Experimental investigation into high strength bolted shear connections for simple on-site assembly of composite beams

In recent years, composite beams with simple on-site assembly using high performance steel and concrete are widely promoted in many parts of the world. It is proposed to use high strength steel bolts to be embedded with fibre-reinforced high strength concrete to form effective shear connections between steel beams and concrete slabs. In order to assess the structural behaviour of these shear connections, a pilot study in the form of a systematic experimental investigation was conducted, and a total of 17 single-sided push-out tests were carried out with shear connections of three different connection configurations. Details of the experimental investigation together with key test results of the bolted connections are thoroughly described in this paper, including shear resistances, failure modes and load-slippage curves. It was demonstrated that the proposed bolted shear connections with various connection configurations, concrete types and bolt arrangements were able to provide a wide range of shear resistances applicable for construction of large composite structures. Moreover, the use of high strength concrete reinforced with steel fibres and steel blocks was shown to be able to improve both strength and ductility of these shear connections at large deformations. The measured shear resistances of these connections were compared with the design resistances to BS EN 1994-1-1, and a reasonable comparison was found for many of these shear connections. This pilot study provides important test data and insights on the structural behaviour of these bolted shear connections which will facilitate further experimental and numerical investigations for development of complementary design rules to cover the use of fibre reinforced high strength concrete and steel blocks for effective engineering applications.