Minimum low temperature for dual hot-wedge seaming

June 1, 2014  |  Q&A: GMA Techline

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

June 1, 2014  |  News

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 … <div><a…
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FS for anchor trench calculations?

June 1, 2014  |  News

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…
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Geomembranes for pipes?

June 1, 2014  |  News

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 informatio…
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Geogrid reinforcing behind rigid concrete retaining walls

June 1, 2014  |  Q&A: GMA Techline

From the GMA Techline I participated in the Bologna Symposium and I [was] very happy and honored to see you live. I read a [GMA Techline] answer published in Geosynthetics magazine (Oct./Nov. 2009, p. 58), “Geogrid use behind rigid concrete retaining walls.” You refer to the Japanese rai…
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HDPE liner panel orientation?

June 1, 2014  |  Q&A: GMA Techline

From the GMA Techline I am reviewing a construction report where a landfill cell has HDPE one-sided texture laid about 45 degrees from the direction of steepest slope across approximately one-third of the sideslopes. I am looking for quantitative data on any testing done with this type of orientatio…
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