Buckling tests on steel plates restrained at discrete points in the retrofit of reinforced concrete beams

Steel plates may be bolted to the sides of reinforced concrete beams in order to both strengthen and stiffen them. When these steel plates are subjected to their design actions, bending, shear and axial stresses may be produced in the plate and this can precipitate local buckling. The local buckles are unilateral, since the concrete beam constrains the steel to buckle locally away from the concrete core. This type of behaviour is referred to as a contact problem, and research into its structurally based applications has only accelerated over the last decade or so. This paper presents the description and results of a so-called local buckling push test undertaken on bolted plates of various configurations to calibrate the theoretical solutions developed elsewhere by the authors. This analytical method, based on the Rayleigh–Ritz method with polynomial displacements and a tensionless foundation, is found to be in good agreement with the test results, and furthermore these test results provide benchmark data for future studies.