The Woodhouse Tunnel is suffering severe concrete damage and deterioration as a result of prolonged, extensive chloride ingress from winter de-icing salts.
The damage is so severe that the structural capacity of components is now being affected.
The tunnel needs extensive concrete repairs to the roof and walls of both tunnel bores and strengthening for vehicle impact loading to the area of the tunnel supporting the Leeds General Infirmary buildings.
Strengthening work for vehicle impact loading and protection to the rest of the tunnel is also required.
The 23 month job will be split into two phases. First the successful contractor will be asked to provide advice on how the works can be delivered most effectively.
Construction works proper will then start and last 20 months.