Local buckling of compression flanges of H-beams with corrugated webs

• Experimental studies on the flexural strength of compression flanges of beams with corrugated webs are presented.
• Corrugated webs apply rotational restraint on the local buckling behavior of compression flanges.
• A formula for calculating critical buckling stress of compression flanges is proposed.
• Initial geometric imperfections cause a reduction of 28% of the critical buckling stress of compression flanges.

This paper presents theoretical and experimental investigations on the local stability of compression flanges of H-beams with corrugated webs. Firstly, a simplified model of the flange plate considering the rotational restraint from webs is established. A formula for calculating the critical buckling stress of flanges is deduced. After verifying the proposed theoretical model against finite element analyses using ANSYS, parametric studies are carried out to investigate the influence of the tension flange, beam length and corrugated web on the resistance of compression flanges against local buckling. Secondly, experiments are carried out on three groups of corrugated web beams. The finite element modeling of the test specimens is validated against the available experimental results of their ultimate load-bearing capacity. The influence of the initial geometric imperfection of compression flanges and residual stresses on the critical buckling stress of compression flanges are studied using the FE model. It is concluded that initial imperfections may reduce the critical buckling stress by 28% while residual stresses may lead to a reduction of 14%. Finally, a correction factor of 70% is suggested for the critical outstand-to-thickness ratio of flanges to account for these two effects on the stability of steel beams with corrugated webs.