A Plastic Optical Fiber Sensing System for Bridge Deflection Measurement

Area of Science:

• Civil Engineering
• Structural Health Monitoring
• Optical Sensing

Background:

• Bridge deflection is critical for structural health monitoring.
• Existing deflection measurement techniques face limitations for operational bridges.
• There is a need for reliable, non-invasive monitoring systems.

Purpose of the Study:

• To propose a novel sensing system for measuring bridge deflection.
• To utilize changes in optical fiber intensity for deflection detection.
• To develop a system independent of external ground references.

Main Methods:

• A system using connected pipes filled with liquid to measure deflection.
• Employing a plastic optical fiber sensor to detect liquid level changes.
• Conducting experimental tests for performance evaluation.

Main Results:

• The system demonstrated accurate linear response and high reliability.
• Deflection measurements showed agreement with a linear variable differential transformer (LVDT) within 2.1% error.
• The system proved effective under various environmental conditions.

Conclusions:

• The proposed liquid-based optical fiber sensing system is a viable method for bridge deflection measurement.
• This system offers a potential solution for the health monitoring of long-span bridges.
• The system's independence from external references simplifies deployment.