Construction World October 2015

PROJECTS AND CONTRACTS

STABILISING BUILDING platforms in Mpumalanga

Five geosynthetic reinforced retaining walls using precast concrete retaining blocks manufactured by Aveng Infraset have played a crucial role in creating stable terraces for the construction of Emoyeni Mall, a recently completed shopping centre situated on the R538 between Nelspruit and Hazyview in Mpumalanga.

the perimeter of the property to reinforce an embankment which rose to 12 m at its highest point from a service road below. “We only had five to six metres to work with on this wall and the installation of extensive sub-surface drainage was required before construction of the wall could begin. Sub-soil drains were installed on top of the foundations three-to-four blocks below kerb level. Fin drains , wrapped in A2 bidem which go right back to the cut face, were laid to trap water at the top, sides and bottom of the embankment. “We also installed 250 mm Kaytech wick drains which were wrapped with bidem. And in areas with the heaviest water flows we positioned 100 mm slotted pipes covered with stone and Geomesh geotextile to trap the water at the cut face. All ground water drains into a pipe at the bottom of the wall which runs parallel to the foundation and feeds into the stormwater drainage system. “The foundation of the perimeter wall was steel reinforced. One metre wide, it varied between 450 mm and 300 mm in depth depending on the height of the wall.

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The mall was built by one of the country’s leading rural retail

which also offered better functionality. “There are substantial quantities of sub-surface water on this site and our design had to make provision for extensive drainage. In fact there were some embankment sections where one could actually see water oozing from the ground. “Three walls were open-face designs and were built with Aveng Infraset’s Terrace Blok® TB 490 and TB 300 retaining wall blocks. The other two walls were closed-face and built with the Infrablok™ 350.” The largest wall, some 200 m long, was built in an open-face configuration at an angle of 70˚. It was constructed on

centre development specialists, McCormick Property Develop- ment, a company with a strong focus on the emerging markets of South Africa. Engi- neered Interlock Solutions (EIS) in conjunc- tion with TMV Consulting Engineers designed the geosynthetic reinforced concrete block retaining walls. The walls were built by EIS in close collaboration with the main earthworks contractor, Joubert en Seuns. EIS owner, Manie Troskie, says that EIS won the retaining wall tender on the basis of an alternative and more cost-effective design

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The 200 m perimeter wall built with Aveng Infraset’s TB 490 and TB 300 concrete retaining blocks.

The 200 m perimeter wall at its highest point of 12 m.

CONSTRUCTION WORLD OCTOBER 2015