Property development often requires cut and fill slopes, that consequently need to be stabilised to prevent erosion by the elements. In this case, a new lifestyle and shopping complex in Simons Town was built into a hill in the Dido Valley, leaving several steep and exposed cut slopes in need of stabilisation.
When Dassenberg Retaining Systems, Terraforce Recommended contractor, was approached by Quantity Surveyor, Chris Stumke from CSQS, to form a stable ramp on site, Andre Rheeders, Dassenberg’s CEO, managed to convince the client, Latitude Properties, to use the Terraforce retaining wall system to retain the resulting slopes.
Says Georg Brand, Dassenberg Retaining Systems: “The platform was handed over to us by Civils 2000 late 2017. We then hand excavated the footing and filled it with 25/19 Mpa reinforced concrete. The bottom 3rd of the structure was installed with a double skin of Terraforce L11 blocks, that were also filled with 25/19 Mpa concrete.
Added reinforcement consists of Findrain 2m c/c, Rockgrid 200/200 as tiebacks and 3% sand/cement stabilized backfill. As a result, the Terraforce wall can carry a surcharge of 10kN/m², 1.5m away from the top, which comes in at 7.1 m above the parking area.
“One of the challenges we faced on site was presented by a natural spring situated in the hill above the development. A soak away had to be designed by Fred Laker, ICOS Engineering and long-time Terraforce wall design specialist, to effectively redirect the excess water towards the subsurface drainage. In total, 11 400 Terraforce L11 blocks were installed by our team, expertly overseen by team lead and foreman, Rudi De Klerk”.
Finally, landscaping of the wall focussed on the water wise and indigenous vegetation of the area, the sourfigs trailing over the top and fynbos shrubs lining the foot of the wall add a lovely softening touch to the structure.
Special thanks to Dassenberg Retaining Systems for executing a technically complex job with the usual professional approach and skill.
Architect: WSP/ Parsons Brinkerhoff
Engineer: Fred Laker, ICOS Engineering
Quantity Surveyor: Chris Stumke, CSQS
Main Contractor: Civils 2000
Sub-Contractor: Dassenberg Retaining Systems, Andre Reeders CEO, Georg Brand, Estimator and Rudi De Klerk, Team Foreman