Refurbishment of structures on the Manchester Metrolink phase 3

The Metrolink phase 3 project in Manchester, UK, has created around 60 km of new tram lines and has incorporated over 380 structures including 160 bridges and tunnels. Nearly 80 bridges were refurbished, repaired or strengthened to provide a low-maintenance system with a minimum 50-year structural design life. The new tram lines have been built on new dedicated alignments and on former railway corridors, reusing existing structures with an age of up to 140 years. Various contractual and technical approaches were taken to address the risk due to structure condition, including risk-sharing arrangements and phased scope determination. Particular issues encountered by the project include: limited information on structure condition; corrosion of metallic structures; scope risk; strategy for repair versus replacement; vehicle incursion risk; determining appropriate specifications; retention of cast-iron structures and modifications to parapets due to electrification. The conclusions include lessons learned for projects dealing with the renewal and upgrade of legacy structures in an affordable manner.