摘要
本文建立钢筋混凝土T形约束梁耐火性能分析的有限元计算模型,将分析结果与已有试验进行对比,验证本文计算模型的正确性。同时,利用上述模型,考虑轴向约束的影响,研究高温下钢筋混凝土T形约束梁耐火极限、破坏形态、变形特点以及内力重分布现象。研究表明,轴向约束增加了约束梁的耐火极限;实际工程中轴向约束下框架梁的受火情况与简支梁、固接梁差别较大;无转动约束梁只有跨中出现塑性铰,而有转动约束梁的两端和跨中共出现3个塑性铰;轴向弹簧约束越大,承担的轴力比重越大,内力重分布现象越明显。
A finite element model is proposed to simulate the fire performance of T-shaped simply supported reinforced concrete beams with axial constraints. Furthermore,the results are compared with the test results to confirm the correctness of the simulation model. Considering the influence of the axis constraint,the fire resistance limit,failure mode,deformation feature and stress redistribution of T-shaped reinforced concrete beams under high temperature are studied using the simulation model above. The results reveal that the axial constraint improves the fire resistance limit of the T-shaped reinforced concrete beams. It shows a great difference in fire resistance performance among frame beams under axis constraint,simply supported beams and fixed beams in practical engineering. Only one plastic hinge will occur at mid span of the beam without rotation restraints. However,plastic hinges will occur at mid span as well as at the two ends of the beam with rotation restraints. The stronger the axial constrains are,the more proportion of the axial force the spring shares,and the phenomenon of stress redistribution is more obvious.
出处
《建筑科学》
CSCD
北大核心
2016年第9期34-40,共7页
Building Science
关键词
耐火性能
约束
钢筋混凝土
T形简支梁
fire performance
restraint
reinforced concrete
T-shaped beam
