Earth Retention Retaining Walls

SECTION 32 32 00

EARTH RETENTION RETAINING WALLS

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** NOTE TO SPECIFIER ** Presto Geosystems; Geoweb Cellular Confinment System, Earth Retention Retaining Walls.
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** NOTE TO SPECIFIER ** This section is based on the products of Presto Geosystems, which is located at:
670 N. Perkins St. P. O. Box 2399
Appleton, WI 54912-2399
Toll Free Tel: 800-548-3424
Tel: 920-736-1336
Fax: 920-738-1222
Email:request info ()
Web:
[Click Here] for additional information.
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The Presto Geoweb earth retention system is a structurally-sound green alternative to modular block retaining walls. The system meets all design requirements while providing desired aesthetics through a completely vegetated face. Horizontal terraces are formed where vegetation can flourish in the exposed outer cells. The Geoweb system is easy to transport and construct even in difficult-access or remote locations and it performs well in soft soil environments. The system is a low-impact solution that contributes to LEED® green building credits for reducing site development, impervious cover and storm water runoff.
Consult Presto Geosystems for assistance in editing this section for the specific application.

PART 1 GENERAL

1.1 SECTION INCLUDES

** NOTE TO SPECIFIER ** Delete items below not required for project.

A. Earth Retention Retaining Walls.

1.2 RELATED SECTIONS

** NOTE TO SPECIFIER ** Delete any sections below not relevant to this project; add others as required.

A. Section 31 20 00 - Earth Moving.

B. Section 31 32 13.13 - Asphalt Soil Stabilization

C. Section 33 46 13.13 - Foundation Drainage Piping.

D. Section 32 10 00 - Bases, Ballasts, and Paving.

E. Section 32 90 00 - Planting.

F. Section 32 92 13 - Hydro-Mulching.

1.3 REFERENCES

** NOTE TO SPECIFIER ** Delete references from the list below that are not actually required by the text of the edited section.

A. AASHTO M 288 - Geotextile Specification for Highway Applications.

B. ASTM D 638 - Standard Test Method for Tensile Properties of Plastics.

C. ASTM D 1505 - Density of Plastics by the Density-Gradient Technique.

D. ASTM D 1603 - Standard Test for Carbon Black in Olefin Plastics.

E. ASTM D 1693 - Environmental Stress-Cracking of Ethylene Plastics.

F. ASTM D 5199 - Measuring Nominal Thickness of Geotextiles and Geomembranes.

G. ASTM E 41 - Terminology Relating to Conditioning.

1.4 SUBMITTALS

A. Submit under provisions of Section 01 30 00 - Administrative Requirements.

B. Product Data: Submit manufacturer's product data.

C. Shop Drawings: Submit manufacturer's shop drawings including laying pattern and anchoring.

D. Samples: Submit manufacturers sample.

E. Certificates:

1. Resin manufacturer's certification of polyethylene density and environmental stress crack resistance (ESCR).

2. Reports showing test results of actual minimum shot term and long term seam strengths for the products provided.

3. Product certificates signed by the manufacturer certifying material compliance of polyethylene used to make Geoweb.

4. ISO Certification certifying manufacturer's quality management system is currently registered to ISO 9001:2015 quality standards.

5. Reports showing test results of that the high-density polyethylene resin for Geoweb sections has been tested using in seam samples under varying loads to indicate that the seam peel strength shall survive a loading of at least 160 lbf (73 kg) for a minimum of 10,000 hours.

F. Installation Instructions: Manufacturer's printed installation instructions. Include methods for maintaining installed products.

G. Manufacturers warranty.

H. Manufacturer's Certificates: Certify products meet or exceed specified requirements.

1.5 QUALITY ASSURANCE

A. Manufacturer ISO Certification: ISO Certification certifying manufacturer's quality management system for its Geoweb system is currently registered to ISO 9001:2015 quality standards.

