ABSTRACT
Deterioration of pre-stressed concrete https://www.w3.org/1998/Math/MathML"> ( P C ) https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429227196/8b5c0a5d-ddea-4c88-8eea-7152f7afb008/content/eq2257.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> bridges may not be detected during periodic visual inspections, such as corrosion in PC tendons which could lead to a collapse of the whole bridge as reported in literature. Vibration-based structural health monitoring techniques could be a possible method to detect such invisible damage. It was reported in literature that the stiffness of corroded and un-corroded PC beams did not have significant difference within the elastic range although it drastically dropped with corrosion only beyond the elastic range. Among the dynamic characteristics, modal damping ratio has been identified as a damage sensitive parameter in some previous studies. In the present study, stable identification of modal damping ratio was investigated in existing PC bridges to use it as an indicator of invisible damage. As a practically convenient method, vibration measurement by using wireless sensors under normal service conditions was used for experimental modal identification.
