LAUSR

ABSTRACT Hybrid coupled wall (HCW) systems, especially with properly designed steel coupling beams, are efficient lateral load resisting systems. To further improve the seismic resiliency of HCW structures after major earthquakes, a new hybrid system consisting of steel plate composite structural wall piers and steel coupling beams with a replaceable fuse was developed. This paper presents an experimental program of three half-scaled subassemblies subjected to pseudo-static cyclic loading. Each test specimen consisted of two segments of composite wall piers and a steel coupling beam with and without a replaceable fuse. The details of the wall piers were identical for the three subassemblies, but three different coupling beams with the same span/depth ratio were used. One subassembly using a steel coupling beam without a replaceable fuse served as the control specimen, which was loaded up to 10% chord rotation following a preselected loading protocol. The other two specimens employed the new hybrid system. The fuse in these two subassemblies was replaced in situ after subjecting the coupling beam to 2% chord rotation, and the specimen was subsequently loaded up to 10% chord rotation. A detailed evaluation of the test results indicates that the new hybrid system can exhibit excellent performance and the replaceable fuse (and its connection details) proved to be a reliable technique to restore the performance after subjecting the coupling beam to chord rotations that are expected during design-level earthquakes. The load transfer mechanism and seismic performance varied depending on the details of the replaceable details of steel coupling beams.