2017
Aberdeen, Scotland
Transport Scotland
AWPR JVC
AWPR JVC
Aberdeen Western Peripheral Route: Temporary Bridge & Reinforced Earth Solution on the A96
View of the Green Terramesh® slope
View of the Green Terramesh® slope
Heavy lifting crane supported by the Green Terramesh® slope
View of the completed works
24m span bridge with bank seats directly over the Green Terramesh®
Challenge
The Aberdeen Western Peripheral Route (AWPR), one of the largest road infrastructure projects in the UK in 2015, required the realignment of the A96 to bypass a low headroom bridge that had caused persistent traffic congestion and frequent vehicle strikes. As the A96 is a major and heavily trafficked route, maintaining traffic flow during construction was a critical requirement.
To minimise disruption to road users, the project team selected a temporary bridge solution. This approach allowed construction vehicles to safely cross over live carriageways without interrupting traffic below. However, the installation of a temporary bridge introduced significant geotechnical and structural challenges.
A temporary works design was required to ensure the stability of steep embankments constructed using 6N fill material. These embankments needed to be built at a 70-degree slope, requiring a reinforced soil solution capable of maintaining stability under demanding conditions. In addition, reinforced fill was required between temporary support frames and the integral bank seat to enable the construction of the bridge deck and parapet beams prior to dismantling the temporary works.
The design also needed to accommodate substantial horizontal and vertical loads, including braking forces from traffic on the temporary bridge and heavy construction loads, while preventing deformation within the reinforced earth structure.
Solution
The temporary bridge, subcontracted to Balfour Beatty, was installed in late 2015 and remained in place for approximately six months, ensuring uninterrupted progress on the AWPR project. Working in collaboration with Balfour Beatty, Maccaferri delivered an innovative reinforced earth solution combining Green Terramesh® and Paralink geogrids.
To construct the 70-degree reinforced soil slopes, over 600 m² of BBA-approved Green Terramesh® units were installed. This system provided a robust, flexible, and efficient method for creating steep, stable embankments suitable for temporary bridge support.
To address the horizontal load of 50 kN/m applied to the bank seat by vehicle braking forces, Maccaferri engineered a solution using high-strength Paralink 350 geogrid. Rather than using a traditional shear key, which could risk deformation in the reinforced soil structure, the Paralink geogrid was cast directly into the bank seat and extended into approximately 1.5 metres of compacted granular fill. This created a frictional anchorage system that effectively resisted horizontal forces while maintaining structural integrity.
Additional layers of Paralink geogrid were installed beneath the bank seat to manage vertical loads, including a 100 kPa backseat load and a 240 kPa crane load. This ensured load distribution and minimised settlement or deformation within the reinforced soil system.
The completed temporary bridge spanned 24 metres and supported construction vehicles carrying loads of up to 80 tonnes. This reinforced earth solution enabled safe, efficient construction while maintaining full traffic flow on the A96, highlighting the effectiveness of geogrid-reinforced soil systems in complex temporary works and bridge support applications.
Used Products
