Nonlinear seismic performance study of D‐type self‐centering eccentric braced frames with sliding rocking link beams

Abstract

AbstractThis paper presents a nonlinear numerical simulation study of the D‐type self‐centering eccentric braced frame system with a sliding rocking link beam (SCEBF‐SRL) to overcome the beam‐growth problem. The re‐centering capability of such SCEBF‐SRLs is enabled by post‐tensioned (PT) steel‐stranded cables. Replaceable hysteretic dampers termed RHD are used as seismic fuse devices for energy dissipation, while the friction force due to the relative movement of the sliding rocking link beam inside the column corbels would also contribute to the energy dissipation capacity of the system. Analytical load versus displacement relationships of an SCEBF‐SRL module frame were formulated and cross‐validated with nonlinear finite element (FE) analysis results. The seismic performance of the proposed system was studied through nonlinear static and dynamic analysis of three‐ and six‐story prototype SCEBF‐SRL buildings. A set of twenty‐two far‐field ground motions from the FEMA P695 database was adopted for nonlinear dynamic analysis (NDA). NDA results revealed that the ensemble median of the maximum inter‐story drift ratios (IDRs) of both SCEBF‐SRL prototypes were less than 1.4% and 2.0% at the design basis earthquake (DBE) and the risk‐targeted maximum considered earthquake (MCER) levels, respectively. Additionally, both SCEBF‐SRL buildings fully re‐centered themselves at MCER with negligibly small residual drift (<0.01%). The parametric study results suggest that with an energy dissipation ratio, between 25% and 60% and a minimum stiffness ratio of 5%, the ensemble median of the maximum IDR of the considered prototype building could be made less than 1.5% and 2.3% at DBE and MCER levels, respectively.