** NOTE TO SPECIFIER ** Delete the following paragraph if on-site installation assistance is not desired.

B. Manufacturer's Field Representative Qualifications:

1. Manufacturer shall provide a qualified field representative on site at the start of construction to ensure the Geoweb system is installed in accordance with the Contract Documents.

2. Manufacturer's field representative shall have a minimum 5 years documented installation experience with the specified products in the specified application.

** NOTE TO SPECIFIER ** Retain the following paragraphs if required to suit project. Delete if not required.

C. Installer Qualifications: Experienced in performing work of this section and who has specialized in installation of work similar to that required for this project.

D. Preinstallation Meeting: Convene a meeting a minimum of two weeks prior to start of earth retention retaining wall system. Verify project requirements, subbase conditions, manufacturer's installation instructions and coordination with other work. Require attendance of parties directly affecting work of this section, including the Contractor, Engineer, installer, and manufacturer's representative.

1.6 DELIVERY, STORAGE, AND HANDLING

A. Delivery: Deliver materials to site in manufacturer's original, unopened containers and packaging, with labels clearly identifying product name and manufacturer.

B. Storage: Store materials in accordance with manufacturer's instructions.

C. Handling: Protect materials during handling and installation to prevent damage.

1.7 WARRANTY

A. Warranty: Manufacturer's ten year limited warranty.

PART 2 PRODUCTS

2.1 MANUFACTURERS

A. Acceptable Manufacturer: Presto Geosystems, which is located at: 670 N. Perkins St. P. O. Box 2399; Appleton, WI 54912-2399; Toll Free Tel: 800-548-3424; Tel: 920-736-1336; Fax: 920-738-1222; Email:request info (); Web:

** NOTE TO SPECIFIER ** Delete one of the following two paragraphs; coordinate with requirements of Division 1 section on product options and substitutions.

B. Substitutions: Not permitted.

C. Requests for substitutions will be considered in accordance with provisions of Section 01 60 00 - Product Requirements.

2.2 MATERIALS

** NOTE TO SPECIFIER ** Geoweb® Cellular Confinement System is used for Earth Retention Retaining Walls.

A. Geoweb: Geoweb Cellular Confinement System.

1. Materials: Polyethylene Stabilized with Carbon Black.

a. Density: 58.4 to 60.2 pound/ft3 (0.935 to 0.965 g/cm3) in accordance with ASTM D 1505.

b. Environmental Stress Crack Resistance (ESCR): 5000 hours in accordance with ASTM D 1693.

c. Ultra-Violet light stabilization with carbon black.

d. Carbon Black Content: 1.5 to 2 percent by weight, through addition of a carrier with certified carbon black content.

** NOTE TO SPECIFIER ** Tan or green colored front fascia is typical for Geoweb walls. Delete the following paragraphs if a colored front fascia is NOT required.

2. Polyethylene Colored and Stabilized with HALS (Front Wall Fascia)

a. Density shall be 58.4 to 60.2 pound/ft3 (0.935 to 0.965 g/cm3) in accordance with ASTM D 1505.

b. ESCR shall be 5000 hours in accordance with ASTM D 1693.

** NOTE TO SPECIFIER ** Select the desired wall color.

c. Color: Tan.

d. Color: Green.

e. Colorants shall be non-heavy metal types homogeneously distributed throughout the material.

f. Ultra-Violet Light Stabilization with HALS.

g. HALS Content shall be 1.0 percent by weight, through addition of a carrier with a certified HALS concentrate.

h. HALS shall be homogeneously distributed throughout material.

3. Cell Properties:

a. Individual cells are uniform in shape and size when expanded.

b. Individual cell dimensions (nominal) shall be plus or minus 10 percent of the specified dimensions.

c. GW30V-Cell

1) Length: 11.3 inches (287 mm).

2) Width: 12.6 inches (320 mm).

3) Nominal Area: 71.3 in2 (460 cm2) plus or minus 1 percent.

4) Nominal Depth:

a) 6 inches (150 mm).

