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Introduction to Cellular Introduction to Cellular GeosyntheticsGeosynthetics
(Geofoams and Geocombs)(Geofoams and Geocombs)
A Manhattan College Center for GeotechnologyTechnology Transfer through Distance Learning Program
Educational Product
Presentation prepared by
John S. Horvath, Ph.D., P.E.Professor of Civil Engineering
Director/Center for Geotechnology
Manhattan CollegeSchool of Engineering
Bronx, New York, U.S.A.
© 3 September 2001 by John S. Horvath. All rights reserved.
Manhattan College · School of Engineering · Center for Geotechnology
Construction Material Changes
• improvements to traditional materials (steel and PCC)
• development of new functions (roles) and applicationsfor existing materials
• development of new materials
• use of recycled waste materials
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Manhattan College · School of Engineering · Center for Geotechnology
Construction Material Changes
• improvements to traditional materials (steel and PCC)
• development of new functions (roles) and applicationsfor existing materials <<< geocombs and some geofoams
• development of new materials <<< some geofoams
• use of recycled waste materials <<< some geofoams
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Manhattan College · School of Engineering · Center for Geotechnology
Geofoam ...
Generic term for any closed-cell foam used in a geotechnical application that is manufactured either in a fixed plant or in-situ from an expansion process using a blowing agent:
• polymeric (plastic)– polyethylene (PE)– expanded polystyrene (EPS) <<< predominant– extruded polystyrene (XPS)– polyurethane (PUR)
• glass (cellular glass)
• cementitious
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Manhattan College · School of Engineering · Center for Geotechnology
EPS block in temporary storage after molding.The entire block weighs less than the person handling it!
05
Manhattan College · School of Engineering · Center for Geotechnology
Example of one of at least three different designs ofEPS-shape geofoam "anti-buoyancy" blocks
developed in Japan (dimensions in millimetres).
06
Manhattan College · School of Engineering · Center for Geotechnology
Geocomb ...
… the newest "geo" material (geosynthetic), formerly referred to as "structures alveolaires ultra légères" (SAUL) or "ultra light cellular structures" (ULCS) in France where it was developed and has been used since the 1980s.
… defined as an open-cell (honeycomb shaped in cross-section) polymeric (PP, PVC) material created by an extrusion process. Typically supplied as a panel- or block-shaped final product.
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Manhattan College · School of Engineering · Center for Geotechnology
PP (left) and PVC (right) geocombs.
typical tube (~ 25 mm/1 in)
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Manhattan College · School of Engineering · Center for Geotechnology
Benefits of Using Geofoams and Geocombs
• efficient use of solid material • work with the forces of nature, not against them
• can be useful for both new construction and with existing structures, permanent and temporary, all climates/weather, "good" and "poor" ground
• provide unique geosynthetic functions
• can be multifunctional in many applications
• compatible and synergistic with other types of geosynthetics
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Manhattan College · School of Engineering · Center for Geotechnology
Overview of Design Process
• design by function to identify desired properties
• define parameters for desired analyses and obtain relevant technical information for these parameters
• generally treat as an equivalent earth material and use conventional geotechnical analytical methods
• economic assessment (construction + O&M)
• relevant standards and specifications
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Manhattan College · School of Engineering · Center for Geotechnology
Geosynthetic Functions
• thermal insulation (1960s) >>> geofoams only
• lightweight fill (1970s) >>> geofoams & geocombs
• drainage (1970s) >>> geofoams & geocombs
• noise/vibration damping (1980s) >>> geofoams only
• compressible inclusion (1980s) >>> geofoams only
• structural (1990s) >>> geofoams only11
Manhattan College · School of Engineering · Center for Geotechnology
Important Aspects of Material Behavior andOther Technical Issues for Design
• index properties
• mechanical (stress-strain-time) behavior
• thermal properties
• constructability and safety
• durability
• environmental impact
12
Manhattan College · School of Engineering · Center for Geotechnology
Factors to Consider in an Economic Assessment
• design aspects of initial construction
• constructability aspects of initial construction
• reduced costs of operation and maintenance
13
Manhattan College · School of Engineering · Center for GeotechnologyManhattan College · School of Engineering · Center for Geotechnology
Standards and Specifications
• standards constitute technology documentation and are the foundation of any technology
• specifications are the project-specific application of relevant standards to define the minimum acceptable results in a given application
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Manhattan College · School of Engineering · Center for GeotechnologyManhattan College · School of Engineering · Center for Geotechnology
Thermal Insulation Benefits
• life-cycle energy cost savings
• construction cost savings
• improved geotechnical/structural performance
15
Manhattan College · School of Engineering · Center for GeotechnologyManhattan College · School of Engineering · Center for Geotechnology
Thermal Insulation Applications
• buildings and storage tanks (all climates)
• landfill liners (all climates)
• shallow buried structures (all climates)
• earth retaining structures (cold climates)
• pavements and railways (cold climates)
• underground conduits (cold climates)
• shallow foundations (cold climates)16
Manhattan College · School of Engineering · Center for Geotechnology
Test of landfill-liner thermal insulation alternatives in the U.S.A.17
Manhattan College · School of Engineering · Center for Geotechnology
Use of geofoam behind an earth retaining structure to prevent seasonal freezing of the wall drainage system
and retained soil.Note that the drainage system could be incorporated into the geofoam product for overall increased efficiency and
reduced cost.
