Investigation on the seismic performance of concrete piers reinforced with FRP confined ECC core

Reinforced concrete (RC) piers have been widely studied and applied in bridge construction practice. To ensure the normal operation of RC piers under corrosive environments and seismic effects, new corrosion-resistant materials with good mechanical properties need to be introduced. In this study, fiber reinforced polymer (FRP), engineered cementitious composite (ECC), and stainless steel plates were used in concrete piers for the first time, introducing a novel concrete pier reinforced with FRP confined ECC core (FCEC). A spiral stirrup confined and three stainless steel plate confined concrete piers reinforced with different FCEC heights were constructed, and a quasi-static test was performed to assess their seismic performance. For comparison, a conventional RC pier was also tested. The analysis focused on the failure modes and hysteresis behavior of the specimens. The test results indicated that plastic hinges formed at the pier base of all specimens, except for the concrete pier reinforced with 250mm-height FCEC. The concrete piers reinforced with FCEC demonstrated higher load-bearing capacity but lower ductility than the conventional RC piers. Interestingly, a reduction in FCEC height was found to enhance the ductility of these novel concrete piers. To support effective design practices for concrete piers reinforced with FCEC, a simplified bearing capacity calculation model and an appropriate FCEC height calculation model were developed based on experimental findings and mechanical analysis.