Seismic performance of novel bolt-connected precast concrete walls strengthened by UHPC

Existing bolted precast concrete walls (PCWs) have shown disadvantages in terms of high precision in production or insufficient seismic performance compared with cast-in situ walls. Based on this background, new bolt -connected PCWs enhanced by ultra-high performance concrete (UHPC) and connected by spliced bolted joints for use in low-to mid-rise residential systems were proposed. Seven specimens, including one monolithic concrete wall and six bolt-connected PCWs, were tested at a low axial compression ratio and reversed cyclic loads. The effects of the UHPC enhancement area, bolt arrangement, joint position and bolt hole shape of the steel plate on the seismic performance of the PCW were evaluated. The test results indicate that three types of failure patterns could be observed in PCWs, i.e., wall toe compressive failure, joint shear failure and flexural failure. The PCW enhanced by UHPC was able to achieve equivalent performance to the monolithic wall in terms of lateral resistance and energy dissipation. In addition, theoretical calculations for the flexural strength of PCWs corre-sponding to different failure modes were proposed. The predicted results approximated the test values and were all within the safe range.