Steel Truss girder support for wood trusses? 1

[structurebeton]

Has anybody had any experience with steel truss girder supporting roof wood trusses? Is a wood nailer possible on the top chord of the girder truss?

Input will be appreciated.
Thanks.

Stephan

 

[JAE]

Yes, you simply have a series of bolts spaced along the top chord of the steel truss and bolt down a wood nailer plate to it. We usually have one 2x nailer bolted to the steel, and then have a second nailer on top of that to cover the bolt head. Then the wood trusses are connected to the twin nailers.

The bolts can be either through bolted in the top flange via holes, or can be welded, threaded studs welded to the top flange.

 

[structurebeton]

Thanks for your answer.

1.In the same line of thought, do you think a normal nailing connection is sufficient for lateral bracing? I am looking at 40 ft span steel truss girders, supporting 65 ft span wood trusses at mid point (2'-0' o.c.).

2. Also, do you have any reason to not use steel truss joist at the edges of a building instead of regular steel beams?

 

[UcfSE]

I'm not sure how much help this will be to your 2nd question, but usually the beams around the edge of the building have out-of-plane wind/seismic load in some fashion. Many times they act as a support for curtain walls. We (my company for instance) have trouble getting truss engineers to design simple gables for out-of-plane loads, much less having a truss chord support the top of a wall below or have its members support lateral load. That's why I don't use trusses at the perimeter. It's easier for me to just design a beam than get an Act of Congress to get the truss guy to do it. From my experience the problem isn't the engineering itself but rather getting the proper engineering done as required.