Shear strength of tapered steel plate girders

Abstract

Hot rolled beams can show insufficient strength or inertia and result in the inclusion of steel plate girders in the design (portal frames, steel and composite bridges). More efficient structural elements can often be achieved by designing these plate girders with a tapered girder profile. One of the main distinctive features of tapered steel plate girders is the significant slenderness of the web. In this paper, an analytical model to evaluate the shear capacity of tapered plate girders is presented. The model is based on diagonal tension field theory. The analytical formulation presented, obtained on the basis of numerical studies of plate instability and shear capacity, takes into account the real geometry of the tapered plate girder and the actual boundary conditions of the web panel. The shear model considers the bending stresses on the web panel, which appear as a result of the variation of the structural depth of the steel girder. Finally, analytical results of shear strength of tapered steel plate girders obtained using the proposed model are compared with those derived from the numerical model, which is based on the finite element method.