Cyclic behavior and analysis of steel plate reinforced concrete coupling beams with a span-to-depth ratio of 2.5

Steel plate-reinforced concrete (SPRC) coupling beams, in the form of a reinforced concrete (RC) beam with one (or more) internally embedded steel plate, have become a promising alternative in concrete coupling beam design. While existing studies have been carried out to demonstrate the favorable seismic performance of SPRC coupling beams, the effects of various factors on the seismic behavior of such coupling beams have not yet been fully investigated. In addition, existing studies have been mainly focused on relatively short SPRC coupling beams dominated by shear failure. Against this background, five SPRC coupling beams with a span-to-depth ratio of 2.5 were tested under reversed cyclic loading in the present study. One diagonally reinforced concrete coupling beam was also tested for comparison. The experimental variables included the steel plate configuration, steel plate ratio, and longitudinal steel bar reinforcement ratio. The test results confirmed that the SPRC coupling beams possessed high load-carrying capacity and large plastic deformation. The test results also demonstrated that the steel plate ratio and steel bar reinforcement ratio had significant effects on the behavior of SPRC coupling beams: the strength increased with the steel plate ratio or the steel bar reinforcement ratio while the ductility reduced obviously as the steel bar reinforcement ratio increased. Finally, a theoretical analysis was proposed to evaluate the failure mode and the load-carrying capacity of SPRC coupling beams.