5" Glulam Deck on Steel Beams

[GalileoG]

I am designing a 5" Glulam Deck on steel beams. A couple of questions:

1. I would like to rely on the 5" glulam deck to laterally brace the steel beams? How can I achieve this? What would the connection look like?

2. Would you consider the 5" glulam deck a flexible or rigid diaphragm?

Thanks in advance.

 

[msquared48]

Are you talking about 5" deep glulams glued and lagged together to form a 5" thick diaphragm? Are the beams laid flat?

As for the connection to a steel beam, I would use Nelson wood sill plate anchors or 1/2" round threaded rod welded to the top of the steel beam, drilled for the threaded rod, with the nuts and washers dapped-into the top of the glulam flooring. I would not use a sill plate here on the top of the steel beam in this circumstance.

I feel that lateral bracing of the top flange of the steel beam could be achieved here with little problem if the glulam members are glued and screwed together.

Mike McCann
MMC Engineering

 

[JAE]

We just did a building with steel joists supporting a tongue and groove decking. There is only limited information on the ability of T&G decking to serve as a diaphragm so we typically cover the decking with plywood sheathing. We used a self-tapping screw connection from the deck down through the top chords of the joists - then nails for the sheathing to the decking.

The decking, with the sheathing on top, was assumed to adequately brace the joists. For beams I would think this would be similar.