The biggest redevelopment of its kind in Western Europe, London Bridge has been crucial to Network Rail’s Thameslink Programme that will transform north-south travel through London.

London Bridge is busy. Platform 6 was the most used in the country and in total more than 56m people a year stop or pass through the station to Cannon Street and Charing Cross.

The huge, street level concourse is the largest in the United Kingdom, and is roughly the size of the pitch at Wembley Stadium. Overall, the project has created two-thirds more space for passengers, enabling almost twice as many passengers to use Britain’s fourth busiest station every day.

A redevelopment of this size has provided a number of construction and civil engineering challenges.

Open-heart surgery

The first and most important aspect has been to keep an important transport hub open for business while prioritising the safety of passengers around a live construction site, which was bounded on all sides with limited working space outside. In the London Bridge office we described the project process as “performing open-heart surgery on a patient that is jogging”.

London Bridge also differs from other major London stations like Waterloo and Euston as it acts as both a terminus and a ‘through station’ to central London. Increasing capacity has necessitated changing the station’s original layout of nine terminating and six through platforms to six terminating platforms and nine that are through, enabling more journeys further in and out of the city centre.

Finally, as an important infrastructure upgrade it also came with unmovable deadlines – which have been met on time. And our ability to meet these challenges has been due to a complex staging process and management of the risks surrounding design and construction.

The staging involved demolishing the old platforms and a proportion of arches below the platforms and then progressively reconfiguring the tracks to construct the new station in nine stages, each stage of which must come into service before the next stage can commence. Effectively, each stage becomes an enabling stage for the following one.

One benefit of the extended and phased nature of the project is that it has been possible to take learning from earlier in the construction process into later design. This means our designs were completed early in the construction process, which reduced the risk of delayed construction.

Collaboration in action

Where the project has excelled is in its collaboration. WSP the lead consultant in a joint venture with Arcadis, working for main contractor Costain and Network Rail, with a number of sub-consultants forming part of the team, including Grimshaw.

Together, we were co-located in one office next to the station, with the design team peaking at more than 240 full-time equivalent staff. I have worked in other co-located offices before, but this has been to a higher level of engagement than any other project I have been involved in and we have adhered to the BS 11000 collaboration standard throughout.

From the outset, Network Rail has wanted to improve efficiency in the design and construction process by reducing the amount of ‘man-marking’ from the client team, which has meant the project team was formed of individuals from the key organisations all working under the direction of Costain.

Again, this has engendered a very close collaborative attitude across the whole project, with the assurance, operations and construction specialists embedded within the design team to ensure their input is provided at the most appropriate time and that they also ‘own’ the design.

Historic value prioritised

The station is of undoubted historic importance to the UK’s railway, with the first section of the station being constructed in 1836 and following developments taking place in a number of stages up to mid-1890.

Throughout the station original Victorian features have been sympathetically incorporated within the final design where possible. This has necessitated detailed condition surveys both from conservation and structural perspectives, and careful cleaning and repair specifications agreed with relevant authorities.

While the different eras of development created something of a labyrinth underneath the platforms, the new design pays homage to its Victorian roots, with quadripartite arches lining increased retail and leisure space, keeping the aesthetics while enhancing London Bridge as a destination in itself.

WSP has also been involved in the wider London Bridge Quarter redevelopment since working as the engineers for the neighbouring Shard and Place (now called the News Building). The station’s completion will accelerate further development opportunities, particularly to the south of the station, which will become accessible to the riverfront via a free walkway through the now pedestrianised Stainer Street.

As London Bridge officially opens today, it’s very exciting to be able to see the results of many years of hard work by the whole project team.

Adrian Tooth, Design Director at WSP