The gross bearing capacity of a footing is 450 kN/m2. If the footing is 1.5 in wide and is at a depth of 1 m in a clayey soil which has a unit weight of 20 kN/m3, then the net bearing capacity is

The gross bearing capacity of a footing is 450 kN/m2. If the footing is 1.5 in wide and is at a depth of 1 m in a clayey soil which has a unit weight of 20 kN/m3, then the net bearing capacity is Correct Answer 430 kN/m<sup style="">2</sup>

Concept:

The net bearing capacity of footing is given as:

Q_nu = q_u­ - Overburden pressure (q)

Where, q_u is gross bearing capacity

q = γD_f

where,

γ is the unit weight of soil above footing

D_f is the depth of foundation.

Calculation:

Given

Gross Bearing capacity of footing, q_u = 450 kN/m²

Depth of foundation, D_f = 1 m.

Unit weight, γ = 20 kN/m³

Now

Q_nu = 450 – 20 × 1 = 430 kN/m³