Limit Analysis of Welded Tee End Connections for Hollow Tubes

Abstract

This paper presents a limit analysis, based on the yield line approach, for predicting the ultimate capacity of welded tee end connections for hollow tubes. Five failure mechanisms are identified. The failure mechanisms range from simple mechanisms such as yielding of the cleat plate or the tube, to the more complex mechanisms involving a combination of hinge formation in the cap plate and local yielding in the tube. It is shown that the dimensions of the connection components involving the tube, the cap and the cleat plate sizes determine which is the controlling failure mechanism. Results presented are applicable to welded tee end connections for hollow tubes of both circular and rectangular sections. A previous series of tests on this type of end connection was conducted on tubes of circular hollow section. A further series of tests on tubes of square hollow section is presented. The theoretical prediction, based on the yield line approach, agree very well with test results from 36 welded tee end connections on circular and square hollow tubes.