多元线性回归在桥梁应变监测温度效应分析中的应用

Application of Multiple Linear Regression Model in Analysis of Temperature Effect on Strain Monitoring for Bridge Structures

应变监测是桥梁结构进行施工监控、运营状况监测及评定试验的主要内容。测量得到的应变通常包含温度效应。温度对于结构的影响非常复杂,各种温度作用对结构的作用机理是不一样的。提出将各种温度作用作为自变量,测点应变作为响应变量,建立多元线性回归模型,分析应变监测的温度效应,掌握温度的作用规律。温度作用根据温度测点计算确定,主要有体系温差、梁日照温差、塔日照温差、索梁温差等,具体视桥型而定。对上海恒丰北路斜拉桥应变监测的温度效应,建立多元线性回归模型进行分析。结果表明,各温度作用与测点应变线性关系显著;模型拟合效果好,物理意义明确,不需要大量样本数据,对温度效应能进行准确预测;用总应变测量值减去拟合得到温度效应值,可有效地将温度效应分离。

Strain monitoring is a main content of construction monitoring,health monitoring and assessment test for bridge structures,which is usually affected by temperature.The effect is very complex,since each type of temperature actions has its own mechanism and leads to different effect on the bridge structures.To analyze the temperature effect and to master the regularity of such effect,it is proposed to establish relationship between measured strain and different temperature actions by multiple linear regression model.In this model,temperature actions are set as independent variables,and measured strain is set as the response variable.Temperature actions are determined by certain calculation of temperature data,which are obtained from temperature sensors.In this paper,an application example is given.And the results indicate that linear relationship between measured strain and temperature actions is remarkable,and the model fits measured results well.The model has clear physical meanings,and can be used to explain the mechanism of each temperature action.Temperature effect can be calculated by the model,and separated by deducting itself from the total measured strain.For establishing the model a large amount of sample data is not necessary,and temperature effect still can be predicted correctly by the established model.