Direct Answer
Shear studs (or headed shear connectors) are short steel pins welded to the top flange of steel beams to mechanically connect the steel beam to the concrete slab above. They transfer horizontal shear between the beam and slab, making the composite system act as a single structural unit, which significantly increases the beam's load capacity and reduces deflection.
Full Explanation
Shear studs are typically 3/4" diameter × 3" or 4-1/2" long AWS Type B headed studs, stud-welded to the beam's top flange by a stud gun. AISC 360 Chapter I governs composite design; the number and spacing of studs is specified by the structural engineer. Stud welding requires a qualified stud welding operator, a properly maintained stud gun, and the correct ceramic ferrule for each stud diameter. After welding, studs are inspected per AWS D1.1 or project specification — typically a bend test (4° bend with no failure) on a percentage of studs.
What This Means for Your Shop
Shear studs can be installed in the shop (shop-welded) or in the field (field-welded after deck installation). Shop installation is faster and better quality-controlled; field installation is required where the deck layout prevents shop access to the top flange. Confirm with the structural engineer and GC which approach is specified.
Common Mistakes
Installing shear studs through deck flutes without verifying that the stud height provides the required minimum coverage above the deck flute. AWS D1.1 requires minimum 1-1/2" concrete cover above the top of the stud.
Recommended Process
Review the composite beam schedule for stud count, diameter, and spacing. Verify stud height clears the deck flute height and provides minimum cover. Conduct pre-production stud weld qualification tests at the start of each shift per AWS D1.1.