基于概率分析运营阶段钢箱梁温度作用

Temperature effect of steel box girder at operation stage based on probability analysis

针对钢箱梁日照温度场在中国中西部地区研究成果较少的现状,对四川省泸州市沱江四桥运营阶段钢箱梁温度场进行长期监测,利用ANSYS软件计算分析其钢箱梁温度场,并对比了计算值和现场实测值。基于该桥夏季运营阶段钢箱梁顶板、底板温差最大时的温度实测数据,采用指数函数描述钢箱梁日照温度梯度分布形式。选用高斯混合模型描述该桥钢箱梁夏季日最大正温差的概率分布,并在其基础上计算钢箱梁日照竖向正温差标准值。研究结果表明:计算值与现场实测值吻合较好,温度随时间变化趋势基本一致,验证了该有限元模型的准确性。采用统计分析方法,得到竖向正温差标准值为18.4℃,略高于公路桥涵设计通用规范中按线性内插得到的钢箱梁竖向正温差标准值,并得到了该桥运营阶段钢箱梁竖向正温度梯度模式,该模式可为泸州及其周边地区运营阶段钢箱梁桥竖向温度梯度取值提供借鉴,也为后续规范温度梯度相关条文的修订和完善提供了数据支撑。

Aiming at less research on the sunshine temperature field of steel box girder at the middle and western areas of and western China,the temperature field of the steel box girder in the operation stage of the Tuojiang 4th bridge in Luzhou,Sichuan Province was monitored for a long time,the temperature field was then calculated and analyzed using the ANSYS software.The calculated value was compared with the measured data.Based on the measured data of maximum temperature difference between roof and bottom of operational steel box girder in summer,the exponential function was used to describe the sunshine temperature gradient distribution of steel box girder.The Gaussian mixture model was used to describe the probability distribution of the maximum daily positive temperature difference of the steel box girder in summer,and the standard value of vertical positive temperature difference was then calculated.The results show that the calculated temperature agree well with the measured data,and the trend of temperature changing with time is basically the same.Consequently,the accuracy of the finite element model is verified.The standard value of vertical positive temperature difference is 18.4℃obtained by statistical method.The value is slightly higher than that was calculated by linear interpolation according to general code for design of highway bridges and culverts.Finally,the vertical positive temperature gradient model of operational steel box girder was obtained.The model can be used for the taking values of vertical temperature gradient of steel box girder bridge in Luzhou and its surrounding areas,and the data can be supported for the revision and improvement of relevant provisions on temperature gradient.