Question

A simply supported isotropically reinforced square slab of side 4 m is subject to a service load of 6 kPa. The thickness of the slab is 120 mm. The moment of resistance required as per yield line theory is

• A. 9 kN-m
• B. 9 kNm/m
• C. 13.2 kN-m
• D. 13.2 kNm/m

Answer 1

The correct option is B 9 kNm/m

Moment of resistance = $\frac{w_0{L}^2}{24}$

Self weight of slab = $0.12\times 25=3kN/m^2$

Service load = $6kN/m^2$

Ultimate load = $1.5\times (6+3)=13.5kN/m^2$

Ultimate moment capacity

=$\frac{13.5\times 4^2}{24}=9kN-m/m$