Steel Beam top flange bracing

[Buleeek]

Hello everyone,

I have a steel beam (W16X31) running parallelly to floor WOOD trusses (18" deep). The beam is located in the floor (bottom flush), above a garage. On top of the steel beam there will be a nailer and all will be "bounded" with floor sheathing.
The beam spans 29' and there are two significant point loads from above. It seems there is nothing that could provide bracing for top flange. What can I do to shorten Lb of the top flange for that beam?

Any advice greatly appreciated.
Thanks,

 

[Tomfh]

Why can’t your floor diaphragm brace the beam?

 

[KootK]

1) Some folks, including me, will use the plywood to brace the beam top flange. The difficulty with it lies in evaluating the stiffness and strength of the sheathing to perform the bracing function. AISC appendix 6 has guidance for this but applying it to wood is messy.

2) To provide enough strength and stiffness in the wood diaphragm doing the bracing. you obviously need a healthy width of sheathing beside your beam. Without getting into that detailed checking, I like my sheathing beside my beam to extend at least 1/3 of the beam span. That's just me making stuff up though.

3) I like to run some strapped blocking into the floor sheathing at about 6' oc. In your case, I'd be sure to put some of that at the locations of those two point loads.

 

[Buleeek]

Thanks for your replies.

KootK, the sheating is most likely going to be 1/2" plywood. It is a big room above the garage. Do you think running full height WOOD blocking (pack out web) every 4' would help?

Tomfh, what part of the diaphragm do you mean ?

 

[KootK]

KootK, the sheating is most likely going to be 1/2" plywood. It is a big room above the garage. Do you think running full height WOOD blocking (pack out web) every 4' would help?

Indeed I do.

Tomfh, what part of the diaphragm do you mean ?

He'll have meant the sheathing that we've been discussing.