A 5,000-tonne load test was specified for the future main build structure of the new 21 Moorfields building in the City of London, a mixed retail and office redevelopment.
The 16-storey building that will bridge 55 metres over Moorgate underground station and a Crossrail ticket hall. 21 Moorfields is to be the new London headquarters of Deutsche Bank.
The developer is Land Securities, architect is Wilkinson Eyre and main contractor is Mace.
Heavy lifting specialist ALE performed a bespoke onsite load application using equipment it designed and built in-house to load the test pile progressively. It was the first load test of its kind in Europe, ALE says, and at 5,121t it was also the highest load test on a pile within Europe.
Specialist weighing equipment needed to be positioned before starting test truss assembly. The pile test loading and unloading cycle fluctuated in load up to a maximum of 52.2Mn in line with the engineer’s requirements. The test then took place over a three-day period, running 24 hours a day.
“Our unique method allowed for a very progressive and accurate load application with real- time monitoring,” explained project engineer Pete Cox.
“Using this method meant that our client had the insight that our solution was able to distribute the load across a varying number of reactive piles during the load application sequences. Not only does the client now have the confidence that this monitoring and control solution can now be implemented for their load schedule for the pile test criteria, but there is the potential to apply this high load test time-saving methodology on other sites.”
The load test operation was completed in September 2018. ALE is currently preparing for the additional scope for the 21 Moorfields project in March. This involves removal of construction plant with specially-designed high-level grillage.