Further Insights into Postbuckling of Web Panels. II: Experiments and Verification of New Theory

This study brings light to the source of plastic hinge-like failure modes often observed in tests. It is found that such failure modes, accompanied by severe flange deformations, are not due to the anchoring action of the flanges, but are due to direct shear force acting on the flange cross sections. This study also examines why the horizontal anchoring mechanism cannot develop in interior panels or in end panels with a heavy end stiffener. The results obtained in this study, along with the findings reported in the companion paper (Part I), reveal that the anchoring mechanism is virtually nonexistent in normal plate girders. That is to say, the postbuckling strength of the web panel in normal plate girders is mostly attributable to the postbuckling mechanism developed by means of lateral supports provided by the flanges and the transverse stiffeners. It is also found that a tension field can develop in the end panel and it is recommended, therefore, that any restriction contrary to this observation found in current design codes be repealed.