EXPERIMENTAL RESEARCH ON THE PERFORMANCE OF COMPOSITE CONFINED REINFORCED CONCRETE CIRCULAR COLUMN WITH MULTIPLE SPIRAL STIRRUPS UNDER AXIAL COMPRESSION

In order to study the axial compression behavior of composite confined reinforced concrete circular column with multiple spiral stirrups, a total of 8 specimens were tested under axial compression. Three parameters including spiral stirrup spacing, steel cage spacing and number of spiral stirrups were taken into consideration. The failure process and mode of specimens were observed, and the load-deformation curve, peak load, and peak deflection were obtained. Furthermore, the effects of different parameters on axial compression behavior were analyzed. The results showed that the failure process and mode of circular columns with triple spiral stirrups were similar to those of circular columns with double spiral stirrups under axial compression. It had greater initial compression stiffness and better ductility and energy dissipation capacity, but increasing the amount of steel did not effectively improve its bearing capacity. Increasing the spacing of spiral stirrup could significantly reduce the steel consumption without significantly reducing the bearing capacity, while the peak deformation, initial compression stiffness, ductility and energy dissipation gradually decreased. With the increase of steel cage spacing, the reduction of steel consumption was greater than that of bearing capacity, and the ductility and energy dissipation capacity were improved, but the peak deformation and initial compression stiffness had no obvious regularity.