Construction World March 2016

PROJECT PROFILE

Material decisions Murray & Roberts Infrastructure conducted its own geotechnical tests to enable it to optimise use of the material available in close proximity to the project. “By doing this we were able to determine the most suitable material from each area for use on the hard stands as well as on the various road works that formed part of our contract,” Venter says. Cut and fill quantities were balanced accordingly. The project had significant quantities of hard rock and Venter says that the construction programme also had to take cognisance of these difficult excavation areas. Blasting had to be done for 30 of the 35 base excavations due to the rocky ground conditions on the site. Significantly all material excavated on site was reused on the contract and depending on material specification this was either as fill on the roads or hard stands or for backfilling of the foundations on the wind farm site. In addition to this, three different areas were located on site with material that was considered suitable to crush for wearing course. Bedding material was also supplied for the trenches. The only material imported was the concrete aggregate. The decision for Murray & Roberts Infrastructure to erect a batch plant to service this project was strategic and facilitated ready access to concrete, as and when required. The plant is located on a farm adja- cent to Noupoort. The readymix being produced uses AfriSam OPC and includes fly ash content facilitating a lower carbon footprint for the construction and a reduction in cost. In total 20 000 m 3 of concrete will be used for the construction of the foundations and ancillary structures. Road works The wind farm site is spread across three different landowners’ prop- erties and it was necessary to construct access roads that would firstly allow construction to take place and secondly facilitate the delivery of all the wind turbine components for installation. Construction of these roads required mass earthworks and cut to fill operations. The road width is approximately 5 metres with a side drain for storm water management. This gravel road scope of work also included the provi- sion of cattle grids between the different landowners’ properties on the boundary fences. Maintenance of a 10 km section of the Oorlogspoort Road from Noupoort to site was necessary. Part of the Murray & Roberts Infra- structure scope of work included modifications at Cradock and the Oorlogspoort/N9 intersection to accommodate the deliveries of the wind turbine components. The blades, nacelle and hub are imported and shipped the Port of Ngqura, in Port Elizabeth and then transported to site, whereas the tower sections are manufactured locally, in Atlantis, in the Western Cape. The locally manufactured turbine tower sections mean that Noupoort Wind Farm has been able to achieve local content commitments exceeding 40% of the project’s total value. Environment and community Before construction activities began, Murray & Roberts Infrastructure subcontracted an environmental consultant to conduct a search and rescue on the flora and fauna in the immediate locality. While no endan- gered species were identified, steps were taken to relocate all vulner- able species to areas with similar habitat and climatic conditions. Around 230 individuals from the local community were employed on the contract, and these ranged from general labourers up to machine operators. Murray & Roberts Infrastructure places an enormous focus on training, both in terms of competency and safety, and this was provided at all levels, with certificates of competency issued. The company has also continued its strong focus on supporting the local communities and in a joint initiative with Mainstream, Murray & Roberts Infrastructure has started a programme to upskill a local contractor to repair the roofs of local buildings. Jerome Govender, executive chairman of Murray & Roberts Construction, comments that he is very pleased with the progress on the project considering the weather and other challenges that had to be overcome, and with the approach adopted with the environment and the community.

The hard stand areas were cleared and grubbed and rock fill brought in to level the area after compaction of the in-situ material. This was followed by the addition of wearing coarse material which was also compacted to give its final surface finish. Venter explains that load bearing testing was done on each hard stand to ensure it is capable of carrying the mobile crane’s weight during wind turbine erection.

A completed hardstand at Noupoort Wind Farm awaiting erection of the turbine tower.

A completed concrete base and plinth before backfilling at Noupoort Wind Farm.

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Steel reinforcement for one of the concrete bases at Noupoort Wind Farm.

CONSTRUCTION WORLD MARCH 2016