Shear performance of bolted side-plated reinforced concrete beams

Although the bolted side-plating (BSP) technique is feasible to upgrade the shear capacity of reinforced concrete (RC) beams, related studies on its strengthening effect have yet to be sufficient. Therefore, an experimental study of seven specimens was conducted to investigate the shear performance of BSP beams. The failure mode was found shifting from shear-tension to shear-compression after strengthening. The decrease of bolt spacing, the increase of plate breadth and thickness improved the shear capacity, stiffness and ductility effectively. Although the additional stiffeners improved the stiffness considerably, it exhibited no obvious improvement in the shear capacity and caused a serious reduction in ductility. Due to the shear deformation of bolt shaft and the tensile principal stress in the steel plates that was perpendicular to the main diagonal crack, uneven relative longitudinal and transverse slips existed on the interface between the bolted steel plates and the RC beams. An analytical model was developed according to the force equilibrium and deformation compatibility of the beam segment in the shear span. A design procedure, which can be conducted conveniently using ordinary computing software or even a calculator by structural engineers in their strengthening design practise, was also provided to estimate the shear bearing capacity of BSP beams.