Abstract:With the rapid development of urban transportation, its construction requirements are increasingly high, urban bridges are mainly ramp bridges, ramps and other non-regular bridges. In order to obtain the damage mechanism and hysteresis characteristics of the fabricated pier under the combined seismic action of compression-bending- shearing-torsion, the quasi-static test for three types of bridge piers including prefabricated piers with grouting sleeves(GS), prefabricated piers with grouting sleeve and concrete-filled steel tube(GSS) and cast-in-place reinforced concrete (RC) pier subjected to combined loads was carried out. Combining the shearing-torsion correlation curve in the existing code for design of concrete structures, the shearing and torsion load capacity of the fabricated pier under the combined load was analyzed and compared with the test results. The results show that the GS specimen and RC specimen are dominated by compression bending and torsion damage, while the GSS specimen with inserted steel tube shear keys undergo plastic hinge uplift and exhibit shear torsion damage. GS and RC specimens have better bending energy dissipation capacity, while GSS specimen with the steel tube shear key has a larger bending capacity. The assembled pier joints resulted in weaker integrity, and the torsional load capacity of the GS and GSS specimens were less than that of the RC specimen. The shear torsion correlation of each specimen under combined load is close to the quarter-circle theoretical curve in the specification. The research results can provide a reference for the seismic performance analysis of fabricated piers with grouting sleeves under the combined action of compression-bending-shearing-torsion.