4. Strip Properties and Assembly

a. Perforated Textured Strip/Cell

1) Strip sheet thickness (before surface disruption) 50 mil (1.27 mm), minus 5 percent, plus 10 percent in accordance with ASTM D 5199.

2) Polyethylene strips are surface textured with a multitude of rhomboidal (diamond shape) indentations.

3) Textured sheet thickness 60 mil plus or minus 6 mil (1.52 mm plus or minus 0.15 mm).

4) Indentation surface density 140 to 200 per in2 (22 to 31 per cm2).

5) Strips perforated with horizontal rows of 0.4 inch (10 mm) diameter holes.

6) Perforations within each row are 0.75 inches (19 mm) on-center.

7) Horizontal rows are staggered and separated 0.50 inches (12 mm) relative to hole centers.

8) Edge of strip to nearest edge of perforation are a minimum of 0.3 inches (8 mm).

9) Centerline of spot weld to nearest edge of perforation is a minimum of 0.7 inches (18 mm).

10) Provide with a slot of 3/8 inch by 1-3/8 inch (10 mm by 35 mm) in the center of the non-perforated areas and at the center of each weld.

b. Non-Perforated Textured Strip/Cell

1) Non-perforated textured strip/cells shall only be used on the front face of earth retention systems.

2) Strip sheet thickness shall be 50 mils (1.27 mm), minus 5 percent, plus 10 percent in accordance with ASTM D 5199. Determine thickness flat, before surface disruption.

3) Textured sheet thickness shall be 60 mils plus or minus 6 mils (1.52 mm plus or minus 0.15 mm).

4) Polyethylene strips shall be textured surface with a multitude of rhomboidal (diamond shape) indentations.

5) Indentation surface density shall be 140 to 200 per in2(22 to 31 per cm2).

6) Thickness of the textured sheet shall be 60 mil plus or minus 6 mil (1.52 mm plus or minus 0.15 mm) determined in accordance with ASTM D 5199.

c. Assembly of Cell Sections

1) Fabricate using strips sheet polyethylene 142 inches (3.61 m) long and a width equal to cell depth.

2) Connect strips using full depth ultrasonic spot-welds aligned perpendicular to longitudinal axis of strip.

3) Ultrasonic weld melt-pool width shall be 1.0 inch (25 mm) maximum.

4) Weld spacing for GW30V-cell sections shall be 17.5 inches plus or minus 0.10 inch (445 mm plus or minus 2.5 mm).

5. Performance: Minimum seam strengths are required by design and shall be reported in test results submitted for approval. Materials submitted with average or typical values will not be accepted.

a. Minimum seam strengths are required by design and shall be reported in test results. Materials submitted with average or typical values will not be accepted. Written certification of minimum strengths must be supplied to the engineer at the time of submittals.

b. Short-Term Seam Peel-Strength Test

1) Cell seam strength shall be uniform over full depth of cell.

2) Minimum seam peel strength:

a) 480 lbf (2,130 N) for 6 inch (150 mm) depth.

c. Long-Term Seam Peel-Strength Test

1) Conditions: Minimum of 7 days in a temperature-controlled environment that undergoes change on a 1 hour cycle from room temperature to 130 degrees F (54 degrees C).

2) Room temperature shall be in accordance with ASTM E 41.

3) Test samples shall consist of two, 4 inch (100 mm) wide strips welded together.

4) Test sample consisting of 2 carbon black stabilized strips shall support a 160 pound (72.5 kg) load for test period.

** NOTE TO SPECIFIER ** Delete the following paragraph if a colored front fascia is not desired. Contact Presto Geosystems for assistance.

5) Test sample consisting of a carbon black stabilized strip and HALS stabilized strip shall support a 140 pound (63.5 kg) load for test period.

d. 10,000 Hour Seam Peel-Strength: Seam peel strength shall survive a loading of at least 160 lbf (73 kg) for a minimum of 10,000 hours.

