RCC Design (IS 456)

Limit state design checks ultimate (collapse) and serviceability (deflection, cracks) limits using partial safety factors — the standard method in IS 456 for Indian concrete structures.

IS 456 is the Indian Standard code of practice for plain and reinforced concrete — it governs mix design, cover, reinforcement detailing, and limit state checks on every Indian site.

Split the moment into the balanced part M_u,lim carried by the singly reinforced section and the excess carried by a compression-steel/tension-steel couple, then size A_sc and the additional A_st for the excess moment.

Decide one-way versus two-way from the aspect ratio l_y/l_x, design a 1 m wide strip spanning the shorter direction for the ULS moment, and verify the span/depth deflection limit which usually governs slab depth.

For a short axially loaded column use P_u = 0.4 f_ck A_c + 0.67 f_y A_sc to find steel; for the footing size the base area from P/q_safe and then check one-way and two-way (punching) shear, which usually governs the depth.