Monitoring of Bridges by a Laser Pointer: Dynamic Measurement of Support Rotations and Elastic Line Displacements:...

Area of Science:

• Civil Engineering
• Structural Health Monitoring
• Optical Measurement Techniques

Background:

• Bridge health and bearing capacity rely on monitoring deck inclination and vertical displacements.
• Existing monitoring methods often lack precision, automation, or cost-effectiveness for static and dynamic analysis.

Purpose of the Study:

• To develop and validate a precise, automated, and low-cost system for monitoring bridge inclination and displacement.
• To enable simultaneous static and dynamic monitoring of bridge structures.

Main Methods:

• Utilized a common laser pointer and high-definition video for measuring elastic line inclination.
• Developed custom Matlab® code for image processing to determine instantaneous rotation and displacement.
• Synchronized load positioning (via GNSS or video) with structural response data.

Main Results:

• Achieved a precision of 0.01 mrad for elastic line inclination measurements.
• Successfully correlated truck positioning with measured bridge inclination and displacements during a dynamic load test.
• Demonstrated the system's capability for real-time structural response analysis.

Conclusions:

• The proposed laser and image processing system is suitable for dynamic load testing of bridges.
• This method provides an accurate and cost-effective solution for bridge control and monitoring.
• The system facilitates detailed analysis of bridge behavior under mobile loads.