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

摘要

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 beamsreinforced with external steel plates as a tensile reinforcement with a combined stirrup (triangle and rectangle) has beenperformed in this study. The beam uses a prefabricated cage, where the steel plate remains exposed and stirrups are weldedto the steel plate. The prefabricated cages were composed of the steel-plate that is equivalent to tension reinforcement of thecontrol beam. As a part of the investigation, a fifteen-sample theoretical and experimental research were done to explore theshear and flexure behaviour of PCB with triangle and combined stirrup shapes and compared the result with the conventionalRC beam. Instead of tensile bars, steel plates of similar thickness (1.6 mm) were added to the tension zone of all beams astensile reinforcement. The parameters such as ultimate loading, load versus deflection relationship, cracking pattern, ductilitybehaviour have been comparatively studied with respect to the control reinforced concrete (RC) beams without employingthe steel plates. There are total five sets of experimental conditions carried out with each containing three units of concretebeams, which included one-set of plated concrete beam with triangle stirrup, one set of plated concrete beam with trianglestirrup with crank, one set plated concrete beam with combined stirrup, one set plated concrete beam with combined stirrupwith crank bar and finally one set of control beam. These have been carried out to establish the most economically feasiblestructure in the context of achieving the superior flexural capacity and strength. Notably, this study has been conducted in twoparts, where the first part involves the in-house experimental work, whereas the second part involves the numerical modellingof the tested specimens using a high-end Finite Element Analysis platform. The obtained experimental data indicated a firmagreement in terms of ultimate-loading in the range of around 2 to 15 with that of the ultimate-loading of the referencebeam and plated concrete beam with triangle stirrup beam. In addition, the parameters such as crack width, concrete strainand number of cracks have also been found to be reduced on the steel-plated beams.