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MEDUPI POWER STATION POSES HUGE CHALLENGES ESKOM INFRASTRUCTURE Eskom’s power generation capacity will be significantly boosted when the new dry-cooled, coal-fired power station’s six generating units start to come on line towards the end of 2011 at an estimated total project cost of R130-billion. LARGEST OF ITS KIND 14.5-million tons of coal a year for the next Scaffolding was called upon to provide Located on a 883 ha greenfield site at 40 years. A full environmental impact study innovative formwork solutions for the Lephalahle in Limpopo province, the power was carried out through the Department of construction of the condenser slab and tie station consists of six boilers which will each Environmental Affairs and Tourism (DEAT) beams for the second to sixth power drive a 800 MW turbine. Once all six units and a licence was granted by the National generation units. Each condenser unit has are commissioned, Medupi will have the Energy regulator. four corner columns constructed of concrete potential to add between 4,200 and 4,500 rising up 20 m to support a 9 m square MW of electricity to the national grid. It is INNOVATIVE SOLUTION REQUIRED concrete slab. recognised as the world’s largest dry-cooled, Civil engineering and construction work is coal-fired power station. well underway and formwork solutions are Two horizontal tie beams between all four playing a serious role in the condenser columns on each condenser are required for The Lephalale site near Ellisras was selected as section. Two condensers are required for increased structural strength and are situated it is near Exxaro’s Grootgeluk coal mine, each generating unit for a total of 12 in all. approximately 7 m apart. To construct these which has been contracted to supply up to Formwork specialist Wiehahn Formwork & tie beams, Wiehahn designed and made up Huge columns dominate the Medupi site. Special Wiehahn structural steel support to 9 m x 9 m x 1.5 m deep top slab. FORMWORK MEDUPI POWER STATION MAIN CONTRACTOR Medupi Power Station Joint Venture (a Murray and Roberts, Grinaker-LTA Civil Engineering and Concor consortium) Contracts manager Adrian Steele CLIENT Crane-handled Quickshore Tower for safe access to 8 m high column. Eskom eight sets of heavy duty brace frames in a shoring and crane-handled into position cantilever position, allowing two sets per 18 m above ground level.” column. LIGHTWEIGHT SLAB FORMWORK EIGHT METER HIGH SHORING For the slab base, SRZ walers and GT24 Wiehahn technical manager Pieter Potgieter wooden girders and a plywood soffit were said the brace frames were crane-lifted into used with stop-ends 1.5 m deep. Wiehahn’s position. lightweight, panel PERI DOMINO formwork system was employed as it does not require a “An access system was also designed using crane and is easy to handle. “The DOMINO Wiehahn’s Quickshore heavy duty shoring system was deliberately designed to work as system, eight metres high per unit, was crane a single-sided form, thereby eliminating the lifted and placed on the already cast need for 9 m-long ties, which would columns, cantilevering out on CB brackets definitely move,” said Potgieter. that were fixed on two corners of the columns. This allows the steel reinforcing to “The system was supported by props with be fixed for the next concrete pour as well as the tensile loads going back into the soffit making the arrangement of the formwork which was designed to take such a load.” required much easier and safer to execute. Wiehahn is also involved in the formwork for This procedure is then repeated for the next the construction of fifteen 3 m x 3 m horizontal tie beam.” concrete tunnels, each 200 m long, which carry electrical cables to the various units “The tie beams are 1.5 m deep and 1 m wide within the overall power station. Head Office 021 880 7777 with steel reinforcing.” The slab which forms Cape Town 021 907 2100 the foundation of the condenser at the top of LIGHTWEIGHT WALL FORMWORK Midrand 011 729 2300 the 20 m vertical columns is large, being 9 m The base wall and vertical walls of the tunnels Durban 032 533 9307 square and 1.5 m deep. are being constructed with Econoform panels Nelspruit 013 758 1521 Bloemfontein 051 433 3150 and Wiehahn deployed its PERI SKYDECK, a Port Elizabeth 041 463 1141 SPECIAL SUPPORT SYSTEM lightweight aluminium panel formwork George 044 878 0105 “For the top slab support a special bracket system which was the formwork solution best Polokwane 015 298 8511 and steel beam support system is used, on suited to the construction of the tunnel East London 043 731 2807 Richards Bay 035 797 5299 top of which there are mini purpose- soffits. In some instances the side walls and Rustenburg 014 592 2816 designed beam trusses pre-assembled and the soffit were executed in a single pour. Klerksdorp 018 462 1408 delivered to the Medupi site. These keep the National ☏ 0861 70 80 system as light as possible and allow for Contracts have been placed with Hitachi to www.wiehahn.co.za easier placement. supply the boilers and Alstom to provide the steam turbines. At R33.6-billion, these are the Authorised distributor The shoring on top of the steel beam support biggest single contracts ever placed by were all pre-assembled Quickshore standard Eskom.
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