Carrying the A939, a weathering steel bridge provides a new crossing of the River Gairn on the important north-south route between Deeside and Speyside
Replacing an overused Category A-listed structure built in 1749, the Gairnshiel Jubilee Bridge is named to commemorate Queen Elizabeth II’s Platinum Jubilee in 2022 – the year in which construction began.
Accommodating two traffic lanes and able to carry heavy goods vehicles, the new bridge protects the nearby historic crossing from further vehicle strikes and allows it to be retained for future use.
The project called for a modern, resilient replacement bridge that would improve access
without overwhelming its sensitive Highland setting. Six possible alignments were explored, balancing road length, land boundaries, topography, flood risk and the relationship with the existing bridge.
Award: Gairnshiel Jubilee Bridge
- Architect: Moxon Architects Ltd
- Structural engineer: Arcadis
- Steelwork contractor: J&D Pierce Contracts Ltd
- Main contractor: Wills Bros Civil Engineering Ltd
- Client: Aberdeenshire Council
The selected route runs parallel to its historic neighbour and connects with the road network at a low point in the landscape. River flood levels required a single clear span, while the low highway alignment demanded a shallow structural depth.
Structural steelwork provided the strength and efficiency needed to span 35m, while maintaining a slender profile and carrying full highway loading. Working compositely with the concrete deck, the steel structure delivers the required capacity without creating an unduly deep or visually dominant crossing.
The primary structure comprises bespoke fabricated weathering steel box girders that evolved from an earlier plate-girder proposal. Although unconventional for a bridge of this span, the closed-box solution brought significant benefits for erection, durability and maintenance.
The girders supported the permanent formwork soffit panels and the wet concrete loads during construction, while their enclosed form removed external ledges and reduced areas where water and debris could collect.
“Weathering grade steel was used as it requires little or no maintenance and over time develops a muted russet tone, complementing the colours of the glen and contrasting with the lighter granite above,” says Dan Banks, J&D Pierce Contracts’ business development manager – bridges.
The slender steelwork is paired with precast concrete parapets faced in locally reclaimed granite and coping stones sourced from Aberdeen Harbour.
The granite-faced parapets and wing walls taper into the landscape, echoing the form of the historic crossing without attempting to imitate it.
“This new bridge is located close by to the 18th-century listed stone structure it replaces, and the design thoughtfully responds to its context. The slender, 35m-long weathering steel structure with its ‘recycled’ stone parapets integrates effortlessly into the Highland landscape. Carefully detailed, this bespoke structure is elegant, efficient and designed for minimal ongoing maintenance”
The use of reclaimed granite alongside a durable, fully recyclable steel structure also supports the project’s material-efficiency objectives, combining long-term performance with reduced demand for newly quarried stone for the parapets.
“This was a major infrastructure development that required a partnership between our working services, design teams and the contractors, in order to overcome the challenges of building such a structure at this location,” comments Councillor Alan Turner, chair of the Aberdeenshire Council Infrastructure Services Committee.
The remote site, reached by single-track roads, imposed strict limits on deliveries, storage and onsite fabrication.
Too large to be transported as one piece, the bridge was delivered in two sections and then precisely aligned and welded together to create the finished span. The work required careful control of geometry and workmanship to maintain the structural integrity and clean appearance of the bespoke box girders.
Produced by BCSA and Steel for Life in association with Construction Management.
