MasterFormat: 2020
Download this Earth Retention Retaining Walls Specification for   WORD | WORD-Canadian | WP | RTF | TEXT
Find over 500 more construction specifications | Arcat.com
         
Presto Geosystems Earth Retention Retaining Walls
 
         
SECTION 32 32 00
 
         
EARTH RETENTION RETAINING WALLS
 
         
 
         
Copyright 2012 - 2022 ARCAT, Inc. - All rights reserved

          ** NOTE TO SPECIFIER ** Presto Geosystems; Geoweb Soil Stabilization System.
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: http://www.prestogeo.com
[ Click Here ] for additional information.
PRESTO GEOSYSTEMS partners with architects and engineers to offer a full range of solutions for creating long-lasting porous pavements and solving challenging soil stabilization problems. The GEOBLOCK grass pavers and GEOPAVE® gravel pavers deliver durable, low-maintenance, permeable options to support any loading requirement and manage stormwater on-site. The GEOWEB® 3D soil stabilization system provides benefits in diverse environmental design applications including permeable pavements, slope erosion control, channel, and shoreline protection, vegetated MSE retaining walls and surface protection applications. The GEORUNNER® and GEOTERRA® systems are strong, yet light-weight construction mats ideal for site access and 40-70% more economical than timber or heavy HDPE mats. Presto offers free project evaluation service.
 
          PART 1GENERAL
 
          1.1SECTION INCLUDES
          ** NOTE TO SPECIFIER ** Delete items below not required for project.
 
          A.Earth Retention Retaining Walls.
 
          1.2RELATED 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: 02200 - Site Preparation.
 
          C.Section 31 32 13.13 - Asphalt Soil Stabilization
 
          D.Section 33 46 13.13 - Foundation Drainage Piping.
 
          E.Section 32 10 00 - Bases, Ballasts, and Paving.
 
          F.Section 32 90 00 - Planting.
 
          G.Section 32 92 13 - Hydro-Mulching.
 
          1.3REFERENCES
          ** NOTE TO SPECIFIER ** Delete references from the list below that are not actually required by the text of the edited section.
 
          A.American Association of State Highway and Transportation Officials (AASHTO):
          1.AASHTO M218 - Steel Sheet, Zinc-Coated (Galvanized) for Corrugated Steel Pipe.
          2.AASHTO M288 - Geotextile Specification for Highway Applications.
 
          B.American Society of Testing and Materials (ASTM):
          1.ASTM D1505 - Density of Plastics by the Density-Gradient Technique.
          2.ASTM D1603 - Standard Test for Carbon Black in Olefin Plastics.
          3.ASTM D1693 - Environmental Stress-Cracking of Ethylene Plastics.
          4.ASTM D5394 - Standard Test Method for Environmental Stress-Cracking of Ethylene Plastics.
          5.ASTM D5199 - Measuring Nominal Thickness of Geotextiles and Geomembranes.
          6.ASTM D5596 - Standard Test Method for Microscopic Evaluation of the Dispersion of Carbon Black in Polyolefin Geosynthetics.
          7.ASTM D5721 - Standard Practice for Air-Oven Aging of Polyolefin Geomembranes.
          8.ASTM D5885 - Standard Test Method for Oxidative Induction Time of Polyolefin Geosynthetics by High-Pressure Differential Scanning Calorimetry.
          9.ASTM D6693 (Type IV) - Standard Test Method for Determining Tensile Properties of Nonreinforced Polyethylene and Nonreinforced Flexible Polypropylene Geomembranes.
          10.ASTM D7328 - Standard Test Method for Effect of Exposure of Unreinforced Polyolefin Geomembrane Using Fluorescent UV Condensation Apparatus
          11.ASTM E41 - Terminology Relating to Conditioning.
 
          C.US Army Corps of Engineers (USACE):
          1.Technical Report GL-86-19, Appendix A.
 
