Design-Level Seismic Estimation of Self-Centering Energy Dissipation–Braced Frame Structures with Partial Recentering Capacity

Abstract

Self-centering (SC) techniques have attracted widespread interest for the improvement of the seismic resilience of building structures. One typical representative is the self-centering energy dissipation (SCED)–braced frame structure, which is characterized by the ease of substitution with other conventional braced structures. Previous studies on the seismic performance of SCED-braced moment-resisting frame (MRF) structures were based on the expectation of full SC capacity. However, full SC performance is generally limited by the available deformation stroke of the SC mechanism in the SCED brace. Consequently, two partial SC design concepts, (1) reducing the structural SC ratio to ensure sufficient brace deformation capacity and (2) activating a sliding mechanism after the brace exhausts the available deformation stroke, are proposed to solve the noted design problems. To comprehensively understand the seismic performance of such partial SC structures, the SCED-braced MRF is represented by a dual-system single-degree-of-freedom (SDOF) model to consider the respective contributions of the frame and brace portions. An extensive parametric study, in which five levels of structural design parameters were considered, was performed to evaluate the seismic performance of SCED-braced MRFs designed with different partial SC concepts based on the dual-system SDOF model. Several useful suggestions for the design of SCED-braced MRFs with partial SC capacity were gleaned. The analysis results indicate that the SCED-braced MRF with a low SC ratio of 0.4 still has a satisfactory control effect on both the maximum displacement response and residual displacement. Moreover, the sliding mechanism is favorable for the structure in the medium to long range of the structural vibration period to control the amplified residual deformation within a limited range.