Bridge maintenance is a critical, ongoing infrastructure priority in the United States. According to the 2021 ASCE Report Card for America’s Infrastructure, 42% of U.S. bridges are 50 years old or older and 7.5% are structurally deficient. Differential settlement, where part of a structure settles faster than another, affects bridge safety, and even a small change can impact the reliability of the structure. Traditional bridge inspections range from 12 to 48 months based on bridge age, condition, usage, and location.
For a recent paper in the Journal of Infrastructure Systems, researchers Henry L. Teng, Juan I. Meriles, Gaofeng Su, and Khalid M. Mosalam offer a method using lasers to more accurately measure the differences in settlement between bridge piers – and in real time. Their proposed projected laser system can track displacement by monitoring targets on structures and identify changes over time. A combination of laboratory and field testing was performed to develop a robust, compact, and accurate working prototype. Learn more about this research and how it could reduce the need to physically inspect for differential settlement at https://doi.org/10.1061/JITSE4.ISENG-2401. The abstract is below.
Abstract
The assessment of bridge settlements is a challenging and significant problem. Moreover, aging of highway bridges is a growing concern in the US, especially when continuous monitoring is lacking. To facilitate expedient monitoring of bridges, this paper presents a projected laser system (PLS) method for monitoring that can autonomously measure and remotely report relative vertical settlements of bridges. The method uses a vision-based measurement system involving the projection of a laser pattern from a laser unit to a target unit. A cost-effective prototype implementing the PLS method was built using low-cost electronic hardware parts. The prototype of the proposed embedded system design was shown to have sub-millimeter accuracy in a laboratory experiment, and was deployed in the field to monitor a pedestrian–vehicle bridge to evaluate its overall performance.
Get the specifics on how a coordinated laser system can monitor differential settlement in real time at the ASCE Library: https://doi.org/10.1061/JITSE4.ISENG-2401.
