Presto GEOWEB^® Slope Protection System
For comprehensive information on the Geoweb^® Slope Protection System, please click on the web site link listed above.

Presto Products Company, the leader in cellular confinement, provides fully engineered solutions to soil stabilization problems from engineering design, to quality documentation and on-site support availability.

Engineering advancements are on-going at Presto. Recent advancements include the introduction of the perforated Geoweb^® system, high-strength tendons, ATRA^® Clips and the ATRA^® Anchoring System.

ISO-Certified Quality
Presto’s commitment to quality begins with manufacturing and continues through final installation.  The quality management system for the sale, design and manufacture of the Geoweb® system is certified to ISO 9001:2000 and materials are specifically engineered in accordance with established geosynthetic industry guidelines.

SPECMaker^® Specification Development Tool
Presto developed the SPECMaker^® Specification Development Tool, a user-friendly software program that lets designers and/or contractors develop complete material and construction specifications.

PP-Product Presentation
Presto’s Geoweb^® system is an expandable polyethylene, honeycomb-like structure used to confine unstable soils, sands or gravel.  The Geoweb system provides solutions to slope and channel protection, earth retention and load support problems.

The Geoweb^® Slope Protection System can be used to meet a wide range of performance and aesthetic requirements. The three-dimensional system confines the determined infill material to resist anticipated hydraulic flows, inhibit erosion and prevent the downward migration of embankment materials. Single or multi-layered protection systems provide sustainable solutions for a wide range of structural and run-off problems.

A variety of infill materials can be used with the Geoweb Slope Protection System. The choice of infill materials is based upon the demands of the specific project or problem.  Infill materials include:

• Topsoil with various selected vegetation
• Aggregates from sand and gravel to larger rock or stone
• Concrete of various strengths and surface finishes
• Combinations of the above to meet specific conditions

On vegetated slopes, the system increases erosion resistance by encapsulating and protecting the vegetative root zone. The system helps prevent rills and gullies from forming, particularly in areas of concentrated flow over erosive soils. Perforations allow roots to grow from cell-to-cell, creating greater vegetative mass lockup and stability against short-term hydraulic events. Concrete infill provides hard, durable protection of slopes exposed to severe hydraulic or mechanical stresses.

The Geoweb Slope Protection System offers a broad range of surface protection treatments for all slopes. The system is designed for flexibility and can be combined with a variety of simple, yet positive anchoring techniques to allow the application of both vegetated and hard surfacing materials on steep slopes. The Geoweb system also provides a means of fully vegetating slope surfaces that otherwise could not support plant life.

The Geoweb system provides long-term stability and effectiveness of slope cover materials in the following applications

• Embankment slopes
• Containment dikes and levees
• Abutment protection
• Landfill lining and covers
• Dam faces and spillways
• Shoreline revetments
• Cut slopes
• Detention ponds and lagoons

The Perforated Geoweb System
The perforated Geoweb^® system has an engineered hole pattern, increasing frictional interlock with a broad range of coarse infill materials, including gravels, crushed rock and concrete. The perforations allow lateral drainage through the cell walls, facilitating parallel slope drainage of the infilled cell.

In saturated conditions, an overall weight reduction of the infill material reduces down slope sliding potential, resulting in a more stable system. In vegetated systems, roots can grow from cell-to-cell, creating greater vegetative mass lockup. Perforations provide greater frictional resistance between the cell wall and aggregate and other coarse infill materials. Perforations allow concrete infill to flow through the cells, resulting in a superior armored slope system.

CP-Components, Parts
Tendons
Polymeric tendons incorporated into the Geoweb system through pre-drilled holes provide additional stability when anchoring Geoweb sections to embankments and slopes. Tendons are particularly useful when a geomembrane underlayer or naturally hard soil/rock prevents anchoring with stakes.  Standard tendons are manufactured from knitted multi-filament high-strength polyester and polyproplylene. The tendons are available in ultimate tensile strengths from 3.11 kN (700 lbf) to 13.34 kN (3,000 lbf) to meet specific requirements.

The ATRA^® Anchoring System
Presto’s high-strength polyethylene ATRA^® Clip provides time and material cost savings during Geoweb system installation. Inserted on the end of a stake, the ATRA^® Anchor provides an in-line, easy to drive anchoring system, replacing J-Pin anchors. When used with tendons, the ATRA^® Anchor provides resistance to excessive sliding and/or uplift forces and toe or crest anchoring for slope protection systems.

