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建立考虑材料非线性、几何非线性、几何初始缺陷、残余应力影响的有限元模型,对反复水平荷载作用下偏心常轴压箱形钢柱的受力性能进行模拟分析。通过与相关试验结果的比较,验证了有限元模型的正确性。在此基础上,对85个箱形构件进行数值分析,研究反复水平荷载作用下常偏压箱形钢柱的抗震性能。研究结果表明,腹板宽厚比是影响构件抗震性能的最主要因素,腹板宽厚比越大,构件的刚度、承载力退化越严重,延性越差。对于中等长细比的构件,当轴压比较小时,构件的抗震性能受整体失稳、局部屈曲和塑性变形的相互影响;但当轴压比较大时,整体失稳将起控制作用。柱顶弯矩使构件的骨架曲线发生平移,但柱顶弯矩对构件抗震性能的影响相对较小。根据有限元计算结果,回归出反复荷载作用下偏心常轴压箱形钢柱可承受的最大柱顶剪力和位移延性系数的拟合公式。
A finite element model considering material nonlinearity, geometrical nonlinearity, initial geometric imperfections and residual stress was established to simulate the mechanical behavior of eccentric steel box columns with eccentric constant axial load under repeated horizontal loads. The correctness of the finite element model is verified by comparison with the related test results. On this basis, the numerical analysis of 85 box-shaped members was carried out to study the seismic behavior of normally-biased box-shaped steel columns under repeated horizontal loads. The results show that the ratio of web width to thickness is the most important factor affecting the seismic performance of members. The greater the ratio of web width to thickness, the more serious the degradation of stiffness and bearing capacity of the members, the worse the ductility. When the axial compression ratio is small, the seismic performance of members is affected by the overall instability, local buckling and plastic deformation. However, when the axial compression ratio is large, the overall instability will play a controlling role. The bending moment of the column translates the skeleton curve of the member, but the influence of the bending moment on the seismic performance of the member is relatively small. According to the finite element calculation results, the fitting formulas of the maximum columnar shear force and displacement ductility coefficient of the column under eccentric load are deduced under repeated load.