As work on the 310m-high Shard gathers pace, a battery of instruments is making sure nearby London Bridge’s overground and underground stations remain unaffected.
The Shard promises to be one of the major landmarks on the London skyline. Due for completion in 2012, this mixed use structure will stand 310m tall. When completed the building will be the tallest in the UK with a total of 72 occupiable floors.
The activities associated with building the tower all have a considerable impact on the surrounding ground and structures. These include the removal of load resulting from the demolition of the existing tower, constructing a three level deep basement and the subsequent surcharge of the Shard itself. Checking the impact of these activities calls for robust monitoring solutions.
The Shard replaces Southwark Towers, a 24-storey 1970s office block. The foundations of the Shard sit immediately above, and adjacent to, one of world’s oldest stations, London Bridge. Support for the station comes from a network of Victorian brick vaults that house the Shunt Theatre, the London Dungeons and many busy commercial units.
In order to determine the performance of London Underground and Network Rail assets, an extensive monitoring regime was designed and introduced before demolition and subsequent construction started.
Escalators, running tunnels, pedestrian passageways and the “vaults” market hall require monitoring in real time to determine infrastructure performance and allow normal operation of the railway network.
The detailed predicted settlement footprint meant that neighbouring building facades, including Guy’s Hospital, office blocks and viaduct arches, also required real-time monitoring. Additionally the basement development of the Shard was monitored to determine the structural performance as the construction phase started.
The fully commissioned system consists of 20 high precision robotic total stations working in networks and monitoring absolute three-dimensional movements, combined with over 250 classical instruments monitoring discrete relative movements and 19 inclinometers monitoring basement wall performance.
Complementing the automated monitoring is a rigorous regime of full-time manual monitoring of structures using traditional surveying methods.
All of the data from the automated instruments is wirelessly collected and processed within SolData’s Geoscope software package, as are the manual survey results.
Interested parties can view the data remotely via the web as well as carrying out more in depth analysis on software-enabled computers. Predetermined trigger breaches automatically notify key personnel from the contractor and client so that prompt mitigating action can be started, if required.
The Shard is being developed by Sellar Group, Mace is the principal contractor and SolData is the monitoring service provider.