Effect of column axial load on composite connection behaviour

摘要

The design methods currently available for composite joints do not allow for possible reductions in moment capacity due to the pres- ence of axial load in the column. Using a previously validated FE model developed by the authors, joint behaviour under varying levels of column axial load for both symmetric and non-symmetric joints has been studied. It was established that the level of column axial load does not significantly affect moment capacity for sym- metric joints, whereas non-symmetric joints have their moment capacity reduced by the presence of high axial load in the column. The reason was found to be directly related to the type of failure of the non-symmetrically loaded joints, which is controlled by the effective resistance of the column web in shear. Both theoretical and FE results are then used to develop a design method for the non--symmetric joints that allows for the influence of a varying level of column axial load, including the beneficial effect of the possible presence of some level of moment on the other side of the connec- tion. The method is illustrated by worked examples.