Civil Designer Showcase

The Mfuleni Bulk Earthworks Project

Liebenberg & Stander was commissioned by the City of Cape Town (Tygerburg Administration) to handle the design, construction monitoring and contract administration of the Mfuleni Bulk Earthworks contract

Marthinus Retief, a Candidate Engineer who worked closely on the project, describes his involvement. "This was my first participation in a project of this nature and I found it to be an interesting learning experience. We liaised with the environmental town planners and other relevant bodies to develop the 80 hectares of land required to create 4000 new erven for residential use".

"This involved shaping the existing dunes to accommodate future township services. The design of the earthworks platform had to take cognisance of the 50 year Kuils River flood line that fixed levels on the west side of the site, as well as the integrated stormwater and road concept designs. We minimised infrastructure costs by optimising land use".

"Dumper trucks and excavators were used to move 850 000m of earth on the 80 hectares," Marthinus explains.

"We followed a systematic procedure that started with a survey of the existing terrain, and involved a concept study of the stormwater overland flow. The information was then transferred into Civil Designer where a model of the bulk earthworks platform was created with the use of the Survey & Terrain module".

"Points were inserted into the model so that the cut and fill volumes could be calculated accurately in order to optimise the mass haul cartage and eliminate the import and export of material. The program allowed me to create contours and move points around. I found the quick contour function to be very helpful during this phase," says Marthinus smiling.

"During the cutting process, care was taken on the use and handling of topsoil. In order to prevent increased costs for stockpiling, the cut topsoil was immediately used on fill areas and then spread to final levels. This promoted soil fertility and resulted in lots of green growth during the winter months. In addition, we ploughed straw into the top 100mm of finished platform levels to stablise soil and prevent wind erosion. It helped that the project was completed during a rainy winter, as this aided the compaction of soil".
 
Mfuleni Bulk Earthworks | Liebenberg & Stander


The team at Liebenberg & Stander found an alternative use for the trees and shrubs that were cleared from the ground. "Instead of dumping this, we tried to prevent waste by using the trees and shrubs to supply fire wood for the local community during winter. The remaining shrubs were further used to create wind barriers and to stabilise soil where the design platform banked onto existing ground levels".

"My primary objective during the design of the bulk earthworks was to create a platform with high and low points so that there would be sufficient drainage and thereby create an area conducive for residential use. This involved long discussions with town planners so that enough space could be created for school sites, retention ponds and open spaces. Looking back, I feel that this objective was met," Marthinus says.

When asked what his most rewarding experience was during the five-month project, Marthinus says enthusiastically: "it definitely was seeing the finished earthworks project and being part of a process of creating 4000 new homes for families and a pleasant living space for the community".


 
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