Tuesday, August 26, 2025

FOOTING DESIGN CALCULATIONS

Project Name : S. FERNANDO BAMABNG
Client Name : AR. MENDOZA
Engineer Name : FRANZ CESAR DULAY
Design File : C:\Users\franz\OneDrive\Documents\projects\AR. MENDOZA\SAN
FERNANDO BAMBANG PROJECT\FOOTING DESIGN\FOOTING
DESIGN.rcdx
Analysis File : C:\Users\franz\OneDrive\Documents\projects\AR. MENDOZA\SAN
FERNANDO BAMBANG PROJECT\STRUC ANALYSIS WITH
DESIGN\SAN FERNANDO BAMBANG PROJECT.STD
Analysis Last Modified : 8/25/2025 11:54:11 PM

Definitions:
1. A = Plan area of footing base in 'sqmm'
2. Ast (min) = Area of longitudinal reinforcement as per code 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 in
'sqmm'
5. Av = Area of shear reinforcement required in 'sqmm/m'
6. AvPrv = Area of shear reinforcement provided in 'sqmm/m'
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 in 'mm'
13. BoffT = Footing offset along B below column in planin 'mm'
14. B1 = Width of sloped footing at top in 'mm'
15. ColOff = Column offset in sloped footing in 'mm'
16. Cx = Width of column in 'mm'
17. Cy = Length of Column in 'mm'
18. D = Depth of footing in 'mm'
19. d = Effective Depth of footing in 'mm'
20. Dfd = Depth of founding layer in 'm'
21. Dw = Ground water level in 'm'
22. Ec = Modulus of elasticity of concrete in 'N/sqmm'
23. Es = Modulus of elasticity of steel in 'N/sqmm'
24. Foss = Safety factor against sliding
25. Fosu = Safety factor against uplift
26. Fst = Stress in steel in 'N/sqmm'
27. F'c = Characteristic strength of concrete in 'N/sqmm'
28. Icr = Moment of Inertia of concrete crack section in 'mm4'
29. L = Length of footing base in 'mm'

1
 Tuesday, August 26, 2025

30. Leff = Effective length of footing in 'mm'

31. Loff = Footing offset along L in 'mm'
32. LoffL = Footing offset along L on left side of column in 'mm'
33. LoffR = Footing offset along L on right side of column in 'mm'
34. L1 = Length of sloped footing at top in 'mm'
35. Mcr = Cracking Moment
36. Mx = Bending Moment along column D in 'kNm'
37. Mex = Eccentricity moment along column D
38. Mxx = Total Bending Moment along column D (Mx + Mex)
39. My = Bending Moment along column B in 'kNm'
40. Mey = Eccentricity moment along column B
41. Myy = Total Bending Moment along column B (My + Mey)
42. Muy = Factored moment along column B in 'kNm'
43. Mux = Factored moment along column D in 'kNm'
44. Netdown = Net downward load in 'kN'
45. OB = Maximum permissible offset On bottom side Of column
46. OL = Maximum permissible offset On left side Of column
47. Or = Maximum permissible offset On right side Of column
48. OT = Maximum permissible offset On top side Of column
49. P = Axial load For footing sizing In 'kN'
50. Pcr(axial) = Design pressure at the critical section in 'kN/sqm'
51. P1 = Soil pressure at corner 1 In 'kN/sqm'
52. P2 = Soil pressure at corner 2 'kN/sqm'
53. P3 = Soil pressure at corner 3 'kN/sqm'
54. P4 = Soil pressure at corner 4 'kN/sqm'
55. q = Surcharge Load In 'kN/sqm'
56. sp = Spacing Between bars at outer most layer In 'mm'
57. SPu = Upward Soil Pressure In 'kN/sqm'
58. SPuL = Upward Soil Pressure from left
59. SPuR = Upward Soil Pressure from right
60. SPuB = Upward Soil Pressure from bottom
61. SPuT = Upward Soil Pressure from top
62. Temp1 = Peak Hydration temperature In Degree
63. Temp2 = Seasonal Temperature Variations In Degree
64. Vs Capacity = Shear strength capacity Of provided shear reinforcement
'kN'
65. Vs = Nominal shear strength provided by shear reinforcement, in
'kN'
66. Vc = Nominal shear strength provided by concrete in 'kN'
67. Vu = Design shear force in 'kN'
68. Vus = Strength of shear reinforcement in 'kN'
69. Vx = Shear along major axis in 'kN'
70. Vy = Shear along minor axis in 'kN'
71. Waterpr = Upward water pressure in 'kN/sqm'
72. Waterup = Upward force due to water in 'kN/sqm'

