方钢管混凝土组合异形柱轴压承载力计算方法研究

Calculation Methods of Axial Load-Bearing Capacity of Special-Shaped Column Composed of Concrete-Filled Steel Tubes

钢管混凝土结构计算方法较多,不同的规范规程之间计算公式均不相同,而且均没有针对方钢管混凝土组合异形柱的计算方法.因此本文首先总结近10年的14组方钢管混凝土组合异形柱轴压试验数据,依据ANSI/AISC360-05、GB50936、CECS159和DB29的计算方法分别推导了针对异形柱的计算公式,并在DB29叠加理论的基础上,提出了基于单肢失稳的叠加承载力计算方法ADVANCED.通过不同计算方法得到的极限承载力值与试验值进行比较,发现本文基于不同规范推导的承载力计算公式得到的计算结果与试验结果吻合良好;GB50936和DB29计算得到的数值均比试验值小,偏于安全,但是误差偏大;LRFD和CECS159的误差较小,但是试验承载力值小于计算值,因此偏于不安全;ADVANCED计算方法误差较小,且大部分计算值低于试验值,结果偏于安全,而且计算简单易行,推荐采用.

The axial load-bearing capacity of concrete-filled steel tubular structures can be calculated using numerous methods employing different codes and standards.However,a calculation method for the special-shaped column composed of concrete-filled square steel tubes(SCFST column)is not yet available.Thus,this paper first evaluated the approximate 10-year test data of the axial loads of 14 groups of SCFST columns.Calculation methods based on four national or local standards,namely,ANSI/AISC 360-05,GB50936,CECS159,and DB29 were proposed.Another calculation method based on mono-column instability,which we called the ADVANCED method,was then proposed.The ultimate bearing-capacity and experimental values obtained by the different calculation methods were compared.The comparison revealed that the calculated result obtained by deducting the calculation formula of the bearing capacity based on different standards in this paper agreed with the experimental value.Numerical values obtained through both GB50936 and DB29 calculation methods were less than the experimental values;thus,these methods were partially safe but with insufficiently large errors.Errors in load and resistance factor design(LRFD)and CECS159 were considerably insignificant,although most numerical values were larger than the experimental bearing-capacity value,thereby making them partially unsafe.Errors in the ADVANCED method were considerably insignificant,and the numerical results were less than the experimental value.These results indicated that the ADVANCED method is safe,and thus recommended.