Single-Camera-Based Bridge Structural Displacement Measurement with Traffic Counting.

Zulhaj Aliansyah,Kohei Shimasaki,Taku Senoo,Shuji Umemoto,Idaku Ishii

doi:10.3390/s21134517

Abstract

Vision-based structural displacement methods allow convenient monitoring of civil structures such as bridges, though they are often limited due to the small number of measurement points, constrained spatial resolution, and inability to identify the acting forces of the measured displacement. To increase the number of measurement points in vision-based bridge displacement measurement, this study introduces a front-view tandem marker motion capture system with side-view traffic counting to identify the force-inducing passing vehicles on the bridge’s deck. The proposed system was able to measure structural displacement at submillimeter resolution on eight measurement points at once at a distance of 40.8–64.2 m from a front-view camera. The traffic counting system with a side-view camera recorded the passing vehicles from two opposing lanes. We conducted a 35-min experiment for a 25 m-span steel road bridge with hundreds of cars passing over it and confirmed dynamic displacement distributions with amplitudes of several millimeters when large vehicles passed.

Highlights

IntroductionBridges have served a vital part in the transportation system by allowing road traffic and other loads to traverse over physical obstructions caused by topological and structural conditions, e.g., rivers, valleys, railways, elevated roads
Received: 1 June 2021Accepted: 28 June 2021Published: 1 July 2021Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Bridges have served a vital part in the transportation system by allowing road traffic and other loads to traverse over physical obstructions caused by topological and structural conditions, e.g., rivers, valleys, railways, elevated roads
We introduce a single-camera-based deflection distribution measurement method with subpixel digital image correlation (DIC) analysis for a dozens-of-meters-span road bridge; this is extended from the tandem-marker-based motion capture method [6] that allows measurement of structural dynamic displacement from multiple tandem-distributed points at once without decreasing measurement accuracy by installing a front-view camera positioned with a small angular delineation to the bridge’s axis

Summary

Introduction

Bridges have served a vital part in the transportation system by allowing road traffic and other loads to traverse over physical obstructions caused by topological and structural conditions, e.g., rivers, valleys, railways, elevated roads. A bridge’s inability to serve its purpose may result in a longer travel route or an isolated area removed from the transport network. Bridge failures often result in casualties and large-scale monetary loss; such failures need to be prevented. A bridge is constantly subject to damages from environmental factors or inherent usage loads during its service life. The damages to a bridge can be categorized into three kinds of effects [1]:. Assign ID_right or ID_left from previous frame. A single-vehicle blob can be assigned with two IDs (right-going 100) to handle momentary occlusion between left-going and right-going vehicles. The final ID is selected based on whether the ID value matches the movement direction

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Results

Conclusion