Experiments on Composite Beams

This paper describes the behaviour of seventeen simply supported composite T-beams under static concentrated and distributed loading applied on the axis of the beam. The amount of shear connexion (welded studs) was varied within the range which might be contemplated for design purposes and the effect of interface slip on elastic and ultimate load behaviour was observed. Recommendations are made concerning design of the beam section and of the shear connectors. The use of ultimate load design for the composite section may lead to working stresses approaching the yield stress, because of the large shape factor. It is suggested that, notwithstanding the method used for designing the section, the shear connexion should be designed to carry the horizontal shear force existing in the beam at ultimate load. For this purpose it is recommended that 80 per cent of the experimentally determined ultimate capacity of the shear connectors should be used. In the case of uniformly loaded beams, a uniform spacing of shear connectors is satisfactory, notwithstanding the triangular distribution of the external shear force.

J.C. Chapman and S. Balakrishnan