A simply supported RCC one-way slab for an office floor has clear dimensions of 4 m × 10 m with 230 mm walls all-around. What is the effective length of the slab? (Take the effective depth of the slab as 160 mm)

Concept:

Effective length of the simply supported beam or simply supported one-way slab:

Effective length (\(l_{eff}\)) = minimum of {\(l_o+w,\,l_o+d\)} 

Where \(l_o\) = clear span, w = width of support, and d = depth of beam or slab.

Calculation:

Given

Clear dimension of slab = 4 m × 10 m

Width of wall (w) = 230 mm or 0.23 m

Effective depth of slab (d) = 160 mm or 0.16 m

We design the slab according to a shorter span;

Effective length of the slab (\(l_{eff}\)) = minimum of { 4 + 0.23, 4 + 0.16 } = 4.16 m

Effective length of the slab (\(l_{eff}\)) = 4.16 m

The effective length of the slab is 4.16 m. Hence the correct answer is option (2).