A new approach to testing concrete coupling beams subjected to reversed cyclic loading

Abstract

This paper presents an innovative experimental rig developed for tests of full-scale concrete coupling beams of tall shear wall buildings subjected to reversed cyclic loading. The coupling beams are generally subjected to very high bending moment and shearing force owing to rotations of the beam ends, which are forced by the deflection of shear walls under the action of lateral loading. Because no direct loads are generally applied to the beams, how to create the boundary conditions where two beam ends are forced to rotate equally and displace vertically is challenging in the laboratory tests. This can further be complicated by the requirement of applying reversed cyclic loading to the connected shear walls. The developed test rig allows for proper modelling of loading and boundary conditions in both monotonic and reversed cyclic load cases. Tests of the full-size specimens with different span-to-depth ratios can be conducted without changing the beam depth, which allows for direct comparisons of specimens and experimental results. The rig is capable of performing tests for investigating strength and ductility of the specimens with large rotational and vertical displacements. Available experimental methods to test coupled shear walls are reviewed to demonstrate the simplicity, accuracy and effectiveness of the proposed test rig and the method.