Noncontact Measurement of Bridge Load Response Using He–Ne Modulated Lasers

• Published in: Journal of bridge engineering 2019-11, Vol.24 (11)
• Main Authors: Attanayake, Upul, Aktan, Haluk
• Format: Article
• Language: English
• Subjects: Bridge construction; Bridge loads; Calibration; Civil engineering; Construction; Deformation; Deviation; Displacement; Girder bridges; Lasers; Load; Loads (forces); Measurement; Monitoring; Potentiometers; Schedules; Sensors; Steel; Steel bridges; Steel structures; Structural steels; Technical Papers; Translations
• ISSN: 1084-0702; 1943-5592
• DOI: 10.1061/(ASCE)BE.1943-5592.0001468

AbstractStructural deformation under known loads is required for assessment and model calibration. In addition, deformations need to be measured under transient as well as intrinsic loads. These loads have significantly different application durations requiring significantly different sampling rates. Measurement of deformations and translations with traditional sensors is challenging because it requires sensor mounting to a fixed reference. In the case of monitoring structures during construction, limited access and schedule constraints necessitate placement of the monitoring equipment outside the active construction zone. This article presents an implementation as well as proof of concept of a noncontact technology for obtaining accurate measurements with minimum impact to the structure and construction activities. Indoor and outdoor calibration showed that the deviation of measurements made at an 81-m (266-ft) range was about ±7% of the linear displacement potentiometer sensors. The maximum deviation of deflection measurements made during load testing of a steel girder bridge was 8.3% of the linear displacement potentiometer sensors. The measurements included three-dimensional (3D) displacements at each location, a significant advancement over traditional technologies.