Fire resistance of concrete-filled high strength steel tubular columns
Fire resistance of concrete-filled high strength steel tubular columns
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DOI：
10.1016/j.tws.2013.05.005
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发表时间：
2013-10
影响因子：
6.4
通讯作者：
K. Wang;K. Wang;B. Young
中科院分区：
文献类型：
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作者：
K. Wang;K. Wang;B. Young
采用有限元法研究了高强结构钢对钢管混凝土柱在恒轴压作用下耐火性能的影响。开发了一个三维有限元模型，进行数值传热和非线性应力分析。有限元模型中考虑了混凝土-钢筋界面模型。在有限元模型中还考虑了柱的初始几何缺陷。有限元分析结果与试验结果进行了对比验证，表明有限元模型能够准确预测钢管混凝土柱的耐火极限。此外，进行了广泛的参数研究，以调查钢管混凝土圆柱的行为和强度。试验参数包括柱体尺寸、钢筋强度、混凝土强度、荷载比、骨料种类和混凝土含水率。测定了柱温-时间曲线和轴向缩短曲线。结果表明，混凝土直径和强度对钢管混凝土柱耐火极限的影响较大，而钢材强度对耐火极限的影响较小。在相同荷载比下，钢筋强度越高，耐火极限越低;混凝土强度越低，耐火极限越高。但在相同荷载下，屈服强度为690 MPa的钢管混凝土柱的耐火极限明显高于屈服强度为275 MPa的钢管混凝土柱。
The main objective of this study is to investigate the effects of high strength structural steel on the fire resistance of concrete-filled steel tubular (CFST) columns under constant axial load using finite element analysis. A 3-D finite element model was developed to carry out both the numerical heat transfer and nonlinear stress analyses. The concrete–steel interface model was carefully considered in the finite element model. The initial geometric imperfections of the columns were also considered in the finite element model. The results obtained from the finite element analysis have been verified against experimental results, and showed that the finite element model can accurately predict fire resistance of the CFST columns. Furthermore, an extensive parametric study was performed to investigate the behaviour and strength of CFST circular columns. The parameters included the column dimensions, steel strength, concrete strength, loading ratio, different types of aggregates and moisture contents of the concrete. The column time–temperature and time–axial shortening curves were evaluated. It is shown that the diameter and strength of concrete have a relatively larger influence than the strength of steel on the fire resistance time of the CFST columns. At the same load ratio, the fire resistance is generally decreased with higher steel strength, and increased with the lower concrete strength. However, under the same load, the fire resistance of the CFST columns with the tubes yield strength of 690 MPa showed significant improvement than those steel tubes having yield strength of 275 MPa.