Railway Bridge Structural Health Monitoring Using Wireless Acoustic Emission Sensor Network

Acoustic emission monitoring of fracture-critical components of load-bearing structures such as railway bridges, provides a valuable input to condition-based maintenance planning and the allocation of maintenance resources. This paper presents a prototype wireless acoustic emission (AE) sensor network system for the structural health monitoring of aging steel railway bridges. It involves an AE sensor node, consisting of four AE channels and one strain gage input channel. Advances in data acquisition and communications instrumentation and the application of the fundamentals of fracture mechanics and artificial intelligence in signal processing have led to the development of a comprehensive, integrated system for acoustic emission monitoring. An active fatigue crack, when stressed due to the load of the on-coming freight train, emits AE. The strain gage channel senses the oncoming train and wakes up the AE channels from their hibernation mode. The wireless instrument digitizes the information, analyzes, compresses, and then transmits the filtered information to a central processing station for review by bridge engineers.