Monitoring double-track railway masonry bridge piers using ground-based interferometric radar and augmented reality

Masonry bridges are heritage assets still mostly under service. Ensuring safety and continuous operations of these structures requires robust structural health monitoring (SHM) programs and methods for continuous and fast data collection. Remote sensing, specifically the ground-based interferometric radar (GBIR) has proven viable in monitoring bridge structures. The GBIR system is a highly regarded electromagnetic method in SHM due to its non-invasiveness and the possibility to provide collection of high accurate data in static and dynamic mode. However, system measurement control to understand signal propagation patterns against target position is needed to increase accuracy and significance. Piers are the supporting system of bridge structures, and they define their boundary conditions. They directly affect the structures vibration and natural frequency. In this paper, the dynamic behaviour of a double track railway masonry bridge pier was investigated through the integration between GBIR and augmented reality (AR). The viability of an AR-based interactive user interface for GBIR measurements developed in previous scoping studies was here tested for system measurement control on a real-life structure. Data were analysed using signal processing techniques for feature extraction. Results have proven the viability of integrating AR into GBIR monitoring of bridge structures for real-time monitoring.