基于长期监测的开口截面组合梁斜拉桥温度场分析

Analysis on the temperature fields of cable-stayed bridges with open-section composite girder based on long-term monitoring

通过灌河大桥长期监测数据对组合梁斜拉桥的温度场分布进行研究.首先,分析了温度变化规律、相关系数以及统计特征;之后,采用高斯混合模型描述温度概率分布,并通过赤池信息量准则(AIC)和贝叶斯信息准则(BIC)判别最优的高斯分布数量;接着,借助广义极值分布获取正、负温差的极值分布;在此基础上,通过外推方法计算了不同设计基准期、超越概率下的温差标准值,并得到灌河大桥的温度分布模型.结果表明,当高斯分布数量为3时,通过高斯混合模型能够准确描述温度的概率分布;竖向与横向温差的极值服从广义极值分布;基于监测数据的竖向正温差标准值为16.0℃,与现行公路桥梁规范的标准值相当,而负温差标准值仅为-5.3℃,其数值小于现行规范;实测的横向正温差标准值可达14.6℃,而负温差标准值为-12.3℃.

The temperature distribution of a cable-stayed bridge with a composite girder is studied through long-term monitoring of Guanhe Bridge.First,the temperature variations,correlation coefficients and statistical characteristics are analyzed.Gaussian mixture models are then employed to depict the probability distributions of temperatures,while the Akaike information criterion(AIC)and the Bayesian information criterion(BIC)are utilized to determine the optimal number of Gaussian distributions.Next,the generalized extreme value distribution is used to fit the extreme value distributions of positive and negative temperature differences.Building upon these analyses,characteristic values of temperature differences are calculated for various design reference periods and exceedance probabilities using an extrapolation method,and the temperature distribution models of Guanhe Bridge are obtained.The results indicate that the probability distribution of temperatures can be accurately described by Gaussian mixture model when the number of Gaussian distributions is 3;the extreme values of vertical and horizontal temperature differences obey the generalized extreme value distribution;the characteristic value of vertical positive temperature differences based on the monitoring data is 16.0℃,equivalent to that of the current code for the highway bridges,while the characteristic value of negative temperature differences is-5.3℃,lower than that of the current code;the measured characteristic value of transverse positive temperature differences can reach 14.6℃,while that of negative temperature differences is-12.3℃.