运用有限元分析软件ANSYS建立了单面火灾作用下矩形钢管混凝土柱截面温度场计算模型,并将计算结果与以往试验结果进行对比,理论分析结果与试验结果吻合良好.在此基础上,对单面火灾和四面火灾作用下矩形钢管混凝土柱截面温度分布形式进行了对比分析,分析表明,单面火灾作用下,矩形钢管混凝土柱截面温度整体较低,材料损伤程度较轻,因而有利于提高构件的抗火性能.但截面温度分布呈单轴对称,产生初始挠度与附加偏心距,明显区别于四面火灾作用下构件的耐火性能.在工程常用范围内,分析了升温时间、含钢率、截面宽度、高宽比、保护层种类及厚度等参数对矩形钢管混凝土截面温度场的影响规律.结果表明:升温时间、截面宽度、保护层种类及厚度对矩形钢管混凝土温度场影响较大.温度场研究结果为单面火灾作用下矩形钢管混凝土柱耐火性能分析和抗火设计提供了理论基础.
The computational model of cross-sectional temperature distributions of concrete-filled steel tubes(CFSTs)with rectangular cross-sections in exposure to one-side fire has been established with the finite element analysis software package,ANSYS,and the comparison shows that the theoretical analysis results are in good agreement with the former test results.Cross-sectional temperature distributions of CFSTs with rectangular cross-sections in the cases of one-side fire and four-side fire have been analyzed,which indicates that the cross-sectional temperature in the case of one-side fire is generally lower and the material deterioration is slighter,leading to better fire resistance performance of the columns.As the crosssectional temperature is single-axis symmetrical in distribution in the case of one-side fire and there are initial deflection and additional load eccentricity,the fire performance is different from that in the case of four-side fire.Within the range of engineering application,effect of parameters including exposure time,steel ratio,width of the cross section,depth to width ratio,type and thickness of fire-proof coating,on cross-sectional temperature distribution of CFSTs with rectangular cross-section has been analyzed.Analysis results show that the exposure time,width of the cross section,type and thickness of fireproof coating have much effect on the temperature distribution of CFSTs.Study in the paper on temperature distribution has provided theoretical basis for analysis of fire resistance performance and fire design of CFSTs with rectangular cross-sections in exposure to oneside fire.