Experimental Study On Restoring Force Characteristics Of Solid- Web Steel Reinforced Concrete T-shaped Columns

Steel reinforced concrete special-shaped columns are new structure, of which steel and a moderate amount of longitudinal reinforcement and stirrup are arranged in the section. The structure can give full play to respective advantages of the two kinds materials of steel and concrete. It not only has high rigidity and bearing capacity, good seismic performance and ductility and large axial compression ratio limit, but also has significant advantages of special-shaped columns, such as making better use of available space and improving the esthetic appearance of structure. It has a good application prospect in the earthquake intensity area and the high-level structure aspects.Based on seismic performance test of the solid-web steel reinforced concrete T-shaped columns, the restoring force characteristics was analyzed systematically and the restoring force model applicable to the structure was proposed in this paper.10 solid-web steel reinforced concrete T-shaped columns members according to the proportion of 1:2 scale were designed and the seismic performance test were conducted by using the loading device of parallel four-linkage. The mechanical characteristics and failure modes during the loading process were observed, and the hysteresis curve,skeleton curve, ductility performance, displacement angle, energy dissipation capacity,strength degradation and stiffness degradation of the solid-web steel reinforced concrete T-shaped columns were analyzed. The results indicated that hysteresis curve of the solid-web steel reinforced concrete T-shaped columns is symmetry at the positive and negative direction, the hysteresis loops are plump, overall ductility and bearing capacity stability are good, and energy dissipation ability is strong.Theoretical analysis and regression fitting were conducted, and the calculationmethod of each characteristic value for the yield point, peak point and the failure point at the skeleton curve of the solid-web steel reinforced concrete T-shaped columns were given. Trilinear skeleton curve model was proposed. Combined with the skeleton curve model, stiffness degradation rule and hysteretic characteristics, restoring force model of the solid-web steel reinforced concrete T-shaped columns was established.The results could lay a solid foundation for the elastic-plastic time history analysis of the solid-web steel reinforced concrete T-shaped columns. At the same time, the calculation methods and ideas in this paper can provide reference for the establishment of the restoring force model of steel reinforced concrete special-shaped columns with the same type or other types.