Seismic behavior of steel reinforced concrete T-shaped columns: Experimental and restoring force model analysis

Abstract

To improve the seismic behavior of the conventional reinforced concrete T-shaped column, the steel skeleton was introduced to form the steel reinforced concrete T-shaped columns. To evaluate the effective of the novel T-shaped column, five 1/2-scale steel reinforced concrete T-shaped columns and one reinforced concrete T-shaped column were constructed and tested subjected to the cyclic loading. Test variables were steel skeleton form and axial compression ratio. The cracking development, failure mode and hysteretic curve of the T-shaped column were recorded. The strength and stiffness, energy dissipation capacity, and ductility were also compared. Test results indicated that the steel reinforced concrete T-shaped column exhibited excellent bearing capacity, ductility, energy dissipation capacity and stiffness degradation when compared with the reinforced concrete T-shaped column. The column SRTC1 with solid-web steel and HRTC1 with hollow-web steel exhibited 39.9 % and 28.0 % higher peak load than TC1, respectively. The HRTC1 exhibited 1.7 times larger ductility and 2.0 times greater cumulative energy dissipation than specimen TC1, respectively. The T-shaped column with T-shaped steels and one square steel tube achieved better seismic performance in the premise of proper axial compression ratio, which had positive influence on the seismic performance. A tri-linear skeleton curve model for the T-shaped column was proposed by the test fitting approach. Based on the restoring force model, the calculated hysteretic curves were closely matched the experimental results, indicating that the established restoring force model can accurately reflect the hysteretic behavior of the steel reinforced concrete T-shaped column.