混凝土桥梁健康监测中的温度滞后效应

Temperature Hysteresis Effect in Health Monitoring of Concrete Bridges

挠度是桥梁健康监测的重要指标,影响运营阶段桥梁结构挠度的因素众多,其中温度的影响往往不亚于活载。温度效应特别是日照温差效应的存在,使健康监测数据的评估分析变得困难,因此需要研究温度监测值与挠度监测值之间的规律,为监测数据中温度效应的分离提供支持。分析了日照温度传导的计算理论,发现要通过求解微分方程来确定桥梁温度场在工程上较难实现。通过对江津长江大桥箱内外温度及跨中挠度的监测数据进行分析,发现箱内温度变化较箱外温度平缓且存在滞后性;温度监测值和挠度之间存在很强的相关性,其中箱内温度监测值与挠度相关性更强;跨中挠度监测值较箱外温度值变化具有滞后效应。故从挠度监测数据中分离温度效应时,应将滞后时间考虑在内,以期得到更准确的结果。

Deflection is an important indicator of bridge health monitoring,affected by many factors during operation,the influence of temperature is usually no less than the live load,especially sunshine temperature difference,making the analysis of health monitoring data difficult.Therefore,the study of the laws between temperature monitoring values and deflection monitoring values is needed to support the separation of temperature effects in monitoring data.The calculation theory of solar radiation temperature was analyzed,revealing the difficulty of solving differential equations to achieve the bridge temperature.The analysis of the monitoring data of the temperature inside and outside the box and the mid-span deflection of the Mtro Yangzte river bridge shows that the temperature change inside the box is gentler than outside the box and there is hysteresis;there is a strong correlation between the temperature monitoring value and the deflection,and the inside temperature monitoring value has stronger relation to the deflection.Compared with the temperature value outside the box,the monitoring value of the mid-span deflection has hysteresis,the lag time should be taken into account in order to obtain more accurate results.