EXPERIMENTAL STUDY ON THE SEISMIC BEHAVIOUR OF FLUSH END PLATE COMPOSITE CONNECTIONS

摘要

This paper deals with the cyclic behaviour of composite joints. Four flush end plate joints under cyclic loading were tested. The investigation mainly focuses on the effects of longitudinal reinforcement ratio and column types on the behaviour of flush end plate joints under cyclic loading. The test results indicated that the moment capacity, initial stiffness and ultimate rotation capacity under the negative moment increases with increasing of the longitudinal reinforcement ratio. However, the moment capacity and initial stiffness under the positive moment for all joints is alike because the failure is governed by tensile resistance of the bottom bolts. When the longitudinal reinforcement ratio is large, the anchorage failure of longitudinal reinforcement easily occurs. The partially concrete encased composite column can enhance the initial rotation stiffness under both positive and negative bending, but splitting and spalling appeared on the concrete of the panel zone under cyclic loading have the influence on the positive moment resistance and the positive ultimate rotation capacity. After attaining the peak load, the strength degradation for all joints is very obvious as the number of cycles increases, but the strength is still large enough to endure many times cyclic loading.