = Area of shear reinforcement provided in sqmm
7. A1 = Bearing area of footing at slope of 1:2 in sqmm
8. A2 = C/s Area of column in sqmm
9. B = Width of footing base in mm
10. Beff = Effective width of footing in mm
11. Boff = Footing offset along B in mm
12. BoffB = Footing offset along B above column in plan
13. BoffT = Footing offset along B below column in plan
14. B1 = Width of sloped footing at top in mm
15. ColOff = Column offset in sloped footing in mm
16. D = Depth of footing in mm
17. d = Effective Depth of footing in mm
18. Dfd = Depth of founding layer in m
19. Dw = Ground water level in m
20. Ec = Modulus of elasticity of concrete in N/sqmm
21. Es = Modulus of elasticity of steel in N/sqmm
22. Foss = Safety factor against sliding
23. Fosu = Safety factor against uplift
24. Fst = Stress in steel in N/sqmm
25. F'c = Characteristic strength of concrete in N/sqmm
26. L = Length of footing base in mm
27. Leff = Effective length of footing in mm
28. Loff = Footing offset along L in mm
29. LoffL = Footing offset along L on left side of column
30. LoffR = Footing offset along L on right side of column
31. L1 = Length of sloped footing at top in mm
32. Mx = Bending Moment along column D in kN-m
33. Mex = Eccentricity moment along column D
34. Mxx = Total Bending Moment along column D (Mx +
Mex)
35. My = Bending Moment along column B in kN-m
36. Mey = Eccentricity moment along column B
37. Myy = Total Bending Moment along column B (My +
Mey)
38. Muy = Factored moment along column B in kN-m
39. Mux = Factored moment along column D in kN-m
40. Netdown = Net downward load in kN
41. OB = Maximum permissible offset on bottom side of
column
42. OL = Maximum permissible offset on left side of
column
43. OR = Maximum permissible offset on right side of
column
44. OT = Maximum permissible offset on top side of
column
45. P = Axial load for footing sizing in kN
46. P1 = Soil pressure at corner 1 in kN/sqm
47. P2 = Soil pressure at corner 2 kN/sqm
48. P3 = Soil pressure at corner 3 kN/sqm
49. P4 = Soil pressure at corner 4 kN/sqm
50. Ntot = Design vertical load on footing in kN
51. q = Surcharge Load in kN/sqm
52. sp = Spacing Between bars at outer most layer in
mm
53. SPu = Upward Soil Pressure in kN/sqm
54. SPuL = Upward Soil Pressure from left
55. SPuR = Upward Soil Pressure from right
56. SPuB = Upward Soil Pressure from bottom
57. SPuT = Upward Soil Pressure from top
58. Temp1 = Peak Hydration temperature in Degree
59. Temp2 = Seasonal Temperature Variations in Degree
60. Vs Capacity = Shear strength capacity of provided shear
reinforcement kN
61. Vu = Design shear force in kN
62. Vus = Strength of shear reinforcement in kN
63. Vx = Shear along major axis in kN
64. Vy = Shear along minor axis in kN
65. Waterpr = Upward water pressure in kN/sqm
66. Waterup = Upward force due to water in kN/sqm
67. WFoot = Add. Wt. due to difference in concrete and soil
density in kN
68. WFootc = Weight of footing and column with concrete
density in kN
69. WSoil = Weight of soil covering footing area in kN
70. Zx = Section modulus of footing base along L in mm 3
71. Zy = Section modulus of footing base along B in mm3
72. Vs = Nominal shear strength provided by shear
reinforcement, in KN
73. Vc = Nominal shear strength provided by concrete in
kN
74. Cx = Width of column in mm
75. Cy = Length of Column in mm
76. Pcr(axial) = Design pressure at the critical section kN/sqm
77. Φ = Strength reduction factor in shear
78. Φ1 = Strength reduction factor in concrete bearing
79. Φ1Pnb = Bearing strength of column in kN

Code References:
ACI 318M:2011
Sr.No
Item Clause / Table
.
1. Ptmax : 10.3.5
2. Ptmin : 7.12.2.1/10.5.4
3. Vc : 11.11.2.1
4. Av : 11.4.7.2
5. Max Stirrup Spacing : 11.4.5.1
6. Vs : 11.4.7.9

Design Code : ACI 318M - 2011

Footing No : FC5

Column No : C5 ( 400mm X 250mm)

Analysis No : 47

Concrete Grade : C20

Steel Grade : Fy275

Clear Cover : 75 mm

Dfd : 1.5 M

Dw : 1M

Density of Soil = 18 KN/cuM

Soil Bearing Capacity = 150 kN/sqm

Permissible SBC Increase for = 33 %
EQ
Permissible SBC Increase for = 33 %
Wind
Live Load Reduction = 0 %

