Experimental study on ultimate shear strength of web panels

Numerous works have been presented over the years on the ultimate shear beh avior and postbuckling strength of plate girder web panels. Research by Bas ler has been adopted in AASHTO, and the work by Porter et al. has been adop ted in British Standard. However, a recent nonlinear finite-element study b y Lee and Yoo reveals that considerable discrepancies exist concerning the failure mode between the assumed failure mechanisms and the numerical analy sis results; although theories by Basler and Porter et al., yield reasonabl e ultimate shear strengths for all practical designs. In this study, 10 sca led plate girder models were tested to investigate the shear behavior of we b panels up to failure. Test results are compared with values obtained from theoretical models and the finite-element study. Based on this study, the following conclusions are made with regard to the behavior of the plate gir der web panels: (1) The boundary condition at the flange-web juncture in pr actical designs is much closer to the fixity; (2) in all existing failure m echanisms, the through-thickness bending stress effects on the ultimate she ar strength are neglected, however, it has been found that very high bendin g stresses develop at failure; and (3) an anchoring system, such as flanges , is not needed for the development of the postbuckling strength.