Performance-based seismic design of multistory frame structures equipped with crescent-shaped brace

Abstract

The primary objective of the “performance-based seismic design” is to provide stipulated seismic performances for building structures. However, a certain degree of design freedom is needed for matching a specific seismic response. This design freedom is not obtainable by the conventional lateral resisting systems because their stiffness and strength are coupled. Here, we put emphasis on the role of the unconventional lateral resisting systems in adding more flexibility to the design. In this paper, we seek to explore the seismic design of moment-resisting frame structures equipped with an innovative hysteretic device, known as “crescent-shaped brace.” One conspicuous feature of this device is its distinctive geometrical configuration, which is responsible for the enhanced nonlinear force-displacement behavior exhibited by the device. A new performance-based approach for the seismic design of the crescent-shaped brace is proposed. The performance of the device is evaluated, and its application in multistory shear-type structures is investigated. Two case studies were established to illustrate the design methodology. The first is a new two-story RC structure, and the second is an existing three-story RC structure. Nonlinear time history and pushover analyses are performed to evaluate the behavior of the controlled structures. The analyses show that for each of the two case studies, the acceleration–displacement capacity spectrum conforms to the performance objectives curve. This finding confirms the validity of the proposed design approach and the effectiveness of the new hysteretic device in resisting lateral forces.