Correct Answer - Option 4 : one way slab

__Explanation:__

As per IS 456:2000,

The slab is one-way if \(\frac{{{\ell }_{y}}}{{{\ell }_{x}}}\geq2\)

Where, ℓy, ℓx are the lengths of the longer and shorter spans respectively.

The minimum percentage of reinforcement is 0.15% of the gross area if a mild steel bar is used and 0.12% of the gross area if the HYSD bar is used.

Maximum dia of reinforcement, \({{\phi }_{max}}<\frac{D}{8}\)

(i) Main Bars are spaced at \(min\left\{ \begin{matrix} 3d \\ 300~mm \\ \end{matrix} \right.~\)

(ii) Distribution Bars are spaced at \(min\left\{ \begin{matrix} 5d \\ 450~mm \\ \end{matrix} \right.\)

__Important Point:__

The minimum percentage of reinforcement is 0.12% of the gross cross-sectional area if HYSD bars are used.