Experimental Comparison Study on Cyclic Behavior of Coupled Shear Walls with Two-Level-Yielding Steel Coupling Beam and RC Coupling Beam

Coupled shear walls are widely used in high rise buildings, since they can not only provide efficient lateral stiffness but also behave outstanding energy dissipation ability especially for earthquake-resistance. Traditionally, the coupling beams are made of reinforced concrete, which are prone to shear failure due to low aspect ratio and greatly reduce the efficiency and ability of energy dissipation.  For overcoming the shortcoming of concrete reinforced coupling beams (RCB), an innovative steel coupling beams called two-level-yielding steel coupling beam (TYSCB) is invented to balance the demand of stiffness and energy dissipation for coupled shear walls. TYSCBs are made of two parallel steel beams with yielding at two different levels.  To verify and investigate the aseismic behaviour improvement of TYSCB-coupled shear walls, two 1/3 scale, 10-storey coupled shear wall specimens with TYSCB and RCB were tested under both gravity and lateral displacement reversals. These two specimens were designed with the same bearing capacity, thus to be easier to compare. The experimental TYSCB specimen demonstrated more robust cyclic performance. Both specimens reached 1% lateral drift, however, the TYSCB-coupled shear wall showed minimal strength degradation. Additionally, a larger amount of energy was dissipated during each test of the TYSCB specimen, compared with the RCB specimen. Based on the experimental results, design recommendations are provided.