Presto GEOWEB^® Earth Retention System
For comprehensive information on the Geoweb^® Earth Retention 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 ongoing 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^® Earth Retention System meets all structural requirements and provides construction flexibility and aesthetics through a completely vegetated face. Horizontal terraces are formed where sustainable vegetation can flourish in the exposed outer cells. The system meets site challenges, particularly when subgrades are comprised of compressible, unstable soils.

The primary function of a Geoweb earth retention structure is to provide a very steep or vertical surface that minimizes erosion and is structurally stable under its self-weight and known externally imposed loads. The near vertical change in grade requires that earth materials be stacked higher and steeper than their internal shear strength properties will permit. Consequently, the magnitude of lateral earth pressure that these earth structures must resist is directly related to:

Height of the change in grade
Internal shear strength of the earth materials
Geometry of slope above the structure
Magnitude of any imposed surcharge loading

Key criteria for the selection of certain types of Geoweb earth retention structures include the project site soil conditions, availability of suitable backfill materials, project economics and the desired aesthetics of the completed site.

A variety of infill materials can be used with the Geoweb Earth Retention System based upon the demands of the specific project/problem. Infill materials include:

Granular materials such as sand, gravel or graded stone
Concrete of various strengths and surface finishes
Topsoil with various selected vegetation

UA-Uses, Applications
The use of earth retention structures has expanded in recent years as transportation and highway upgrades require steepened slopes to accommodate existing rights-of-way. In addition, the development of prime industrial, residential and commercial property has spilled over onto sites requiring additional improvements. The Geoweb cellular confinement system has been specifically developed to meet the challenges of change-in-grade construction, particularly when the subgrades are comprised of compressible soils. The Geoweb system’s versatility offers many earth retention applications, including:

Widening within existing rights-of-way
Adding a lane of traffic or parking
Grading development sites to boundary limits
Providing truck or emergency vehicle access
Expanding sports fields and storage yards
Reshaping and stabilizing storm water channels
Building storm water retention structures
Repair of failed slopes and retention structures
Safety barriers along transportation corridors
Energy absorbers
Noise abatement walls

MF-Materials, Finishes
The Perforated Geoweb System
The perforated system improves frictional interaction between the perforated cell wall and soil, resulting in greater back wall friction, potentially reducing horizontal destabilizing forces and increasing vertical stabilizing forces. Perforated cells with the appropriate infill material can meet drainage needs and eliminate the need for more complex drainage systems. Hydrostatic forces will be reduced in a better-drained system, resulting in a potentially lower mass and more economical wall structure.

Colored Facing
The Geoweb^® Earth Retention System is available in a variety of natural colors – black, green or tan – to meet desired facia aesthetic requirements. Coloring pigments contain no heavy metals and the polyethylene is ultraviolet light stabilized with carbon black or Hindered-Amine Light Stabilizer (HALS) to resist color fading and increase system durability.

Durability
The Geoweb Earth Retention System is extremely durable, manufactured from polyethylene material that is resistant to penetration by chemicals and water. The Geoweb material eliminates any potential for cracking, spalling, splintering or corrosion that typically affects concrete, steel and timber-based earth retention systems. This makes the system very adaptable to structures exposed to seawater, extreme pH soils, or road de-icing salts and chemicals.

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
Tan, Green, Other Colors with no heavy metal content
Stabilizer: Hindered amine light stabilizer (HALS) 1.0% by weight of carrier

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 (0.391 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 8mm (0.3 in) 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 Earth Retention Applications

Geoweb® Cell Dimension
GW30V Cell
Cell Depth: 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)

GW20V Cell
Cell Depth: 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)

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-strength shall be:

Cell Depth Minimum Cell Seam Strength

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). Room temperature is defined in ASTM E41.

Section Properties

Geoweb® Section Dimensions

Section Length

Section Width Cells Length

GW30V 2.64 m (8.67 ft) – 8 Cells 3 .80 m (2.63 ft)

4 1.07 m (3.50 ft)

5 1.33 m (4.38 ft)

6 1.60 m (5.25 ft)

7 1.87 m (6.13 ft)

Depth for All Sections: 150 mm (6 in)

Face Area for all Sections: 0.40 m² (4.33 ft²)

GW20V 2.67 m (8.75 ft) – 10 Cells 3 .63 m (2.06 ft)

4 .84 m (2.75 ft)

5 1.05 m (3.44 ft)

6 1.26 m (4.12 ft)

7 1.47 m (4.81 ft)

Depth for All Sections: 150 mm (6 in)

Face Area for All sections 0.41 m² (4.38 ft²)

OP-Overall Product
Flexible Design Solutions
The basic Geoweb system can be adapted to a wide range of design requirements and site conditions. The system’s extreme versatility results from its inherent flexibility, unique load deformation behavior and suitability for a wide range of infill materials and foundation soils. The Geoweb system can cost-effectively replace many conventional earth retention structures constructed as:

Concrete cantilever
Mechanically stabilized earth (MSE) or earth-anchored
Soldier pile and lagging with or without tiebacks
Concrete gravity
Concrete crib
Timber crib
Sheet pile
Steel bin type

Retaining Walls
The Geoweb system’s multi-layered design makes it very adaptable to specific retaining wall application requirements. Classic methods of stability analysis can be applied, and computerized evaluation is available for a broad range of infill, backfill and surcharge parameters. The system offers a range of non-structural colored facias allowing vegetative growth in the outer cells for better blending with the environment. Simple, effective construction techniques make the Geoweb system ideal for installations in remote or restricted access sites.

Gravity Retaining Walls
The Geoweb system confines and reinforces granular fill, producing a uniform structural mass that resists lateral pressures and maintains structural integrity. Significant subgrade deformation can occur without loss of structural integrity. Geoweb sections can be used in vertical or stepped designs and the system supports non-structural facias or natural vegetative cover.

Composite Retaining Walls
Cellular confinement with the Geoweb system eliminates the need for expensive structural facia panels. The Geoweb system creates a totally confined wall facing that can be united with the backfill using a variety of tie-back systems. Outer cells can be filled with topsoil to support natural vegetative cover.

The Geoweb retaining wall system blends into the environment with vegetated facings and a choice of natural colors. The vegetated face treatment also provides a surface that has noise-absorbing tendencies.

Earn USGBC LEED™ credits for reduced site disturbance.

AC-Availability, Cost
Geoweb retention structures are cost-competitive with conventional earth retention systems. Geoweb retention systems can offer a 25% to 50% cost savings over cast-in-place concrete retaining walls. The installed cost for all earth retention systems will vary with site-specific conditions such as accessibility, soil conditions, cost of infill and compaction, labor rates, surcharge loading, length of wall and other factors.

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. Stretcher frames or stretcher bars are typically used for expanding Geoweb sections and maintaining dimensional tolerances in earth retention applications.

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

MR-Manufacturer

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
Web site: http://www.prestogeo.com

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.