Experiment Study on Seismic Performance and Shear Capacity Calculation of H-Shaped Steel Reinforced Concrete Columns Under Combined Torsion
摘要
This research utilized a low-cycle reciprocating examination to investigate the earthquake resistance of HSRC columns subjected to axial force, bending moment, shear force, and torque. Tests were conducted on 12 H-shaped steel reinforced concrete columns (HSRC) and 1 reinforced concrete column to assess cyclic loading, bending, shear, and torsion. The seismic behavior of HSRC was examined in relation to member dimensions, steel percentage, longitudinal reinforcement percentage, stirrup volume percentage, and stud placement. Observations were made on the failure modes of the specimens subjected to combined torsion, with comparisons and analysis of hysteretic curves, skeleton curves, stiffness degradation, energy dissipation, and ductility of each specimen. The findings indicate that all specimens experienced flexural-torsional failure when exposed to compression-bending-shear-torsion stress. The hysteresis curve for top displacement of the load column is complete and fusiform, while the curve for torque-torsion angle is shaped like a pinched ‘S’. HSRC columns exhibit significantly higher flexural and deformation capacities compared to RC columns, showing improvements of 15.69% to 21.09% and 40.54% to 83.24%, respectively. Increasing the section size can effectively improve the torsional energy dissipation capacity of HSRC columns, and the maximum increase is 71.22%. Welding studs at the flange of steel can effectively improve the flexural energy dissipation capacity of HSRC columns, and the maximum increase is 71.43%. Increasing the stirrup ratio from 0.56% to 1.35% results in a 33% increase in torsion ductility coefficient and a 31% increase in bending ductility coefficient for the specimen. Furthermore, the Chinese, European, and American codes suggest a theoretical formula for the shear bearing strength of specimens subjected to combined torsion, with test results aligning well with the calculated values.