The Shard (London Bridge Tower)
London, England · 2009-2012 · £435 million (contract cost only)
The judgement call
Account-gated at launch"Top-down" construction: Allowed the first 23 storeys of the concrete core and much of the surrounding tower to be built before the basement was fully excavated, a first for the UK. - Hybrid structure: Combination of concrete (basement, levels 41-69) and steel (ground to level 40, levels 70-95 spire) optimized for different uses and improved dynamics. - Hat truss at level 66: Used to increase stiffness and reduce lateral acceleration, with bolts tightened only after significant shortening had occurred. - Modular pre-assembly and dry-run of spire: To minimize work at height and identify risks, the spire was pre-assembled in modules and a full dry-run was conducted in Yorkshire. - Use of ground-granulated blast furnace slag in concrete: Substituted 70% of Portland cement, reducing carbon footprint and CO2 emissions.
Key engineering challenges
Wind sway and acceleration: Controlling horizontal acceleration was crucial, especially for hotel and residential sections, with a limit of 0.15 m/s² at level 65. - Differential shortening: The building shortened during construction due to foundation settlement, elastic compression, shrinkage, and creep, requiring complex deflection calculations and building floors slightly off-horizontal. - Spire assembly at height: Assembling the 60m, 23-storey steel and glass spire at 300m height, with wind speeds up to 100 mph, was a significant challenge. - Massive concrete pour: The base slab required the UK's largest ever continuous concrete pour (5,500 m³ over 36 hours).
Project facts
- Client / owner
- State of Qatar (95%), Sellar Property Group (5%)
- Lead contractor
- Mace
- Lead designers
- Renzo Piano Building Workshop, Adamson Associates Architects
- Project type
- new build
- Scale
- Architectural height: 309.6 m (1,016 ft), 95 floors (72 habitable), Floor area: 127,071.3 m2, 36 lifts/elevators
- Disciplines
- Structural Engineering; Geotechnical Engineering; Building Services Engineering; Architecture
- Standards & frameworks
- UK Building Regulations; US National Institute of Standards and Technology (NIST) report guidelines
Sources: https://en.wikipedia.org/wiki/The_Shard