Geosynthetics April/May 2021 - 10

Modular geosynthetics
construction
By E. Silva, T. D. Stark and Duff Simbeck

E. Silva is vice president at
E2 Technologies.
T. D. Stark is professor of civil
engineering at the University of Illinois
at Urbana-Champaign.
Duff Simbeck is vice president of
Simbeck and Associates.
All figures courtesy of the authors

Geosynthetics | April May 2021

odular construction is a process in which a building or other item is constructed
primarily off-site; under controlled factory conditions; and using the same design,
materials, equipment, testing and construction quality control and assurance (CQC/CQA)
techniques as a field-constructed facility-but usually in about one-half the time (Modular
Building Institute). Roof trusses, wood or concrete tilt-up walls, shower enclosures, tile patterns and other items are all examples of products that have adopted modular construction.
In modular construction, portions of the project are produced in " modules " that, when
put together on-site, reflect the design, specifications, materials and quality of the most
sophisticated field or on-site constructed facility (Modular Building Institute). In addition,
the factory-controlled process generates higher quality, less waste, fewer site disturbances,
and a more predictable and shorter construction schedule.
This article focuses on the use of modular construction for geosynthetics. The same
benefits of using modular construction for buildings can be realized with geosynthetics.
For example, installation of a factory-fabricated geomembrane can occur simultaneously
with site work, allowing the project to be completed in as much as one-half of the time
required for traditional field fabrication. Another example is factory-fabrication of geosynthetic tubes for coastal protection, cofferdams or a dam system to isolate parts of a river
channel for sediment removal (Fraser and Neal 2021). More importantly, weather delays
can be significantly reduced because 60%-100% of the fabrication can be completed inside
a factory instead of the field, which mitigates the risk of weather delays. This results in
the containment system being utilized sooner and creating a faster return on investment
(Modular Building Institute). Removing approximately 60%-100% of the geomembrane
fabrication from the site also significantly reduces site disruption, vehicular traffic and
hydrocarbon-powered equipment, and improves overall site safety and security.
Factory-fabricated geosynthetics are constructed with the same materials, equipment and
technicians, and to the same design standards, as field-fabricated geosynthetics. However,
the constant and favorable factory-controlled environmental conditions yield higher quality-such as seams between individual geomembrane rolls-than field-fabricated seams.
Stark et al. (2020) compared factory- and field-welded thermal geomembrane seams for
a large off-stream water reservoir project. This comparison showed that factory-welded
seams exhibit higher seam peel and shear strengths at yield, less variability and more consistency than field-welded thermal seams. In particular, the results showed that factory
seams are about 10% stronger than field seams in shear and about 9% stronger in peel

Geosynthetics April/May 2021

Table of Contents for the Digital Edition of Geosynthetics April/May 2021