【摘要】 为分析震后火灾环境下混凝土结构的反应,试验设计了3榀足尺单层单跨框架结构,以低周反复水平荷载试验模拟地震动,以框架梁、柱裂缝宽度ω为损伤指标,试件KJ1历经损伤ω=0.5 mm后进行火灾试验,KJ2历经损伤ω=0.1 mm后进行火灾试验,试件KJ3作为对比试验无损伤,直接进行火灾试验。从3榀框架结构的裂缝变化规律、框架柱轴向变形、截面温度场分布、承载力退化等方面进行了对比分析。试验结果表明:损伤后混凝土材料的热传导性能提高,相应截面所经历的最高温度也增高;框架结构的高温变形恢复能力变差,梁截面承载力下降幅度比柱截面大。最后提出了损伤指标与结构抗火性能退化之间的量化关系。更多还原

【Abstract】 In order to analyze responses of RC structure under secondary fire after the earthquake,three RC frame structural models were designed and fire tests were carried out to two specimens with the concrete crack width of 0.5 mm and 0.1 mm respectively which were taken as the damage index caused by earthquake.The third specimen was directly studied under fire test.The law of concrete crack development,fire response and bearing capacity degradation of RC frame were preliminarily studied.The experiment shows that,thermal conductivity of concrete is increased after damage.Maximum temperature of cross-section is also much higher;Ability of deformation recovery is decreased.The residual flexural capacity of beam is much lower than that of column.At last,relationship between ω and degradation for concrete frame structure is put forward.更多还原