Multiple handover stages at London Bridge
Due to the operational constraints, the London Bridge Station Redevelopment was constructed in stages, meaning there were effectively a series of new stations and infrastructure configurations before the final layout was delivered.
Each stage comprised all aspects of construction and disciplines, without a single discipline being ‘practically complete’ at the end of a stage; therefore, all disciplines could be deemed as in an ‘interim’ condition at the end of each stage.
The first logic applied to the transition into maintenance and hand back, was one that corresponded with the completion of the construction stages, where it was envisaged that a set of deliverables could be provided to facilitate hand back into maintenance.
This would mean that at any one time, part of the station (that part in construction) would be under the maintenance and control of the designated Principal Contractor whilst other areas would be maintained by the Route’s Maintenance Organisation. The operational areas of the station would also fall into the Route’s Station Operation’s Team.
The table (figure 1 in the full document PDF below) broadly outlines the original approach.
During the course of the project, it was identified that there were some practical issues with transitioning back to maintenance in this way, for example:
- Sub-optimal arrangement due to the partial maintenance responsibility for incomplete systems and assets. (Both for the project and the operational maintenance teams)
- Sub-optimal arrangement due to the increased administrative burden of producing and revising documentation many times before final iteration
- Mis-alignment to the logical sequence of construction tasks and disciplines
- Unclear safety and management responsibilities with interface arrangements and boundaries subject to regular changes due to construction progress
- Numerous organisations working on and in the vicinity of operational assets increasing the risk of issues arising on the operational railway
- Costs in terms of Route Asset Management (RAM) review time as the whole deliverable containing all disciplines would be presented at every stage, whereas each RAM would have a natural preference to be presented with their specific discipline.
It was therefore agreed between the London Bridge Station Redevelopment team and the Route Asset Management team that an improved approach would be to progressively hand back the station in the order of construction sequence and importantly, the disciplines.
The advantage of this approach would be that each RAM discipline (i.e. Track, Structures, Buildings) would have a defined list of packages, that could be gradually built up, reviewed and accepted as assurance and records became available in parallel with the construction.
Under the new approach, the official ‘handback’ of the infrastructure to maintenance could therefore only be undertaken when the construction work was fully finished, defects were remedied and assurance documentation was delivered and accepted. This meant that, in the interim, the new infrastructure was ‘Entered into Service’ and the maintenance responsibility stayed with the Principal Contractor.
However, assurance documentation would be built up in parallel ensuring that there was full visibility of the progress throughout the project life-cycle and indeed whole disciplines may be ‘accepted in principle’.
The main advantages of the approach were:
- Logical alignment to the construction sequence, meaning the first element of construction completed would be the first to be presented for the RAM to sign off*, in accordance with the sub-contractors’ demobilisation and final accounting.
- Progressive assurance built up with acceptance in principle de-risked the handback process at the end
- Increased engagement with the maintainer throughout the progressive assurance process.
*For example: under the ‘by stage’ strategy approach – the RAM team would receive many layers of construction in a single submission, but each submission would be incomplete as a whole asset group.
Under the progressive approach, the RAM (Structures) would receive packs such as ‘Piles & RC Buttress Walls’, ‘Pile Caps, Columns & Cross Heads’, ‘Bridge Decks’, the RAM (Buildings) would receive packs such as ‘Station Accommodation’, ‘Platforms’, ‘MEP System’ as whole and complete packs for the entire station.
Circa 40 no. separate package elements were identified, an extract from the London Bridge Station Redevelopment Programme AMP breakdown is shown in figure 2 of the full PDF document below.
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