Finite element analysis and design for section moment capacities of hollow flange steel plate girders

Abstract

This paper describes a numerical study on the section moment capacity of a doubly symmetric hollow flange steel plate girder (HFSPG) for use in long span applications. The HFSPG is manufactured by welding industrially available cold-formed rectangular hollow sections to a steel web plate. Suitable finite element models were developed first to simulate the section moment capacity tests conducted on the proposed HFSPGs using a four-point bending test arrangement. The experimental conditions in terms of boundary conditions, lateral restraints, mechanical properties, initial geometric imperfections and residual stresses were modelled carefully. The comparison of ultimate moment capacities, moment versus deflection plots and failure modes proved the validity of the developed finite element models to investigate the section moment capacities of HFSPGs. However, the slenderness of the tested HFSPGs was limited to the inelastic region. Hence the validated finite element models were used in a detailed parametric study to extend the results to a wider slenderness range. The parametric study results of the section moment capacities were compared with the predictions of the relevant Australian, American and European hot-rolled and cold-formed steel design standards and suitable recommendations were made in relation to their accuracy in predicting the capacities of compact, non-compact and slender HFSPGs. Finally this paper proposes a new Direct Strength Method based design for HFSPGs.