钢框架厂房火灾后的破坏形态

端部约束不同的构件在火灾中的破坏形态不同,研究整体结构构件在火灾中的破坏形态,可以为钢结构抗火研究与设计提供依据。某钢结构框架厂房发生火灾,大火历时3个多小时,火场最高温度达1000°C以上。火灾后,框架梁均有不同程度的破坏,钢梁端部下翼缘屈曲破坏较普遍;由于钢梁顶没有设置抗剪键,钢梁与顶部的混凝土现浇楼板脱开,火灾后残留有较大的挠屈变形;钢柱在火灾后未有明显的破坏现象,但有侧向变形产生。这些现象与实验室中标准试验的结果不同。

The Failure Mode Analysis of Steel Structural Frame Workshop after Fire

Components with different end constraints present different failure modes in fire.The studies on failure modes of members in whole structure can provide basis for fire resistance design of steel structures.The fire in a workshop with steel structural frame was selected as an example.The fire lasted for more than 3 hours,and the elevated temperature in the fire up to 1000°C according to judgments.After the fire,beams were damaged to different degrees,in which the buckling failure of the bottom flange at the steel beam end was common.Because no shear key was set up at the top of the steel beam,the steel beam detached from the cast-in concrete floor which resulted in serious flexural deformation after fire.There was no obvious damage on the steel columns after the fire except the lateral deformation.The phenomena were not in accordance with the results obtained in laboratory.