Seismic behavior of a novel prefabricated thin-walled CFST double-column pier system for simple on-site assembly

To expedite the development of concrete-filled steel tubular (CFST) piers for simple on-site assembly (SOA), a novel prefabricated thin-walled CFST double-column pier system is proposed with the advantages of accelerated on-site construction, facilitated transportation, reasonable constructional cost, and good seismic performance. Two prefabricated thin-walled CFST double-column pier specimens were tested under quasi-static loading, and their failure modes, deformation characteristics, hysterical responses, energy dissipation capacity, stiffness degradation, and residual drift ratio are discussed in detail. The test results indicate that the proposed prefabricated thin-walled CFST double-column pier system shows a fairly good seismic performance with reasonable failure mode, sufficient energy dissipation, and relatively small residual deformation, and the SOA connections can effectively guarantee the overall deformation of the system under a maximum drift ratio of 4.8%. The specimen with double RC tie beams is superior in lateral resistance and initial stiffness to the one with a single RC tie beam, while they show similar performance in ductility and energy dissipation efficiency.