960 MPa高强度钢材轴压构件整体稳定性能试验研究

为研究960 MPa高强度钢材轴压构件的整体稳定性能，对6个焊接工字形和等边箱形截面试件进行了静力试验研究，测量了试件的几何初弯曲、荷载初偏心以及截面残余应力分布等初始缺陷，分析了试件的失稳破坏形态，得到了整体稳定承载力，并与规范设计曲线进行了对比分析。利用试验结果验证了有限元分析模型，并进行参数分析。研究结果表明：试件的破坏模态均为整体弯曲失稳，除两个几何初始缺陷过大的试件外，其他试件的整体稳定系数试验值均明显高于规范设计值；参数分析结果表明，960 MPa钢材焊接截面轴压构件的整体稳定系数较普通钢材显著提高，建议采用GB 50017-2003中的a类柱子曲线设计此类轴压构件，同时拟合了960 MPa高强度钢材的柱子曲线公式。

Overall buckling behavior of 960 MPa high strength steel welded section columns subjected to axial compression

To investigate the overall buckling behavior of 960 MPa high strength steel columns under axial compression, a static experimental program was conducted, including six welded I and box section columns. The initial imperfections such as the initial bending, loading eccentricity and residual stress were measured before the test. The buckling failure mode was analyzed and the buckling capacity was obtained and compared with the design curves in national standard. A three-dimensional finite element model was developed and further validated by utilizing the present experimental results. A number of parametric analysis were carried out by employing this numerical model. It is found that the overall flexural buckling mode governs the failure mode of all specimens, and the buckling strength of most specimens exceeds the corresponding design curve. Based on the parametric analysis results, it is indicated that the buckling strength of 960 MPa high strength steel welded I and box section columns is improved significantly, and the design curve a in GB 50017-2003 was suggested for the design of such columns. A new design curve was also proposed through nonlinear fitting.