London 2012 Central Park Bridge

Olympic Delivery Authority

Two short span bridges at the centre of the Olympic Park that will form a key connection between the Olympic Stadium, Aquatics Centre and Handball Arena. After the Games, temporary structures are removed to expose Carpenters Lock on the river Lea.

Summary

We congratulate the Olympic Delivery Authority for holding a design competition for this engaging project which we believe has resulted in an exemplary scheme. We support the sophisticated concept and its translation into a simple and elegant design proposition. We congratulate the design team for thinking through how the bridge will be used and made from the first. The level of integrated design thinking demonstrated lives up to the ODA's Design Strategy and should be seen as an exemplary methodology to inform the emerging approach to the Park as a whole.

We admire the rigour with which the design team have tackled this complex project, and are confident that the following comments and concerns have either already been considered or will be addressed in the resolution of the design detailing. We think the design team should be retained to ensure that the quality of the project is safeguarded through the process of testing and value-engineering to completion.

Site character and function

We welcome the design response to the difficult site context that reveals hidden and historic aspects of the Lower Lea Valley. We applaud the design team for anticipating the Legacy landscape character by forming the two bowls as part of the enabling works and budget for the Olympic bridges. This scheme successfully characterises the sectional nature of the site and fuses Olympics and Legacy in one convincing design proposition, that we think works equally well in either mode.

Given the nature of the site as the potential focal point of activity for the whole area, it will be important to ensure that the bridges continue to inform and be informed by the evolving masterplan proposals for the landscape function and character of the Legacy Parklands. The intensive Legacy occupation of the site will need to be anticipated as a fundamental part of the current proposition to ensure that the design does not preclude possible future use patterns.

First, we think the way that people will move between the upper concourse and lower water levels is critical. We encourage the design team to make the most of the functionality and expression of the landscape bowls. They should be confident that the bowls, as currently proposed, do not inhibit people's conscious or subconscious use of these spaces in Legacy. Second, we think this project should set in place a strategy that anticipates how the lower level might be used if and when Carpenters Lock is restored to working order in future; this should set the standard for other schemes in the immediate area. It should be possible for the relevant agencies to state what the impacts of a working lock will be.

Details and materials

In order to safeguard the strong and beautiful form proposed for this footbridge and achieve the fine finish required, it is essential that the design team retains control of the construction tolerances and precise details. To avoid the risk of key details and materials being substituted by inferior versions at a later date, we also urge the planning authority to condition the precise nature of the bridges, including the stainless steel specification.

The quality of the highly reflective keel surface will be central to the success of this potentially exquisite object. The finish, detailed junctions and performance of the stainless steel cladding will therefore need to be carefully considered to ensure that it performs as intended visually. For example, as currently proposed the illustrations suggest a rippled rather than the desired highly polished effect. We welcome the proposal to produce mock-ups to anticipate likely problems in the material specification, coating and constructional details. In addition to thoroughly testing the performance of the stainless steel cladding against the dark and low-lying river conditions, we encourage the design team to consult cleaning and maintenance contractors on what measures would be required to maintain a highly polished stainless steel surface in this context. The local authority should assure itself that the steel chosen is of a high enough grade to perform as intended throughout the 120 year life span without interim polishing, given the susceptibility to rusting as a result of iron contamination on site.

We note that the intersection of the floating reflective keel and the heavy concrete abutments appears to have been well resolved.

Lighting

We acknowledge the thought that has gone into lighting the bridges both during and after the Games. However, while we welcome the concept of the ‘bones’ of light on the keel, unless the difficult junctions with the stainless steel skin are carefully resolved in detail, there is a danger that their vertical emphasis will weaken the dynamic horizontality of the elegant form. Equally, while the proposition looks joyful and celebratory in the images presented, we are not convinced that throwing light up into the air during the Olympics is a worthwhile investment. We urge the design team to consider alternative options to achieve a memorable lighting effect.  

Bridge surface

In order to realise the potential for the vast space of the Olympic bridge to become an extraordinary spectacle, it is essential that the design team carefully control the blend, colour balance and costs of the temporary rubber surface; gloomy confetti is unlikely to produce the celebratory effect desired. The design team should work closely with Sarah Weir and to ensure the proposals are aligned with the ODA’s arts and culture strategy. 

Finally, we would like to draw LOCOG's attention at this stage to the potential of signage and other visual clutter to undermine the clarity of the bridge concept in Legacy. This should be thought through to avoid undermining the elegant design.