Award-winning TerraTrel Ro-Ro ramp for Second Severn Crossing
This Reinforced Earth® wire mesh facing system earned its first British Construction Industry Award for its innovative use in the construction of the Second Severn Crossing. New Civil Engineer commented, “It is unusual for a temporary structure to be entered for an award, but the Geoquest’s TerraTrel Ro-Ro ramp is no ordinary structure. This is a creative, bold, and cost-effective solution.”
The project involved the transportation of massive caissons for the bridge piers, which were cast on land and moved 500 meters to a sea-going barge. These caissons, each weighing up to 2,600 tons, were then placed on the seabed and filled with concrete. This operation required the construction of a 12-meter-high jetty ramp to facilitate the movement of the caissons on crawlers. These were the heaviest loads ever transported in Europe and needed a robust, reliable structure to meet the estuary’s challenging 15-meter tidal range.
The TerraTrel ramp was selected as the safest, most economical, and environmentally friendly solution. Built directly on the estuary floor, it minimised damage to the seabed while delivering exceptional strength and stability. The structure featured a 76° slope face leading to a vertical jetty face, with crawler tracks passing within just one meter of the ramp’s edge. The ramp used 25mm to 200mm quarry rock backfill reinforced with high-adherence strips up to 10 meters long. Construction of the 4,000 m² ramp was completed in just three months in the autumn of 1992.
The first caisson was transported in January 1993, and a total of 37 caissons of various sizes were successfully moved during the project. Despite an overnight storm that caused a large sea barge to collide with the ramp, resulting in damage to 20 m² of facing and ruptured reinforcing strips, the ramp was operational within 24 hours following swift repairs recommended by Geoquest engineers.
This project showcases the strength, resilience, and cost-effectiveness of the TerraTrel system, demonstrating its ability to perform under extreme loads and challenging environmental conditions. The innovation and reliability of this structure earned it recognition as an award-winning engineering solution.
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