Circular Corrugated Steel Tube Columns Connected With High Performance Concrete Joints Under Sagging Moment

Precast concrete-filled corrugated steel tubular (CFCST) columns with connection joints are increasingly used in structural applications, but their flexural performance with high-performance concrete (HPC) joints remains underexplored. This study experimentally investigates the flexural behavior of precast circular CFCST columns subjected to bending until failure. The columns were encased in corrugated steel sheets and connected using strain-hardening cementitious composite (SHCC) or ultra-high-performance concrete (UHPC) joints. The influence of joint geometry was examined by varying the reinforcement development length (150, 200, and 300 mm). Results show that longer development lengths significantly enhance cracking resistance and load-bearing capacity. Columns with SHCC and UHPC joints exhibited superior energy absorption and stiffness compared to normal concrete (NC) joints. SHCC connections increased energy absorption and stiffness by 53% and 19%, respectively, while UHPC connections achieved 124% and 41% improvements. Overall, SHCC and UHPC joints provided flexural performance comparable to that of monolithic NC columns, demonstrating their potential to enhance both strength and ductility of precast CFCST systems for improved structural resilience.