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

August 1, 2022  |  GSI News

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 Geosynthe…
New GSI test method for resistance of conductive geosynthetics

June 1, 2022  |  GSI News

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 d…
New GSI method for strain hardening of HDPE geomembranes

April 1, 2022  |  GSI News

Traditionally, high-density polyethylene (HDPE) geomembranes are checked for stress crack resistance using the ASTM D5397 single point-notched constant tensile load (SP-NCTL) test (Hsuan, Lord and Koerner [1990]). This test uses notched specimens, surfactant, and elevated temperatures to accelerate …
Reinforced levees to induce seepage path around geogrid layers?

February 1, 2022  |  GSI News, News

The Geosynthetic Institute (GSI) has been asked if a geogrid-reinforced levee will induce a seepage path adjacent to and around the geosynthetic layers. This question has been asked on several occasions for different applications and various styles of geogrids. At this point, GSI has no case histori…
New anchorage and connection strength tests for geosynthetics

October 1, 2021  |  GSI News, News

Connections can have a significant impact on the performance of exposed geosynthetic systems. The connection must be considered as a limiting strength factor and evaluated by the same performance standards as the material alone. If used in critical structures with design lives of more than 30 years,…
GSI’s new GCL test method

August 1, 2021  |  GSI News, News

The Geosynthetic Institute (GSI) has a new standard test method for “Determination of the Polymer Loading in Geosynthetic Clay Liners (GCLs).” It was developed over several years without consensus of the membership. GSI forged ahead with it because we see many such products in the market and bel…
An open solicitation to join in a round-robin effort to find a substitute for Igepal CO-630

June 1, 2021  |  GSI News

Improved stress-cracking resistance in high-density polyethylene (HDPE) geomembranes has been a quest of our industry and a hot research topic for years. The Geosynthetic Institute (GSI) has been working in this area since the mid-1980s.
A new specification for geotextile grout filled mattresses

April 1, 2021  |  GSI News

By George R. Koerner Geotextile grout filled mattresses (GGFM), also referred to (in ASTM D18.25/D35.05) as fabric-formed concrete (FFC) or fabric-formed concrete revetments (FFCR), are erosion-resistant concrete linings made from durable, permeable fabric forms that are filled with high-strength gr…
Extreme direct shear testing

February 1, 2021  |  GSI News

By George R. Koerner The Geosynthetic Institute (GSI) is doing direct shear testing under extreme environmental conditions (i.e., specifically extreme temperatures). At the prompting of two member companies, we have initiated an effort in this regard. This work looks at response curves over a wide r…
Testing wind-resistant geosynthetics

October 1, 2020  |  GSI News

By George R. Koerner As you can see by Figure 1, we are experiencing a new age of geosynthetics. Over the past 15 years, we have seen a propensity of polymeric materials left exposed to rather than covered from the environment. This is in large part due to the strides geosynthetic manufacturers and …