圆不锈钢管混凝土曲杆受压力学性能研究

Behaviour of circular curved concrete filled stainless steel tubular struts under compression

制作了12根不锈钢管混凝土曲杆和3根不锈钢管混凝土直杆、1根空不锈钢管曲杆对比试件,对曲杆进行两端中心受压试验,对直杆进行偏心受压试验.试验的主要参数是名义长细比(λn=24、48和72)和初始弯曲度(u0=0~140mm).试验结果表明,随着试件名义长细比和初始弯曲度的增大,不锈钢管混凝土曲杆的初始刚度减小,极限承载力也随之降低;不锈钢管混凝土曲杆与不锈钢管混凝土偏压直杆的受力性能及破坏形态总体上类似,其承载力和刚度均略高于相应的偏压直杆.基于有限元分析软件ABAQUS建立了数值模型,对不锈钢管混凝土曲杆受力特性进行分析,有限元分析结果和试验结果吻合良好.在此基础上,对不锈钢管混凝土曲杆受压承载力进行了参数分析,结果表明,不锈钢管混凝土曲杆承载力较相应的偏压直杆提高均在5%以内,采用现有规范中计算普通钢管混凝土压弯构件承载力的方法计算不锈钢管混凝土曲杆受压承载力偏于保守.

A total of 16 specimens,including 12 curved concrete filled stainless steel tube(CCFSST),3 straight concrete filled stainless steel tube(CFSST)and one curved hollow stainless steel tube(CHSST)were tested to study the influence of slenderness ratio(24,48 and 72)and initial deflection(0-140mm)on the performance of the circular curved composite members.The CCFSST members were concentrically loaded at the specimen ends,the behaviour and failure modes of the CCFSST members were investigated and compared with those of conventional CHSST and eccentrically-loaded CFSST members.The test results showed that the failure mode of CCFSST members is overall buckling failure,with increasing slenderness ratio(λn)and initial deflection(u 0)at the mid-height,the initial stiffness and the ultimate loads decrease.In the post-peak stage,the load decrease becomes slower for CCFSST specimens with largerλn or u 0.It can be found that,the performance of CCFSST members is similar to that of reference eccentrically-loaded CFSST members,and the load-carrying capacity of CCFSST member subjected to concentrial compression is slightly higher than those of the corresponding straight CFSST columns.Finite-element models(FEMs)for analyzing the mechanical performance of curved circular stainless steel tubular struts were established and verified by the test results.The parametric analysis shows that the difference between load-carrying capacity of CCFSST and CFSST members is within 5%.After that,comparisons were made between the experimental results and the predicted load-carrying capacity using existing design code DBJ/T 13-51-2010.It turned out that the result is conservative.