The Geosynthetic Materials Association (GMA) offers the GMA Techline, a resource for technical questions about geosynthetics. E-mail: gmatechline@ifai.com for fast, free, direct answers to your technical questions.
GMA serves as the central resource for information regarding geosynthetics and provides a forum for consistent and accurate information to increase the acceptance, and to promote the correct use, of geosynthetics.
Browse the entries below list to find past answers highlighted in Geosynthetics magazine.
The CQA plan on tests and their frequencies is the right and duty of the CQA organization, since they are signing off on the completed project.
The first test using multiple interfaces was actually conducted in the bed of a dump truck in about 1985.
One can construct a wraparound geotextile reinforced wall to the effect that 100% of the lateral load is carried by it and zero goes to the concrete, which now acts as a facing.
Let me mention that moisture in the seam area to be bonded is the most important detriment to the making of quality seams.
GRI–GG5 was the original test method on the subject but, subsequently, ASTM provided its own.
I think that many field welding technicians would love to weld at 104°F during the summer. It is really very doable, especially on a white sheet.
Following the information listed in Designing with Geosynthetics, 5th Edition, the statement 1-2 meters is the typical spacing for PVDs.
I doubt if thickness is calculated by most engineers and they simply “go with the flow.”
The GRI–GM11 Test Method has now been superseded by ASTM D7238 and ours has been discontinued.
The two groups, ASTM and ISO, act independently from one another although ASTM does have liaison people attending the ISO meetings as observers.
Defining the terms warp and fill mean with regard to tear strength of a polypropylene liner.
Back in 1985, the state of Pennsylvania felt uneasy about geonets so we did a full-scale experiment on a landfill cell measuring about 400m by 50m.
Using such a geosynthetic material over the entire footprint of a building will simply not cure a uniformly weak subgrade soil.
There are probably 30,000 technical articles on geosynthetics at the current time.
The Purpose of Drainage for Green Roofs
The Purpose of Filter for Green Roofs
Filter Components
For retention:
For permeability:
What are Geocomposite Drains?
Source: “How to Design Green Roofs & Landscapes” presented at the 2009 IFAI Expo, Sept. 22, 2009, in San Diego, hosted by the Geosynthetic Materials Association (GMA)