Design methods for geogrid reinforced flexible pavements

Amir Shahkolahi

The use of geosynthetic materials has become an acceptable practice in road construction including flexible pavements as a sustainable environmentally friendly solution. Studying the behaviour of geogrid reinforced roads over the last 40 years has led to several empirical and mechanistic-empirical methods being developed for the design of geosynthetic reinforced unpaved and paved roads. There is no unique design method for this application in the world as the road conditions vary from one region to another. Adopting a design method from another region or indeed country requires local verification and calibration. In Australia, the peak organisation of Australasian road transport and traffic agencies (Austroads) offers a design method for unreinforced flexible pavements and gives some recommendations for using geosynthetics but unfortunately there is no design guideline for geogrid reinforced pavements. Local road authorities such as Queensland Transportation and Main Roads has published a specification for geogrids in subgrade reinforcement, but again without providing a design method for this application. This presentation reviews some of the available design methods for geogrid reinforced flexible pavements, considers the available design methods in Australia, and provides a design procedure in accordance with Australian design guidelines for flexible pavements based on international and local experience and test results.

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