2
 Tuesday, August 26, 2025

73. WFoot = Add. Wt. due to difference in concrete and soil density in
'kN'
74. WFootc = Weight of footing and column with concrete density in 'kN'
75. WSoil = Weight of soil covering footing area in 'kN'
76. y = Neutral axis depth.
77. Zx = Section modulus of footing base along L in 'mm4'
78. Zy = Section modulus of footing base along B in 'mm4'
79. Φ = Strength reduction factor in shear
80. Φ1 = Strength reduction factor in concrete bearing
81. 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
7. fs,perm : 10.6.4
8. fc,perm : 10.2.7.1
9. Wcr : Eq 4.2(a)

Design Code : ACI 318M - 2011

Footing No : FC10
Column No : C10 ( 400mm X 250mm)
Analysis No : 119

Concrete Grade : C20

Steel Grade : Fy410
Clear Cover : 75 mm
Dfd : 1.5 m
Dw : 2m

Density of Soil = 18 kN/cum

Soil Bearing Capacity = 100 kN/sqm
Gross Bearing Capacity = 127 kN/sqm
Permissible SBC Increase for EQ = 0 %
Permissible SBC Increase for Wind = 0 %
Live Load Reduction = 0 %
Permissible area of loss of contact = 0 %

3
 Tuesday, August 26, 2025

Design cross section by Consider : Average pressure

overburden pressure
Consider overburden pressure

Footing Type : Pad

Footing Size (L x B x D) : 1500mm X 1500mm X 250mm
Soil Wt. + Footing Wt. = 62.44 kN

Offset Along L (Loff) = 550 mm

Offset Along B (Boff) = 625 mm

Check For Maximum Soil Pressure:

Critical Analysis Load = 118
Combination
Critical Load Combination = [18] : 0.9 (LOAD 5: DL) +(LOAD 2: EQ -X)
Pcomb = 160.11 kN
P = Pcomb + Effective Self Weight x 0.9
P = 216.3 kN
Mx = 0 kNm
My = 0 kNm
P/A = 96.13 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm
Maximum Soil Pressure = 96.13 kN/sqm
Allowable Soil Pressure = (1 X 100) + 27 kN/sqm
= 127 kN/sqm

Check For Minimum Soil Pressure:

Critical Analysis Load = 224
Combination
Critical Load Combination = [32] : 0.42 (LOAD 5: DL) +
(LOAD 1: EQ +X)
Pcomb = 34.27 kN
P = Pcomb + Effective Self Weight x 0.42
P = 60.5 kN
Mx = 0 kNm
My = 0 kNm
P/A = 26.89 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm
Minimum Soil Pressure = 26.89 kN/sqm
> 0

4
 Tuesday, August 26, 2025

Design For Bending:

Bottom Reinforcement Along L:
Critical Analysis Load = 217
Combination
Critical Load Combination = [60] : 1.68 (LOAD 5: DL) +0.5 (LOAD 6: LL) +(LOAD 2:
EQ -X)
Pu = 281.82 kN
Mux = 0 kNm
Muy = 0 kNm
P/A = 125.25 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm

