Construction World March 2016

SIMPLIFYING GROUND STABILISATION PROBLEM

Kaytech’s TriAx geogrid has been proven to functionally out-perform the best performing bi-axial geogrids available, so it was no surprise that this product was specified to solve a pavement subsidence problem at the upmarket Lynnwood Bridge Shopping Centre in Pretoria, Gauteng.

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The trouble occurred above the storm- water services which had been installed five to six metres deep on the side of the jockey slab. When DG Consulting Engi- neers identified insufficient compaction of the material above the stormwater services, Kaytech’s tried and tested TriAx geogrid was the immediate choice. After removal of 300 mm of the faulty mate- rial, contractor Bold Green, installed 120 m 2 of TriAx TX 160 subsequently covering it with imported G5 material. The hexagonal struc- ture of TriAx geogrid, coupled with increased rib thickness and junction efficiency, provides significantly improved aggregate confinement and interlock, leading to improved structural performance of the mechanically stabilised load-bearing sub-base. With no previous experience using TriAx, the contractor was greatly impressed with its ease of >

transportation as well as its simple installation: “It was easy to use: we used pruning scissors to cut it, and cable ties to bind overlaps together”; it’s not heavy at all so I was able to collect 120 m² from Kaytech in Jhb and roll it up and carry it on my bakkie with ease” said a represen- tative from Bold Green. TriAx provides radial stiffness thus producing a truly multi-directional product with near isotropic properties. The use of TriAx on this project saved both time and money, since any alternative option would have necessitated a far deeper excavation of material. Since TriAx geogrids have proven perfor- mance in trafficking trials and can reduce base thickness, increase bearing capacity, control differential settlement and cap weak deposits, developer, Atterbury Properties can rest assured that these repairs at its Lynnwood Bridge Shop- ping Mall are of the highest quality.

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1. Excavating the site. 2. Compacting the base layer. 3. Laying TriAx with overlapping ends. 4. Compacting the surface layer. 5. Laying the paving layer.

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CONSTRUCTION WORLD MARCH 2016