- Project: The restoration and repair of the historic Adam Bridge
- Principal Contractor: Smith & Garratt
- Client: Marchmont Estate
- Project Lead: Grant Williamson, Area Sales Manager
- Key Benefit: UniShore® provided support to the bridge structure allowing the extensive repair works to be undertaken while securing the remaining structure.
Introduction
Smith & Garratt reached out to MGF for support with the restoration requirements after seeing the success of a previous project.
The Marchmont Estate is home to the historic stone arched Adam Bridge, which spans Swardon Burn and received a Grade B listing by Historic Environment Scotland.
Built in the mid 1700’s, the bridge has deteriorated due to the effects of weathering and time.
The contract with MGF helped to repair Adam Bridge and restore the historic stonework, allowing it to continue servicing the Marchmont Estate.
The Solution
The restoration required the removal of the road and overburden on the arch to facilitate the extensive repairs to the bridge and its parapet walls.
The stone arch structure and abutment walls needed to be propped both around the arch and across the springing points to prevent movement while the bridge deck was removed and works undertaken.
The river bed was checked and found to be rock suitable for use as a foundation for the system avoiding works in the river. A UniShore medium duty spreader beam was used to support vertical and horizontal components to form a base for the arch support.
The supports in the river were minimised to avoid obstruction to the water flow as Swarton Burn regularly floods during wetter periods. Allowances were made for potential impacts on the props from debris in the flooded river.
Horizontal propping to the arch springing point was provided by adding screw jacks to the horizontal top member of the frame. This prevented the abutment walls moving together and “bursting” the arch when the road deck and fill were removed as part of the repair works.
UniShore light props were installed with header beams following the line of the arch to provide support and prevent any movement of the stones during the works to the bridge deck.
“We are pleased with the way the structure went together quickly and safely, allowing us to progress the works”
Managing Director of Smith & Garratt, Hugh Garratt
The Verdict
Working closely with our client, the MGF structural support team created a solution that met a series of needs at Adam Bridge.
The combination of UniShore light and medium sections created a solution that minimises interruption to the river flow and required no works on the river bed.
Standard UniShore light duty components provided the flexibility to create the arch support while the low component weights reduced risk and programme time while being installed under the bridge allowing work to restore this historic structure to continue.
