LATERAL BUCKLING IN CONTINUOUS COMPOSITE BRIDGE GIRDERS

The buckling of the support region of steel beams in continuous composite bridge construction is studied using an ultimate strength finite element analysis, the particular form of failure addressed being distortional lateral buckling of the beam lower flange and web. Results for a series of both practical and extreme girders are used to illustrate the inappropriate nature of the present BS 5400: Parts 3 and 5 design approach. A relatively small modification to this is suggested, which leads to very good predictions of all the numerical results. This revised design approach may be presented in chart form to show that, over most of the practical range of girder proportions, lateral buckling will not occur at moments below the full cross-sectional moment capacity. (TRRL) (Author/TRRL)