Corrie Meintjes, senior partner of Jeffares & Green Engineering and Environmental Consulting, has recently been honoured with the prestigious Branch Chairman’s Award for a lifetime’s achievement for innovation in expanding the use of concrete by the KwaZulu-Natal Branch of the Concrete Society of Southern Africa.
This is a lifetime achievement award, so special that this is only the fifth time it has been presented over the last 18 years.
The award is made extremely judiciously to ensure that the merit of the award is maintained.
Meintjes has been involved with design and construction of many bridges during his career, but the two most notable bridges recognised by the award are the innovative prestressed concrete ribbon bridges – one over the Mkomaas Valley and the other the pedestrian bridge over the Metolong Dam.
Mkomaas Valley footbridge
The Mkomaas Valley in KwaZulu-Natal (KZN) was the remote setting for the first prestressed concrete ribbon bridge built in Africa. The single-span bridge boasted a clear span of 150 m, equalling the then world record for this type of footbridge.
Corrie Meintjes had been approached by the KZN Provincial Department of Transport to “think out the box” and produce an innovative design to prevent the swaying motion associated with the cable or suspension-type bridges which the people of the area were averse to using.
After extensive research Meintjes came across the concept of a prestressed pedestrian bridge, used in Czechoslovakia during World War II and rarely applied outside the Balkans.
The Mkomaas River Bridge consists of a ribbon of precast concrete elements that are suspended from cables tensioned between abutments. The elements are joined and compressed in the long direction of the bridge by tensioning a second set of cables placed in ducts through the elements.
Such compressive strength not only provides continuity in the deck but also compensates for tensile stresses resulting from live loads.
His proposal of using this concept for the Mkomaas River Footbridge was met with enthusiasm from his client and hence the first prestressed concrete ribbon bridge was designed and built on the African continent.
The Metolong Dam Pedestrian Bridge
When Meintjes was appointed to find a solution for a pedestrian bridge to cross the valley chasm that would be filled with water from the Metolong Dam, he proposed the concept of a prestressed concrete ribbon bridge similar to the Mkomaas Valley footbridge, except that this was a multi-span bridge where the Mkomaas Bridge was a single-span structure. A visit to the Mkomaas Valley was enough to convince the client.
The bridge deck is continuous over two spans 102 m and 127,5 m long respectively. The total walkway length, including the approaches over the abutments is 249 m. The central support of the bridge consists of a 35-m-tall reinforced concrete pier, seated on top of a sandstone cliff 15 m above the river bed.
Construction of the Metolong Dam Pedestrian Bridge was completed in December 2013. It was only the second prestressed concrete ribbon bridge built in Africa and the first multi span bridge of this kind on the continent.
Meintjes designed the entire structure, with the exception of the rock anchors which were designed by a geotechnical expert. He was often on site during construction to give direction and expert advice.
Corrie Meinjes has received many awards – personally, or to projects he designed and supervised:
•1980 SAICE Award of Merit for an elevated reinforced concrete reservoir in Botswana
•1986 SAICE Pietermaritzburg Regional Award and a Commendation from Fulton Awards Committee for the 600-mlong multiple-arch Mhlahlane River Viaduct on the Broodsnyersplaas to Richards Bay Coal Line.
•1989 SAICE Pietermaritzburg Regional Award for the Manning Avenue incrementally launched bridge in Pietermaritzburg.
•March 2007 Concrete Society of Southern Africa’s Concrete Achiever of the Year for the design of the first prestressed concrete ribbon bridge on the African continent
•This bridge also received the Concrete Society of Southern Africa’s (CSSA) 2007 Fulton Award for Design Aspects, the South African Association of Consulting Engineers Award for projects under R5 million and the runner-up of the SAICE Award for Excellence.
•2007 CSSA Fulton Award for Aesthetic Appeal for the Bosmansdam Rd Footbridge in Cape Town.
•2014 SAICE Pietermaritzburg Regional Award for Technical Excellence and the SAICE National Awards for Best International Projects and for Structural Engineering Excellence for the Metolong Dam Pedestrian Bridge.
•2014 CESA Aon Award for Best International Project, also for the Metolong Dam Pedestrian Bridge.
More information from Charmagne Denny, Tel: +27(0)11 231 2200 / http://www.jgi.co.za