drainage layer
geofoam
18
Manhattan College · School of Engineering · Center for Geotechnology
Rebuilding an existing road in Norway with geofoam insulation.19
Manhattan College · School of Engineering · Center for Geotechnology
Rebuilding an existing railway in Norway with geofoam insulation.20
Manhattan College · School of Engineering · Center for Geotechnology
Use of geofoam above an underground conduit to locally modify the depth of seasonal freezing to allow shallower conduit embedment. Note that the geofoam could also be
designed to act as a compressible inclusion to reduce forces acting on the conduit.
geofoam
normal conduit depth
depth of seasonalfreezing
21
Manhattan College · School of Engineering · Center for Geotechnology
Typical Frost Protected Shallow Foundation concept application.
geofoam
depth ofseasonalfreezing
footing depthwithout insulation
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Manhattan College · School of Engineering · Center for GeotechnologyManhattan College · School of Engineering · Center for Geotechnology
Lightweight Fill Applications
• embankments and fills: transportation water resources foundation support architecture and landscaping
• earth retaining structure backfill and fills
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Manhattan College · School of Engineering · Center for Geotechnology
Rebuilding a failed road embankment in the U.S.A.in the winter using EPS-block geofoam.
24
Manhattan College · School of Engineering · Center for Geotechnology
Spraying a PCC facing on a "geofoam wall" type road fillin the mountains of Japan.
25
Manhattan College · School of Engineering · Center for Geotechnology
Constructing an EPS-block geofoam road embankment in Norwayfor a combined bridge approach fill and bridge abutment foundation.
Note the wooden formwork for the abutment footing.26
Manhattan College · School of Engineering · Center for Geotechnology
Using EPS-block geofoam to construct an abutment backfillfor a new road bridge in Chile.
27
Manhattan College · School of Engineering · Center for Geotechnology
Completed approach embankment and abutment backfillusing EPS-block geofoam for a new road bridge in Canada.
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Manhattan College · School of Engineering · Center for Geotechnology
Constructing an approach embankment and abutment backfillusing geocomb blocks for a road bridge in France.
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Manhattan College · School of Engineering · Center for Geotechnology
Rehabilitating and raising a levee in the U.S.A. using EPS-block geofoam.30
Manhattan College · School of Engineering · Center for Geotechnology
Building basement wall in the U.S.A. backfilled using EPS-block geofoam.31
Manhattan College · School of Engineering · Center for Geotechnology
Anchored bulkhead in Japan partially backfilledusing EPS-block geofoam.
32
Manhattan College · School of Engineering · Center for Geotechnology
Barbed connector plates used between blocks of EPS geofoamin Japan (dimensions are in millimetres, 25 mm = 1 in).
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Manhattan College · School of Engineering · Center for Geotechnology
100 mm (4 in) square barbed connector plateused between blocks of EPS geofoam in the U.S.A.
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Manhattan College · School of Engineering · Center for GeotechnologyManhattan College · School of Engineering · Center for Geotechnology
Drainage Applications
• fluid transmission using geofoams: ground water around below-grade structures ground water behind earth retaining structures leachate collection systems in landfills ground-borne gases around below-grade structures
• fluid transmission and storage using geocombs
35
Manhattan College · School of Engineering · Center for Geotechnology
EPS-shape geofoam product developed in the U.K. specifically for collecting and draining ground-borne gases
such as methane and radon. Note that it also provides thermal insulation for the structure. 36
Manhattan College · School of Engineering · Center for Geotechnology
Geofoam drainage geocomposite available in Asia, Europe and theU.S.A. that uses a glued polystyrene porous block core.
glued polystyrene porous blockhigh-permeability core
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Manhattan College · School of Engineering · Center for Geotechnology
Geofoam sheet-drain product composed of pieces ofrecycled PE that was developed in The Netherlands.
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Manhattan College · School of Engineering · Center for Geotechnology
Drainage (fluid transmission and storage) applicationsusing geocomb panels and blocks developed in France.