The ATRA^® Clip restraint pin connects to tendons at specific load-transfer points replacing the need for dowels or other less-secure load-transfer mechanisms.

Perforated GEOWEB^® System Performance & Material Specification

Base Material
Material Composition
Polymer – Polyethylene with density of 0.935 – 0.965/cm³ (58.4-60.2 lb/ft³)
Test Method: ASTM D1505
Minimum Environmental Stress Crack Resistance (ESCR): 3,000 hr
Test Method: ASTM D1693

Color
Black – from Carbon Black
Stabilizer: Carbon black content 1.5% - 2% by weight

Strip Properties
Sheet Thickness
1.27 mm -5% +10% (50 mil –5% +10%)
Test Method: ASTM D5199

Surface Treatment
All Geoweb material shall be textured with a multitude of rhomboidal (diamond shape) indentations having a surface density of 22-31 per cm² (140 – 200 per in²).
Performance:  The polyethylene strips shall be perforated such that the peak friction angle between the surface of the perforated plastic and a #40 silica sand at 100% relative density shall be no less than 85% of the peak friction angle of the silica sand in isolation when tested by the direct shear method per ASTM D 5321. The quantity of perforations shall remove 19.6% ± 3% of the cell wall area.
Material:  The polyethylene strips shall be perforated with horizontal rows of 10 mm (0.4 in) diameter holes. Perforations within each row shall be 19 mm (0.75 in) on-center. Horizontal rows shall be staggered and separated 12 mm (0.50 in) relative to the hole centers. The edge of strip to the nearest edge of perforation shall be 8 mm (0.3in) minimum and the centerline of the weld to the nearest edge of perforation shall be 18 mm (0.7 in) minimum.

Cell & Seam Properties for Slope Protection Applications

Geoweb® Cell Dimension
GW20V Cell
Cell Depth:  75 mm (3 in), 100 mm (4 in), 150 mm (6 in) and 200 mm (8 in)
Nominal Cell Width: 259 mm (10.2 in)
Nominal Cell Length: 224 mm (8.8 in)
Nominal Cell Area: 289 cm² (44.8 in²)
Use 3, 4 or 6-inch depth for only the most severe conditions

GW30V Cell
Cell Depth:  75 mm (3 in), 100 mm (4 in), 150 mm (6 in) and 200 mm (8 in)
Nominal Cell Width: 320 mm (12.6 in)
Nominal Cell Length: 287 mm (11.3 in)
Nominal Cell Area:  460 cm² (71.3 in²)
Use 3, 4 or 6-inch depth for all general conditions.

GW40V Cell
Cell Depth:  75 mm (3 in), 100 mm (4 in), 150 mm (6 in) and 200 mm (8 in)
Nominal Cell Width: 508 mm (20.0 in)
Nominal Cell Length: 475 mm (18.7 in)
Nominal Cell Area: 1206 cm² (187.0 in²)
Use 3, 4 or 6-inch depth for only the most mild conditions.

Short-Term Seam Peel Strength

Short-term cell seam peel-strength shall be uniform over the full depth of the cell. Minimum short-term seam peel-strengths shall be:

Cell Depth	Minimum Cell Seam Strength
75 mm (3 in)	1060 N (240 lbf)
100 mm (4 in)	1420 N (320 lbf)
150 mm (6 in)	2130 N (480 lbf)
200 mm (8 in)	2840 N (640 lbf)

Long-Term Seam Hang Strength Test
Long-term seam peel-strength test shall be performed on all resin or pre-manufactured sheet or strips. A 100 mm (4.0 in) wide seam sample shall support a 72.5 kg (160 lb) load for a period of 168 hours (7 days) minimum in a temperature-controlled environment that undergoes change on a 1-hour cycle from room temperature to 54°C (130°F). Ambient room temperature is per ASTM E 41.

