Lateral Torsional Buckling
Lateral Torsional Buckling
(OP)
I am designing a beam supporting wood joists. A wood plate runs the top of the beam and is bolted through the top flange. The span is 25 ft. Are the wood joists considered a bracing point? This project is an upgrade and the existing beam was not braced and would be considered inadequate if the joists are not considered bracing. Thanks!






RE: Lateral Torsional Buckling
http://www.awc.org/pdf/tr14.pdf
www.SlideRuleEra.net
RE: Lateral Torsional Buckling
RE: Lateral Torsional Buckling
RE: Lateral Torsional Buckling
What some engineers do for this case is assume an unbraced length larger than the joist, such as assuming a brace only in the middle. It helps the beam design but is more conservative than hoping an existing connection using wood and probably toe nails will have the strength and stiffness to brace a steel beam. The AISC 3rd ed. lrfd manual has bracing design requirements. You should check those, imo.
RE: Lateral Torsional Buckling
RE: Lateral Torsional Buckling
Unless I misunderstood the original configuration, I don't think the wood plate is bracing the top flange of the steel beam. Also, depending on your load (gravity vs. uplift) you might need to have the lower flange braced as well?
Thanks,
JS.
RE: Lateral Torsional Buckling