Headed Stud Strength

[atilashorse]

60-ksi shear studs are welded to 36-ksi base metal plates or beams. All books I have read use the 60 ksi value when calculating stud strength. I have always used the lower, 36-ksi base metal strength, but I have found so many authors using the 60 ksi value, that I am truly concerned I am overdesigning my shear stud connections. Any comments?

 

[UcfSE]

I think it was in the PCI manual that I read the plate to which headed studs are welded should be at least 2/3 of the stud diameter. I don't know how they arrived at that rule but that may preclude failure in the plate and allow you to design using the shear strength of the studs without having to check plate strength. That may be why you don't see anyone checking things like plate tear-out in a typical design. I'm sure you could check that however with the AISC. Because of this and the fact that you use the stud area it seems logical to me to use the stud strength associated with that area. I've always used the 50 or 60 ksi stud strength. I don't recall stud strength usually controlling my embed values very often either way you go.

 

[atilashorse]

Yes, PCI recommends plate thickness to be 2/3 of stud diameter.
OK, that may be the reason, I am not quite convinced on how the union between the stud and plate will perform. I guess test have been done and it is well determine that stud failure controls.
Regarding what controls, I have found that tipically concrete failure controls in traction, while stud failure controls in shear, don't you agree?

 

[UcfSE]

I think it depends on what method you use. I've mostly used the ACI 318 Appendix D. I've heard that when using that method compared to other methods such as those in the PCI Manual you will get lower results for concrete strength. That coupled with the fact that I really don't design a lot of headed studs is probably why I've found concrete to control in several of the cases I've done, plus I use the higher stud strength of 50 or 60 instead of 36 ksi.