Experimental validation of RC shear wall structures with hybrid coupling beams

The seismic performance of reinforced concrete (RC) shear wall structures can be significantly improved by hybrid coupling beams installed with metallic dampers. The damper yields first during an earthquake, thus absorbing a large amount of energy, and protecting the RC part of the coupling beam. This study began by proposing a particular configuration installed with a metallic damper with slits. Design equations were suggested for the strength and the stiffness, which were validated by quasi-static tests. Then, a parametric study was conducted on an 18-story frame-shear wall structural system by nonlinear time history analyses. The results indicated the optimized strength and stiffness to control the overall responses of the structure. Finally, the effectiveness of the hybrid coupling beam was fully demonstrated by a set of online hybrid tests, where the bottom part, containing six stories of coupled walls, was treated as the experimental specimen, while the rest of the coupled wall and the frame were implemented as two numerical substructures. They were managed in the separated-model framework for the online hybrid test, where the dynamic responses of the entire structure were modeled by a simplified mass-spring model. Two specimens were constructed and tested, one with the traditional RC coupling beams, and the other with the hybrid coupling beam. It was found that the hybrid coupling beam could reduce the base shear force by more than 30.0%. The damage to the RC parts was well controlled, significantly improving the seismic performance of the structure.