火灾中钢筋混凝土框架节点试验研究

Experimental study on behavior of reinforced concrete frame joints in fire

对2个钢筋混凝土足尺框架节点在ISO834标准升温曲线作用下的抗火性能进行了试验研究。基于试验结果,分析了试件的温度场分布规律、变形特点、混凝土爆裂现象、耐火极限及破坏特征。同时采用ABAQUS软件的有关单元运用顺序耦合的方法对高温下试件非线性行为进行数值模拟。研究结果表明,梁端竖向位移初期增长缓慢,试件约在升温80min后梁端位移明显加快,破坏带有突然性。冷却后试件存在明显的残余变形;温度-时间曲线约在100℃附近出现平台现象;升温过程中,沿着试件外围向核心区方向,各截面的实测混凝土和钢筋的温度存在逐步降低趋势。

The experimental studies are carried out on two full-scale reinforced concrete frames joints under ISO834 standard heating curve.According to the experimental result,the distribution of temperature field,deformation characteristic,concrete bursts,limited enduring fire and failure characteristic were analyzed.At the same time,ABAQUS is used to analyze the distribution of temperature field,deformation of joints and limited enduring fire.The results show that: the vertical displacement of the beam end grew slowly in the early fire,and then grew rapidly 80 minutes later;brittle destruction and significant residual deformation were observed after cooling;there was a platform for temperature-time curve at about 100 ℃;and there was a decline of the temperature along the direction of the periphery to the core area of the specimen in heating process.