Special Joists

[sonnyson]

Due to drift loads and point loads, we specified special open web bar joists on a project with detailed load diagrams. The joist manufacturer supplied shop drawings for these joists with the load diagrams as shown on our plans. They will not provide signed and sealed drawings. how do we insure the special joists were designed properly without a PE certification? The company stated that they do not provide signed and sealed shop drawings. Anyone else run into this? how did you resolve it?

 

[JedClampett]

I've never run into that exact situation. But I've learned from bad experiences that joist manufacturers are extremely independent and could care less about your documentation requirements. And believe me, if you got any calculations, they'd be worthless.
I've used two approaches to this. The first is to stay away from joists. I use wide flange members or design my own trusses and when someone wants to know why I explain about poor support from the joist manufacturers. The second is to use the "K" style joists. They have specified moment and shear capacity. Figure out your forces and there's a joist to match. And you can control any extra margin.

 

[strguy11]

Jed -

I assume you meant a "KCS" style joist???

 

[strguy11]

If you specified this, and the contractor cannot deliver the required documentation, you are in no way obligated to approve the shop drawings. However, since the joists are essentially a performance based sysem, i wouldnt have a problem (assuming they are a member of the SJI and are one of the larger, more well known suppliers. By them showing that they understood your drawings and the special load requirements, they would be negligent if they didnt design the joist accordingly.

Also, I would notify the owner, and have him ask the contractor for a credit for not supplying this information which was required in the contract documents.

 

[JedClampett]

That's the trouble when I try to do something from memory. I meant "KCS" joists.
Good catch.

 

[msquared48]

This is way outside the norm. Personally, I would question the professional structural expertise of any joist manufacturer that will not do this, let alone cannot. Something smells here. Go to another steel joist manufacturer.

Mike McCann
MMC Engineering