Performance evaluation of RC frame with RC wall piers equipped with unbonded steel rod dampers subjected to in-plane loading

Abstract

Brittle shear failure of partial Reinforced Concrete (RC) wall pier system is usually observed in post-earthquake investigations, which affects the building functions seriously. A new RC wall pier system with unbonded steel rod dampers is introduced in this study. Numerical simulation using solid element method, validated by existing experimental results, was adopted firstly to investigate the behaviors of dampers, lateral force capacity, stiffness degradation, and ductility of the frame with the new RC wall pier system considering the influence of the dampers and the frame axial compression ratios. To decrease the huge computational costs of the solid element model, macro element model was further developed and verified. Performance evaluation of a twelve-story RC frame structure with three models of RC wall piers, namely damper model, slit model and rigid model, was conducted with the macro element model. Results show that RC frame with RC wall piers equipped with dampers possesses a stable lateral, and the designed dampers provide more than 20% of the lateral force to the frame. It is advised that the axial compression ratio of frame column shall be within 0.1 from the perspectives of plastic regions of dampers and lateral force capacity of frame. The nonlinear responses of the new RC wall pier system can be well captured by the macro element model with less computational costs. By comprehensively considering the structural drift ratios, the energy dissipation and the shear force in the frame beam, the damper model is suggested to be the best among the three models. The new RC wall pier system highlights an alternative for the conventional RC wall pier systems in the engineering practice.