Highbury Corner bridge in central London was one of the eight highest priority structures on Transport for London’s (TfL) road network that were identified as needing intervention and investment. It had to be replaced to reduce the need for disruptive emergency closures in the future. Despite unusual complexities and constraints, full deck replacement took place with only a 20-day road closure and a 195hr rail possession.
• Unusual complexities and constraints
• Part of the Structures and Tunnels Investment Portfolio (STIP)
• A partnership approach
• Ramboll’s involvement and responsibility
• Advance works - Demolition of the station forecourt surface
• Key phases of the remaining works
• Essential works road/rail works led to beneficial outcomes for cyclists and pedestrians
The bridge arrangement is unusual. Originally built around 1850, it needed to be replaced due to its poor condition. It is formed of two spans in ‘V’ formation and has become an integral part of the A1 road and station forecourt. The bridge cannot be seen at street level because Highbury & Islington Station and a Marie Curie Charity Shop are built on it.
Despite its modest twin spans (approx. 8m), the bridge is very wide. It carries the A1 road over two sets of overground tracks: the North London Line, which is overhead electrified; and the East London Line, which is 3rd rail electrified. It is owned partly by TfL and partly by Network Rail.
Further project constraints involved the continued operation of the Highbury & Islington Station, and accommodation of the concurrent works going on below to replace the North London Line.
TfL appointed Ramboll and Parsons Brinckerhoff in a joint venture (RPB) to begin design work across the STIP portfolio to improve London's roads and public spaces. The STIP part of the Road Modernisation Plan will cost around £250m to deliver overall, which includes £36m investment to rebuild Highbury Corner Bridge.
This project falls within Work Package 1 of STIP and was delivered in partnership with TfL, Hochtief UK (HUK), Ramboll and Parsons Brinckerhoff joint venture (RPB), and Skanska.
RPB’s role was Permanent works designer, and RPB engineers attending the site did so in an advisory role. The responsibilities of RPB staff included as required:
- Assisting site staff in interpreting permanent works design details
- Commenting on constructed permanent works
- Commenting on the possible implications of events on site on the permanent works
- RPB was instructed by Hochtief UK (HUK) to provide on-site support during the Highbury Corner Bridge demolition and reconstruction works over the Christmas 2017 period.
Ramboll was responsible for the preliminary and detailed design stages of the two-span highway bridge deck replacement scheme over railway, including Public Realm Improvements and the demolition of a Post Office on the bridge.
We also provided independent checking of Highbury Corner Bridge. Designs were comprehensively examined to ensure compliance with the requirements of the TfL and Network Rail technical approval documents. This included checks associated with highway and utilities structures.
As part of the works to replace Highbury Corner Bridge, the first section of the bridge above the Overground East London Line was successfully demolished and replaced between 25 July and 10 August 2016.
Part of the old bridge outside the station entrance was demolished and replaced with new steel structures, some of which included pre-installed space for utility service pipes. Ducting for power and telecommunications services was also installed before new concrete was laid and waterproofing work carried out. New tarmac was laid in front of the station to allow part of the forecourt to be reopened to the public.
Watch the demolition here
Following the advance works, the second phase of replacement (North London Line) took place in April 2017.
Works involved relocation of gas, water, electricity and telecommunication pipes and cables, and complete bridge reconstruction, which included:
- Installation of the new steel bridge deck
- Steel work
- Overhead line equipment works
- Concrete deck installation
- Finishing works
Highbury Corner is a key junction and roundabout in London and these works were essential to ensure that it can continue to remain usable and safe for years to come. Replacement of this congested Victorian bridge opened opportunities for redesigning the Highbury Corner gyratory to make it safer for pedestrians and cyclists. In 2015 the old post office outside Highbury and Islington station was demolished to remove a dangerous pinch point that put pedestrians too close to traffic. A new cycle route and public spaces will make the roundabout safer and more convenient for cyclists and pedestrians in the future.