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The GMA Techline is 15 years old

February 1st, 2020 / By: / GSI News

By Robert M. Koerner

The GMA Techline was initiated on Sept. 1, 2004, as a free worldwide answer center for questions involving any, or all, aspects of geosynthetics. There were no constraints put on the questioners, or on the answers that were provided by the Geosynthetic Institute (GSI). To date, 3,500 Q and As have been provided, which averages 19.5 per month over the 15-year period. So, as to compare and contrast the overall activity, we have done summaries in incremental sets of 500 Q and As. Thus, comparisons could be done using bar charts to observe trends over the years. The following were specific categories focused upon in this manner:

  • Location (by continent) of the questioner 
  • Occupation of the questioner
  • Application category of the questions asked
  • Details on the unique question of lifetime/durability
  • Difficulty level of the questions

Regarding the location of the questioner, the majority were from the U.S. (54%), followed by other parts of the world (varying from 2.5% to 11%). Regarding the occupation of the questioner, the largest group was designer/consultants (38%), followed by manufacturers (19%), agencies (17%), owners (9%), academics (9%) and installers (8%). Regarding the type of geosynthetic, geomembranes were the most often asked about at 31%, with multiple-layered geosynthetic questions at 21%. Geotextiles (18%), geogrids (14%), drainage composites (6%), GCLs (5%) and the other three categories in the lower percentages (1%–2%) made up the rest.

Regarding the particular focus of the questions, designs and related specifications were most frequently asked about (32%), followed by lifetime/durability (17%), installation (16%), strength (11%) and the other three categories for the remaining percentages (5%–10%). Interestingly, the lifetime/durability questions have been asked about consistently over the entire duration of the program. For each set of 500 Q and As, the percentage of questions asked in this single category was a consistent 19% ± 2%. See the Figure 1 for some specifics in this regard.

Figure 1

The difficulty level of each question was ranked on a sliding scale of 1 (hardest) to 5 (easiest). While certainly subjective on our part, there were 18 1s in the most recent set of 500 Q and As (3.6%). A few have been selected for this issue of Geosynthetics.

The entire 28-page report is available free at 

General Remarks

We usually respond to the Techline questions ( within one or two days and sometimes within hours. This rapid turnaround time often engenders the questioner to come back against our answer with another related question. It sometimes goes back and forth for several iterations, but this is the nature of such electronic dialogue. In this regard, the GMA Techline is analogous to questions asked during webinars, which we offer on behalf of both the Geosynthetic Institute (GSI) and the American Society of Civil Engineers (ASCE). At the close of each of these webinars, we are now suggesting that participants go to the GMA Techline for further interaction. The two efforts (Techline and webinars) appear to be very complementary, and we enjoy doing both.

This entire 15-year process of responding and answering to the 3,500 asked questions was very insightful to us and interesting as well. It was a pleasure in so doing. Perhaps the most disconcerting aspect is that there has been too little movement between the seven discrete sets of 500 questions over time. Perhaps this is due to new people entering the geosynthetics industry asking familiar questions about our evolving technology, but this is not known to be fact. Regarding the questions in this most recent set, the categories we selected are completely repetitive from past sets of 500 Q and As. As you will note in the full report, there are patterns that have been set over time. Note Figure 4 and particularly Figure 5 in the report. In turn this observation suggests that the “educational” status of geosynthetics has not advanced significantly nor have large numbers of new professionals been exposed to geosynthetics. Clearly, education is at the heart of growth and robustness of any technology—geosynthetics included. Much greater advancements in this regard to both faculty and professionals seems to be warranted and is hereby encouraged.