Upgrade of London Underground Bridge D70: Chiswick Park

Abstract

Bridge D70 is a single-span steel plate girder bridge dating from the 1930s. It carries four tracks of London Underground's District and Piccadilly lines, the latter being one of the capital's main rail links to Heathrow Airport. Situated next to Chiswick Park tube station the bridge spans over a busy traffic route. This paper describes the project as part of the public private partnership contract to modernise the London Underground system. The paper describes the reasons why upgrading of the existing structure was chosen over complete renewal. The primary aims during the works were to avoid unnecessary closure of the railway line, to minimise the risk of unplanned disruption and to protect the safety of the travelling public. The paper explains the method of construction and the constraints on carrying out work to an existing bridge while in service to passenger trains. This required the extensive use of temporary works to support the tracks. It also describes the challenges in refurbishing a bridge in a residential area in terms of access to the site and reducing the environmental impact of the work. The designer and project manager was Metronet Rail SSL, and the main contractor was Edmund Nuttall (BAM Nuttall).