桥梁结构动应变监测的温度效应实时分离与动荷载识别

应变指标是对桥梁结构进行健康监测和状态评估的一项主要内容。但在实际工程中，应变监测值往往受到温度效应的极大影响，使得由动荷载引起的应变监测值湮没在温度效应中，同时导致监测系统中预先设置的固定预警指标无法实现有效预警。该文以合肥某斜拉桥的动应变及温度监测数据为实际工程背景，研究了一种从应变监测值中实时分离温度效应的工程方法。首先对斜拉桥主梁的温度监测数据分布情况进行了分析，提出了桥梁监测中的温度传感器布点建议；之后通过对实测应变监测数据的分析，提出采用时变的平均值法得到温度效应时程曲线，并将其应用于桥梁在线监测系统中监测数据的实时温度修正和动态预警阈值的设置。最后，以经该方法处理后的应变监测值为基础进行了动荷载识别。

REAL-TIME SEPERATION OF TEMPERATURE EFFECT ON DYNAMIC STRAIN MONITORING AND MOVING LOAD IDENTIFICATION OF BRIDGE STRUCTURE

Strain monitoring is an important content of health monitoring and condition assessment for a bridge structure.However,in practical engineering application,the value of strain monitoring is usually affected greatly by temperature,so that it is not able to distinguish the strain monitoring value caused by a moving load from the total measured strain,which lead to the loss of efficacy of a pre-established early-warning index.Based on the monitoring results of strain and temperature of a cable-stayed bridge in Hefei,an engineering method for the real-time separating temperature effect from strain monitoring is derived.First,the temperature distribution in the girder of the bridge has been analyzed,and a suggestion for temperature sensors distribution is put forward.Then,according to the analysis of the monitoring value of strain,the temperature effect value is obtained by the time-varying average value method.The simple and efficient method can be applied to the real-time temperature correction of monitoring data and the setting of dynamic early-warning index in an online bridge structure health monitoring system.The residual strains of different locations can be used to identify the moving load of a bridge structure.