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MOS is shortlisted in the category *Product and Innovation Award* in the Ground Engineering Awards 2016 for our works at Crossrail's Farringdon Station


Fiber Optic sensors can be employed in a wide range of structural monitoring applications on both new-build and existing structures. These are just a few examples of applications where FO sensors have been successfully used.

Suspension Bridge

On bridges it is particularly important to verify that the strain in the structural components do not trespass certain safety values. Strain measurements at constant loads are also a standard approach to the verification of structural health. FO strain sensors can be installed on a bridge and left in place for years, while the measurements can be undertaken either continuously or during the scheduled test campaigns. FO sensors can also be used to monitor continuous traffic induced strains. These in suspension bridges can be often directly related to the number and weight of the vehicles, therefore providing a traffic management tool together with the structural monitoring tool.

Concrete Retaining Wall

The control of landslides is a critical issue in mountain areas. Often the only way to protect towns and roads is by the use of retaining walls.

Engineers constantly research new designs and materials to achieve higher levels of protection with lighter and more environmentally friendly structures.

A long term monitoring system using Monitor Optics embedded Fibre Bragg Gratings (FBG) based sensors was employed to monitor the performances of an element of a retaining wall characterised by an innovative design and concrete mix. The monitoring system is expected to provide information on the structural performances of the prototype element for a period of 3 to 5 years. While the element is being monitored with other conventional techniques, only the FBG sensors can provide information on what happens inside the structure.

A total of 7 sensors were embedded into one of the concrete elements of the retaining wall. The sensors were located in selected measurement points within the proximity of the tensioning wires. Part of the sensors was located on the outer side of the structure and part on the ground side. Each sensor was provided with temperature compensation to prevent the pollution of the acquisition of strain measurements by any temperature effects on the Bragg Gratings.


Road Pavements

Sensing cables are particularly well suited to monitor road pavement. Sensing cables can be laid over long distances while providing measurements at the required discrete intervals. This makes possible the automatic monitoring of ground strains, especially important where the pavement is subject to subsidence phenomena
MOS continuous distributed FBG based sensors are designed for the maximum ease of installation  

Cultural Heritage Buildings

Cultural heritage buildings are often subject to loads that were not foreseen when they were first built. It is important to keep their structural health continuously under control and to have a reliable method of verification of the validity of restoration and conservation programs.
Often these buildings present structural and aesthetics considerations that force the use of minimally intrusive sensors. FO thanks to their small size are perfectly suited for these applications. Strain gauges (not illustrated) can be glued like conventional strain gauges or spot welded on steel structures.

Other Applications

New Builds

Displacement sensors and some strain sensors can be embedded in concrete structures during the manufacturing process while displacement sensors can be bolted to concrete and stone structures. Strain sensors can be glued or welded. The use of an integrated monitoring system on new build structures allows the designers to start monitoring the structural behaviour right from the construction phase.


Tunnels require monitoring both during the construction and the operation phases. Moreover fire detection in road tunnels is very important and can be implemented as part of the structural monitoring system. Axial and circumferential strains measurement and Fire detection are typical requirements.

Airport Paving

Airport pavements are under constant stress during take-offs, landings, and taxing. Fiber Optic sensors designed by Monitor Optics can be easily embedded during construction or retrofitted to existing installations. Due to the design of the Monitor Optics sensors they can measure stress over large areas. In partnership with Applied GeoMechanics, Monitor Optics has successfully completed testing with the FAA.

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