An open solicitation to work on development of a new GSI specification for EIA geomembrane

August 1st, 2022

GSI has a long history of writing specifications for geosynthetics. Like all engineered materials, geosynthetics are used in many applications and need general requirements for plans and specifications. When the NSF ceased servicing NSF #54 “Specification for Geomembranes” in 1991, The Geosynthetic Institute (GSI) was requested by its membership to continue the effort. With a […]

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Geosynthetic clay liner with aquiclude

August 1st, 2022

Q: We are trying to design and construct an aquiclude with a geosynthetic clay liner (GCL). Do you have any experience with this application where a GCL has been used as the impervious barrier between a flowing stream and the underlain geologic formation? A: I have not heard of a GCL being used alone in […]

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Working on an ethylene interpolymer alloy (EIA) specification

August 1st, 2022

Q: I have an upcoming project that will use ethylene interpolymer alloy (EIA). Is the Geosynthetic Research Institute (GRI) working on a specification for this material? A: Nice to hear from you and thanks for your Techline question. We have been working on this subject for a long time. GRI-draft GM34 standard specification revision 4 […]

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What is the CSI code for geosynthetics?

August 1st, 2022

Q: What is the CSI code for geosynthetics? A: Originally founded in 1948, the Construction Specifications Institute (CSI) is a United States national association of more than 8,000 construction industry professionals who are experts in building construction and the materials. It is the founding institution for organizing and coding specifications related to construction projects. The […]

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Do you have experience with T seams?

August 1st, 2022

Q: I have a question about T-intersections where three panels of geomembrane meet. In my experience these intersections have all needed to be repaired with a patch. However, a recent project fusion welded straight through these intersections. Air channel testing was completed on the first seam prior to completion of the perpendicular seam. After the […]

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New GSI test method for resistance of conductive geosynthetics

June 1st, 2022

The Geosynthetic Institute (GSI) has a new test method for resistance measured across positions on conductive geosynthetics. Conductive geosynthetics contain an electrically charged backing (usually a thin layer of polyolefin with letdowns containing 20%–30% carbon black) that allows leaks to be detected in lined systems without the need for a conductive subgrade beneath the liner […]

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Geotextile filtration clogging resistance

February 1st, 2022

Q: I have a question about the Filter Criteria in the Federal Highway Administration (FHWA) procedure "Filter Performance and Design for Highway Drains" procedure, specifically the geotextile filtration clogging resistance equation 2-10. This seems to require a particularly large pore size; for example, if the D15 of the soil was for 70 microns, the minimum […]

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Sewn versus welded seams

February 1st, 2022

Q: On your GMA Techline website list of sample questions and answers, a question is asked about a recommendation for sewn versus welded seams for geotextiles. Bob Koerner answered this question by stating that you have done a study for joining geosynthetic clay liner (GCL) overlap seams via eight methods. Can you share that study […]

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EPDM geomembrane for a water application

February 1st, 2022

Q: We are looking at a life-cycle study for the usefulness of an ethylene propylene diene monomer (EPDM) geomembrane for a water conservation application. Request to kindly share the information for our study. Regards. A: An EPDM geomembrane is going to lie flat on the subgrade soil without wrinkles (no field-induced stress). Therefore, it will […]

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Geosynthetics for pipe wrapping

February 1st, 2022

Q: I need impervious geosynthetics for pipe wrapping that will be placed within heavy clay. Do you have any suggestions? A: One wraps nonpolymeric pipes for many reasons. Below are some examples: Insulation (sound and thermal)Corrosion protectionWaterproofingImpact resistance Most wraps are tapes or mastics. Polyvinyl chloride (PVC), butyl rubber and bituminous wraps are common. A […]

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