Short answer
Shear studs are headed steel stud anchors welded to the top flange of a steel beam so that the beam and the concrete slab on top act together as one composite member. They are counted per beam, usually shown in brackets after the beam size or in the beam schedule, and priced per stud.
What they do
Without studs, a concrete slab sits on a steel beam and the two bend separately. With studs, the slab and the beam share load, which lets the engineer use a smaller beam or a longer span. The studs carry the horizontal shear between the two, hence the name.
They are commonly 3/4 inch in diameter and are welded through the metal deck into the beam flange with a stud gun, usually in the field by the erector or deck installer, though some shops weld them in the shop on beams without deck.
How are they shown on drawings?
Look for a number in brackets after the beam size, like W16x26 [24], meaning 24 studs on that beam. Schedules often have a studs column. Some drawings note stud spacing instead (for example, studs at 12 in on center), in which case you work out the count from the beam length. General notes give diameter, length and the requirement.
A stud takeoff means counting per beam, multiplying by the number of identical beams, and totaling. On a large floor, studs run into the thousands, so a small miscount adds up.
How do you price studs?
Studs are priced each, covering material, welding and testing, and the price differs for shop versus field installation. Check who is responsible for them in the contract, since stud installation is sometimes carried by the steel erector and sometimes by the deck subcontractor. Also check the inspection requirement, as bend tests and inspector time cost money.
Studs also interact with camber and deck layout. See the beam camber estimating guide and metal deck takeoff guide.
Counting studs: an example
A floor has 14 beams, each with 24 studs, and 4 girders with 32 studs each. Studs = 14 x 24 + 4 x 32 = 336 + 128 = 464. If the schedule gives stud spacing instead, say 12 in on center on a 24 ft beam, the count follows from the spacing and the beam length, less the end distances the detail gives. Double-check the layout rules in the general notes, because the code allows spacing to vary within limits.
On big floors studs reach thousands. Even a small error per beam multiplies, so build the stud count into the same table as the beam count.
Are studs part of the structural steel package?
It depends on the contract. In many projects the steel erector welds studs through the deck once the deck is placed, and the stud material is supplied by the steel fabricator or the erector. In others the deck subcontractor handles it. The scope letter should say who supplies, installs, tests and pays for them. Do not assume.
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