** NOTE TO SPECIFIER ** Select all components required from the following paragraphs and delete those not required. ATRA anchors may be used to temporarily hold Geoweb wall sections during infilling and are typically not required for permanent anchoring. ATRA keys shall be used to connect adjacent cells including the front face of the wall. Staples shall only be used to connect the front fascia strips.

B. Panel Accessories:

1. ATRA Clip

a. Molded, high-strength polyethylene device available in standard (0.5 inch) and metric (10- 12 mm) versions.

2. ATRA Anchors:

a. Standard (0.5 inch) or metric (10 to 12 mm) steel reinforcing rod with an ATRA Clip attached as an end cap.

3. Assemble ATRA anchors by inserting the ATRA Clip onto the reinforcing rod so that the end is flush with the top of the ATRA Clip. Prior to attaching the ATRA Clip, the reinforcing rod shall be free from all burrs and beveled.

4. ATRA Key

a. Constructed of polyethylene and provide a high strength connection.

b. Used to connect Geoweb panels together at each interleaf and end to end connection for all applications including the front face of the walls.

5. Staples: 1/2 inch, Stanley Bostitch, SL5035, used to connect the adjoining front fascia sections of walls.

2.3 CELL INFILL MATERlALS

** NOTE TO SPECIFIER ** Select infill material type(s) required from the following paragraphs and delete those not required. Contact Presto Geosystems for assistance. Coordinate infill materials with Section 31 20 00 - Earth Moving and Section 32 10 00 - Bases, Ballasts, and Paving as required.

A. Cell Infill General:

1. Infill material shall be free-flowing and not frozen when placed in the Geoweb sections.

2. Clays and silts are not acceptable infill material.

3. Infill material shall be free of any foreign material.

B. Non-Vegetated Wall: Cell infill material shall be gravel, crushed aggregate or stone with a maximum particle size of 3 inches (75 mm).

C. Non-Vegetated Wall: Cell infill material shall be concrete with a minimum strength of 3000 psi and air content of 2 to 4 percent in accordance with ACI and ASTM standards as specified in Section 03 30 00 - Cast-in-Place Concrete.

D. Vegetated Wall: Cell infill material shall be an engineered fill consisting of topsoil and aggregate mixture for vegetated surfaces.

1. Engineered infill shall be a mix of topsoil and aggregate having a homogeneous mixture of a clear crushed aggregate having an AASHTO #5 or similar designation blended with pulverized topsoil and a minimum 30 percent void space for air and/or water.

2. Mixture will be suitable to promote vegetation growth and provide structural support.

3. Aggregate portion shall have a particle range from 0.375 to 1.0 inches (9.5 to 25 mm) with a D50 of 0.5 inches (13 mm).

4. Percentage void space of the aggregate portion when compacted shall be at least 30 percent.

5. Pulverized topsoil portion shall equal 25 percent of the total volume. Topsoil shall be blended with the aggregate to produce a homogeneous mixture.

6. Once placed, the mixture shall be compacted to a 95 percent Standard Proctor.

7. Coordinate with vegetation specified in Section 32 92 13 - Hydro-Mulching.

PART 3 EXECUTION

3.1 EXAMINATION

A. Before beginning installation, verify site conditions are as indicated on the Drawings. Notify the Architect if site conditions are not acceptable. Do not begin preparation or installation until unacceptable conditions have been corrected.

3.2 PREPARATION

A. Subgrade:

** NOTE TO SPECIFIER ** Coordinate paragraphs below with earthwork specified in Section 32 10 00 - Bases, Ballasts, and Paving.

1. Prepare subgrade as specified in Section 32 10 00 - Bases, Ballasts, and Paving. Shape subgrade in accordance with earth retention system manufacturer's instructions and the approved shop drawing layout of structure.

2. Ensure foundation soil meets minimum strength requirements through proof rolling or other conventional method and is approved an Engineer registered at the project location. If unacceptable foundation soils are encountered, excavate affected areas and replace with suitable quality material as directed by the Engineer.

