01707745

Monograph

http://www.trb.org/Main/Blurbs/179162.aspx

This report summarizes the results of non-contact deflection monitoring system developed for timber railroad bridges. Considering the abundance of timber railroad bridges in the nation that have exceeded their design life, a cost-effective and safe deflection monitoring system is essential for their regular maintenance. As existing techniques typically require access to the bridge structure that poses safety challenges for the bridge maintenance crew, this project has developed a completely non-contact and low-cost bridge deflection monitoring system using cameras. The project demonstrated the feasibility of using camera as a bridge deflection measurement sensor by implementing the techniques in CSX-owned railroad bridges in South Florida. The project team carefully studied the characteristics of timber railroad bridges in the nation based on AREMA guidelines. Accordingly, the project team analyzed the suitable camera parameters to capture bridge deflections. The recommended parameters are discussed in the report. In order to scale the images captured by cameras, the project methodology adopted laser scanner or total station and a linear feature- based registration technique. With the single camera, 2D deflections can be recovered. When two or more cameras are used, 3D deflections can be derived using the demonstrated project methodology. The project team developed necessary mathematical models and workflow to derive 2D/3D deflections from the images acquired by cameras. The project investigators demonstrated the feasibility of the developed methodology in both lab environment and the field conditions. As for field testing of project methodology, the investigators worked with CSX Transportation and selected several candidate bridges and used two of them. The image sequences (video) captured by the camera were used to automatically track the deflection of specific points of interest when a dynamic load was applied. The derived results were compared with dial gages and finite element analysis for validation.

Rail Safety IDEA Project 35

English

33p

2019-3

Safety IDEA Program Project Final Report

Final Report

Digital/other

Figures; References; Tables

Deflection; Railroad bridges; Remote sensing; Structural health monitoring; Wooden bridges

Bridges and other structures; Data and Information Technology; Maintenance and Preservation

TRIS, TRB, ATRI

Jun 7 2019 11:43AM