Sidesway Web Buckling Question
Sidesway Web Buckling Question
(OP)
A question came up recently whether sidesway web buckling for wide flange beams being used for temporary needle beam shoring (laterally unbraced) could be satisfied by wedging in hardwood blocking on both sides of the web between the top and bottom flanges at the bearing (jacking) points rather than welding stiffener plates.
Requirements for web crippling and local web yielding for this case has been satisfied.






RE: Sidesway Web Buckling Question
I've attached a sketch in an attempt to clarify the question. The contractor (building mover) would like to avoid having to weld in steel stiffeners into his beams only to have to grind them out after the job is done.
Does anyone have an opinion regarding the use of wood blocking to satisfy Sidesway web buckling for this temporary condition?
RE: Sidesway Web Buckling Question
Best regards,
BA
RE: Sidesway Web Buckling Question
Good point. Thanks.
Perhaps the hardwood blocking could be clamped tight against the web to avoid drilling the web.
RE: Sidesway Web Buckling Question
Yes, a couple of C-clamps might just do the trick.
Best regards,
BA
RE: Sidesway Web Buckling Question
compared to stiffeners.
RE: Sidesway Web Buckling Question
RE: Sidesway Web Buckling Question
For one thing, make sure that SSWB is the right limit state. Take a look at Fig. C-J10.1 and the accompanying description of hte limit state. I think it's counter-intuitive.
RE: Sidesway Web Buckling Question
RE: Sidesway Web Buckling Question
For the time being, the contractor was told that steel stiffener plates will be required. This type of shoring work will be ongoing with this contractor for other projects in the future though, so I thought I'd throw the question out there.
The flexural load of the needle beams approaches the working load (yes...I'm an old ASD guy), but web crippling and web yielding don't appear to be a concern. SSWB however is exceeded by 10%.
Normally, with this small of an overage, I'd just watch the beams closely during the jacking process, but on this project, I won't be on site. I figure Murphy's law could end up ruling and over-jacking (higher reaction loads) could occur, so I figured steel stiffeners would be the appropriate solution for this project.
I am interested in whether we can find a way to get a timber blocking solution to work though and that it will satisfy the intent of the code for SSWB.
Again, thanks for all your comments and suggestions.
RE: Sidesway Web Buckling Question
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RE: Sidesway Web Buckling Question
I did talk to the contractor before about bolting angles to the web, but given the two stel stiffener choices he had, he preferred welding. Welds can be ground flush. Holes are forever.
I understand this might be a question that tests the limits of what the code will permit, but considering the high wattage of the crew on this forum, I'm confident the subject is able to be brightly illuminated.