Composite Beam (Steel-Concrete)
Steel beam + concrete slab made to act as one section via shear connectors
A composite beam is a steel beam connected to an overlying concrete slab by shear connectors (typically headed studs) so the two act as a single, much stiffer and stronger section: the concrete slab carries the compression and the steel section the tension, using each material in its strong mode. Design follows IS 11384 (code of practice for composite construction in structural steel and concrete) together with IS 800, with the shear connectors transferring the longitudinal interface shear that makes composite action possible.
Composite construction gives significant savings in steel weight and structural depth, faster floor construction (metal-deck slabs), and improved stiffness/vibration performance, making it the standard system for steel-framed buildings, car parks and steel bridge decks. Design must address the effective slab width, full vs. partial shear connection, construction-stage stresses (steel beam carrying wet concrete before composite action develops, unless propped), longitudinal shear in the slab, and deflection/vibration serviceability — the construction-stage check is a common oversight.
- Steel-framed building + car-park floors
- Steel bridge decks (composite girders)
- Long-span, shallow-depth floor systems
- Metal-deck composite slab construction
- Strengthening existing steel beams by composite action