部分预制装配型钢混凝土柱受火后轴压性能试验研究

Experimental study on axial compression performance of partially prefabricated steel reinforced concrete columns after fire exposure

为研究部分预制装配型钢混凝土(PPSRC)柱在受火后的受压性能,开展了8个足尺PPSRC柱试件在历经ISO 834标准明火试验后的轴压试验和1个未受火PPSRC柱对比试件的轴压试验,研究核心部分混凝土强度、配箍间距及截面尺寸对标准受火条件下试件截面温度-时间曲线、轴压荷载-位移曲线和剩余承载力的影响。结果表明:RPC预制外壳能对内部型钢和核心混凝土起到良好保护作用;箍筋间距、现浇混凝土强度对截面温度场影响不大,型钢保护层越大,截面内部温度升高越慢且最高温度越低;PPSRC柱受火后轴压破坏形态与常温下类似;核心混凝土强度增加,试件承载力增大;箍筋间距减小对受火后试件承载力提高有利。

To investigate the mechanical performance of partially precast steel reinforced concrete(PPSRC) columns after fire exposure, eight specimens were firstly heated under ISO 834 standard fire and then axially compressed to failure, and an additional composite column specimen was axially compressed to failure without experiencing fire. The effects of compressive strength of the internal concrete, stirrup spacing and section size on the temperature-time curves, load-displacement curve, and residual bearing capacity of the specimens were studied. The results show that the prefabricated RPC shell can protect the internal steel and core concrete. The stirrup spacing and internal concrete strength have little effect on the section temperature field. The thicker the concrete cover of steel, the lower the rising rate of the internal temperature and the peak temperature. The failure mode of PPSRC columns under axial compression after fire is similar to that under room temperature. With the increase of internal concrete strength, the residual capacity of specimens increases. The decrease of the stirrup spacing is favorable to the improvement of the residual bearing capacity of the specimens after fire exposure.