In theory, there are multitude of algorithms that could be successfully applied to structural health monitoring and damage detection if noise-free simulations were employed. In practise, these algorithms are limited by many uncertainties. To start with, the level of resolution of the measured structural response needed to capture damage is often too small compared to noise. But technology is advancing rapidly and facilitating the implementation of new algorithms that would have been unthinkable in previous decades.
In the context of structural health monitoring of bridges, drive-by algorithms use indirect measurements collected in a vehicle driving over a bridge structure to assess its condition. While there are obvious advantages in the use of an instrumented vehicle to monitor a large bridge network (i.e., no need for bridge installations or closure), first developments are limited mostly to theoretical investigations and its efficiency still needs be demonstrated in the field.
In the context of road profiling, Greenwood Engineering has patented a measuring concept using Doppler laser sensors that allow gathering highly accurate deflection patterns from roads and rails driving a vehicle known as Traffic Speed Deflectomer (TSD) over the surface at normal traffic speeds (up to 80 km/h). A TSD is able to provide continuous pavement profiles with high definition, down to microns.
The high levels of resolution of the TSD makes possible to measure bridge deflections when driven over a bridge and led to the proposal of ESR12 project. This project combines theoretical developments on drive-by monitoring in academia with state-of-the-art laser technology for road profiling in Greenwood Engineering to extend TSD applications to bridge damage detection. As part of this collaboration, fellow Daniel Martínez visited the Head Office of Greenwood Engineering in Brøndby, Denmark, from 30th September to 1st October 2015. There, he met with Dr Jørgen Krarup, who will be his mentor during his secondment in Greenwood Engineering. As part of his training, Daniel attended some calibration sessions for the TSD developed by Greenwood. In the photograph, Daniel is pictured with the TSD. Daniel also did a presentation on the techniques that he intends to apply to TSD measurements to extend its capabilities to bridge monitoring, i.e., processing the data extracted by the TSD while crossing a bridge structure. This project is an example of the close collaborations between industry and academia undertaken in TRUSS.