Isolated footing with axial load and moment Design Input Grade of concrete - 35 Grade of steel - 460 Allowable soil pressure – 200 KN/m2 Column load – 1260 KN(D.L+L.L) Moment – 100 kN.m Condition about overburden of soil - No L&T-GES

Design procedure Checking the footing area Arrive footing size By ACI 318 Design procedure Checking the footing area Arrive footing size Total load=wt of footing+column load Average soil pressure q= total load / footing area Allowable soil pressure > Average soil pressure Then footing are is ok L&T-GES

Finding factored loads Factored column load=1.4xdead load+1.7xlive load Average factored soil pressure qnet=Factored column load/footing area Average dv=total thick – cover - bar dia Eccentricity e = Mu/Pu Solving two equations to get q1 and q2 Service load equation Vertical equilibrium L&T-GES

Check for One way shear Check for Two way shear Take the critical section as ‘d’ distance from the face of the column (as per ACI 318 ) 1.find pressure at critical section 2.find Vu 3.find Vu If Vu>Vu Check for Two way shear Take the critical section as ‘d/2’ distance all around the face of the column (as per ACI 318 ) find pressure at critical section Find the value of bo 2.find Vu 3.find Vu is smallest of these L&T-GES

Safe against two way shear Otherwise increase the depth L&T-GES

Check for flexural reinforcement Max moment occurs at the face of the column Find average pressure Find required moment Mn=Mu/ Find required Ast Min Ast=0.0018bh Max spacing=18 in Development length L&T-GES

Isolated footing with axial load and moment Word document (IS Method) Word document (ACI method) Spread sheet (ACI method) STAAD output (ACI method) L&T-GES

Final comparison 3366 mm2 CODE manual design and spread sheet design STAAD DESIGN Area of steel IS 456 3366 mm2 Not available in STAAD ACI 318 5.55 in2 (3580.64 mm2) 5.15 in2 (3322.57 mm2) % difference in steel quantity 10.6% 1.3% L&T-GES

Thank You L&T-GES