箱形钢柱受力性能分析及抗震设计建议

基于箱形钢柱拟静力试验，通过有限元分析，研究腹板宽厚比、构件轴压比及平面外长细比、柱顶弯矩等因素对偏压箱形钢柱抗震性能的影响。研究结果表明：腹板宽厚比和平面外长细比对箱形钢柱抗震性能影响较大，随着腹板宽厚比、平面外长细比的增大，箱形钢柱延性和承载力均有所减小，抗震性能变差；柱顶弯矩使箱形钢柱的正向延性增大，而降低其反向延性，柱顶弯矩对箱形钢柱抗震性能的影响相对较小。在此基础上，对箱形钢构件提出与受力状态相关联的腹板宽厚比、平面外长细比限值建议。引入箱形钢柱位移角概念，进而提出大跨度空间钢结构的构件抗震等级划分方法。并给出箱形钢构件腹板宽厚比、构件平面外长细比的抗震验算流程。

Mechanical behavior and seismic design suggestions of steel box column

Based on quasi-static experimental results of steel box columns and numerical results of calculated members, the effects of width-to-thickness ratio of web plate, slenderness ratio, axial compression ratio and bending moment on the seismic behavior of eccentrically constant-compressed steel box columns under cyclic lateral loading were investigated. The study results show that the width-to-thickness ratio of web plate and the slenderness ratio have very significant effect on the seismic behavior of columns. When the width-to-thickness ratio of web plate or the slenderness ratio of the column increases, the ductility and load-bearing capacity of the column decrease rapidly, which indicates the seismic resistance of the column is deteriorated. The ductility of the column on one side is improved by the effect of bending moment at the loading joint of the column, while the ductility of the column on the other side is decreased. The effects of bending moment on the seismic behavior of the columns are relatively small. Based on the experimental and numerical results, the limits of width-to-thickness ratio and slenderness ratio of steel box columns in large span structures were proposed, which were dependent on the stress state of the columns. The concept of member displacement angle was introduced, and the method to determine seismic grade of steel members was also developed. Finally, the seismic design procedure of width-to-thickness ratio and slenderness ratio of steel box columns was suggested.