Testing of coupling beams with equal end rotations maintained and local joint deformation allowed

Abstract

The strength and ductility of the coupling beams in coupled shear walls can significantly affect the nonlinear behaviour and earthquake resistance of the whole building structure. However, although extensive testing of coupling beams has been performed, the boundary conditions—that the rotations at the two ends of a coupling beam are equal and that local deformation occurs at the beam–wall joints, which could have substantial influence on the test results—have not been correctly simulated. Herein, a new method of testing reinforced concrete coupling beams that ensures equal rotations at the ends of the beam specimen and takes into account local deformation at the beam–wall joints is developed. The method has been successfully applied to test typical reinforced concrete coupling beams with relatively small span/depth ratios and proven to be suitable for studying the post-peak behaviour and failure characteristics of short coupling beams. Test results obtained so far indicate that reinforced concrete coupling beams with small span/depth ratios behave quite differently from ordinary beams in frame structures and that the local deformation at beam–wall joints is quite substantial. Complete load–deflection curves have been acquired and the strength and ductility of the coupling beams evaluated.