Bridging the gap at Sundays Hill
Gavin and Doherty Geosolutions (GDG) has recently completed the design of an interesting reinforced earth wall solution for an 11m high bridge abutment. The technical solution comprised Macwall sitting over Paralink LTP in Southampton at the new Sundays Hill development.
Maccaferri Construction was appointed by Breheny to build the new Sunday’s Hill bypass in Hampshire. A housing development consortium, which comprises of Bovis Homes, Bloor Homes and Linden Homes and required to build the new bypass from Pylands Lane to Heath House Lane, Bursledon near the M3 – M27 intersection. The project entails reinforcement of the local infrastructure related to the consortium’s new development of 1,350 new homes on the site of a former golf course at Boorley.
The new bypass is 1.1 km in length with a 20m single-span concrete bridge on green land which will open up much-needed housing development in the area. The Macwall for the approaching bridge ramps has a maximum height of 11m for a total length of approx. 100m in length. The MSE abutment walls were designed by specialist geotechnical designer Gavin and Doherty Geosolutions (GDG). The approach embankments to the bridge were done with Macwall BBA. Due to the challenging ground condition and loading involved, the MSE walls were supported by Paralink placed over the piled foundation acting as a load transfer platform.
The Paralink + Macwall solution was also designed to support, as part of the construction works, a crane for moving bridge elements into place. A load of maximum pressure 198kPa was transferred to four steel bearing plates over the designed MSE wall.
The site which is ecologically sensitive had a great deal of work done to preserve the local flora and fauna. The bridge also allows animals to pass through the valley of their natural habitat whilst avoiding traffic.
Works were completed in May 2018 by Maccaferri Construction and the new route is supposed to be opened shortly. Maccaferri and Maccaferri Construction demonstrate another time how value engineering a very challenging and complex project. Project which it was not only demanding from the geotechnical point of view but also from the construction and heath & safety aspects as the MSE wall and the Paralink foundation were installed into very tight spaces.