STEEL
constructionmanagermagazine.com
CROSSING THE LINE LANDSEC’S 21 MOORFIELDS DEVELOPMENT – OVER A LIVE TUBE STATION – HAS EMPLOYED NUMEROUS DIGITAL TOOLS TO DELIVER A COMPLEX STRUCTURAL DESIGN AND CONSTRUCTION METHODOLOGY. CM REPORTS
Bridging a 55m-span over Moorgate Station, the 17-storey 21 Moorfields development is a new landmark feat of engineering for the City of London. The 60,000 sq m commercial building project, which straddles three Tube lines, Underground sidings and Crossrail, required a complex structural design – which was developed in conjunction with the build strategy – aided by cutting edge digital tools. The approach to the Landsec project was conceived and delivered by the team of engineers at Robert Bird Group (RBG), working with architect Wilkinson Eyre and contractor Sir Robert McAlpine.
Steel frame erection progress, taken from Moor Lane, to the west of the site
Logistically and technically, RBG had to take a holistic view of the design and construction process, bringing its in-house construction engineering division to work with the main design team from concept stage. “The consideration of buildability within the permanent structural system was fundamental to our design philosophy,” says RBG project director Nick Cole. From the outset, it was nonnegotiable that Moorgate Station had to remain operational throughout demolition and construction activities. Other constraints the team had to negotiate included the limited loading capacity of the slab
which forms the existing station roof, which had to support construction activities, including cranes, plus safely constructing the structural frame directly over the live station. For these reasons, RBG decided to use an early construction methodology and erection sequencing approach with the structural design, plus integrated erection stress analysis. This approach, usually applied at later project stages, allowed the team to understand risk, cost and programme for the works, and validate the construction methodology and programme with LandSec and Transport for London.
28 | CONSTRUCTION MANAGER APRIL 2021
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