【摘要】 以润扬大桥斜拉桥为分析对象,提出了扁平钢箱梁结构的多尺度可靠度分析方法。采用子结构方法将扁平钢箱梁整体结构尺度模型和局部构件尺度模型相互衔接,在此基础上采用改进响应面法分析了扁平钢箱梁结构的静力可靠度。分析结果表明:①采用改进响应面法能有效地解决传统响应面法存在的收敛失败和计算误差大的缺点;②采用钢箱梁多尺度模型可以较准确地计算斜拉桥在活荷载作用下的静力可靠指标;③钢箱梁活荷载的分布方式和斜拉桥的几何非线性对斜拉桥静力可靠度具有较大的影响;④采用钢箱梁多尺度模型,可以较真实地研究钢箱梁局部构件损伤对斜拉桥静力可靠度的影响。钢箱梁局部构件损伤对斜拉桥静力可靠指标的影响程度要明显大于对斜拉桥静力特性的影响。因此,在斜拉桥钢箱梁的可靠度设计与状态评估中需要计入结构多尺度效应的影响。更多还原

【Abstract】 The multi-scale reliability analysis method for steel box girder is presented with respect to Runyang Cable -stayed Bridge.The full-scale structural model and fine-scale local member model of steel box girder are connected by the substructuring method,on the basis of which the static reliability analysis is performed using the improved response surface method.The analysis results reveal that(1)The improved response surface method can effectively overcome the shortcomings of the traditional method for convergence failure and calculation errors;(2)The employment of multi-scale models of steel box girder can correctly calculate the static reliability index of cable-stayed bridge subject to live loadings;(3)The distribution characteristics of live loading and geometric nonlinearity of cable-stayed bridge have remarkable effects on the reliability index;(4)The employment of multi-scale models of steel box girder can effectively realize the reliability analysis of cable-stayed bridge subject to the local damage of the girder.The local damage of steel box girder has more remarkable influence on the static reliability index of cable-stayed bridge than the static properties.Hence,it is necessary to consider the structural multi-scale effect in the reliability analysis and condition assessment of steel box girder of cable-stayed bridge.更多还原