road users, surrounding communities and affected landowners.
The overall objective was to upgrade the route to a divided freeway standard with a 120 km/h design speed. Access to the N7 will be via grade-separated interchanges only. The route traverses a relatively flat topography with rolling terrain which is typical of the area. A total of 12 bridge structures were constructed for this contract. Nine of these will be new and three will replace existing structures. The design of the bridge structures has largely been dictated by cost, constructability, construction sequencing, road geometry and future geometric requirements as well as hydraulic requirements, where applicable. Full structures reports detailing the structure options and findings were required by SANRAL. There were two river crossings along the project section at the Sout River and at the Swart River. The N7 only crosses each of these rivers once while a newly proposed extension of the Klein Dassenberg Road also crosses the Swart River about 300 m east (downstream) of the N7. Detailed hydrology and hydraulic investigations were conducted for each of the river crossings to determine the capacity of the existing structures and newly proposed structures. The outcome of the investigations was that the existing bridge structures need to be replaced by larger structures. On this project in particular ecological sustainability was a key feature and priority. An EIA process for this project began in July 2012. The scoping phase of this process required the development of multiple project proposals. The proposals were developed through desk top studies, site observations, preliminary design investigations, as well as the requirements of the Project Brief, and were done in consultation with SANRAL, SLR Environmental Consulting and the municipal and provincial roads authorities. The scoping phase concluded in September 2013 with the Department of Environmental Affairs approving the Final Scoping Report and providing further conditions for the impact assessment phase of the process.
improved secondary road network that links to the N7 via grade-separated interchanges. This had a significant impact on the surrounding landowners, communities and other roads authorities. The Environmental Impact Assessment (EIA) process included numerous proposals for the improved road network layout for the N7 upgrading, each of which were assessed by a process with comment from all interested and affected parties. AECOM also undertook separate meetings with the directly affected landowners, as required during the land acquisition process, and initiated meetings with the provincial and municipal roads authorities affected by changes in their road networks. Several alternative layouts were reviewed during the preliminary design stages until a preferred road network was finally selected for the detailed design stage. This process, which required extensive planning, innovative design and consultation, took more than two years mainly due to all the impacts on stakeholders,
PROJECT INFORMATION
• Company entering: AECOM • Client: S ANRAL • End date: 25 October 2020 • Main Consultant: AECOM (SA) • Subconsultant (Design and Construction Monitoring): ERO Engineers • Environmental Consultant: SLR Consulting (Design Stage), J G Africa (Construction Stage) • Main Contractor: Haw & Inglis Civil Engineering Construction (Previously Triamic Construction) • Piling Subcontractor: Keller-Africa (Legacy Franki Africa)
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21 st Best Project Awards 2022
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