Costain’s Geotechnical Services Division (GSD) is expanding its services to include surveying instrumentation and hopes that its new sensor could lead to a steady stream of royalty income if the device proves successful in the marketplace.
The sensor, known as a ‘mote’, measures inclination, or movement, in structures and detects any widening of cracks. Such sensors already exist, but the selling point of Costain’s mote is that several can be linked together in a ‘mesh wireless’ network. This means that they can communicate via each other and then to a gateway that transmits data to a monitoring station via 3G modem.
Should a problem arise with the wireless link between two sensors, they will create a new wireless pathway that avoids the problem area.
Costain says that other advantages of the sensors include high resolution – they can measure changes in inclination to 0.01° – and very low power consumption that means the batteries last around a year. They can also be installed quickly.
The devices are the result of research by Cambridge University’s engineering department, a member of which set up a company called Wisen to exploit the invention. Costain technical director Bill Hewlett, who has links with the university, came across the mote and realised it could useful.
“We have a trial installation using four motes at one of the shafts in the Brighton and Hove project to bring cleaner seas to Sussex ,” said senior survey manager Nigel Drayton.
A group of 13 motes and two gateways is also operational at the Crossrail tunnel portal project at Pudding Mill Lane, East London, measuring any movement in two axes on a retaining wall.
Costain is also in the early stages of a project with Cambridge University to develop a mote using an infra-red laser to measure convergence in tunnels and shafts. This would be utilised on the National Grid London Power Tunnels project to monitor existing tunnels during tunnelling.
“Through their use at Brighton and Hove we’ve developed a second-generation mote that’s smaller and more robust,” added Nigel. “We’re now negotiating with Wisen and are planning to develop it further.”
If an agreement is struck between Costain GSD and Wisen for GSD to become agents for Wisen in Europe, GSD would then be in a position to install motes for in-house contracts or third-party monitoring schemes.
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