A structural engineer is designing a steel-framed building with composite floor slabs. The specifications call for shear studs to be welded to the steel beams. What is the primary function of these shear studs in a composite beam system?
- ATo resist horizontal shear forces at the steel-concrete interface, allowing composite action.
- BTo provide anchorage for non-structural elements like ceiling grids.
- CTo increase the fire resistance rating of the steel beam.
- DTo prevent the concrete slab from separating vertically from the steel beam.
Show answer & explanationAnswer & explanation
Correct answer: A. To resist horizontal shear forces at the steel-concrete interface, allowing composite action.
Shear studs (headed steel studs) are welded to the top flange of steel beams to create a mechanical connection with the concrete slab. Their primary function is to resist the horizontal shear forces that develop at the interface between the steel beam and the concrete slab when the composite section is subjected to bending. This resistance allows the steel beam and concrete slab to act as a single, composite unit, significantly increasing the stiffness and strength of the floor system.
Why the other options are wrong
- B. Shear studs are structural elements; anchorage for non-structural elements is not their primary purpose.
- C. Shear studs do not inherently increase the fire resistance rating; fire protection is achieved through other means (e.g., spray-on fireproofing).
- D. While shear studs do prevent vertical separation, their primary role is related to horizontal shear for composite action, not just vertical separation.
Shear Studs (Composite Beams)
Headed steel studs welded to the top flange of steel beams to connect them structurally with a concrete slab, enabling composite action.
- Resist horizontal shear forces at the interface.
- Crucial for achieving composite beam behavior.
- Enhance strength and stiffness of floor systems.
Memory trick: Concrete and steel link up with studs to share the load.