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桥梁结构遭受火灾时内部会产生不均匀的温度场,温度场的分布及其随时间的变化十分复杂。开展室内火灾试验,使3片足尺预应力混凝土空心板梁经受不同程度的火损,探究试验梁的温度场分布、梁体变形以及应力应变的变化规律。3片试验梁在相同的火场温度(仅受火时间不同)下进行火灾模拟,各片梁的爆裂程度却不相同,在进行温度场计算时需考虑每片梁的混凝土爆裂程度。借助有限元软件ANSYS模拟梁体的温度场时考虑实际爆裂情况,得到的计算结果与试验数据吻合度较好。各片梁经受火灾时的应变变形具有相似的规律性,借助有限元软件ABAQUS得到梁体的受力和变形计算模型,计算结果显示在火损时间小于1 h时,模型与实测吻合较好,可用于分析大部分的实际火灾情况。
The internal structure of bridge structure will produce uneven temperature when it is exposed to fire. The distribution of temperature field and its change over time are very complicated. Indoor fire test was carried out so that three full-size prestressed concrete hollow slabs subjected to different degrees of fire damage explored the variation of temperature field distribution, beam deformation and stress-strain of the test beam. Three test beams were simulated at the same fire temperature (only subject to different fire time). The burst of each beam was not the same. The calculation of the temperature field needed to consider the degree of concrete burst of each beam. With the finite element software ANSYS simulation of the temperature field of the beam body to consider the actual burst situation, the calculated results are in good agreement with the experimental data. The stress and deformation of the beam were similar to each other when subjected to fire. The finite element software ABAQUS was used to calculate the stress and deformation of the beam. The calculation results show that the model is in good agreement with the measured one when the fire damage time is less than 1 h, Can be used to analyze most of the actual fire situation.