Construction World June 2017

ROADS AND BRIDGES

Reinforced Earth ® is the English name given to the material Terre Armee ® which Frenchman Henri Vidal invented in 1963. A SIMPLE, YET COMPLEX MATERIAL

staffed with local employees driven by a shared passion that is a central element of the corporate culture and unites the teams across all geographic borders. RESA has contributed significantly to road, rail and bridgework in Africa. Hundreds of contracts have been completed. Four major contracts are listed: • N1 Diepkloof, Johannesburg 1980 – one of the first true bridge abutments in Africa. Since then some 200 such abutments have been completed or are under construction. • N1 Du Toitskloof, Western Cape 1994 – numerous retaining walls constructed on a new dual carriageway alongside the Molenaars River. • Mbabane Bypass, Swaziland 2004 – 24 true bridge abutments 15 retaining walls and four tiered fills. The most notable and spectacular, are the tiered fill structures which were designed as alternatives to incrementally launched bridges. • Gautrain, Gauteng 2008 – 80 structures

Reinforced Earth ® structures behave as a coherent gravity mass comprising a selected granular fill combined with strong steel or geosynthetic reinforcing strips and a modular facing system, generally in the form of precast concrete panels, welded wire mesh or semi-elliptical steel panels. This unique combination creates a dur- able mass gravity structure which in addi- tion to carrying its own weight, is capable of withstanding significant static and dynamic loads generated by all stresses external to the structure.

numerous applications, in particular road systems. Vidal founded the company Terre Armee Internationale, and so the story of an invention turned into one of legendary entrepreneurship. Reinforced Earth or RESA is the name of the TAI South African company estab- lished in 1975 to provide a Reinforced Earth ® service in sub-Saharan and Eastern Africa and in Ghana and Nigeria. Trademarks Reinforced Earth ® is a trademark belonging to Terre Armee Internationale. It is registered in numerous African countries including South Africa. Wikipedia defines Mechanically Stabilised Earth as follows: “Mechanically stabilised earth or MSE is soil constructed with artificial reinforcing. It can be used for retaining walls, bridge abutments, seawalls and dikes. Although the basic principles of MSE have been used throughout history, MSE was developed in its current form in the 1960s. The reinforcing used can vary, but include steel and geosynthetics. MSE is the term usually used in the USA (and Africa) to distinguish it from the name ‘Reinforced Earth, a trade name of the Reinforced Earth Company, but elsewhere Reinforced Soil is the generally accepted term”. Reinforced Earth ® today The TAI Group The group has 50 companies worldwide and has contributed to more than 50 million square metres of structure face area in over 100 countries. The companies are

The Terre Armee Group The invention using earth as a raw

ingredient, led within a few decades, to the development of a company with a presence in five continents. Easy to install, Reinforced Earth ® rapidly established itself as an ideal construction material in

were constructed on 38 separate sites including true rail over road bridge abutments.

THE INVENTION

John Vorster offramp to Viaduct 5.

“It all began one fine September day on a white sandy beach. I put some pine needles into a heap of sand and noted a certain cohesion. I had in fact created the first Reinforced Earth ® . “Structure made up of two components: granular particles and reinforcing strips. Man’s first building material comprised just one component, granular particles in the form of stones. And then concrete, so two components: granular particles and a bonding agent, in this case cement. Then man invented reinforced concrete made up of three components: granular particles, a bonding agent and reinforcing bars. In simple terms, Reinforced Earth ® involves eliminating the bonding agent and keeping only the granular materials and reinforcement. But it wasn’t easy. “It took me five years to establish the theory based on friction between particles and reinforcing strips and to design a technology that was both economical and quick to install. Then I filed patents and realised that there was nothing else like this in the world. I began building the first structures and started developing an international organisation to allow the structures to be installed rapidly across all continents.” – Henri Vidal

Reinforced Earth ® , Terratrel™ and Terraclass ® – our three solutions improve The N7.

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CONSTRUCTION WORLD JUNE 2017