Oblique Photography Monitoring Method for Bridge Displacement Response Under Earthquake Action

LIN Zili; XU Yunxi

doi:10.13512/j.hndz.2025.01.16

Abstract：As highly destructive natural disasters,Earthquakes often have serious impacts on bridge structures,such as displacements,tilt,and other deformations.An oblique photography monitoring method for bridge displacement response under earthquake action was proposed to monitor and evaluate the response of bridges in a timely and effective manner and to ensure the normal operation of bridges and the safety of personnel.Determining the areas with the most significant or representative displacement change through the optimal bridge deflection curve,and these areas were used as the location of the oblique photography monitoring points.Using drones equipped with cameras,oblique images of the bridge at the monitoring points under earthquake action were collected.The sub-pixel corner points of the images were extracetd by the Harris operator,and the feature descriptors were generated.The sub-pixel template matching method was combined for bridge sub-pixel displacement tracking under earthquake action.By introducing a scaling factor,the sub-pixel displacement values of the bridge displacement response were converted to obtain accurate values of bridge displacement response under earthquake action.The displacement response values from each oblique photography image were then integrated to produce the final monitoring results.The experimental results show that this method has a relatively accurate capability for extracting sub-pixel corner points.The calculated sub-pixel displacement response values of bridges match well with the actual values.The method can effectively realize the monitoring of bridge displacement response under earthquake,with significant application effectiveness.