Detecting Stress Changes and Damage in Full-Size Concrete T-Beam and Slab with Ultrasonic Coda Waves

Abstract

This article describes the use of coda wave measurements in a network of transducers for detecting stress changes and damage in large concrete structures. The applicability of the presented method is examined by performing four-point bending tests independently on two full-size concrete structures; i.e., a 6-m reinforced slab made in laboratory and a 30-m T-beam removed from a bridge after being in service for 15 years. The experiments demonstrate that stress changes and damage can be detected by coda waves for both laboratory and real-world concrete structures. The results also show that by setting up transducer networks appropriately, the tension and compression stress changes in concrete can be distinguished with a high degree of accuracy.