Effects of bolt–plate arrangements on steel plate strengthened reinforced concrete beams

A structure that can behave in a ductile fashion under extreme events is of paramount importance due to safety considerations. Because of such importance, ductility performance of bolted side-plated (BSP) concrete beams under different bolt–plate arrangements is investigated experimentally through four large-scale tests on BSP beams. It is observed that bolt–plate arrangements have a dominant effect on the ductility performance of beams in terms of both the post-elastic strength enhancement (defined as the ratio between the peak strength and the yield strength of the beam), and the displacement ductility (defined as the ratio between displacements at the ultimate and notional yield stages). In order to ensure ductile beam behaviour, the concept of maximum allowable plate–force demand is introduced, of which the strength of additional plates should be kept below the ‘balanced’ failure point, while sufficient shear strength of the bolt connections should be provided so that the strengthened beam will possess both sufficient strength enhancement and ductility.