A square column 410 x 410 mm (along with 4 No. 16 mm bars) carries a dead load of 1020 kN and an imposed load of 410 kN. The foundation soil has a safe bearing capacity of 200 kPa. F_e, 415 is to be used for reinforcement. You have to design a square footing. The column and the foundation are constructed of M20 grade concrete.

Ans:

Plan Area

No details are given regarding the depth of foundation and unit weight of soil. Hence we will assume that the weight of footing and soil above it is 10% of applied load.

Total load = 1020 + 410 + 0.1 x 1430 = 1573 kN

Area required here = 1573/200 = 7.865 m²

Adopt 2800 mm x 2800 mm square footing.

Ultimate Soil Reaction

Factored loads have to be taken

Weight of footing is not to be considered

Design load = 1.5 DL + 1.5 LL = 1.5 x 1430 = 2145 kN

Soil reaction = 2145/(2.80 x 2.80) = 273.6kPa