Geosynthetics October/November 2020 - 42

GSI NEWS

By George R. Koerner

Testing wind-resistant geosynthetics

A

GEOSYNTHETIC
INSTITUTE
GSI's mission is to develop
and transfer knowledge,
assess and critique
geosynthetics, and provide
services to the member
organizations.

www.geosynthetic
- institute.org

George R. Koerner is the
director of the Geosynthetic
Institute in Folsom, Pa.

1020GS_p36-cv4.indd 42

s 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 polymer formulators have made in creating long-term
durable materials.
Open literature is full of cautionary tales of wind uplift on geomembranes. When a geosynthetic is caught in high winds, there is a possibility that it can be damaged (wrinkled,
torn, stretched, etc.), depending on the wind velocity, the
altitude above sea level and
the facility location; however,
the benefits of leaving a geosynthetic exposed, specifically
FIGURE 1 Photo of permanently exposed geosynthetic cover
not needing cover soil, can
of an MSW landfill (Courtesy of Wind Defender)
sometimes outweigh the risk.
One thing that has not
been standardized is a test
method to characterize how
a geosynthetic performs in
the wind. Material wind damage assessments of specific
materials are now available
through two configurations
(flag and awning) wind tunFIGURE 2 Photograph of wind tunnel setup showing motor
nel tests. These tests will
control rheostat (input), and digital manometer (output)
allow us to make practical
recommendations on how to
create more wind-resistant
materials and help us minimize the magnitude of damage caused by the wind on
exposed geosynthetics.
FIGURE 3 Overview schematic of wind tunnel apparatus showing
The "wind whip" behavior
five key components
of geosynthetics is a phenomenon defined by measurable negative property changes in a coupon after exposure to sustained
wind speeds over time. We can now simulate this environmental phenomenon in a controlled
laboratory setting using a commercially available wind tunnel. The properties for evaluation
of exposed specimens can be compared to the unexposed "as-received" material properties,
yielding a percent retained value. The target properties include tensile performance, normalized thickness and mass per unit area. In addition, qualitative observations (wrinkles,
fraying, cracking, flaking, exposed scrim, etc.) of the material can be contrasted before and
after exposure in the wind tunnel with a controlled speed and duration of laminar flow.

9/22/20 1:45 AM


http://www.geosynthetic http://www.institute.org

Geosynthetics October/November 2020

Table of Contents for the Digital Edition of Geosynthetics October/November 2020

Geosynthetics October/November 2020 - Cover1
Geosynthetics October/November 2020 - Cover2
Geosynthetics October/November 2020 - 1
Geosynthetics October/November 2020 - 2
Geosynthetics October/November 2020 - 3
Geosynthetics October/November 2020 - 4
Geosynthetics October/November 2020 - 5
Geosynthetics October/November 2020 - 6
Geosynthetics October/November 2020 - 7
Geosynthetics October/November 2020 - 8
Geosynthetics October/November 2020 - 9
Geosynthetics October/November 2020 - 10
Geosynthetics October/November 2020 - 11
Geosynthetics October/November 2020 - 12
Geosynthetics October/November 2020 - 13
Geosynthetics October/November 2020 - 14
Geosynthetics October/November 2020 - 15
Geosynthetics October/November 2020 - 16
Geosynthetics October/November 2020 - 17
Geosynthetics October/November 2020 - 18
Geosynthetics October/November 2020 - 19
Geosynthetics October/November 2020 - 20
Geosynthetics October/November 2020 - 21
Geosynthetics October/November 2020 - 22
Geosynthetics October/November 2020 - 23
Geosynthetics October/November 2020 - 24
Geosynthetics October/November 2020 - 25
Geosynthetics October/November 2020 - 26
Geosynthetics October/November 2020 - 27
Geosynthetics October/November 2020 - 28
Geosynthetics October/November 2020 - 29
Geosynthetics October/November 2020 - 30
Geosynthetics October/November 2020 - 31
Geosynthetics October/November 2020 - 32
Geosynthetics October/November 2020 - 33
Geosynthetics October/November 2020 - 34
Geosynthetics October/November 2020 - 35
Geosynthetics October/November 2020 - 36
Geosynthetics October/November 2020 - 37
Geosynthetics October/November 2020 - 38
Geosynthetics October/November 2020 - 39
Geosynthetics October/November 2020 - 40
Geosynthetics October/November 2020 - 41
Geosynthetics October/November 2020 - 42
Geosynthetics October/November 2020 - 43
Geosynthetics October/November 2020 - 44
Geosynthetics October/November 2020 - 45
Geosynthetics October/November 2020 - 46
Geosynthetics October/November 2020 - 47
Geosynthetics October/November 2020 - 48
Geosynthetics October/November 2020 - Cover3
Geosynthetics October/November 2020 - Cover4
Geosynthetics October/November 2020 - Geosynthetics Conf. Brochure 1
Geosynthetics October/November 2020 - Geosynthetics Conf. Brochure 2
Geosynthetics October/November 2020 - Geosynthetics Conf. Brochure 3
Geosynthetics October/November 2020 - Geosynthetics Conf. Brochure 4
Geosynthetics October/November 2020 - Geosynthetics Conf. Brochure 5
Geosynthetics October/November 2020 - Geosynthetics Conf. Brochure 6
Geosynthetics October/November 2020 - Geosynthetics Conf. Brochure 7
Geosynthetics October/November 2020 - Geosynthetics Conf. Brochure 8
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