不同保护层厚度的地铁咽喉区钢筋混凝土梁耐火性能分析

Fire resistance performance analysis of the reinforced-concrete beams for subway throat region with different thicknesses of protective layers

以某地铁工程为例,采用ABAQUS有限元分析软件建立了钢筋混凝土梁的计算模型。在标准升温曲线下对钢筋混凝土梁的截面进行了温度场分析,对不同保护层厚度的钢筋混凝土框架梁和非框架梁的耐火性能进行了数值模拟。根据高温条件下梁的相对挠度散点图,经曲线拟合,获得保护层与相对挠度之间的关系。研究结果表明钢筋混凝土梁耐火性能随保护层厚度增加而提升,该地铁咽喉区中的钢筋混凝土梁保护层厚度宜取35mm,研究方法可为地下工程钢筋混凝土梁的耐火设计提供参考。

Taking a subway project as a case,the calculation model of reinforced concrete beam is established by using the finite element analysis software-ABAQUS.Under the standard temperature curve,the temperature field of reinforced concrete beam section is analyzed,and the fire resistance performance of reinforced concrete frame beams and non-frame beams with different thickness of protective layer is simulated.According to the scatter plot of relative deflection of beam under high temperature,the relationship between protective layer and relative deflection is obtained by curve fitting.The results show that the fire resistance performance of reinforced concrete beams increases with the increasing of thickness for protective layer,and the thickness of protective layer should best taken as 35 mm in the throat zone of subway.The research method in this paper can provide reference for the fire resistance design of reinforced concrete beams in underground engineering.