Detection and Characterization of Early-Age Thermal Cracks in High-Performance Concrete

Abstract

Streicker Bridge is a new pedestrian bridge built on the Princeton University campus. Structural health monitoring (SHM) is applied with the aim of transforming the bridge into an on-site laboratory for various research and educational purposes. Two fiber optic sensing technologies are permanently deployed: discrete long-gauge sensing technology based on fiber Bragg gratings (FBG) and truly distributed sensing technology based on Brillouin optical time domain analysis (BOTDA). The sensors were embedded in the concrete during construction. This paper describes the real-time detection and characterization of early-age thermal cracks in the high-performance concrete deck of Streicker Bridge. The deployed monitoring strategy and the monitoring systems, which successfully detected cracking, are described. The observed crack propagation trajectories are presented. Details of a simple finite element model (FEM) of the bridge are given, and the analysis procedure used to demonstrate the formation of thermal cracks using this model is outlined.