预应力混凝土空心板梁火灾中行为特点的试验研究

Experimental Study of Behavior Characteristics of PC Hollow Slab Beam Exposed to Fire

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。

When exposed to fire, a bridge structure will generate an uneven distribution of the temperature field which varies with time is very complex. temperature field inside. The During the indoor fire test, 3 pieces of full-scale pre-stressed concrete hollow slab beam are exposed to different fire degrees, the rule of temperature distribution, structural deformation, and strain and stress of the test beams are studied. When calculation temperature field, the concrete spalling situation of each beam is considered, which differs from each other when exposed to the same fire temperature （differ temperature field of the beams consideri＇ng practical spalling only in burning time） situation is simulated for simulation. The by ANSYS, which demonstrated to be consistent with test data. The thermal strain deformation of each beam demonstrated similar rules, whose stress and deformation calculation model whose calculation result corresponds to the test data when the to analyze most real situations. is obtained by finite element software ABAQUS, burning time is less than lh, which can be used