Axial performance of steel splice connection for tubular FRP column members

A splice connection is proposed for connecting tubular fibre reinforced polymer (FRP) members. This connection consists of a steel bolted flange joint (BFJ) and two steel-FRP bonded sleeve joints (BSJs). The BFJ connects two steel hollow sections, each of which is telescoped into the targeted tubular FRP member through adhesive bond, forming a BSJ. To evaluate the performance of the proposed splice connection under axial loadings, BSJs of four different bond lengths and BFJs of two bolt configurations are tested individually. Finite element (FE) models are developed which feature a bilinear bond-slip relation, contact behaviours and bolt pre-tensioning. Comparisons are made between experimental and FE results in terms of load-displacement behaviours, ultimate capacities and strain responses. Besides being capable of identifying an effective bond length for the BSJ and modelling the yielding process of the BFJ, FE analysis provides insight into the distribution of adhesive shear stress over the bond area of the BSJs, and the steel yield line pattern on the flange-plate of the BFJs. Verified by experimental results, the FE modelling technique is then utilised to understand the integrated axial behaviours of a complete splice connection.