Restoring Force Model of a Cast-In-Situ Recycled Aggregate Concrete Frame

Abstract

The hysteresis behavior of a cast-in-situ recycled aggregate concrete (RAC) frame was analyzed based on shaking table tests on a one-fourth scaled model of a two-bay, two-span and 6-storey RAC frame. Then feature points and the stiffness degradation were defined and the deteriorating four-line-typed restoring force model was put forward. In the hysteresis model, the monotonic behavior is described by a four-line-typed skeleton curve which accounts for concrete cracking, yielding of reinforcing bars, maximum and ultimate point of the RAC frame model. The hysteresis behavior is described through a number of rules for unloading and reloading. Therefore, the restoring force model proposed in this study can capture the hysteresis response of the frame under seismic actions. Moreover, the displacement ductility of the RAC frame structure is evaluated based on the proposed restoring force model. It can be concluded from this investigation that the RAC frame structure with proper design and construction has favorable load-carrying capacity, deformation capacity, energy dissipation ability and seismic performance, and can be applied and popularized in the area with the requirement of aseismic fortification intensity.