基于三原则的卢沟桥预防性保护监测系统构建方法OA

To construct a monitoring system of preventive protection for ancient masonry arch bridges,a monitoring method for risk identification was investigated.Three indicators,which were damage assessment grade,Von Mises stress,and component importance,were used to quantify the most severe damage,unfavorable stress,and critical components.The monitoring target values were solved for the 64 components of the Lugou Bridge based on the loss matrix,force matrix,and importance matrix,and a sensor placement scheme was made accordingly.The results have shown that the method can identify high-value components for monitoring and capture the seasonal fluctuation patterns and cumulative damage risks of Lugou Bridge.Except for the settlement,monitoring data exhibits significant seasonal fluctuation patterns,with peaks in June to July and troughs in January each year.The ratio of winter to summer peak values is 1.577 for strain sensors,0.849 for displacement sensors at the seventh pier from the east,1.206 for displacement sensors at the ninth pier from the east,and 1.549 for transverse inclination sensors.The average seasonal fluctuation ratio ranges from 20％to 60％.The settlement of the fifth pier from the East is 1.156 times that of the ninth pier from the East.Sensors near the central arch bridge or located in severely damaged areas have higher peak values among the same type of sensors.The study provides a scientific basis for the monitoring of preventive conservation of ancient masonry arch bridges.