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高温和荷载共同作用下钢材产生明显的蠕变变形,对钢结构在火灾下的变形和受力性能产生较大影响。为了研究钢材高温蠕变对约束高强度Q460钢梁抗火性能的影响,采用ANSYS有限元软件建立约束钢梁结构分析模型,引入普通钢材高温力学性能和蠕变特性,分析了约束普通Q345钢梁的火灾响应,并与试验结果进行了对比,验证了模型的正确性。采用验证后的模型,引入高强度Q460钢材的高温力学性能和蠕变模型,分析了高温蠕变对约束高强度Q460钢梁抗火性能影响的程度,并将约束普通Q345钢梁和高强度Q460钢梁的抗火性能进行了对比。最后对考虑蠕变效应后影响约束高强度Q460钢梁的抗火性能参数进行了分析。研究表明,钢材高温蠕变对约束高强度Q460钢梁的抗火性能影响很大,蠕变不利于约束Q460钢梁抗火承载力的发挥;约束高强度Q460钢梁比普通Q345钢梁的抗火性能好,约束钢梁的极限状态可以按钢梁达到轴向最大拉力时进行设计。
Under high temperature and load, the steel has obvious creep deformation, which greatly affects the deformation and force performance of the steel structure under fire. In order to study the influence of high temperature creep of steel on the fire resistance of high strength Q460 steel beam, ANSYS finite element software is used to establish the constrained steel beam structure analysis model. The mechanical properties and creep characteristics of ordinary steel are introduced. Response, and compared with the test results to verify the correctness of the model. Using the verified model, the high-temperature mechanical properties and creep model of high-strength Q460 steel were introduced. The influence of high-temperature creep on the fire resistance of high-strength Q460 steel beams was analyzed. The influences of common Q345 steel beams and high-strength Q460 steel beams The fire resistance was compared. Finally, the fire resistance performance parameters of high strength Q460 steel beams with constraint creep effect are analyzed. The results show that the high temperature creep of steel has a great influence on the fire resistance of high strength Q460 steel beams. The creep is not conducive to the restraint of fire resistance of Q460 steel beams. The fire resistance of high strength Q460 steel beams is lower than that of ordinary Q360 steel beams Well, the limit state of the confined steel beam can be designed when the steel beam reaches the maximum axial tensile force.