Seismic Performance of Precast Segmental Concrete-Filled Steel-Tube Bridge Columns with Internal and External Energy Dissipaters

The prefabricated segmental column using posttensioning technology has become an ideal candidate for rapid and environmentally friendly construction. To avoid damage to the segment joint during a seismic event and enhance its energy dissipation (ED), a precast segmental concrete-filled steel-tube (PSCFST) bridge column with internal or external ED bars is proposed. The seismic performance and resilience of the PSCFST bridge columns with internal or external ED bars are investigated. Moreover, the fiber-section model and numerical analysis are used to analyze the optimal setup angle of the external ED bar. More importantly, the deformation mechanism of the PSCFST specimen with internal or external ED bars is provided. Then, two PSCFST columns and one reference monolithic reinforced-concrete (MRC) column were designed and tested under pseudostatic loading. Owing to the confinement effect of the steel tube on the concrete of each segment, the PSCFST column has desirable performance without obvious damage, whereas the plastic hinge region of the MRC column is severely damaged. After the test with a maximum drift of 5%, the residual drift of PSCFST columns is very small, only 0.175–0.209%, whereas the residual drift of the MRC specimen is 3.632%. To investigate the resilience performance of PSCFST column, one column was reloaded after the replacement of the external ED bars. Compared with the original specimen, the reloaded column shows excellent self-centering behavior, no obvious damage, and very small residual displacement.