According to I.S.: 456, slabs which span in two directions with corners held down, are assumed to be divided in each direction into middle strips and edge strips such that the width of the middle strip, is

Explanation:

According to IS 456:2000, Annex D (Clause D-1.1), when a two-way slab is supported on all four sides with corners held down:

1. The slab is assumed to be divided in each direction into:

   • Middle strip

   • Edge strips

2. The middle strip in each direction has a width equal to three-fourths (3/4) of the total width of the slab in that direction.

3. The remaining one-fourth is equally divided into two edge strips (each edge strip = one-eighth of the width).

Additional Information

• A one-way slab is a reinforced concrete slab that primarily bends in one direction only, due to the geometry and support conditions.

• It spans between two opposite supports (usually longer in one direction), and the load is carried along the shorter span.

• As per IS 456:2000, a slab is considered one-way if the ratio of longer span (Ly) to shorter span (Lx) ≥ 2.

• This condition ensures that bending along the longer direction is negligible.