Ultimate shear strength of long web panels

Both the Basler model and the Rockey model developed during the early 1960s and 1970s predict reasonably well the postbuckling strength of plate girder web panels subjected to pure shear for panels having an aspect ratio (stiffener spacing/web depth) less than or equal to 1.5. The accuracy of these models deviates significantly when applied to panels with an aspect ratio equal to or greater than 3.0. The majority of all steel structures in the world have been designed and built based on these two major theories or their derivatives that recognize the reserve strength afforded by tension field action in the postbuckling stage. However, no single theory has ever emerged that explains the seemingly elusive stress distributions present in web panels during postbuckling until Yoo and Lee shed light on the true mechanics of web panel postbuckling behavior in shear.This paper revisits the validity of an arbitrary limit imposed by Basler on the maximum aspect ratio of a transversely stiffened web panel and develops a new method of predicting the ultimate shear strength of web panels with high aspect ratios.