Performance of concrete-filled stainless steel tubular (CFSST) columns after exposure to fire
Performance of concrete-filled stainless steel tubular (CFSST) columns after exposure to fire
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DOI：
10.1016/j.tws.2020.106629
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发表时间：
2020-04
影响因子：
6.4
通讯作者：
Q. Tan;L. Gardner;Lin-Hai Han;T. Song
中科院分区：
文献类型：
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作者：
Q. Tan;L. Gardner;Lin-Hai Han;T. Song
本文研究了不锈钢钢管混凝土（CFSST）柱在整个荷载-火灾历史（包括四个特征阶段：（i）环境温度荷载，（ii）加热，（iii）恒定外荷载冷却和（iv）火灾后荷载）作用下的火灾后性能。采用有限元软件ABAQUS对钢管混凝土柱进行了温度-应力耦合分析，建立了钢管混凝土柱的温度场和结构响应。为了提高有限元分析模型的精度，采用子程序的方法，考虑了湿度对混凝土加热和冷却阶段导热系数和比热的影响。现有的火灾和火灾后的测试数据CFSST列用于验证有限元建模。有限元分析结果与试验结果的比较表明，该模型的精度是可以接受的，有限元模型，然后扩展到模拟的四个特征阶段的钢管混凝土柱。通过对温度分布、荷载-轴向变形关系、破坏模式和内力重分布的分析，解释了钢管混凝土柱在四个特征阶段的性能。通过与相同截面积的传统碳钢管混凝土柱的对比试验，验证了钢管混凝土柱的优良抗火性能。剩余强度指标的研究与一系列的参数分析。试验结果表明，相同火灾暴露时间后，钢管混凝土柱的剩余强度高于钢管混凝土柱，且钢管直径、长细比、受热时间比和荷载比对剩余强度指标有显著影响。
The post-fire performance of concrete-filled stainless steel tubular (CFSST) columns subjected to an entire loading–fire history, including four characteristic phases: (i) ambient temperature loading, (ii) heating, (iii) cooling with constant external loads, and (iv) post-fire loading, is investigated in this paper. Sequentially coupled thermal-stress analyses are performed using ABAQUS to establish the temperature field and structural response of CFSST columns. To improve the precision of the finite element analysis (FEA) models, the influence of moisture on the thermal conductivity and specific heat of the concrete in the heating and cooling phases is considered by using subroutines. Existing fire and post-fire test data on CFSST columns are used to validate the FEA modelling. Comparisons between FEA and test results indicate that the accuracy of the model is acceptable; the FEA model is then extended to simulate CFSST columns subjected to the four characteristic phases. The behaviour of the CFSST columns during the four characteristic phases is explained by analysis of the temperature distribution, load versus axial deformation relations, failure modes and internal force redistribution. The excellent post-fire performance of CFSST columns is examined in comparison with traditional concrete-filled carbon steel tubular (CFST) columns with the same total cross-sectional area. The residual strength index is studied with respect to a series of parametric analyses. It is found that the residual strength of CFSST columns is higher than that of CFST columns after the same fire exposure, and that the diameter of the stainless steel tube, slenderness, heating time ratio and load ratio have a significant influence on the residual strength index.