Holdfast Training Services Trial Blog

21 Moorfields will be a 17-storey office and commercial building, ear marked to become the London HQ of Deutsche Bank, in the heart of the City of London. It is a fascinating project that pushes the boundaries of light-weight steel structural design and threads the needle, in some cases quite literally, through the maze of site constraints. The project is estimated to cost upwards of £350M and is scheduled for practical completion in 2022.

The East Face above the Crossrail station entrance

The development spans over the 6 live London Underground (LU) lines running into Moorgate Station and is immediately above the western ticket hall and access shaft for the London Liverpool Street Crossrail (CRL) station. The ‘ground floor’ of the site is also the roof of Moorgate Station and is a composite steel beam and RC slab deck supported on a series of piled columns known as the retained deck (RD).

Architects impression showing the two LU lines and the Crossrail running tunnels – piling through this lot was literally threading the needle. 

The steel superstructure spans 55m across the retained deck between two parallel rows of giant piles (the largest of which is 2.5m diameter and 57m long). Each pair of piles supports a 10-storey arch and truss to span the gap with a number of temporary works stages to ensure stability of the structure through to completion.

Truss and arch system with cantilevered East Face Truss

I have been assigned to manage the superstructure concrete package, starting with the pile heads, steel base plates and mezzanine deck, moving onto deck and beam work at every level.

All very good but there is one small problem… we aren’t allowed on site.

The early works contractor (Mace), failed to secure the second-stage (i.e. superstructure) contract and so are vacating the site – slowly. Until they do so (the end of this week) we are sitting in an office down the road with only the high camera for site updates. To complicate this, the D&B contract between McAlpine’s (my lot) and the client (Land Securities) has yet to be signed so when works do start on Monday no one will be under contract to anyone else.

The closest any one can get to site until Monday

This enforced exile has given me ample opportunity to read into my works package and spend time with the QS team to fully understand their processes. I have also already experienced almost every type of contractual arrangement I can recall from PPO and PCM – we have PCSA, Letters of Intent, Contract Administrators Instructions, Frameworks and, hopefully soon, a JCT D&B contract.

Come Monday I can sharpen my stadia rod and don my finest hi-vis vest for a bit of Engineers in the Wild excitement on site. Until then I’m back to my bills and quotes, spreadsheets and delivery notes.

John I remember you telling us in Phase 1 you are always amazed at the scale of temp works that are involved in creating the permanent works. For my project the team are spending AUS $2.5M on establishing and running a precast yard. Below are some pictures from the trial erection currently underway in China of the pre-cast bridge segment forms. The forms are designed to be adjustable to accommodate the curves with the new segment cast next to the previous one to ensure continuity.

The average segment will be 11m long, 2m wide and 4.7m high. I’m not sure what the size the forms are but you can get an idea of their scale from the size of the people in the photographs. I’ll post more detail when they are installed on site and I understand more.