Experimental and numerical studies of square concrete-filled double steel tubular short columns under eccentric loading
Experimental and numerical studies of square concrete-filled double steel tubular short columns under eccentric loading
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DOI：
10.1016/j.engstruct.2019.109419
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发表时间：
2019-10
影响因子：
5.5
通讯作者：
Mizan Ahmed;Q. Liang;V. Patel;M. Hadi
中科院分区：
文献类型：
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作者：
Mizan Ahmed;Q. Liang;V. Patel;M. Hadi
内嵌圆钢管的方钢管混凝土梁柱由于具有较高的结构性能，在组合建筑结构中得到了越来越多的应用。本文对偏心加载方形薄壁CFDST柱的结构响应进行了试验和数值研究。对20根短方CFDST柱进行了试验，其中16根柱受偏心荷载作用，4根柱受同心荷载作用。实验中检测的参数包括横截面尺寸、内外管的宽厚比和加载偏心。给出了实测极限强度、荷载缩短响应、荷载-侧向位移曲线、应力-应变曲线和观察到的破坏模式。建立了结合纤维分析的数值模型，预测了CFDST柱的弯矩-曲率响应和轴向荷载-弯矩强度包络线。该模型明确考虑了内圆钢管对核心混凝土的约束作用和外圆钢管局部后渐屈曲的影响。开发了有效的计算机算法来实现反二次法，对分析中产生的非线性动态平衡方程产生收敛解。试验测量值用于验证所提出的数值模型。结果表明，理论与实验结果吻合较好。利用计算机模型验证了各种参数对CFDST薄壁短梁柱性能的影响。
Square concrete-filled double steel tubular (CFDST) beam-columns consisting of an internal circular steel tube have increasingly been utilized in composite building structures because of their high structural performance. This paper describes experimental and numerical studies on the structural responses of square thin-walled CFDST columns loaded eccentrically. Tests on twenty short square CFDST columns were undertaken that included sixteen columns under eccentric loading and four columns under concentric loading. The parameters examined in the experiments included the cross-sectional dimensions, the width-to-thickness ratios of outer and internal tubes and loading eccentricity. The measured ultimate strengths, load-shortening responses, load-lateral displacement curves, stress-strain curves and observed failure modes are presented. A numerical model incorporating the fiber analysis is developed that predicts the moment-curvature responses and axial load-moment strength envelops of CFDST columns. The model explicitly accounts for the influences of the confinement exerted by the internal circular steel tube on the core concrete and the progressive post-local buckling of the external steel tube. Efficient computer algorithms implementing the inverse quadratic method is developed to produce converged solutions to the nonlinear dynamic equilibrium equations generated in the analysis. Measurements from the tests are employed to validate the proposed numerical model. It is shown that there is a good agreement between theory and experiment. The computer model is utilized to demonstrate the significance of various parameters on the behavior of thin-walled short CFDST beam-columns.