Located in the cultural heart of London, Centre Point is one of city’s most iconic buildings and has been a part of the skyline since 1966, gaining English Heritage grade II listed status in 2009. It is currently being converted into luxury flats with panoramic views. During the full renovation, the 34 storey, 117m tower required monitoring over concerns that the building may become unstable under the stress of all the construction.
Site Engineering Surveys Ltd (SES), one of the UK’s leading land and engineering surveying companies, was appointed to carry out structural monitoring and chose to use optical systems in combination with manual surveys. A reliable and discreet tilt monitoring systems was required to corroborate data and to provide both workers and public with a further reassurance of safety.
SES brought onboard Senceive to carry out the wireless tilt monitoring of Centre Point tower, after many other successfully collaborations in the past.
40 FlatMesh™ wireless tilt nodes were quickly and easily deployed on façade panels on all four sides of the building, as well as on the central lift shaft. Retro targets for optical surveying were also fitted at each tilt sensor location. Data was then wirelessly transmitted to the mobile network, via 3G gateways, one of which was solar powered. Data from all the nodes could then be viewed remotely and simultaneously on Senceive’s secure WebMonitor visualisation software by registered users.
Senceive’s tilt sensors were so sensitive that they even detected the tiny swaying movements tall buildings exhibit due to high winds and minor earth tremors, as well as the diurnal movements caused by temperature variation.
With the nodes set to a reporting rate of 30 minutes, a battery life of up to 15 years and the solar 3G gateway positioned on the roof. The monitoring continued without interruption for a period of 12 months with no maintenance required at all.
The equipment provided the ability to detect movement in all areas of the building, including the lift shaft and the façades, to ensure constant monitoring. Any detected movement would then trigger alerts to the team immediately via SMS text message. It provided an early warning system to the onsite team whilst the complicated structural alteration works and façade retention were in progress and allowed for the safe construction during this period.
The FlatMesh™ system proved its ease of installation and redeployment and its reliability. It was a key enabler of successful monitoring by SES.