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SL.

No DESCRIPTION REFERENCE
1 FOOTING DESIGN- F1
1.1 INPUT
Grade of concrete fck 25 N/mm2
Grade of steel fy 500 N/mm2
Density of soil ρs 1.8 T/m3
Density of concrete ρc 2.5 T/m3
Depth- bottom of base plate to bottom of raf D 2.5 m
Ht of pedestal above FGL h 0.3 m
SBC of soil 15 T/m2
Clear Cover to reinforcement(Earth face) 0.075 m
Clear Cover to reinforcement 0.05 m
L B d
Size of Raf 6 2.5 0.5 m
Size of pedestal 6 0.5 2.0 m
1.2 DEAD WEIGHT OF SOIL AND CONCRETE
Area of Footing
= (LxB) 15 m2
Weight of Concrete
= Vol of(Raf + Pedestal) x density of Concrete 33.75 T
Weight of Soil
= (Area of footing - Area of pedestal) x (depth of
foundation - depth of raf) x density of Concrete 36.72 T
1.3 SECTION MODULUS
Zxx = L x B2/6 6.25 m3
Zzz = B x L2/6 15.00 m3
1.4 LOAD INPUT FROM STAAD
All loads are in "Tons"
Critical Load P
Sl no. Combinations
Fx Fy Fz Mx My Mz M'x M'z M'x = (Fz X D) + Mx
1 13 21.00 8.00 0.00 0.00 0.00 0.00 0 52.5 M'z = (Fx X D) + Mz
1.5 BASE PRESSURE CHECK Base Pressure
P1 P2 P3 P4 P=(Fy/A) ± (M'x/Zxx) ±
(M'z/Zzz)
8.7 1.7 8.7 1.7
Pmax 8.73 T/m2
Pmin 1.73 T/m2
1.6 CONVERTING NEGETIVE PRESSURE TO POSITIVE PRESSURE
To calculate Qmax 1.73 Interpolation method
To find out X X
i.e (+VE Pr) + (-VE Pr)/span= +VE Pr/x
X = 5.007
P = 1/2 x (+ve pr) x span
P = 26.19 T 8.73
P = 1/2 x Qmax x X 6.00
Qmax = 10.5 T/m2
SBC shall be increased by 33% for wind load As per IS 875 Part-3
Allowable SBC = 15 T/m2
IF Qmax < Allowable SBC SAFE

06% of Raf area(Both X and Y dir) Pt 0.1 IS456:2000 Required Area of steel Asty 510 mm2 Asty = (Ptxbxd)/100 Providing 12 dia 200 Spacing Provided Area of steel Asty 565 mm2 Asty=π xdia2/4xspacing Provided percentage of steel Pty 0.37 T-m Partial factor of safety 1.26.1 (SP-16:1980) Design shear strength of concrete τc 0.10 N/mm2 Table-20 (IS 456 :2000) Pt provided Ptprovd 0.12 % Hence Ptx 0.5 T-m Muy / bd2 0.2.1 (IS 456 :2000) Maximum Shear Stress of Concrete τc (max) 3.Y direction Cantilever bending moment Cantilever distance ly 1 m At support My= W X ly2/2 My 4.89XPt β 21.8 1.5.5 Ultimate moment in y dir Muy 6.06 % Required Area of steel Ast 270 mm2 Providing 10 dia 200 Spacing Provided Area of steel Ast 393 mm2 Provided percentage of steel Pt 0.000 0.13 % Bottom Reinforcement .2.7 DESIGN OF RAFT Bottom Reinforcement .43 m Shear force in X.1 IS456:2000 Percentage of steel Ptx = 0.0 T-m Mux / bd2 0.8Xfck/6.Xdirection Cantilever bending moment Cantilever distance lx 0 m At support Mx= W X lx2/2 Mx 0.5 Ultimate moment in x dir Mux 0.1 IS456:2000 Percentage of steel Pty 0.12 % Hence Pty 0.00 N/mm2 Required Min ANNEX G-1.09 % 1. Hence Base pressure W 8.8 CHECK FOR SINGLE SHEAR SHEAR CHECK IN X DIR Shear distance in cantilever portion dx -0.1 IS456:2000 Required Area of steel Astx 510 mm2 Astx = (Ptxbxd)/100 Providing 12 dia 200 Spacing Provided Area of steel Astx 565 mm2 Astx=π xdia2/4xspacing Provided percentage of steel Ptx 0.12 % Cl.8fck)X sqrt(1+(5β-1)))/6β Hence τv < τc SAFE SHEAR CHECK IN Y DIR .1 (SP-16:1980) τc = (0.dir Vx -22.36 N/mm2 Required Min ANNEX G-1.13 % Top Reinforcement .X&Ydirection Min Providing 0.731 T/m2 1.00 Cl 4.0 T-m Partial factor of safety 1.85 X sqrt(0.12 % Cl.13 % Beeta = 0.08 0.5.3 T Vx = W X L X dx Shear stress along X-dir τvx=Vx/Bd -0.26.13 N/mm2 Cl 40.28 N/mm2 Cl 4.

575 m Shear force in Y.19 N/mm2 IS456:2000 cl.85 X sqrt(0.31.3.943 m2 Shear Vu 119 T/m2 = W X (LXB) of Raf-area τv = Vu/bod 0.1 (SP-16:1980) Design shear strength of concrete τc 0.2.09 % Beeta = 0.25 xsqrt fck 1. Shear distance in cantilever portion dy 0.8Xfck/6.8fck)X sqrt(1+(5β-1)))/6β Hence τv < τc SAFE 1.89XPt β 31.31.1 (SP-16:1980) τc = (0.4 1.dir (Vy) Vy 12.6.1 (IS 456 :2000) Maximum Shear Stress of Concrete τc (max) 3.1 τc = 0.6.25 N/mm2 IS456:2000 cl.7 m Area of critical section A 5.9 CHECK FOR PUNCHING SHEAR Perimeter of critical section bo 14.10 N/mm2 Table-20 (IS 456 :2000) Pt provided Ptprovd 0.00 Cl 4.6 T Vy = W X B X dy Shear stress along Y-dir(Tvy) τvy=Vy/Bd 0.1 IF τc>τv τc > τv SAFE .23 N/mm2 Cl 4.18 N/mm2 Cl 40.