Maccaferri’s Green Terramesh system has been employed in the creation of an embankment to support a temporary bridge on the Aberdeen Western Peripheral Route.
The longest new road project currently being undertaken in the UK is the new ring road around Aberdeen Western Peripheral Route (AWPR).
The project will involve realigning the A96 to avoid a low headroom bridge which has been the cause of congestion and bridge strikes.
As the A96 is an extremely busy local and commuter road, several options were considered to minimise disruption. The final decision was taken to install a temporary bridge over the road. This bridge will allow construction wagons to cross carriage traffic without disturbing road users.
The bridge undertaken by Aberdeen Western Peripheral Route and Balmedie-Tipperty construction works, which was sub- contracted to Balfour Beatty, began late last year and is expected to stay in place for 6 months until building works are completed.
Working with Balfour Beatty, Maccaferri designed a Green Terramesh embankment to support the temporary bridge.
The units consist of pre-fabricated of double twisted wire mesh units (made from heavily galvanized GalMac and polymer coated steel wire) lined with an erosion control blanket and stiffened with a welded mesh panel. As all components are factory fitted, Green Terramesh is more rapid to install than competitor reinforced soil systems. The unit is simply erected on site, the bracing angles support the face at the designated angle without the need for any external formwork or shuttering. Structural backfill is placed upon the soil reinforcement geogrids. As a result over 600m2 of Green Terramesh was installed in just 4 weeks to form the supporting embankments.
There is an approximately 50kN/linm of horizontal forces imposed on the bankseat caused by traffic breaking on the bridge which needed to be separately addressed. A traditional shear key setup would potentially cause deformation in the reinforced soil structure therefore Maccaferri proposed to utilise their high strength Paralink 350 geogrid to act as a frictional anchorage by casting it into the bankseat and compacting an average of 1.5m of granular fill above. Paralink was also installed directly beneath the bankseat to reduce the potential of any deformation caused by the 100kPa vertical bankseat load and 240kPa crane load.
Paralink is an ultra-strong reinforcement geogrid which consists of parallel strips of high strength Paraweb synthetic fibres encased in a tough and durable polymeric sheath produced by Maccaferri company Linear Composites Ltd.
Watch the bridge being erected in fast motion on a video created by AWPR.
For further information about this project, please contact us.