Flexural resistance of laterally restrained point loaded slender i-section beams

Abstract EN

The flexural strength of slender sections is determined using either the effective width method or the direct strength method.

In the effective width method the effect of local buckling is considered by assuming reduced dimensions of the section, while in direct strength method the ultimate strength is determined directly using equations that are function of the elastic local buckling loads of these sections.

Both methods consider the beams subjected to uniform bending moments.

However, beams are often subjected to lateral transverse loads that cause moment gradient that.

The present study is aimed at studying the flexural strength of laterally supported beams subjected to transverse concentrated load in which the ultimate loads will be affected by the combination of the shear and bending strengths.

As such, an extensive finite element analysis is conducted.

The finite element model accounts for both the geometric and the material nonlinearities.

The effects of flange and web width-thickness ratios are considered in the study.

Based on the numerical results, it is found that the flexural resistance of slender sections subjected to moment gradient is higher than that of beams subjected to pure uniform moment.

Moreover, the strength varies according to the flange and web width-thickness ratios.

Finally, an equivalent moment factor that correlates the flexural strength of beams subjected to moment gradient to that of beams subjected to uniform moments are suggested.