Deff = 167 mm
Beff = 1500 mm
SPu = 125.25 kN/sqm
Mu = SPu X B X Loff X Loff / 2
= 28.42 kNm
Ast Rqd = 750 sqmm
Ast (min) = 750 sqmm
Ast Prv (Distributed Across Total = 9 - #16 @ 200
Width)
= 1787.04 sqmm

Bottom Reinforcement Along B:

Critical Analysis Load = 217
Combination
Critical Load Combination = [60] : 1.68 (LOAD 5: DL) +0.5 (LOAD 6: LL) +(LOAD 2:
EQ -X)
Pu = 281.82 kN
Mux = 0 kNm
Muy = 0 kNm
P/A = 125.25 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm

Deff = 151 mm
Leff = 1500 mm
SPu = 125.25 kN/sqm
Mu = SPu X L X Boff X Boff / 2
= 36.7 kNm
Ast Rqd = 750 sqmm
Ast (min) = 750 sqmm
Ast Prv (Distributed Across Total
= 9 - #16 @ 200
Length)
= 1787.04 sqmm

5
 Tuesday, August 26, 2025

Design For Shear:

One Way Shear Along L:
Critical Section @ d from Column Face
= 167 mm
Critical Analysis Load = 217
Combination
Critical Load Combination = [60] : 1.68 (LOAD 5: DL) +0.5 (LOAD 6: LL) +(LOAD 2:
EQ -X)
Pu = 281.82 kN
Mux = 0 kNm
Muy = 0 kNm
P/A = 125.25 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm

Deff = 167 mm
Beff = 1500 mm
SPu = 125.25 kN/sqm
Vu = SPu X (Loff - d) X B
= 71.96 kN
φVc = 157.22 kN
Vu < φVc

One Way Shear Along B:

Critical Section @ d from Column Face

= 151 mm
Critical Analysis Load = 217
Combination
Critical Load Combination = [60] : 1.68 (LOAD 5: DL)
+0.5 (LOAD 6: LL) +(LOAD
2: EQ -X)
Pu = 281.82 kN
Mux = 0 kNm
Muy = 0 kNm
P/A = 125.25 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm

Deff = 151 mm
Leff = 1500 mm
SPu = 125.25 kN/sqm
Vu = SPu X (Boff - d) X L
= 89.06 kN
φVc = 144.34 kN
Vu < φVc

6
 Tuesday, August 26, 2025

Design For Punching Shear:

Critical Section @ d/2 from Column Face
= 80 mm

Critical Analysis Load = 217

Combination
Critical Load Combination = [60] : 1.68 (LOAD 5: DL) +0.5 (LOAD 6: LL) +(LOAD 2:
EQ -X)
Pu = 281.82 kN
Mux = 0 kNm
Muy = 0 kNm
P/A = 125.25 kN/sqm
Mx/Zx = 0 kN/sqm
My/Zy = 0 kN/sqm

Deff = 159 mm
Leff = 559 mm
Beff = 409 mm
Punching Perimeter = 1936 mm
Punching Area = 307824 sqmm
SPu = Average Pressure
= 125.25 kN/sqm
Vu = { SPu [ (L x B)- (Leff x Beff)]}
= 253.18 kN
φVn = 516.24 kN
φVc = 340.72 kN
No Shear Reinforcement
Vu < φVc
Required

Load Transfer Check For Load Transfer From Column To Footing

Critical Analysis Load = 217
Combination
Critical Load Combination = [60] : 1.68 (LOAD 5: DL)
+0.5 (LOAD 6: LL) +(LOAD
2: EQ -X)
Pu = 281.82 kN
A2 = 0.1 sqm
A1 = 1.75 sqm
Base Area = 2.25 sqm
A1 < Base Area
Modification Factor = SquareRoot(A1/A2) < = 2
SquareRoot(A1/A2) = 4.1833
Thus, Modification Factor = 2
Φ1 = 0.65

7
 Tuesday, August 26, 2025

Φ1Pnb = Φ1 X 0.85 X Fck X Modification Factor X Column Area

= 2210 kN
Φ1Pnb > Pu, Hence Safe.