Martha Terrace, Wick, Caithness

Tel: 01955 604664Fax: 01955 606989 Mob: 07770 807550

Braehour Bridge – Forest Enterprise Scotland

Project: Construction of 44t Concrete Road Bridge
Client:
Partnership between Forest Enterprise Scotland and Summerleaze Ltd

Location:

The bridge is located on a tributary of the River Thurso on a forest road serving Braehour and Strathmore Forest.

Map

Background:

A partnership between Forest Enterprise Scotland (FES) and Summerleaze Ltd (SZL) received funding from the Scottish Timber Transport Fund (STTF) to construct an in-forest haul route linking Strathmore and Braehour forests to remove timber trucks travelling over a fragile section of the Westerdale – Strathmore Public Road. The road required a bridge crossing over an environmentally sensitive tributary of the River Thurso.

The project hopes to encourage other forest owners west of Strathmore to use this road and in anticipation raised the specification of the road and the bridge. The structure is a reinforced concrete bridge with a 4.5 m span and 4.1 m deck width. The bridge was designed by the FES structural engineer to provide a low maintenance structure with a wide deck to accommodate the wide timber harvesting vehicles. The large waterway area is designed to accommodate the spate flows which regularly occur in this catchment area.

The partnership appointed GMR Henderson ltd as the sub-contractor to deliver the construction of the bridge.

Project:

Prior to the work commencing all the staff involved with the project received a tool box talk to ensure that all understood the scope of the works, agreed the risk assessments and the emergency procedures should an incident occur. Protection measures were then erected to protect the watercourse and surrounding area.

The project proceeded as per the programme under the personal supervision of Derry Ross. Derry brought a wealth of experience in concrete construction to this project and ensured that the FES specification was achieved and GMR Henderson’s high quality standards maintained. To speed up the construction time and ensure that the dimensional tolerances achieved the timber shutters were prepared in GMR Henderson’s work shop and then brought onto site when required.

The in-house excavator operator carefully prepared the site removing the unsuitable and storing the top soil and vegetation to be reused for landscaping around the bridge after completion.

The abutment shutters erected with excellent attention to safety detail and accuracy. The concrete pours proceeded smoothly with no incidents utilising concrete prepared on site using a volumetric concrete mixing truck. The concrete finish produced met the high standard required this structure.

To ensure that the deck met the dimensional tolerances required a proprietary shutter was hired and installed. Again a volumetric concrete truck was utilised to produce the required concrete mix (RC 28/35) for the deck and finished to the required tolerances by the GMR team.

Throughout the project concrete test cubes taken at each pour and all met or exceeded the design strength stipulated.

The timber hand rails were fabricated on site and installed with care and attention to detail from timber sourced from FSC certified woodland

Results:

The project was completed to time and budget with no safety or environmental incidents. The finished structure met the required specification with good attention to detail and is an asset to FES. It is anticipated that significant volumes of timber will cross this bridge and 40,000 tonnes had crossed the bridge since it’s opening in September 2013 up to March 2015 with no incidents or maintenance required.

Both FES and SZl are very pleased with the quality of the structure and in the safe and timeous manner of its construction.

Photographs: