LT Buckling of Steel Beams Under Slab

[CDLD]

Hello,

Would you consider new steel beams grouted under an existing slab to be fully supported?

I saw an article once saying that the restoring torque from the slab reaction is sufficient in preventing lateral torsional buckling, but I can no longer track down the article.

Does anyone have a good reference?

Thanks

 

[KootK]

Would you consider new steel beams grouted under an existing slab to be fully supported?

I don't know of a reference but, in my experience, it is certainly common to consider the top flange to be laterally restrained in these situations. That said, usually folks provide some kind of positive, mechanical connection between the beam and slab rather than relying on friction transmitted through the grout for this purpose.

I saw an article once saying that the restoring torque from the slab reaction is sufficient in preventing lateral torsional buckling

Do you need to restrain the beam cross section torsionally as opposed to just restraining the top flange laterally? That changes things a bit. Most simple span beam will not require torsional restraint. It may be required for continuous / cantilevered beams with hogging moments if you plan to use the slab to, effectively, provide lateral restraint to the bottom flange. Usually, you'd just use kickers / discrete bracing for that isn't universally possible.

 

[CDLD]

Thanks Koot.

Just lateral support of the top flange would be sufficient.


Found this:

https://www.youtube.com/watch?v=rNMX962XVsQ&t=2812s

Skip to 33:00 min.