Microwave Radar-Based Cable Displacement Measurement for Tension, Vibration, and Damping Assessment.

Area of Science:

• Structural Engineering
• Non-Destructive Testing
• Remote Sensing

Background:

• Bridge cables are critical for structural integrity and require regular safety assessments.
• Traditional monitoring methods can be labor-intensive and may require sensor installation in difficult-to-access locations.

Purpose of the Study:

• To demonstrate the efficacy of microwave radar for non-contact measurement of bridge cable displacements and vibrations.
• To evaluate the application of microwave radar in assessing cable damping characteristics.
• To validate the proposed methods through field testing on cable-stayed bridges.

Main Methods:

• Deployment of microwave radar systems on bridge decks for multi-cable displacement monitoring.
• Utilizing the LOWESS method to filter out low-frequency noise from deck deformation and radar motion.
• Applying microwave radar to free-decay testing for cable damping evaluation.

Main Results:

• Efficient measurement of multiple cable displacements with full coverage.
• Accurate characterization of cable vibrations, including vortex-induced vibrations (VIVs), directly from displacement data.
• Improved signal-to-noise ratio in damping assessments, enhancing reliability without elevated platform sensors.

Conclusions:

• Microwave radar offers an efficient and reliable non-contact solution for monitoring bridge cable health.
• The technology enables direct vibration characterization and improved damping evaluation, contributing to enhanced bridge safety.
• Field validation confirms the practical applicability and effectiveness of microwave radar for bridge cable assessment.