Project summaryThis was a major redevelopment of an iconic crescent near Regent’s Park originally built in the 1820s and designed by the renowned architect John Nash. The plan was to demolish the existing structure behind the original façade – which was to be completely refurbished – and for the excavation of new basements. The demolition was carried out by specialists McGee and construction undertaken by Midgard, for the client.
Murphy Geospatial was tasked with crucial structural and environmental monitoring in and around the site including monitoring the London Underground, as the Jubilee line runs beneath the development and the Metropolitan line runs adjacent to the site.
We needed to install, commission and maintain three automated multi stations in a live demolition site with moving plant machinery and demolition works under way. We also needed to install, commission and maintain more than 250 wireless tilt sensors in the Jubilee line’s tunnels northbound and southbound during the works over several years.
The monitoring of neighbouring properties, which included medical surgeries and other sensitive facilities, required great thoughtfulness because of the proximity to the demolition and construction works. We provided real time data to inform the construction company and all stakeholders to ensure that the agreed parameters were not exceeded and that the third parties were protected from any noise and other disturbances to enable the construction works to be carried out on budget and on schedule.
Our highly-skilled team installed the following systems above and below ground at Regent’s Crescent:
- Three laser scan station sensors (AMS)
- 300 tilt sensors and electro level beams – 250 below ground and 50 above on site
- Three optical automatic total stations and manual back-up survey equipment
- Three digital image capturing devices
- 20 seismic vibration sensors
- 10 air pressure and noise sensors
- Four air quality and dust sensors
- A wireless data transfer mesh network
- IoT data communication facilities and alarm systems
- Remote-controlled cameras
In addition to our careful building and environmental monitoring, we were also required to monitor the structural health of 600m LUL tunnels. We did this by installing 250 tilt sensors in sections of five sensors around the tunnel circumference in the Jubilee Line and optical automatic total stations for the larger open tunnel sections of the Hammersmith and City Line. The long distance to the next station required ingenuity for the monitoring data transmission. The limited diameter of the tunnels and the proximity of excavation works needed special newly developed algorithms to automatically calculate the deformation and heave and settlement of the tunnel bores.
All sensors were managed remotely from our London office and the three integrated cameras allowed visual oversight of the site works.
This was a complex and highly sensitive project, which required the development of new remote monitoring solutions to enable us to measure without attaching reflectors to the building façade and other technical innovations to transmit data wirelessly from various sensor types.
We have worked with our sensor and software suppliers Senceive UK and Leica Geosystems Switzerland and developed the so-called ‘patch scan’ solution. This has been adapted by the industry in the new specifications for large-scale monitoring projects, avoiding drilling holes into a façade and reducing installation times.
We were delighted that the project was shortlisted for both construction and tunnel awards.
As we have demonstrated with the success of this project and countless others, we develop services to equip our clients with the data and information they need to make critical decisions at each stage of a project or asset life cycle. We consistently draw on the skills and experience of our people to deliver certainty our clients can trust.
Figure 3: Installing the MS60 (multi-station with scanning capability) automated total station and results of scans to sub-millimetre precision.
For the LUL tunnel monitoring and the data communication over some kilometres from the nearest station, we used a fibre optic data cable to transmit the large amounts of data generated by high frequency readings on the tunnel-lining tilt sensors. This was an elegant solution provided by our trusted supplier Senceive, which also supplied the wireless tilt sensor technology.
For more information on this project, please contact Andrew Masters at firstname.lastname@example.org