Quasi-static tests of CFST embedded RC column-to-precast cap beam with socket connection.

• CFST embedded column-cap beam with UHPC grouted connection for high-intensity areas. • Experimental study on reliability and seismic behavior of CFST socket connection. • A model for evaluating the moment capacity of CFST socket connection. The seismic behavior of an embedded concrete-filled steel tubes (CFST) precast column-to-cap beam socket connection of a practical engineering project was investigated through 1:3-scale quasi-static tests. The precast column and cap beam was integrated by ultrahigh-performance concrete (UHPC) grouting to improve the interface bonding behavior and lateral constraint. The influences of embedment depth, socket forming method, and column section size on the cyclic response of the structure were evaluated. The experimental results revealed that when the concrete-filled steel tube (CFST) embedded depth is 1.0 times tube diameter, the specimens can obtain good strength and hysteresis performance. The socket hole formed by a steel pile can further promote the hysteresis performance of the cap beam-column joint, and the ultimate failure of the joint is the fracture of the column longitudinal rebar. A model for evaluating the moment capacity of the CFST socket connection was proposed and verified by the test results, which can be used in the preliminary design the proposed connection. [ABSTRACT FROM AUTHOR]