Beam end restraint 1

[MacGruber22]

I have a few new W16 steel beams supporting wood framing, which are bearing on masonry walls. My end detail for my beams is typical with grouted upper courses, headed bolts, yada yada.

And as I usually do, each beam has a single transverse stiffener adjacent to the anchor bolts. The problem is that the contractor refuses to add the stiffeners, and says he sees beams all the time without them.

I have told him that beams require a mechanism at supports to prevent lateral rotation, which tends to occur at maximum design loading.

Suggestions?

 

[JAE]

Stiffeners are required for several reasons - avoid web buckling, crippling and to resist lateral overturning of the beam.

On a wall - if you are in a pocket, there may be a way to laterally tie the beam down so the overturning doesn't occur.
You can also check the web using AISC chapter J provisions. If they don't want a stiffener plate - then you could consider a heavier beam with an adequate web.

Final thought - ask the contractor to take full responsibility for the structural capacity of the beam(s) - tell him you can write up a limit of liability agreement between you and have him sign it.
If he doesn't want to then tell him to go pound sand.





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[MacGruber22]

Exactly - I do not need the stiffeners for those other limit states; only rotation.

No masonry pocket available.

Yeah, that is what it seems like it is coming to. Ethically, I just hate those things.

I wasn't sure if I could come up with a rational method to check web resisting the rotation and satisfy both of us.

 

[JAE]

Every structural collapse I've seen in person (for moderate sized buildings) has been because there were no stiffeners over columns.

Now a wall can't rotate from under a beam along its length so if the beam is perpendicular to the wall there is less chance of that happening.
But I'd still want to secure the top of the beam anyway.


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[WillisV]

https://www.aisc.org/uploadedcontent/2012NASCCSessions/N3/

Slides 32-40

 

[MacGruber22]

WillisV - you are the man.

Modified LTB span length is an elegant solution.

Now, I wouldn't ever want to use this provision for the type of structure JAE has mentioned, but I feel OK about it for bearing on a continuous wall.

Now to find BS 5950 1985...

 

[MacGruber22]

Link