One of the most challenging operations in the Great Court construction programme was concreting the basements, says Mace project manager Carl Wright. 'It was so unrepetitive, all curves and small slabs, with some areas of long span beams with heavy reinforcement.'
Actual construction was down to specialist contractor John Doyle. Concreteing operations had to fit in around other work on a site where no area of the footprint ever lay fallow for long. 'The sequencing strategy was very bold, ' Wright comments. 'All operations were overlapped - the reading room ceiling restoration took place among a sea of heavy civil engineering, at one point we had demolition, excavation, underpinning and restoration of the south portico occurring simultaneously.'
Post-tensioning the 600mm thick ground floor slab was a key landmark. It took place from north to south, and as each section became available the scaffolding for the main working deck began to rise towards the sky. As the working deck took shape so the prefabricated roof ladders began to arrive. The potential for problems and delays was immense, but thanks to months of pre-contract planning, claims Wright, everything worked, 95% of the time at least.