Monitoring the Fatigue-Induced Strain Evolution of Concrete Bridges using Fiber Optic Sensors

Concrete bridges with low shear reinforcement ratios erected in the mid-20th century are subjected to rapidly increasing traffic loads in the last decades. In the absence of precise methods for assessing the remaining service life, the detection of the slightest damage (e.g., cracks and corrosion) immediately leads to a partial or complete restriction of traffic. Major parts of the ultimate fatigue capacity are therefore not yet utilized. Addressing the aspects of sustainability and capacity of traffic infrastructure, it is crucial to extend the service life of existing bridges by optimized assessment concepts that cover the development of the actual damage state of the critical structural components. Therefore, this paper presents a novel monitoring concept for the strain development of pre-damaged concrete structures. First experimental studies demonstrate that Fiber Optic Sensors (FOS) are ideally suited to capture the strain development of concrete structures under fatigue loading. Therefore, the developed measurement concept is based on this technology and can contribute to extend the service life of concrete bridges through comprehensive monitoring strategies.