中文摘要：

以苏通大桥斜拉桥的扁平钢箱梁为研究对象，基于结构健康监测系统对其温度场进行长期监测。根据温度监测结果对扁平钢箱梁的温度分布特性进行分析，重点研究扁平钢箱梁的横向温差和竖向温差分布特征，在此基础上采用统计学方法建立了扁平钢箱梁温度以及温差的概率分布模型，确定了具有一定重现期的钢箱梁温度和温差标准值。分析结果表明，扁平钢箱梁顶板与底板之间存在较大的竖向温差，顶板存在一定的横向温差，底板的横向温差可以忽略；扁平钢箱梁温度均可以通过2个正态分布函数的加权和来描述其概率密度分布，横向温差和竖向温差均可以通过2个威布尔分布函数的加权和来描述其概率密度分布。

英文摘要：

Taking the flat steel-box girder of Sutong Cable-stayed Bridge as research object, its temperature field is long-term monitored on the basis of the structure health monitoring system. The temperature distribution characteristics of the girder are investigated using the temperature monitoring results, and the transverse thermal differences and vertical thermal differences are analyzed in detail. By statistical method, the probability distribution models of the temperatures and the temperature differences of the flat steel-box girder are established, and the standard values of temperatures and temperature differences with a certain return period are determined. The analysis results reveal that （1） there exists dominant vertical temperature differences between the top plate and the bottom plate, definite transverse temperature differences in the top plate and negligible transverse temperature differences in the bottom plate of the flat steel-box girder; （2） the temperature probability density distributions of the flat steel-box girder can be described by the weighted sum of 2 normal distributions, and the temperature difference probability density distributions of the flat steel-box girder can be described by the weighted sum of 2 Weibull distributions.