London’s skyline is changing dramatically. From 1710 to 1962, St Paul’s Cathedral was London’s tallest building standing at 365ft high. Canary Wharf, The Gherkin and The Shard have all been added to London’s skyline in the last 50 years, and now dominate the cathedral significantly. Leica Geosystems has played a major part in this transformation of London’s landscape over the past 5 decades, and it was heavily involved in the latest addition, The Shard.
High-rise towers need constant checking during construction to ensure that dimensions are controlled within the design requirements. This was the challenge that Leica Geosystems accepted for a monitoring system during construction of the central core of the Shard, Europe’s tallest building and now an icon on the London skyline.
The central concrete core of a skyscraper is usually built rapidly using a slip form system to encase the concrete as it is poured; it can advance as much as 8 metres a day. But dimensional control of the slip-form rig is not easy.
Leica Geosystems proposed a system of TPS total stations, four GNSS receivers and four dual-axis inclinometers located on the rig. The system offered verifiable data from more than one system. The GNSS antennas were co-located with 360° prisms to give a constant check on GNSS positions against total station readings. The combined systems fed data into GeoMoS, Leica’s monitoring software, which can be installed offsite or over the web and provides early warning of any departure from design tolerances.
So successful was Leica Geosystems’ monitoring design that similar systems are now being used in the City of London for the dimensional control of many high-rise buildings during construction.