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Manhattan College · School of Engineering · Center for GeotechnologyManhattan College · School of Engineering · Center for Geotechnology
Noise and Vibration Damping Applications
• attenuation of small-amplitude, ground-borne vibrations from:
motor vehicles trains
• attenuation of noise from trains
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Manhattan College · School of Engineering · Center for Geotechnology
EPS-block geofoam used to dampen noise and vibrations from a railway in Germany . The EPS blocks directly
beneath the tracks are also acting as a lightweight fill for the clay ("Ton") subgrade.
PCC slabEPS-block geofoam
EPS-block geofoam
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Manhattan College · School of Engineering · Center for Geotechnology
EPS-block geofoam used to dampen noise and vibrationsfrom light-rail vehicles (trams/trolleys) in France and Germany.
EPS-block geofoam
PCC layers
PCC ties (sleepers)
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Manhattan College · School of Engineering · Center for GeotechnologyManhattan College · School of Engineering · Center for Geotechnology
Compressible Inclusion Applications
• lateral earth pressure and settlement reduction:
shear-strength mobilization of "normal" soils volume change of expansive/freezing soil/rock structure movement
• vertical stress reduction from expansive soil/rock
• vertical arching above underground conduits
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Manhattan College · School of Engineering · Center for Geotechnology
tensile reinforcement(optional)
geofoam
Use of geofoam compressible inclusion behind a rigid/non-yielding earth retaining structure to reduce
lateral earth pressures(optional use of geosynthetic tensile reinforcement also
shown).
soil movement
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Manhattan College · School of Engineering · Center for Geotechnology
Use of a resilient-EPS geofoam geocomposite in the U.S.A. to act as acompressible inclusion to accommodate integral-abutment bridge
movement. Drainage is also provided by the same product.
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Manhattan College · School of Engineering · Center for Geotechnology
Use of a geofoam compressible inclusion aroundfoundation elements of a structure to
reduce stresses in expansive ground (soil or rock) conditions.
geofoam
ground movement
ground movementground movement
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Manhattan College · School of Engineering · Center for Geotechnology
EPS-block geofoam used as a compressible inclusion around areinforced-PCC grade beam in expansive soil in the U.K.(geofoam also served as formwork during construction).
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Manhattan College · School of Engineering · Center for Geotechnology
EPS-block geofoam used as a compressible inclusion beneath a deep-foundation supported tunnel base slab in
expansive ground in the U.K. 48
Manhattan College · School of Engineering · Center for Geotechnology
EPS-block geofoam product used as a compressible inclusion beneatha deep-foundation supported base slab of a building in Canada
(similar product also developed in U.K.).
49
Manhattan College · School of Engineering · Center for Geotechnology
Use of a geofoam compressible inclusion above anunderground conduit to reduce vertical stresses acting on
theconduit by inducing vertical arching within the overlying
soil.
ground movement
geofoam
ground movement
50
Manhattan College · School of Engineering · Center for Geotechnology
Multifunctional use of a geofoam geocomposite only ~ 150 mm (6 in)thick simultaneously providing compressible inclusion, drainage and
thermal insulation behind a building basement wall in the U.S.A.
51
Manhattan College · School of Engineering · Center for GeotechnologyManhattan College · School of Engineering · Center for Geotechnology
Structural/Miscellaneous Applications
• forms for PCC walls • MSEW facing panels
• void formers for PCC slabs
• crash barriers for motor vehicles and aircraft
• impact cushioning for rock sheds
• void filling and foundation remediation
52
Manhattan College · School of Engineering · Center for Geotechnology
Panels cut from block-molded EPS used as formwork for a reinforced-PCC basement wall in the U.S.A. The EPS also
provides post-construction thermal insulation for the life of the structure. 53
Manhattan College · School of Engineering · Center for Geotechnology
MSEW system developed in the U.K. with geogrid reinforcementand facing panels cut from block-molded EPS.
54
Manhattan College · School of Engineering · Center for Geotechnology
Generic components of EIFS technology used over EPS and XPSto create a wide variety of durable architectural finishes.
mesh reinforcementunderlayment
two-part stucco-likefinish
EPS
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Manhattan College · School of Engineering · Center for Geotechnology
Block-molded EPS used as a lightweight void former for apile-supported structural slab constructed over a soft
subgradein the U.S.A.
56
Manhattan College · School of Engineering · Center for Geotechnology
EPS blocks used as crash-cushioning barriers around an auto-racing track in the U.S.A. Note evidence of extensive
prior collision damage.
Credit: Paul Arch Racing Photos
EPS blocks
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Manhattan College · School of Engineering · Center for Geotechnology
EPS blocks used as protection for PCC rock sheds inmountainous areas in Europe and Japan.
EPS blocks
58