冷弯薄壁C型钢框架体系抗震性能试验研究

Experimental study on seismic performance of C-shaped braced steel frames

目前,对截面形式为冷弯薄壁C型钢背靠背框架体系抗震性能的研究较少.为研究这种结构体系的抗震性能,设计了3组单层单跨冷弯薄壁型钢框架,梁柱均采用冷弯薄壁C型钢组合工字形截面,斜撑采用等边单角钢截面.主要研究改变斜撑布置形式和轴压比对框架抗震性能的影响,得到框架在低周反复荷载作用下的滞回曲线和骨架曲线,对框架的刚度退化、延性、耗能性能和破坏机理进行研究.结果表明:各试件破坏形式均为斜撑净截面被拉断,梁端和柱脚腹板出现局部失稳破坏,框架发生整体失稳破坏,各试件承载力退化稳定,轴压比越大,承载力退化越显著,框架的延性系数均在2.5左右,该结构体系的耗能性能同其它轻钢结构基本一致.

At present, seismic performance of the cross section form of cold-formed thin-walled C steel framework of back-to-back system is less researched. In order to study the seismic performance of this kind of structural system, three groups of specimens were de- signed in one-story one-span of cold bending thin-wall steel frame, beam and column adopted cold bending thin-wall C steel combina- tion, brace adopted equilateral angle steel section. The influence of axial compression ratio and brace layout on seismic behavior of frame were researched. Based on the hysteresis curves and skeleton curves of the frame under low reversed cyclic loading, the stiffness degradation, ductility, energy dissipation performance and failure mechanism of the framework were studied. The test results showed that ： damage form of each specimen is brace net section failure, the beam end and column foot web have local buckling failure, and o- verall buckling failure appears in the framework;the strength degradation of all specimens is stable. The more significant is the axial compression ratio, the greater is the capacity degradation. The ductility coefficient of framework is around 2.5. The energy performance of the structure system is basically the same as that of other light steel structure.