Requirements
The Ponfeigh Bridge gave access to West Douglas Water and Sandilands though due to bridge damage, South Lanarkshire Council had to issue an emergency closure.
The Bailey structure overs-pans the existing masonry arch, however in June 2016 the longitudinal downstream truss failed along its bottom member causing the steel structure to sit down onto the arch at this location.
The recent failure of an existing high pressure water main caused the adjoining wing wall to the north east side of the bridge to be undermined and cause it to partially collapse.
Approach
Following further deterioration of the bridge abutment, Covanburn were approached by the Council through their structures Framework, to determine the best scheme to demolish the bridge safely and within SEPA guidelines.
The Bailey Bridge had to be dismantled and broken down into smaller sections, due to the weight of the bridge and issues with the available working area. Following the removal of the steel structure, the stone arches were removed one at a time, in order that the river could be diverted through the remaining arch.
We presented several options to the Council using 3D modelling, and the safest and most environmentally acceptable scheme was chosen. This involved diverting the river through successive arches.
Result
The existing abutments have been fully removed and the surrounding land reinstated. The area is now ready for the construction of the proposed new bridge.