中文摘要：

采用响应面法对千米级斜拉桥主梁最大挠度进行静力可靠度分析，考察主梁最大挠度随结构材料、几何尺寸及外荷载等不确定因素的变异而发生变化的规律。算例研究表明，主梁挠度可靠指标对各随机变量平均值和标准差的敏感程度不同。同其它随机变量相比，斜拉索弹性模量变异对千米级斜拉桥主梁挠度影响最为显著。主梁截面面积变异对千米级斜拉桥主梁挠度具有显著的影响，但与对千米以下斜拉桥主梁挠度的影响规律不同。

英文摘要：

Nonlinear stochastic static analysis is carried out for the maximum deflection of main girder of a kilometer-class cable-stayed bridge by response surface method （RSM）. The law of main girder＇ s deflection is researched with the variation of structural parameters such as material properties, geometric dimensions and ex- ternal load, etc. Numerical results show that/he reliability index of main girder＇ s deflection has different sensi- tivity to the mean value and standard deviation of random variables. The variation of the modulus of stay cables has significant influence on the deflection of main girder of kilometer-class cable-stayed bridge compared to other random variables. The variation of the section area of main girder also has influence on the deflection of kilometer-class cable-stayed bridge, but is different from the influence on the deflection of under-kilometer cable-stayed bridge.