Reference-free damage identification method for highway continuous girder bridges based on long-gauge fibre Bragg grating strain sensors

Abstract

Damage information is important for bridge condition assessment and maintenance. Extensive research has been conducted to extract this information from the responses of bridges (e.g., displacement and strain). However, among these methods, the responses of intact bridges are required for damage identification, which is difficult to acquire for most existing bridges. For such circumstances, a reference-free damage identification method for highway continuous girder bridges is presented in this paper, which takes advantage of long-gauge fibre Bragg grating strain sensors. A 1:10 indoor model experiment is conducted to verify the practicability of the method, which is effective under various damage and vehicle parameters. The extents of damage identification errors can reach 50% because of experimental errors. Furthermore, the number of bridge spans and road surface roughness are proven to have no effect on the method with a bridge-vehicle coupling system, and the extents of damage identification errors are below 10%.