Seismic performance of FRP-confined steel-reinforced RAC columns

Effective utilization of construction waste is a topic of concern for the research community and the government and society. Recycled aggregate concrete (RAC) is one of the possible approaches to reuse waste concrete. Among the different approaches aiming at effective use of RAC, the use of RAC in composite structure based on the idea of taking advantages of the composite structure to overcome the shortcomings of RAC, appears as an attractive and cost-effective choice. Fiber-reinforced polymer (FRP) confined steel-reinforced RAC column (FCSRAC) is one typical example of such applications. This paper reports an experimental study on the seismic performance of FCSRACs. Eight FCSRACs were tested under constant axial load and cyclic lateral loading, allowing the effects of axial load ratios, replacement of RCA, FRP tube thickness, and steel ratio on the seismic behavior of this composite structure to be fully investigated. Test results show that although the use of RAC has a certain adverse effect on the load-capacity and stiffness degradation behavior of the FCSRACs, their deformation capacity, energy dissipation capacity, and ductility can be improved with the use of RAC, making FCSRAC outperform its counterpart using normal aggregate concrete (NAC) in terms of seismic performance.