North Bridge carries the A7 over Waverley Station providing a vital transport link connecting the Old and New Towns of Edinburgh. The bridge comprises three spans, each of approximately 53m. Each span has six steel main arch girders with a concrete deck, masonry piers and abutments, and a decorative cast iron façade.
In March 2018, the Council agreed to invest in refurbishing the structure after inspections between 2014 and 2017 identified various defects. A complex scaffolding was installed to gain access to areas not accessed for 125 years. As work progressed, it became clear that more repairs would be required than initially anticipated. We are addressing these as part of a major project with various technical challenges.
We are trying to keep disruption to the public to a minimum as the works take place beneath the bridge and on top of the deck. The parapets next to the footpaths are being painted and need temporary hoardings. Pedestrian access is being maintained as best as possible. These works present an opportunity to use modern engineering techniques, technology and understanding. This should ensure that the bridge remains fit to serve future generations.
Changes
The works to North Bridge include:
- grit blast and repaint all structural steelwork, last renovated in 1933
- assessment led repairs to structural steelwork and cast-iron springer bearings
- condition led structural steelwork repairs and cast-iron springer bearing refurbishment
- refurbish historic cast iron bridge façades including the redesign of façade fixings. This will allow for sectional movement and easier future repairs
- grit blast, repair, seal repaint parapets; assess and repair internal vehicle restraint system
- repairs to the topside, underside and full depth replacement in sections of the bridge's concrete deck. This includes a carbon fibre reinforced plastic wrap and anti-carbonation coating for the deck’s soffit
- install cathodic protection and structural health monitoring systems to the reinforced concrete deck
- repair and improve the footway paving and underdrainage
- new waterproof membrane to renovated bridge deck
- public realm improvements including new lighting, bus shelters, and carriageway resurfacing
- improve bridge drainage systems and drainage network tie-ins
- replace steel secondary structures over the abutments and piers with reinforced concrete slabs
- remove all redundant utility pipes and ducts and rationalise those services that remain
- replace the expansion joints with allowance for expansion in sections not originally considered
- repair and repoint masonry in areas most susceptible to deterioration
- restore and repair the King's Own Scottish Borderers War Memorial
- install permanent platforms to improve access provisions for future inspection and minor maintenance
- all temporary scaffolding required to access the structure.
Benefits
The benefits of refurbishing the North Bridge include:
- restore and maintain the historic and vital link for current and future generations. Improve access provisions for future maintenance
- community benefits which are an essential part of the project delivery. One being education via engagement with local schools and universities
- opportunities for placements and collaborations with local community groups, charities and artists
- career support for young people, ex-offenders and people with disabilities Fundraising and volunteering for local charities as part of the project’s social outreach programme.
Timetable
The work is now expected to be completed winter 2025. This delay was partly due to Covid-19 measures and the additional repairs assessed since gaining full access to the structure. This access uncovered significantly more deterioration than first anticipated and the complexity of bringing a Victorian structure up to 21st Century standards, without compromising it’s historic integrity, has proven challenging, technically and logistically.
History of the bridge
The North Bridge was constructed over the period 1894-97 by Sir William Arrol. He was also the contractor responsible for the construction of the Forth Rail Bridge.
The last major refurbishment works were undertaken in 1933. In the early 1990's the decorative facings were painted and new parapets were installed with decorative covers of spheroidal cast iron.
The bridge is category A designated, situated in the Edinburgh World Heritage Site. It provides a key north-south link through the city.