底部加强型工字形截面钢管混凝土柱抗震性能数值分析

为深入研究工字形截面压弯构件的工作机理,进一步分析其各项抗震性能指标,提出了一种在底部区域外侧贴焊钢板的底部加强型工字形截面钢管混凝土柱。在试验基础上,分析了承载力的影响因素,采用ABAQUS软件对不同轴压比、不同混凝土强度等级、不同底部加强钢板高度和厚度的试件进行了有限元数值模拟,并与试验结果进行了对比。研究表明:随着轴压比的增大试件承载力和延性逐步下降;随着混凝土强度等级的提高,试件的承载力提高,但下降段变陡,延性降低;随着加强钢板高度的增加,试件承载力稳步增大,耗能能力提高,延性近似相等;随着加强钢板厚度的增加,承载力提高幅度有限。在满足构造要求下,底部加强型工字形截面钢管混凝土柱结构具有良好的综合抗震耗能能力,可用于高层建筑结构抗震设计。

NUMERICAL ANALYSIS FOR ASEISMIC BEHAVIOR OF BOTTOM STRENGTHENED I-SECTIONAL CONCRETE FILLED STEEL TUBE COLUMNS

In order to study the mechanism of the I-sectional concrete filled steel tube (CFST) column subjected to compression-bending load and further determine its aseismic performance index, a bottom strengthened I-sectional CFST column was proposed, whose flanges close to the bottom of the column were welded with enhancing steel plates. Based on the experimental results, the factors affecting the load-bearing capacity were analyzed. By means of finite element analysis software ABAQUS, the analysis to simulate numerically the specimens with different compression ratios, different strength grades of concrete, different heights and thickness of bottom strengthened steel plates were carried out. The analytical results were compared with the experimental results. The study shows that: the load-bearing capacity and the ductility decrease when the axial compression ratio increases; the bearing capacity also increases with the strength grade of concrete, but its decline gradient steepens and the ductility decreases; when the height of the strengthened plate increases, the load-bearing capacity of specimens increases steadily, the energy dissipation capacity increases, and the ductility is approximately equal to each other; when the thickness of the strengthened plate increases, the load-bearing capacity improves only slightly. The I-sectional concrete filled steel tube column with bottom enhancing plates shows a better aseismic performance and higher energy dissipation capacity if suitable constructional requirements are satisfied. Such structural configuration can be adopted in the design of high-rise buildings.