Composite Metal Deck - Cutting Shear Studs to Length

[Wburger14]

We have some embedded conduit raceways (not part of the original design) being installed flush to the top of concrete slab. The shear studs will encroach the depth of the raceway along some lengths of multiple beams. The as-designed shear studs are currently on site, can the contractor cut these down to the desired length? Rumors tell me they cannot, but I'm having a hard time locating anything in the codes/SDI that tells me for sure.

 

[msquared48]

If the beams are composite, depending on the number and length of the studs, cutting them will negatively affect the composite action.

Normally, upon welding, the studs will be sortened by 1/2 inch or so from the original length.

If you must have shorter studs, you will need to redesign the affected composite members, possibly adding another row or two of shorter studs.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[TXStructural]

AISC dictates the requirements for composite beams using shear studs. The short answer is "no" you cannot shorten them if you expect them to work as designed. The length is typically as short as needed to fit into the required slab, and this is frequently just barely long enough for them to function as required.

Also, the raceways, which apparently cross composite beams, will result in dramatic changes to the function of the beams. You cannot simply reduce the concrete portion of the beam and have it function as designed. Particularly, in the middle of the span, the concrete is in maximum compression, and must be full thickness if the concrete is part of the design (and it would have been.) You say "along some lengths of multiple beams." You probably have to redesign these beams and will likely have to add steel section.