The current end web crippling design equations are based on a collapse mechanism developed for interior web crippling of short-span plate girders. Yield-line theory and the mechanism solution were used to derive an expression for the web crippling capacity of a plate girder subjected to an interior patch load. The general form of this equation was then calibrated using available data to obtain an equation for end web crippling as well. This study examines the origin of the equation and identifies inconsistencies, which result from using the same assumptions for both types of web crippling. A new collapse mechanism, based on modified assumptions, is used to derive a new equation that applies specifically to end web crippling of hot-rolled sections. In addition, three full-scale tests were conducted on steel-concrete composite beams to verify the accuracy of the proposed equation. Finally, the current web crippling equations and the proposed equation are compared for all available end web crippling data, and conclusions and recommendations are made concerning the validity of the proposed end web crippling equation. / Master of Science