Recent Advances in Design of Steel and Composite Beams with Web Openings

Abstract

This paper presents recent advances in the design of steel and composite beams with web openings for full integration with building services. The conventional design approaches, such as ‘ Tee Section Approach’ and ‘ Perforated Section Approach’, are provided as an introduction to the topic. The key findings of a comprehensive finite element investigation into the structural behaviour of steel beams with web openings of various shapes and sizes are presented, and a generalized design rule with a set of moment-shear interaction curves based on the finite element results is also developed for practical applications. It should be noted that based on three structural parameters, namely, the shear utilisation ratio, v, the coupled moment capacity ratio, m̄, and the coupled shear capacity ratio, v̄, the load carrying capacities of steel beams with web openings of various shapes and sizes are obtained readily through the use of the proposed moment-shear interaction curves. Moreover, an advanced finite element study on a composite beam with a pair of large rectangular web openings is also presented, and the structural behaviour of the perforated composite beam with deformable shear connectors of different deformation characteristics is examined. It is found that both the stiffnesses and the resistances of shear connectors are very important to the load carrying capacities of the perforated composite beams. The maximum difference in the load carrying capacities of the perforated composite beams with different types of shear connectors is shown to be around 15%, reflecting the differ1ent deformation states of the composite beams at failure. Moreover, large pull-out forces are also induced in those shear connectors in the vicinity of the web openings which have been neglected in the past. As the values of these pull-out forces are found to be comparable to the shear resistances of the shear connectors adopted in the models in some cases, such forces should be considered properly in design.