有初应力的钢管混凝土偏压构件极限承载力计算

应用有限元方法对有初应力的钢管混凝土偏压试件进行了非线性分析，算例计算结果与试验结果吻合良好．应用该方法，以长细比、偏心率和初应力度为主要参数对有初应力的钢管混凝土偏压构件进行了受力性能分析．分析结果表明，初应力度对于偏压短柱受力的影响与初应力对轴压柱的影响基本相同；对于偏压长柱，稳定极限承载力随着初应力增大呈非线性下降趋势，最大下降幅度可达20％，同时稳定极限荷载所对应的挠度也相应增大．增加钢号等参数，对大量进行了有限元计算，给出了极限承载力的初应力度影响系数（有初应力构件的极限承载力与无初应力构件的极限承载力之比）的简化计算公式．最后，以表格的形式给出仅含两个主要参数（长细比和初应力度）的初应力度影响系数，以供工程中更加简便、偏安全的应用．

Calculation of ultimate load-carrying capacity of eccentrically loaded concrete filled steel tubular (CFST) columns with initial stresses

A nonlinear finite element method is presented for analyzing concrete filled steel tube(CFST) columns with initial stress subjected to eccentric load.Case study shows that the calculation results agree well with the test results.This finite element method is employed to analyze the behavior of eccentrically loaded CFST columns,taking initial stress degree,slenderness ratio,and eccentric ratio as the parameters.It is indicated that the influence of initial stress to the behavior of eccentrically loaded stub columns is almost the same with that to axial loaded columns.However,for the eccentrically loaded long columns,initial stress will make its ultimate load-carrying capacity decrease in a nonlinear tendency downwards,and the maximum descend is about 20%.Formula for predicting the initial stress reduction factor(the ratio of ultimate loads of CFST eccentrically loaded column with initial stress to that without initial stress) through an amount calculation results and adding steel strength as the fourth parameter are presented.Finally,a table of initial stress reduction factors with only two main parameters(initial stress degree and slenderness ratio) is given out to put in practice.