This code details the design and erection procedures for buildings using mixed/composite construction, where structural steel and concrete elements work together. It provides limit state design guidelines for composite beams, columns, and slabs, with a significant focus on the design of shear connectors that ensure composite action.
Building Design and Erection Using Mixed/Composite Construction - Code of practice
Quick Reference Values
Minimum concrete grade for composite membersM20
Partial safety factor for shear connectors (γvs)1.25
Minimum degree of shear connection for beams0.4
Maximum longitudinal spacing of shear connectorsLesser of 600 mm and 4 x slab thickness
Minimum reinforcement in concrete slab (profiled sheets)0.2% of the concrete area above the ribs
Maximum slip at serviceability limit state0.3 mm
Key Formulas
Qd = Qk / γvs — Design shear strength of a stud connector
be = Σbei + bw — Effective width of concrete flange
Nc, Rd = A a * fyd + 0.85 * A c * fcd + Asr * fsd — Design axial compression resistance of composite column
Practical Notes
This standard must be used in conjunction with IS 800 for steel design and IS 456 for concrete design; it is not a standalone document.
The construction sequence (propped vs. unpropped) critically affects the stresses in the steel section and must be accounted for in the design.
Proper detailing and installation of shear connectors are paramount to achieving the intended composite behavior and load-carrying capacity.