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Port Elizabeth - The South African National Roads Agency Limited (Sanral) believes its completion of an R80m slope stabilisation engineering project in Nelson Mandela Bay has saved Africa’s automotive manufacturing capital from power blackouts.
Sanral said in a statement the instability of the R75 on-ramp into Uitenhage was undermining the structural integrity of pylons carrying overhead electrical cables supplying large areas of Uitenhage with power. It has been a source of concern for authorities and industry since 2012 when a part of the slope was damaged by heavy rains.
"Sloughing or erosion problems [of the slope] began in the mid-1980s mainly due to the lack of maintenance. This, in turn, allowed moisture to seep into the slope. Previous methods of stabilisation were not effective as they only dealt with close to surface water or moisture contained within the slope," said Michelle Ah Shene, administrative and communications manager at Sanral.
The R75 was declared a national route in 2011 and was being investigated by Sanral when the failure occurred.
"Every time instability occurred the failure zone encroached on these pylons, undermining the stability of the foundations," Ah Shene said.
Recently, extensive slope landmass movements were triggered by heavy rains during October 2012 in the Nelson Mandela Bay metro. The rains resulted in the movement of soil to the lower parts of the slope which increased the risk of damage to the cables and a potential power black-out of Uitenhage, Sanral said.
This week it concluded a slope stabilisation programme of the R75 on-ramp, and that stability of pylon foundations will no longer be at risk.
The project also included the construction of an earth catch water bank at the summit of the slope to prevent overland flow from the summit flowing down the cut face.
The project created 216 employment opportunities for 13 small and medium-sized enterprises (SMMEs) over a 15-month contract period, Sanral said. The agency also offered SMME training in tendering and pricing, and safety, health and environment aspects.
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