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为比较不同受火时间后预制空心板剩余承载力、跨中挠度和破坏形态的异同,进行了6块预制空心板受火后力学性能的对比试验研究,其中3块为未受火的对比试件,另3块为板底分别受火23、38、53min的试件。受火试验结果表明,各试件在升温过程中的跨中挠度随受火时间增加而显著增加,熄火自然冷却后,跨中挠度大部分可恢复。加载试验结果表明,对比试件和受火试件的最终破坏模式均为弯曲破坏;随着受火时间延长,试件开裂荷载和破坏荷载均有所降低,且破坏荷载与受火时间大致呈线性关系;受火试件初始弯曲刚度较对比试件明显降低,相同荷载作用下,受火试件受拉边缘拉应变和受压边缘压应变,均明显大于对比试件。
In order to compare the similarities and differences of the residual bearing capacity, mid-span deflection and failure modes of precast hollow slab after different fire time, comparative experiments on mechanical properties of six prefabricated hollow slabs subjected to fire were conducted. Three of them were comparative tests without fire Pieces, and the other three were fire 23,38,53 min samples of the plate bottom. Fire test results show that the mid-span deflection of each specimen during heating increases significantly with the increase of fire time, and most of the mid-span deflection can be recovered after the flameout is naturally cooled. The results of loading tests show that the ultimate failure modes of both the specimens and the specimens subjected to fire are bending failure. With the extension of fire time, the cracking and failure loads of the specimens decrease, and the failure load and exposure time are approximately The initial bending stiffness of the tested specimens was significantly lower than that of the comparative specimens. Under the same loading, the tensile specimens subjected to tensile stress and the compressive edge compressive stresses were significantly larger than those of the comparative specimens.