Seismic behavior of prefabricated thin-walled CFST double-column bridge piers.

• Two slender CFST double-column piers are tested under cyclic loading. • The prefabricated connections guarantee the performance of the novel pier system. • FE modeling is carried out to assess seismic performance of pier systems. • The novel pier systems have application potential in bridges of mountain areas. This paper investigates the seismic behavior of a prefabricated thin-walled concrete-filled steel tubular (CFST) pier system composed of circular thin-walled CFST double-column, I-shaped steel beam, and precast reinforced concrete (RC) cap beam. Hysteretic tests were conducted on two slender double-column pier systems: one with prefabricated connections (prefabricated pier system), and the other one with traditional embedded connections (traditional pier system). The test results indicated that, compared with the traditional pier system, the pier system with prefabricated connections demonstrating an 18 % increase in lateral resistance and a 5 % higher ductility coefficient, despite the weld of the steel beam cracked prematurely. Finite-element numerical models were established based on the OpenSees platform and validated by the cyclic loading tests. A comprehensive investigation involving a total of 12 cases, encompassing both CFST piers and RC piers, was conducted to evaluate their seismic performance and economic efficiency. The analysis results revealed that the proposed prefabricated pier system offers notable advantages in seismic performance for both tall and low piers. [ABSTRACT FROM AUTHOR]