Investigation of Deflection Angle Measurement by Sampling Moire Camera and Soundness Evaluation of Bearing Part of Railway Bridge

Abstract

　　　Bearing part is one of the most vulnerable parts of railway bridges. The soundness of railway bridges is usually inspected visually. However, visual inspection to detect deterioration at bearing part is sometimes difficult when trains run on railway bridges. Therefore, deflection angle at bearing part has been used to evaluate the soundness of bearing part of railway bridges. Sampling moire camera is one of the measuring equipment of deflection angle. It can measure deflection angle in safe and without contact. However, a measured value of deflection angle includes a lot of noise due to vibration of substructures, distance between the sampling moire camera and bearing parts, etc. In this paper, improvement in the precision of deflection angle measured by the sampling moire camera was investigated. In addition, practical applicability of the soundness evaluation of bearing part by measuring deflection angle was verified. The results show that deflection angle calculated from a difference of vertical displacement between two targets has enough precision to evaluate the soundness of bearing part of railway bridges.