Construction World April 2019

sets of rod-extensometers underneath the raft foundation of the building. The extensometers will measure settlement, heave, displacement and deformation in soil and rock below the building and will give the engineers forewarning of the development of any sinkholes. Geomech Africa used symmetrix drilling to create holes for the rod-extensometers and Terra Monitoring installed and commissioned them. After the completion of the building, the rod-extensometers will be connected to the Emergency Management System of the building where a warning will be issued if any movement of the rod-extensometers is detected.

the base of the building serve as an early warning system to indicate any formation of sinkholes under the raft foundation building. After the completion of the building, the equipment is then connected to the building management system where they are monitored continuously.

columns and needed to be installed with limited headroom of 2,5 m in places. Twenty eight end-bearing piles were installed to depths between 8-10 m in only two days on site. Piles were installed with a safe working load of 450 kN. Quick facts When did the project start? April 2018 When was your part of the contract completed? April 2018 What were the challenges on the project? The space restriction (30 cm away from existing pile caps, and existing services), work at night, and the work in public spaces where access control was problematic. What services did you supply ? Foundation piling and ductile iron piles How was the geotechnical solution beneficial to the specific environment of the project? Driven, Ductile iron piles were offered as an alternative to micro pile underpinning piles due to the speed of installation. Ductile iron piles also have a much higher resistance to vertical load and buckling than underpin piles. Lastly, the relatively deep founding conditions, of 8 m or more, were also an advantage of the ductile iron system. 

When did the project start? 25 October 2017 When was your part of the contracts completed? 2 November 2017

PILING IN TIGHT SPACES AT BLOEMFONTEIN CENTRAL PARK SHOPPING CENTRE Geopile Africa is able to install ductile piles in extremely tight spaces with minimum head room. An example of this was a recent project to install piles at the Bloemfontein Central Park Shopping Centre. The piles were required as close as 30 cm from existing

What were the challenges on this project? Placing the rod extensometers anchor point outside the fault zones in the boreholes. What services did you supply? Installation of geotechnical instrumentation. How was the geotechnical solution beneficial to the specific environment of the project? The geotechnical equipment installed at

DESIGNING AND INSTALLING GREEN-WALL SOLUTION

Fibertex has worked closely with Siyamba Earthworx contractors, to design and install a green-wall solution, rather than using conventional retaining blocks, for a project in Salt Rock, on KZN’s north coast.

Fibertex FiberRock 20S GSC bags are also used as a medium for planting shrubs, which will eventually cover the entire structure, to attain a green wall with enhanced aesthetics.

“T his project required retaining walls to be built around the property, to allow for excavation of foundations for a new house. Although site conditions were fairly good, it was important that the new construction did not disturb the existing infrastructure and retaining walls of three well-established properties bordering this plot,” explains Jeremy Wayne Muthusamy, Key Accounts Manager, Fibertex SA. “The Fibertex technical design team designed a reinforced wall that is suitable for site conditions and also meets the client’s request for a green-faced structure, with enhanced aesthetics. “Fibertex nonwoven geotextiles, which are manufactured from highly UV stabilised virgin Polypropylene (PP) or recycled Polyester (R-PET) fibres, are gaining popularity in landscaping and building installations. The FiberRock geobag and geogrid system creates an environmentally-friendly green wall, compared with conventional hard-facing concrete structures.” Fibertex FiberRock 20S geosynthetic sand containers (GSC bags) – a lightweight, durable and cost effective substitute for traditional earth retention systems – were used as a facing for the reinforced walls of this installation. GSC-bags are an attractive and efficient protection for slopes and also aid in erosion control.

FiberRock 20S GSC bags are made from a strong and highly porous fabric, which is mechanically needle-punched together. By filling these bags with a free-draining medium, like sand, a durable retaining structure can be built, which allows the free passage of water through the structure. The contractor has used these GSC’s as a medium for planting shrubs, which will eventually cover the entire structure, to attain the green wall requested by the client. Retaining walls for this project were reinforced with Secugrid, which is a soil reinforcing geogrid, in accordance with the engineer’s design requirements. Fibertex Secugrid geogrids – with high modulus extruded monolithic bars and welded junctions – were used to minimise soil deformation under tensile loads over the lifetime of the structure. All variations of Fibertex FiberRock GSC bags are manufactured at the company’s plant in KwaZulu-Natal, according to the consistent quality control policy of the Fibertex group, which is held to stringent international standards. Fibertex UV stabilised virgin PP geotextiles are the only nonwoven geotextiles produced in Africa with certification for durability of over 100 years, in accordance with the latest EN standards. 

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CONSTRUCTION WORLD APRIL 2019