Permissible area of loss of = 0 %

contact

Design cross section by : Average pressure

Consider overburden
pressure

Footing Type : Pad

Footing Size (L x B x D) : 1200mm X 1050mm X 300mm

Effective Self Weight = 9.45 KN

Offset Along L (Loff) = 400 mm

Offset Along B (Boff) = 400 mm

Check For Maximum Soil Pressure:

Critical Load Combination = [2] : (LOAD 3: DL) +(LOAD 4: LL)

Pcomb = 171.79 kN
P
= Pcomb + Effective Self Weight
P = 181.24 kN
Mx = 0 kNm
My = 0 kNm
P/A = 143.84 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm
Maximum Soil Pressure = 143.84 kN/sqm
Allowable Soil Pressure = 1x150 kN/sqm
= 150 kN/sqm

Check For Minimum Soil Pressure:

Critical Load Combination = [10] : 0.6 (LOAD 3:
DL) +0.6 (LOAD 1: EX)
Pcomb = 86.08 kN
P = Pcomb + Effective Self Weight x 0.6
P = 91.75 kN
Mx = 0 kNm
My = 0 kNm
P/A = 72.82 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm
Minimum Soil Pressure = 72.82 kN/sqm
> 0

Design For Bending:

Bottom Reinforcement Along L:
Critical Load Combination = [15] : 1.2 (LOAD 3: DL) +1.6 (LOAD 4: LL)
Pu = 215.67 kN
Mux = 0 kNm
Muy = 0 kNm
P/A = 171.17 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm

Deff = 217 mm
Beff = 1050 mm
SPu = 171.17 kN/sqm
Mu = SPu X B X Loff X Loff / 2
= 14.38 kNm
Ast Rqd = 866 sqmm
Ast (min) = 866 sqmm
Ast Prv = 7 - #13 @ 175
= 887 sqmm
Distributed Across Total Width

Bottom Reinforcement Along B:

Critical Load Combination = [15] : 1.2 (LOAD 3: DL) +1.6 (LOAD 4: LL)
Pu = 215.67 kN
Mux = 0 kNm
Muy = 0 kNm
P/A = 171.17 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm

Deff = 201 mm
Leff = 1200 mm
SPu = 171.17 kN/sqm
Mu = SPu X L X Boff X Boff / 2
= 16.43 kNm
Ast Rqd = 990 sqmm
Ast (min) = 990 sqmm
Ast Prv = 8 - #13 @ 175
= 1013 sqmm
Distributed Across Total Length

Design For Shear:

One Way Shear Along L:
Critical Section @ d from Column Face
= 217 mm
Critical Load Combination = [15] : 1.2 (LOAD 3: DL) +1.6 (LOAD 4: LL)
Pu = 215.67 kN
Mux = 0 kNm
Muy = 0 kNm
P/A = 171.17 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm

Deff = 217 mm
Beff = 1050 mm
SPu = 171.17 kN/sqm
Vu = SPu X (Loff - d) X B
= 32.89 kN
φVc = 134.54 kN
Vu < φVc

One Way Shear Along B:

Critical Section @ d from Column Face

= 201 mm
Critical Load Combination = [15] : 1.2 (LOAD 3:
DL) +1.6 (LOAD 4: LL)
Pu = 215.67 kN
Mux = 0 kNm
Muy = 0 kNm
P/A = 171.17 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm

Deff = 201 mm
Leff = 1200 mm
SPu = 171.17 kN/sqm
Vu = SPu X (Boff - d) X L
= 40.87 kN
φVc = 124.62 kN
Vu < φVc

Design For Punching Shear:

Critical Section @ d/2 from Column Face
= 104 mm

Critical Load Combination = [15] : 1.2 (LOAD 3: DL) +1.6 (LOAD 4: LL)
Pu = 215.67 kN
Mux = 0 kNm
Muy = 0 kNm
P/A = 171.17 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm

Deff = 209 mm
Leff = 609 mm
Beff = 459 mm
SPu = Average Pressure
= 171.17 kN/sqm
Vu = { N - Pcr(axial)[ (Cx +
d) X (Cy + d)]}
= 167.82 kN
φVn = 748.676 kN
φVc = 494.126 kN
No Shear
Vu < φVc Reinforcement
Required

Load Transfer Check For Load Transfer From Column To Footing

Critical Load Combination = [15] : 1.2 (LOAD 3:
DL) +1.6 (LOAD 4: LL)
Pu = 215.67 kN
A2 = 0.1 sqm
A1 = 2.32 sqm
Base Area = 1.26 sqm
A1 > Base Area
Thus, A1 = 1.26
Modification Factor = SquareRoot(A1/A2) <
=2
SquareRoot(A1/A2) = 3.5496
Thus, Modification Factor = 2
Φ1 = 0.65
Φ1Pnb = Φ1 X 0.85 X Fck X Modication Factor X
Column Area
= 2210 kN
Φ1Pnb > Pu, Hence Safe.