Design and performance of an adaptive-stiffness rocking structure for enhanced seismic resilience

Abstract

The rocking structure is widely recognized for its excellent seismic resilience, including damage-free performance. However, it still faces challenges, such as low energy dissipation efficiency and significant higher-mode effects, which hinder its ability to simultaneously control displacement and force responses. To address these issues, this paper proposes the adaptive-stiffness rocking structure (ASRS) by integrating the adaptive stiffness mechanism with the rocking and energy dissipation mechanisms, thereby enhancing energy dissipation efficiency. This integration also effectively mitigates the influence of higher-mode effects, such as acceleration and shear forces. In this study, the ASRS's non-proportional damping distributed parameter model and the distributed transfer function method (DTFM) are used to solve the dynamic equations. The dynamic characteristics, including frequency and damping ratio, are derived, and parametric equations for the modal damping ratio are obtained via curve fitting. The inter-story drift ratio (IDR) design spectrum of the ASRS is calculated using the modal decomposition response spectrum method. Based on this, the preliminary design and performance assessment of the ASRS are conducted. The results show that the ASRS effectively reduces dynamic responses, such as IDR, acceleration, and shear force, by leveraging the combined action of the adaptive stiffness and energy dissipation mechanisms. Furthermore, the IDR design spectrum enables an efficient preliminary design of the ASRS.