Elastic lateral-torsional buckling of girders with corrugated web: equivalent section properties approach

One of the benefits of using corrugated web girders is the increase of lateral-torsional buckling resistance. Different approaches have been presented to obtain the value of the critical moment as a function of the cross-section geometry. Previous research works consider that the increase in buckling resistance must be accredited to a higher warping constant. The paper presents a systematic finite element numerical analysis of girders with different corrugated web shapes. Bending with respect to the weak axis shows that corrugated web implies higher moment of inertia. Torsion analysis results clearly demonstrate that the increase of torsion resistance is mainly due to higher torsional constant. The paper compares the elastic critical moment values obtained by using finite element elastic buckling analysis with the values provided by theoretical expressions introducing equivalent section properties. Results show that the equivalent section properties approach provides values very close to those obtained using finite elements. Finally, the paper presents closed form expressions to directly compute approximate equivalent section properties of any girder with corrugated web, which compare very satisfactory with those values obtained with finite element buckling analysis.The authors would like to acknowledge the support to this research by Fundación Leonardo Torres-Queved