Presto GEOWEB^® Load Support System
For comprehensive information on the Geoweb^® Load Support 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.

Unacceptable road and yard surface problems, resulting from subgrade material failure or base material instability, can be solved using the Geoweb^® Load Support System. The Geoweb system is the right solution because it stabilizes base materials and minimizes surface rutting. After installation, it is ready for immediate access.  The system produces a stiff base with high flexural strength acting like a semi-rigid slab by distributing loads laterally and reducing subgrade contact pressures.

The Geoweb system strengthens structural fill used in load support applications by adding an apparent cohesion to cohesionless materials. When concentrated or distributed loads are imposed on the system, the three-dimensional cellular structure controls shearing and lateral movement of the infill material. The cell hoop strength, passive resistance of adjacent-filled cells, and frictional interaction between the infill and cell walls all contribute to the support structure.

UA-Uses, Applications
The Geoweb system provides a load distribution system over weak soils, base stabilization for paved surfaces and surface stabilization for unpaved surfaces.

The Geoweb system advantages for road base, trackbed and intermodal yard stabilization:

• produces a still base with high flexural strength,
• acts like a semi-rigid slab by distributing loads laterally and reducing subgrade contact pressures,
• prevents the lateral displacement of infill,
• reduces vertical deflections, and
• restrains differential and total settlement even on low-strength subgrades.

The Geoweb system also allows the use of on-site sands and poor quality granular fills in place of more costly imported materials. This is particularly important in areas where quality aggregate is either unavailable or too costly to transport.

Pipe Support
For underground pipe support, the Geoweb system is easy to install and eliminates the need for over-excavation and placement of excessive quantities of stone.  Regular granular bedding material can be used since the system stiffens the pipe bed material through confinement. This results in a firm working slab created with the Geoweb system, limiting long-term differential settlement.

Load Support Applications

• Granular access roads
• Soft access roads
• Porous pavements
• Pavement sub-bases and bases
• Parking lots
• Storage yards
• Intermodal facilities
• Boat ramps
• Retaining wall spread footings
• Foundation mattresses
• Trench inverts
• Low level crossings
• Track ballast structures

CP-Components, Parts
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.

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, 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 (0.4 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 (0.3 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 Load Support Applications

Geoweb® Cell Dimension
GW30V Cell
Cell Depth:  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 in single or multiple layers of 4 and 6-inch depths for both under payment reinforcement and near-surface stabilization.

GW20V Cell
Cell Depth:  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 in single or multiple layers of 4 and 6-inch depths for near-surface stabilization

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
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)

OP-Overall Product
Road Base Stabilization
The Geoweb system creates a road base that holds up under heavy traffic, acting as a semi-rigid slab, distributing loads laterally. The system reduces subgrade contact pressures, and minimizes load deformation and settlement. With the Geoweb system in place, it is possible to use lower quality sand infills for temporary and permanent road construction, even over very soft subgrades.

Selection of infill materials for foundation and road base stabilization is a function of the nature and magnitude of anticipated loads and overall performance requirements. Typically, a wide range of granular materials can be used as infill.

Intermodal Yards
Cellular confinement with the Geoweb system improves load distribution characteristics on paved and unpaved yards. Subgrade contact pressure from dynamic and static loadings are distributed throughout the three-dimensional cellular network of the Geoweb system, reducing pavement deflection and rutting.  Future maintenance costs are minimized, making the Geoweb system a cost-effective solution.

Track Ballast
The Geoweb system prevents lateral displacement of ballast and sub-ballast materials, resulting in improved track structure stiffness for greater rail alignment and stability. Differential and total settlement of the ballast, even on low-strength subgrades, is significantly reduced. Long-term track performance in high-traffic areas such as grade crossings, switches and turnouts, is greatly improved.

Access Roads/Permeable Pavements
The Geoweb system infilled with aggregate provides a permeable pavement system for access roads, parking areas and emergency lanes. With over 98% open area, the Geoweb system maximizes groundwater replenishment and minimizes surface runoff. Utilizing native granular soils provides a functional, cost-effective alternative to hard surface paving. Porous pavements are also ideal in environmentally-sensitive wetland areas. Soft pavements can be vegetated when a properly designed aggregate/topsoil mixture is used for the infill. Traffic frequency and loading are critical considerations.

Earn USGBC LEED™ credits for storm water runoff reduction, reduction of heat island effect, and reducing site disturbance.

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 are typically used for installations where dimensional tolerances are critical.

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
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.