Shear studs in masonry

[thoughtofthis]

I was looking at typical steel joist to masonry connection showing 2 shear studs welded to a bearing plate. ACI 530 doesn't allow studs per se, so I went in search of the ESR to see allowable values...there wasn't one. Concrete only.

So is this configuration technically not allowed in masonry construction? If you had to use a headed bolt, the bearing plates would be bigger and you'd have a bolt projection to deal with. What's really the difference between a headed bolt and a stud in masonry that would be problematic?

 

[JAE]

Is the headed stud "in masonry"? Or is it in 2,000 psi grout (i.e. low strength concrete)?



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[bones206]

It's a good question... ESR reports are pretty specific on the scope of use for various items. If it doesn't specifically say the stud is approved for use in grouted CMU, it isn't covered by that ESR. Got me thinking about a detail I use with a Nelson D2L deformed bar anchor lapped with vertical CMU bars. The ESR for that is only for concrete as well... I'll have to dig into IBC and ACI 530 to see if there is a loophole for this stuff.

 

[thoughtofthis]

Thanks for your responses.

ACI 530.1 allows for A307 Gr A bolts, and specifying S1 makes them weldable. So, an alternative to having the bolts stick through may be to just weld bolts to the bottom of a steel plate.

 

[bones206]

Joist bearing plates with headed studs are commonly used in CMU walls, so I wouldn't change the detail even if it's not specifically covered in ACI 530 or 530.1. If you can show analytically that ASTM A108 headed studs are equivalent to or exceed A307 bolts in all the code requirements, then you could justify it as a substitution.