Experimental and numerical study on shear and bending behaviour of external plate concrete beams with prefabricated cages

It is possible to improve the flexure and shear capacity of PCB (Plated Concrete Beam) specimens using the plating approach; adequate investigations on the strengthening effect have yet to be completed. An experimental investigation on concrete beams reinforced with external steel plates as a tensile reinforcement with a combined stirrup (triangle and rectangle) has been performed in this study. The beam uses a prefabricated cage, where the steel plate remains exposed and stirrups are welded to the steel plate. The prefabricated cages were composed of the steel-plate that is equivalent to tension reinforcement of the control beam. As a part of the investigation, a fifteen-sample theoretical and experimental research were done to explore the shear and flexure behaviour of PCB with triangle and combined stirrup shapes and compared the result with the conventional RC beam. Instead of tensile bars, steel plates of similar thickness (1.6 mm) were added to the tension zone of all beams as tensile reinforcement. The parameters such as ultimate loading, load versus deflection relationship, cracking pattern, ductility behaviour have been comparatively studied with respect to the control reinforced concrete (RC) beams without employing the steel plates. There are total five sets of experimental conditions carried out with each containing three units of concrete beams, which included one-set of plated concrete beam with triangle stirrup, one set of plated concrete beam with triangle stirrup with crank, one set plated concrete beam with combined stirrup, one set plated concrete beam with combined stirrup with crank bar and finally one set of control beam. These have been carried out to establish the most economically feasible structure in the context of achieving the superior flexural capacity and strength. Notably, this study has been conducted in two parts, where the first part involves the in-house experimental work, whereas the second part involves the numerical modelling of the tested specimens using a high-end Finite Element Analysis platform. The obtained experimental data indicated a firm agreement in terms of ultimate-loading in the range of around 2 to 15% with that of the ultimate-loading of the reference beam and plated concrete beam with triangle stirrup beam. In addition, the parameters such as crack width, concrete strain and number of cracks have also been found to be reduced on the steel-plated beams.