Our work, including both soil stabilisation and retaining walls, will help provide better access to Mamelodi in Gauteng, South Africa
Road K54 is a new development in Gauteng South Africa which entails the construction of around seven kilometers of road, most of which is constructed on soil with an extremely low bearing capacity. We were asked to assist with technical design, and subsequently specified segments of basal reinforcement in the form of Paralink, road stabilization using MacTex W2, and four retaining walls using our Terramesh and Green Terramesh Systems.
Road K54 is a 7km road development aimed at providing better access to Mamelodi township in Gauteng, South Africa. The Gauteng Department of Roads & Transport (GauTrans) appointed GMH Consulting as the main consultant, with GMH later requesting the services of Maccaferri Africa in terms of technical knowledge and design work. The project started at the beginning of 2018 and is forecast to be complete in late 2020.
The challenge with this build is where the road crosses two railroads, with the use of 9m high concrete bridges and roadfill, whilst being founded on a mixture of shale, sand and clay strata with CBR values ranging between 1.3 and 3.4 in certain areas. The worst case of poor founding soil exists at the interface between a 2.5m – 3m deep clay layer and a 9m high embankment – the challenge here is to create a stable enough base for safe construction and every-day use, whilst trying to reduce long term embankment settlement – a necessary alignment consideration when considering that the bridges will be founded on piles and are expected to have minimal settlement.
We tackled the poor foundation challenges using Paralink under all segments of road higher than 3.5m; with most road segments under 3.5m high having a road stabilization layer including a pioneer layer underpinned by our MacTex W2 reinforcing geotextile.
The project also includes four separate retaining walls, comprising a total of 3,020m² (620lm) of our Green Terramesh system, and 840m² (200lm) of our Terramesh system. These were implemented to replace the originally planned 8m high mass gravity gabion walls, which would have required an inordinate amount of gabion rock to construct.
We remain committed to engineering a better solution – and will remain an integral part of the K54 project until its completion in 2020.