What’s the word in WRRDA?

June 1st, 2014

By Ron Bygness Geosynthetics! That’s the word all right! For the first time in U.S. history, the phrase “use of geosynthetic materials” is included in an official, passed-by-the-House, passed-by-the-Senate, signed-by-the-president, United-States-of-America law. You can read it yourself right here in the new Water Resources Reform & Development Act (WRRDA) section titled “Use of innovative materials”: […]

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Minimum low temperature for dual hot-wedge seaming

June 1st, 2014

From the GMA Techline Does the Geosynthetic Research Institute (GRI) offer any guidance on the minimum allowable ambient temperature to perform double-track fusion welds of HDPE and LLDPE geomembranes? (Jonathan | South Carolina) Reply: We have GRI-GM9 Standard Practice “Cold Weather Seaming of Geomembranes” and it allows for seaming down to -15 C (5 F). […]

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Geomembranes for pipes?

June 1st, 2014

From the GMA Techline I have been asked to wrap a proposed 30-in. circular/cylindrical sanitary sewer pipe (HDPE) with a geomembrane as a dual containment layer. Could I get some pointers as to what kind of geomembrane(material, thickness, etc.) can be used to achieve this task? Any other information, such as pros and cons, would […]

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FS for anchor trench calculations?

June 1st, 2014

From the GMA Techline Do you have a recommendation for what Factor of Safety to apply to the allowable geomembrane force for anchor trench calculations? (Melanie | Colorado) Reply: Over the years my thoughts have changed from having a high FS for geomembranes in their anchor trenches to treating the situation very differently. The motivation […]

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GM19, Revision 7—Peel separation 5 out of 5?

June 1st, 2014

From the GMA Techline I am looking for a discussion of how peel separation % in the latest revision of GM19 went from 4 out of 5 specimens to 5 out of 5 specimens having to pass the 25% or less requirement. (Gabriel | California) Reply: Others have noticed it as well and in response […]

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Use of geogrids in piggyback landfills

June 1st, 2014

From the GMA Techline Do you have any specific project information on the use of geogrids in constructing piggyback landfills, especially in cold climates? I am interested in examples of the use and evaluation of geogrids when building landfills over closed landfills. Any information you can provide as to landfill sites would be greatly appreciated. […]

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Enter your award-winning geosynthetics projects now

June 1st, 2014

Deadline for 2014 International Achievement Awards (IAAs) is June 30 The deadline for entries in the 2014 International Achievement Awards, sponsored by the Industrial Fabrics Association International (IFAI), is fast approaching—June 30, 2014. For the 2014 IAAs, there are 31 categories, including “#28: Geosynthetic Projects”—and these award-winners will be featured in the February/March 2015 issue […]

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Geonet structure, short-term stress/strain behavior, and creep test methods

June 1st, 2014

Part 1: Allowable stress on geonets By Dhani Narejo and Sam Allen Introduction Several types of geonets are used in numerous applications worldwide. Examples of the types of geonets include biplanar, triplanar, spiked or profiled, cuspated, tubular, and three-dimensional (3-D) filament meshes (see Figure 1 and Table 1). Common and emerging applications for these materials […]

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An association for the geosynthetics industry

June 1st, 2014

By Lucie Passus According to Merriam-Webster, an association is an organized group of people (or companies) that share a common interest. As GMA’s former managing director, Andrew Aho, wrote in his April 2013 GMA column in Geosynthetics on the history of GMA, this association was born out of a need to represent the interests of […]

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Geosynthetics: The science that makes green roofs work

June 1st, 2014

Green roofs 101: From bottom to top By Allan Wingfield Introduction Most green roofs use a variety of geosynthetic materials to support healthy and sustainable installations. Geosynthetics contribute in many ways to the operational success and long-term sustainability of green roof systems. Because they are lightweight, they reduce green roofs’ structural loading on buildings and […]

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