3. Provide adequate drainage from excavated area if area has potential to collect water, when working with in-place soils that have poor permeability.

4. Ensure in-place soil is relatively dry and free from standing water.

5. Uniformly grade base.

6. Level and clear base of large objects, such as rocks and pieces of wood.

** NOTE TO SPECIFIER ** Delete geotextile section below if not required. Contact Presto Geosystems for assistance.

7. Install geotextile separation layer on prepared surfaces ensuring required overlaps are maintained and outer edges of geotextile are buried in accordance with the Manufacturer's recommendations.

B. Base and Spread Footing Installation

1. Place and shape granular base materials. If a free draining granular base is utilized, encapsulate in a non-woven geotextile. Compact to a minimum 95 percent Standard Proctor.

2. Expand Geoweb sections into place and temporarily anchor at corners with ATRA anchors.

3. Overfill Geoweb cells with specified granular infill. Maximum particle size shall be 2 inches (50 mm). Level surface approximately 2 inches (50 mm) above cell walls.

4. Compact fill in Geoweb cells to a minimum 95 percent Standard Proctor.

5. Place and compact fill to a minimum 95 percent Standard Proctor along each side of footing.

6. Screed off excess infill to be level with top of cells.

** NOTE TO SPECIFIER ** An effective drainage system is essential for proper design of Geoweb earth retention systems. Generally, the granular infill provides adequate drainage for relief of hydrostatic pressure. A more comprehensive drainage system may be required for walls where groundwater is a concern.

C. Drainage System Installation

1. Install perforated subdrain and outlet pipes in accordance with Section 33 46 13.13 - Foundation Drainage Piping. Subdrain pipe shall be wrapped with non-woven geotextile or backfilled with clear stone to prevent plugging.

2. Provide a minimum slope of 1 percent for all drainage piping.

3. Wrap outlet pipes which pass through wall fascia with non-woven geotextile to prevent loss of cell infill materials.

4. Ensure outlets for all discharge piping will not cause localized erosion that could undermine the wall.

3.3 INSTALLATION

A. Install and Geoweb sections in accordance with the manufacturer's instructions.

** NOTE TO SPECIFIER ** Select the Gravity Retaining Wall System or the Reinforced Retaining Wall System from the following paragraphs and delete the one not required. Contact Presto Geosystems for assistance.

B. Gravity Retaining Wall:

1. Expand Geoweb sections into place. Hold individual sections in their expanded position with stretcher frames, stretcher bars or ATRA anchors positioned inside selected outer cells

2. Confirm each Geoweb section is expanded uniformly to required dimensions and outer cells of each layer are correctly aligned and upper surfaces are flush.

3. Interleaf edges of adjacent sections and connect with ATRA keys or staples on all connections including the front fascia. ATRA keys are the most expedient connection method.

4. Overfill cells with granular material and level surface approximately 2 inches (50 mm) above cell walls.

5. Compact cell infill material to a minimum 95 percent Standard Proctor with a walk-behind-compactor. Avoid using heavy compaction equipment within 3 feet (1 meter) of the front face of the wall.

6. Place the backfill material behind the Geoweb sections in maximum 8 inch (200 mm) lifts and compact as specified.

7. Screed off excess infill so the infill is level with the top of the cells.

8. When topsoil or special infill materials are specified for exposed face cells of Geoweb sections, temporarily cover outer cells with a moveable board to prevent unwanted spillage during placement of internal fill materials as each layer is installed. Place topsoil or special infill in empty outer cells as each layer is completed. Partial spillage of internal infill material into outer cells may be permitted.

9. When positioning subsequent layers, ensure specified set back of each layer and the vertical alignment of the outer cells are maintained to prevent the loss of infill materials.

C. Reinforced Retaining Wall:

1. Expand Geoweb sections into place. Hold individual sections in their expanded position with stretcher frames, stretcher bars or ATRA anchors positioned inside selected outer cells.