Advanced finite element modelling of perforated composite beams with flexible shear connectors

An extensive research and development programme has been undertaken by the authors to develop advanced analysis and design tools for practical design of long span composite beams in buildings. Both two- and three-dimensional finite element models employing solid and shell elements with material, geometrical and interfacial non-linearity were established to examine the full range structural behaviour of composite beams. In this paper, two-dimensional finite element models employing plane stress elements are established to examine the structural behaviour of perforated composite beams, and shear connectors with non-linear deformation characteristics are incorporated into the models through the use of both vertical and horizontal springs. It is demonstrated that after careful calibration against test data, the finite element models are able to predict the load carrying capacities of composite beams with large rectangular web openings against 'Vierendeel' mechanism satisfactorily. Moreover, a number of important structural quantities such as local axial and shear forces together with local bending moments acting onto the composite and the steel tee sections at failure are obtained after data analyses. Together with the load carrying capacities, these quantities compare favourably with the values obtained from a design method proposed previously by the authors, and hence, this provides quantitative justification to the proposed design method. Furthermore, the finite element models provide detailed information on the structural behaviour of shear connectors along the beam length, such as the longitudinal shear forces, the pull-out forces as well as the slippage of the shear connectors. Based on the findings of the finite element modelling, a number of recommendations on the design and construction of perforated composite beams are suggested.