New performance-based seismic design method for structures with structural fuse system

Abstract

In structural systems combined with structural fuse system, the replaceable fuse elements, with their ductile behavior, are an adequate solution for protecting main structural members and reducing the destructive effects of earthquakes, during and after the event. Relatively low cost and easy repair process in these systems leads to rapid return to occupancy after an earthquake. Performance-based design of these systems is a complicated process because of the interactions between two systems, and so far, no simplified method is introduced for this purpose with adequate accuracy. In this study, by using the performance-based plastic design method (PBPD), an iterative, simple and highly accurate procedure is introduced for designing these dual systems. This method is based on separating the two structural systems considering their interactions. There are three performance objectives in this method: first, elastic behavior in low earthquake hazard level for immediate occupancy, second, inelastic behavior of fuse in moderate earthquake hazard level for rapid repair, and third, inelastic behavior of the whole structure in very high earthquake hazard level for collapse prevention. As design examples, structures with linked column frames (LCF) were chosen. Three structures with 3, 6 and 9 stories, were designed with this method. To evaluate the proposed method, nonlinear static and dynamic analysis was applied, and structures were modeled according to experimental results of the members and ground motions representing various seismic hazard levels. Analyses results showed that the designed structures achieved the performance objectives. Moreover, in moderate earthquake hazard level, only fuse members yielded and other structural members remained elastic.