- Environment & Infrastructure
- Strategic consulting
- Specialist consulting
- The Living City
- Happold Consulting
Stratford Town City Link was a proposal for a new state of the art pedestrian bridge over a railway that links Stratford station in east London to a new shopping complex developed by Westfield.
The 12m bridge width is dictated by predicted crowd flows of up to 80,000 people per hour during the 2012 Olympic Games. It features a full height glazed façade along each side, providing smooth edge containment and an open structure without diagonals provides suitable protection against falling objects without detriment to the people’s experience of bridge. The structure is curved and, to provide further interest and a sense of openness, the inner truss is warped outwards at the central pier. Architectural and functional lighting will be incorporated into the framing that accentuates the rhythm of verticals across the structure.
Client: Westfield Shopping Towns
Architect: Knight Architects
Buro Happold services: conceptual design, scheme design, technical approval, planning, detailed design, construction supervision
The main challenge was to provide a high quality pedestrian area connecting the proposed Stratford City Development with the existing facilities. The bridge also had to be designed to accommodate the anticipated volume of people going in/out of the Olympic Park.
With the two areas being served by a major railway corridor at Stratford Regional Station the bridge must be suited for its railway environment.
A fundamental complication in the construction of the bridge was a lack of assembly area on the station side and only a very limited footprint within the Stratford City development. There were also no suitable locations within a reasonable radius for heavy cranes to be located.
Due to the limitations of the site, an innovative methodology was adopted whereby the bridge would be assembled in sections and launched incrementally in three stages towards its final location.
The structure was built fabricated from weathering steel, which, due to its stable rust layer, requires no painting. This has significant maintenance benefits. The use of weathering steel offers great potential benefits in terms of durability, however it requires skilful detailing. It also provides a virtually maintenance free structure, forming a dark brown patina over time, giving the bridge a pleasing natural appearance.
Due to the positions and levels of the available area the bridge had to be curved in both plan and elevation. Its architectural form requires that the inner girder has a distinct twist so that it leans out and varies in height along its length.
The bold decision to combine the use of weathering steel for the structure with a high quality glazed façade brings a sophisticated urban appearance and makes it unique among architectural footbridges. At 130m long and weighing 1600 tonnes, it is thought to be the largest single footbridge structure fabricated from weathering steel.
By launching the preassembled structure in increments construction activity in the railway environment is minimised and, as a result, the final costs for the whole project are reduced.
The materials selected maximise durability and minimise maintenance of the bridge, which is an important consideration given its location above a busy railway. Its design was also driven by the desire to minimise construction time and impact.
To the public, the bridge brings significant local benefits in terms of connectivity. The project has required close cooperation between the client, designers, main contractor and steel fabricator to deliver a complex structure within a tight timescale. It is a tribute to the team that the project was completed on time and within budget following successful installation using the incremental launch.