Performance of Rayleigh-Based Distributed Optical Fiber Sensors Bonded to Reinforcing Bars in Bending

Area of Science:

• Civil Engineering
• Materials Science
• Sensor Technology

Background:

• Distributed Optical Fiber Sensors (DOFSs) are valuable for monitoring reinforced concrete (RC) structures.
• Unrealistic strain readings in DOFS limit their application in experimental tests.

Purpose of the Study:

• To experimentally induce and identify the physical cause of unrealistic strain anomalies in DOFS.
• To enhance the performance of DOFS for reliable strain sensing in structural health monitoring.

Main Methods:

• Experimental bending of steel reinforcement bars with bonded DOFS under various conditions.
• Analysis of different load types, bonding adhesives, and bar sections.
• Isolation and identification of factors causing strain anomalies.

Main Results:

• Bonding adhesives influenced DOFS performance but not the onset of anomalies.
• Strain anomalies are triggered by reaching a specific strain threshold and changes in the structural deformation behavior.
• The potential causes for anomalies were narrowed down from six to two.

Conclusions:

• Understanding strain anomalies is crucial for advancing DOFS as a performant strain sensing technique.
• Further research is needed to pinpoint the exact cause of these anomalies.
• This study provides critical insights for improving the reliability of DOFS in structural monitoring.