高温后钢骨再生混凝土柱的加固行为分析

针对高温环境对钢骨混凝土受力性能影响的问题，进行了高温（500、700C）作用后钢骨再生混凝土柱的轴压性能试验，分析了碳纤维布（CFRP）加固对其力学性能的影响，得到了高温后钢骨再生混凝土柱及加固试件的失效模式、极限承载力和位移响应与不同骨料取代率的关系曲线。结果表明：500和700C高温作用后钢骨试件出现干缩裂缝，且温度越高干缩裂缝越多，极限承载力越低；对于高温后加固试件，极限承载力和位移得到较大提高，然而其破坏模式变为没有预兆性的脆性破坏；相对于0%和100%取代率的钢骨试件，高温后50%取代率试件加固后的极限承载力提高幅度达到最大的141%。最后，利用ABAQUS有限元模型模拟了钢骨试件的位移和应变发展曲线，与试验结果符合较好；同时针对CFRP对钢骨试件的加固机理进行了分析，揭示了钢骨、再生混凝土和CFRP在受压时的变形协调机理。

Behavior of Steel Tube Reinforced Recycled Concrete Columns After High Temperature and Reinforced By CFRP

To investigate the influences of high temperature on mechanical behaviors of steel tube reinforced concrete column, the central compressive test on steel tube (ST) reinforced recycled aggregate concrete (RAC) column after exposed to 500C and 700C with/without carbon fiber reinforced polymer (CFRP) reinforcement were conducted. The failure modes, ultimate load carrying capacities and displacements, together with the strain response of the ST reinforced RAC columns were studied. The results showed that the high temperature have great influences on the failure modes and ultimate load carrying capacities. For the specimens with CFRP reinforcement, a great increase on load carrying capacity and displacement, however, the failure mode was changed from ductile to brittle failure. Moreover, the highest increase on load carrying capacity was found on the specimens with 50% RAC and CFRP reinforcement when compared to the ones with 0% and 100% RAC. The displacement and strain development curves were calculated by using an ABAQUS code, and the results were in good agreement with the experimental results. For the specimens with CFRP reinforcement, the deformations of steel tube, RAC and CFRP under compressive loading were investigated, and the strengthened mechanism was found.