端部约束钢管混凝土柱耐火性能研究

Fire performance of end-restrained concrete filled steel tubular columns

建立了端部约束钢管混凝土柱耐火性能分析的有限元计算模型,并通过试验验证了计算模型的正确性。同时,利用上述模型,考虑转动约束、轴向约束及轴向约束与转动约束的组合以及偏心距的影响,对火灾下端部约束钢管混凝土柱的变形形态、内力重分布、耐火极限等进行了系统的参数研究。研究表明,轴向约束和转动约束增加了柱的耐火能力,而轴向约束的效果更好;轴向约束条件下,柱的变形为单曲率变形,转动约束条件下,柱为双曲率变形;轴向约束和转动约束共同作用下,火灾作用下柱的挠曲变形较小,耐火性能较好。

A finite element（ FE） model was established to simulate the performance of end-restrained concrete filled steel tubular（ CFST） columns subjected to fire,and the results of the FE model agreed well with the test results. Then,a detailed parametric research was carried out to study the deformation,internal force redistribution and the fire resistance of the CFST columns considering the bend restraint,the axial restraint and the combination of the two restraints,as well as the effect of eccentric ratio by using the FE model. At the same time,the eccentric ratio of the concentrated force loaded on the column ends was chosen one of the parameters. The results show that the axial restraint and the bend restraint can increase the fire resistance of the CFST column,and the axial restraint has more effects than the bend restraint. The deformation of the CFST columns is a single curvature when the axial restraint is used,and the deformation is a double curvature when the bend restrained is used,while the deflection deformation is small and the fire resistance is good when the axial and bend restraint are used at the same time.