Summary: (Blank Abstract)
The fourth limit state for beams is Flange Local Buckling, or FLB for short. It is exactly the same as Web Local Buckling, except the width-thickness ratio is in terms of the flange and not the web. This type of buckling occurs when the width-thickness ratio is not large enough to withstand the moment on the beam. The way to prevent this type of buckling is to limit the with-thickness ratio.
The limits can be computed for flange local buckling. The
width-thickness ratio is compared to
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