端部设肋方钢管混凝土框架柱抗震性能分析

Seismic Analysis of the Square Concrete-filled Steel Tube Frame Column with End Ribs

提出了一种端部设肋方钢管混凝土框架柱,采取在柱端部区域设置纵向加劲肋的方式避免端部过早地发生局部屈曲,以提高其承载力,改善延性和抗震性能.采用通用非线性有限元软件MSC.Marc建立壳-实体精细有限元分析模型对已有试验进行了非线性有限元分析,有限元分析结果与试验结果吻合良好.在验证了有限元模型合理性的基础上,分析了不同参数条件下端部设肋方钢管混凝土框架柱的力学性能.研究表明,端部加劲肋能够延缓钢管壁的鼓曲,提高柱的承载力,显著改善柱的延性和抗震性能.端部加劲肋的设置长度以柱的1~2倍边长为宜,高度和厚度应满足一定的构造要求,可以通过增大加劲肋的厚度或增加每边加劲肋的设置数量来提高柱的承载力,且后者效果更好.

A square concrete-filled steel tube frame column with end ribs was put forward. The end longitudinal rib was used to avoid the premature local buckling of steel tube wall and then to improve the load carrying capacity, ductility and seismic performance of concrete-filled steel tube. Refined nonlinear finite element （FE） models were established by using MS（2. Marc to study the existing experiments, and the results from the FE models fit well with the test data. Based on the reasonability of the FE models, parametric analyses were carried out to further explore the behavior of the square concrete-filled steel tube frame column with end ribs. The analyses have shown that the end ribs can delay the local buckling of the steel tube and improve the load carrying capacity, ductility and seismic performance. The length of the end ribs are to be set at 1-2 times the sectional side length from the column end, and the height and thickness of the end ribs should satisfy certain structural requirements. The increase of the thickness of the end ribs or the number of end ribs on each side can improve the load carrying of the column, and the latter is better.