Nonlinear imperfect analysis of corrugated web beams subjected to lateral-torsional buckling

Abstract In this paper the lateral-torsional buckling (LTB) behavior of steel trapezoidally corrugated web girders is studied by advanced nonlinear finite element (FE) analysis in order to develop new computer-based design method for the determination of the LTB strength of such innovative members subjected to pure bending. Due to the low number of previous investigations the rules of FE modelling for strength determination is not unified nor regulated in the case of corrugated web girders. In addition, standards and specifications do not provide any prescriptions on how to determine the LTB strength of corrugated web girders. The required imperfections have key role in the LTB strength determination. The paper discusses the FE modelling issues on the basis of own test results. Advanced FE model is developed, mathematically verified, and validated by experimental test results. Standards provide equivalent geometric imperfections for conventional flat web I-girders. These proposals have not been, however, investigated for the application to corrugated web girders. Thus in this paper a detailed imperfection sensitivity studies are performed and finally modelling prescriptions and required imperfections – including residual stresses and initial geometric imperfections – are developed and proposed to promote a novel FE analysis based design method for these innovative structures.