Experimental investigation on seismic behavior of steel truss-RC column hybrid structure with steel diagonal braces

Abstract

This paper aims to provide an experimental support on seismic performance evaluation of the steel braced truss-RC (reinforced concrete) column hybrid structure, which could be applied as the air-cooled supporting structural system in large-capacity thermal power plants located in strong earthquake prone regions. A series of pseudo-dynamic tests (PDTs) and quasi-static tests (QSTs) were performed on a 1/8-scaled sub-structure. The dynamic characteristics, lateral deformation patterns, deterioration behavior, hysteretic behavior and failure mechanisms were investigated. Test results showed that the first vibration mode is torsion, which is caused by the small torsional stiffness of this kind of hybrid structure. The lateral deformation shape is shear mode, and the drift ratio of the structure above the corbel is significantly less than that of the column below the corbel. Earthquake energy is mainly dissipated by the RC pipe columns where cracks mainly occurred at the bottom of column and lower part of corbel. The failure mechanisms were identified indicating that the steel braces improved the global stiffness and modified the load transfer mechanism. This study affirms that the steel braced truss-RC column hybrid structure has the sufficient ductility and good energy dissipation capacity to satisfy the design requirements in high seismic regions.