型钢-钢管混凝土短柱轴压承载力可靠度分析

为检验型钢-钢管混凝土短柱轴压承载力计算公式的可靠性，根据GB 50068-2001《建筑结构可靠度设计统一标准》，采用Monte-Carlo模拟法对组合柱轴压承载力计算公式进行可靠度分析，研究了可变荷载类型、荷载效应比、混凝土强度等级、套箍系数及配骨指标对组合柱轴压承载力可靠度指标的影响。分析结果表明：在所研究的参数范围内，型钢-钢管混凝土短柱轴压承载力可靠度指标随可变荷载组合类型的变化而变化，随混凝土强度等级的提高和钢管壁厚的减小而增大，配骨指标对组合柱轴压承载力可靠度指标的影响不明显，随荷载效应比的增大可靠度指标呈先增加后降低的趋势；除个别公式外，各计算公式基本满足统一标准对延性构件可靠度指标的要求。

Reliability analysis of load-bearing capacity of axially loaded CFT-encased steel columns

The formulas of load-bearing capacity of axially loaded CFT-encased steel columns were briefly introduced. Based on ‘Unified standard for reliability design of building structure’(GB 50068—2001), Monte-Carlo method was used to calculate the reliability of the formulas. The influences of combinations of loads effect, specific values of loads, concrete strength grades, confinement coefficients and structural steel indexes on the reliability of the composite column were studied. The results show that, in the ranges of the studied parameters, reliability index varies with the load combination and specific value of loads significantly, and it increases with the increasing strength grade of concrete and the reducing thickness of steel tube. The analytical results indicate that the influence of structural steel index can almost be ignored. It can be concluded that the reliability indexes of the formulas basically satisfy the demand of the ‘Unified standard for reliability design of building structure’(GB 50068—2001) for ductile members, except in individual case.