Section Properties
Geoweb® Section Dimensions

		Section Length (Cells Long: 18, 21, 25, 29, 34)
	Section Width (Variable)	Minimum	Maximum
GW20V	2.3 m (7.7 ft) to 2.8 m (9.2 ft)	3.7 m (12.0 ft)	8.3 m (27.3 ft)
GW30V	2.3 m (7.7 ft) to 2.8 m (9.2 ft)	4.7 m (15.4 ft)	10.7 m (35.1 ft)
GW40V	2.3 m (7.7 ft) to 2.8 m (9.2 ft)	7.7 m (25.4 ft)	17.8 m (58.2 ft)

OP-Overall Product
Geomembrane Protection
The Geoweb Slope Protection System, with a variety of infills, provides protection to geomembranes in the following applications: lagoons, detention ponds, storm water containment basins, dikes, temporary dams and landfill covers.

The inclusion of internal tendons and ATRA^® Clip load transfer pins provides a structural support system that maintains the integrity of the impervious liner or cover.  The system directly protects the geomembrane from accidental puncturing, vandalism and natural degradation, and indirectly prevents soil contamination and erosion.

Vegetated Slopes
Well-established vegetation is recognized as an effective and attractive form of protection for slopes exposed to mild or moderate surface erosion. Cellular confinement with the Geoweb system confines and reinforces the vegetative mat. The cells increase the vegetation’s natural resistance to erosive forces and protect the root zone from loss of soil particles.

The Geoweb cell walls, which contain the topsoil infill, form a series of check-dams extending throughout the protected slope. A predetermined depth of topsoil and the developing vegetative root mass is confined and protected within the individual cells. Rill development, produced when concentrated flow cuts into the soil, is prevented since flow is continuously redirected to the surface. The vegetated Geoweb system is ideal when project aesthetics are an important consideration.

Slope Armoring: Concrete Protection
Poured concrete provides hard, durable protection for slopes that are exposed to severe hydraulic or mechanical stresses. The Geoweb system can eliminate the need for complicated structural elements and expensive, time-consuming construction techniques. Concrete quantities and costs can be controlled with the Geoweb system because of the defined section thickness. The quality, surface finish and thickness of the concrete can be selected to meet specific design needs.

Infilling the Geoweb cells with ready-mixed concrete produces a durable, erosion-resistant slope cover of uniform thickness which retains flexibility and the ability to conform to potential subgrade movement. Special compacted granular bedding layers, necessary with conventional poured concrete slabs, can be omitted. The Geoweb system helps prevent uncontrolled cracking of the concrete and reduces the chances of piping and undermining.

Non-Vegetated Slopes
The Geoweb system also provides effective slope protection by improving the erosion resistance of granular materials such as sand, gravel and larger rock or stone.  Confinement of these aggregates within Geoweb cells permits their use on steeper slopes than would otherwise be possible. Hydraulic energy is dissipated and down-slope migration of individual particles, caused by gravity and hydraulic traction, is minimized. A wide range of slope geometry can be accommodated by selecting the appropriate cell size and cell depth for the aggregate considered.

Earn USGBC LEED™ credits for reduced site disturbance and reducing heat island effect with roof gardens.

AI-Assembly, Installation
The Geoweb system is designed with ease of installation in mind. Geoweb sections collapse into lightweight, compact bundles for easy shipment. During installation, sections remain flexible and easy to handle. Various methods are used for expanding the Geoweb sections.

TS-Technical Support
Presto offers complete design and construction tools for the designer and/or contractor. These tools are available on Presto’s Technical Resources Library CD or at Presto’s web site www.prestogeo.com:

• Application overviews
• Case histories
• Material and design specifications
• AutoCAD^® drawings
• PowerPoint^® presentations
• Installation guidelines
• General and construction videos
• SPECMaker^® Specification Development Tool

Presto Products Company - Geosystems® Products
A Business of Alcoa
P.O. Box 2399
670 N. Perkins Street
Appleton, WI 54912-2399
Tel: (920) 738-1336
Toll-Free: (800) 548-3424
Fax: (920) 738-1222
Toll-Free Fax: (800) 535-8221

PRESTO^®, GEOSYSTEMS^®, GEOWEB^®, ATRA^® and SPECMaker^® are registered trademarks of Presto Products Company. LEED™ is a trademark of the US Green Building Council. © 1998-2004
This information has been prepared for the benefit of customers interested in the Geoweb cellular confinement system. It was reviewed carefully prior to publication.  Presto Products Company assumes no liability for its accuracy or completeness. Final determination of the suitability of any information or material for the use contemplated, or for its manner of use, is the sole responsibility of the user.