Technology & Design....                                                                  

The technology & design methods are as applied in the U.S.A. and adapted as required to SA. conditions. Segmented Retaining Walls have been used successfully in South Africa for the last 20 years.

Experience and Expertise

Michael Arndt of Arndt Consulting Engineers has been involved in numerous segmented Retaining wall designs using, a number of different types of blocks with walls carrying in heights, slopes, angle of fill and superimposed loads.  The most varied of these project is the Velo Drome in Bellville, Cape, which require the implementation of most of the design criteria listed below. Certain sections were dealt with as stable slopes clad with retaining blocks behind which a 300mm coarse sand was placed with a core drain to ensure that the facing was not pushed away from the slope. In other areas 7m high retaining walls were constructed using the reinforced soil approach and flexible gravity wall design methods. In a different old clay fill area which was unconsolidated and subjected to a great deal of seepage flow, only a flexible structure became feasible i.e. a geo-fabric reinforced retaining wall.

ECO-MAX design criteria takes into account the following:

  • soil type both of backfill and in-situ retained soils

  • drainage

  • foundations/levelling pads

Why ECO-MAX?

With the geo-fabric reinforced principle in mind, ECO-MAX has been designed with a large fabric/block friction interface to aid the Segmented Retaining Wall Blocks to key into the reinforced soil system.  The ECO-MAX block is manufactured by the best machinery available, reliably fine tolerances and selected aggregates assures an ECO-MAX wall of enduring quality. The curved, flat or flat rock face derivatives enable the ECO-MAX block to cater for interesting and ecologically friendly architectural requirements. The combination of ECO-MAX blocks, specialist engineering design and accredited installation contractors could lead to cost savings of up to 20% on the contract price. Included in this price is the wall design, engineering supervision on site, and professional design responsibility.

 

Common Problems

Segmented Retaining Walls have become very popular in a short period of time. A lack of knowledge  regarding the dynamics and construction methods of these walls have on occasions led to various problems.  The most common failures associated with this type of retaining structure occur when the cut slope, being dry on inspection is judged to be stable and is clad instead of being reinforced.  Failure occurs when this type of slope is then subjected to water flows.  Another common failure occurs when the cut is stable and clad but the back fill between cladding and the cut surface is poor and without drainage.  This results in hydrostatic pressure, which can result in failure.  In some installations failure has occurred  owing to incorrect design.  Design scepticism has led to a tendency for engineers to prefer the additions of concrete and / or multi-skin segmented retaining walls to offset their perceived risk.

 

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