Construction World November 2015

CONSTRUCTION WORLD

NOVEMBER

2015

PROJECTS AND CONTRACTS

Since the development is built in a cutting, a retaining wall

was crucial in order to secure a three to four metre embankment

left by the excavation. Having noticed a significant amount of

water seepage from the embankment and realising that reinforcement of

the fill material behind the retaining wall was vital, GFC Consulting Engi-

neers contacted Christiaan van Wyk at Kaytech for advice. Van Wyk had

no hesitation in recommending Flo-Drain and RockGrid PC as the ideal

products for the project.

Flo-Drain is a ready-made system consisting of a Flownet drainage core

encased in a filter jacket of Kaytech’s renowned bidim geotextile. Supplied

in lightweight 30 m rolls, Flo-Drain is easy to transport, flexible and simple

to install. Varying heights of Flo-Drain were placed vertically behind the

retaining wall, and connected to a Geopipe at the base of the fin. No

stone was required for this drainage application.

Compared to a conventional aggregate drain, Flo-Drain provides

numerous advantages and may be installed in a wide variety of appli-

cations to greatly reduce the water table or to intercept seepage. It is

the most economical solution to almost any subsoil drainage problem.

For reinforcement and support behind the retaining wall, Rock-

Grid PC 100/100 was installed horizontally in the layerworks of the

backfill material. This composite, reinforcing geotextile consists of a

nonwoven layer in conjunction with high tenacity, bi-axially orientated

multi-filament polyester yarns, the combination of which guarantees

its unique characteristics.

The nonwoven layer provides not only protection to the high

tenacity yarns but vital in-plane drainage capacitry to relieve pore

water pressure in the fill material.

Compared to woven fabrics, polyethylene grids or polypropylene

grids, the high tensile modulus of RockGrid PC provides far superior

reinforcement characteristics withminimum creep deformation. It may

be installed wherever low-bearing capacity soils are encountered and,

being manufactured in South Africa, RockGrid PC is more economical

than any imported alternative.

DOUBLE SOLUTION TO LEISURE BAY

Located between Pretoria and Centurion is the new

Leisure Bay development where two of Kaytech’s

top quality products successfully solved a drainage

and stability problem in an embankment. The 56-

unit, residential complex constructed by Zoned

Earth Development Company, is uniquely situated

overlooking Leisure Bay Lake, a natural dam fed by

water from an underground spring.

ABOVE:

Rockgrid PC reinforces the embank-

ment’s retaining wall.

LEFT:

Flo-Drain installed behind the retaining wall.