Localized Web Buckling of Double-Coped Beams

In beam-to-girder connections, the beam is usually coped to allow a standard connection to the girder web. If the beam and girder are of equal depth, both flanges must be coped. Due to the flexural and shear stresses in the coped portion of the web, web buckling can limit the local strength. The AISC Steel Construction Manual provides a design procedure for web buckling of double-coped beams. However, the equations are not valid if the cope depth exceeds 20% of the beam depth. Although the design equations were developed for beams with equal cope sizes at the top and bottom, it is common for the cope sizes to be unequal. This research addresses three issues related to the local stability of double-coped beams: 1. Cope depths greater than 20% of the beam depth, 2. Unequal cope depths at the top and bottom, 3. Unequal cope lengths at the top and bottom. 54 elastic finite element models were used to determine the effect of each variable on the critical load. A semi-empirical design model, with lateral-torsional buckling as the basis, was used to formulate equations to predict localized web buckling of double-coped beams. A buckling modification factor was determined by curve fitting the finite element data. 

View content