带约束拉杆方形钢管混凝土柱偏压性能

介绍了14个带约束拉杆方形钢管混凝土单向偏压柱试件的试验研究结果,研究试件在不同的含钢率、约束拉杆设置参数以及偏心率下的力学性能。研究结果表明约束拉杆有助提高方形钢管混凝土偏压短柱的承载力和延性。同时,利用国内现有规程GJB 4142—2000、DBJ 13—51—2003以及CECS 159:2004对试件承载力进行计算,规程计算结果总体上低估了带约束拉杆方形钢管混凝土偏压试件承载力试验结果。采用带约束拉杆方形钢管混凝土的本构关系,利用条带法对试件承载力进行数值计算,计算结果与试验结果吻合良好。利用该数值方法对带约束拉杆方形钢管混凝土偏压柱进行参数研究,分析约束拉杆约束系数、钢材屈服强度、混凝土强度、截面含钢率以及长细比等主要参数对N/Nu-M/Mu曲线的影响,在此基础上提出适合带约束拉杆方形钢管混凝土偏压柱承载力简化计算公式。该简化公式计算结果与数值计算结果基本吻合,且总体上偏于安全。

Eccentric-loaded behavior of square CFT columns with binding bars

A total of 14 specimens of square concrete-filled steel tubular(S-CFT) stub columns with binding bars subjected to eccentric loading were tested in order to investigate the eccentric loading behavior of S-CFT stub columns with binding bars that influenced by sectional steel ratio,binding bars and load eccentricity ratio.The experimental results indicate that the binding bars help to improve ultimate strength and ductility of eccentric-loaded specimens.Comparison between the experimental results and the results calculated with the methods of current domestic specifications shows that the specifications undervalue the ultimate strength of specimens with binding bars.A finite-sliced numerical method using the constitutive relationship of S-CFT with binding bars is applied to predict the ultimate strength of the specimens.The predicted results agree well with the experimental results.Furthermore,an extensive parameter study is conducted to investigate the effect of primary study parameters such as constraining factor of binding bars,steel yield strength,concrete cube strength,sectional steel ratio and slenderness ratio on N/Nu-M/Mu curves,based on which a simplified method is put forward.The predicted results by the simplified method agree well with those by the numerical method and in a whole are somewhat conservative compared with those by the numerical method.