          D.International Organization for Standardization (European Union) (EN-ISO):
          1.EN ISO 13438 - Screening test method for determining the resistance of geotextiles and geotextile-related products to oxidation
          2.EN 12224 - Geotextiles and geotextile-related products - Determination of the resistance to weathering
          3.EN ISO 13426 - Geotextiles and geotextile-related products - Strength of internal structural junctions - Part 1: Geocells
          4.EN ISO 10319 - Geosynthetics - Wide-width tensile test
 
          1.4SUBMITTALS
 
          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.Manufacturer's Certificate of Analysis: Manufacturer shall supply certificate of analysis containing the following test results for the cellular confinement material used for project: Base Resin Lot Numbers, Resin Density per ASTM D1505, Production Lot Numbers, Material Thickness, Short Term Seam Peel Strength, and percentage of Carbon Black.
          ** NOTE TO SPECIFIER ** Delete Manufacturer's certification if black front fascia is chosen.
          1.Manufacturer's certification of hindered amine light stabilizer (HALS).
          ** NOTE TO SPECIFIER ** Delete installer qualifications if not desired.
 
          E.Submit qualifications certifying the installer is experienced in the installation of the specified products.
          ** NOTE TO SPECIFIER ** Delete Manufacturer's field representative if not desired.
 
          F.Submit qualifications of Manufacturer's field representative certifying the field representative is experienced in the installation of the specified products.
 
          G.No material will be considered as an equivalent to the GEOWEB material specified herein unless it meets all requirements of this specification, without exception. Manufacturers seeking to supply what they represent as equivalent material must submit records, data, independent test results, samples, certifications, and documentation deemed necessary by the Engineer to prove equivalency. The Engineer shall approve or disapprove other Manufacturers materials in accordance with the General Conditions after all information is submitted and reviewed. Any substitute materials submitted shall be subject to independent lab testing at the Contractor's expense.
 
          1.5QUALITY ASSURANCE AND CONTROL
 
          A.The cellular confinement system material shall be provided from a single Manufacturer for the entire project.
 
          B.The Manufacturer's Quality management system shall be certified and in accordance with ISO 9001:2015 and CE certification. Any substitute materials submitted shall provide a certification that their cellular confinement manufacturing process is part of an ISO program, and a certification will be required specifically stating that their testing facility is certified and in accordance with ISO. An ISO certification for the substitute material will not be acceptable unless it is proven it pertains specifically to the geocell manufacturing operations.
 
          C.The Manufacturer shall provide certification of compliance to all applicable testing procedures and related specifications upon the customer's written request. Request for certification shall be submitted no later than the date of order placement. The Manufacturer shall have a minimum of 20 years' experience producing cellular confinement systems.
          ** NOTE TO SPECIFIER ** Delete pre-installation meeting if not required.
 
          D.Pre-Installation Meeting: Prior to installation of any materials, conduct a pre-installation meeting to discuss the scope of work and review installation requirements. The pre-installation meeting shall be attended by all parties involved in the installation of the cellular confinement system.
          ** NOTE TO SPECIFIER ** Delete section if Manufacturer's field representative is not required.
 
          E.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' installation experience with the specified products in the specified application.
          3.Manufacturer of any substitute materials to be used shall certify that a representative can meet the above criteria and will be on site for initial construction start up. Manufacturers other than Presto shall be required to provide proof the representative meets these qualifications.
 
          1.6DELIVERY, 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.Materials: Stored in accordance with Manufacturer's instructions. The materials shall be protected from damage and out of direct sunlight.
 
          C.The materials shall be delivered, unloaded, and installed in a manner to prevent damage.
 
          1.7WARRANTY
 
          A.The Manufacturer shall warrant each GEOWEB section that it ships to be free from defects in materials and workmanship at the time of manufacture. The Manufacturer's exclusive liability under this warranty or otherwise will be to furnish without charge to the original f.o.b. point a replacement for any section which proves to be defective under normal use and service during the 10 year period which begins on the date of shipment. The Manufacturer reserves the right to inspect any allegedly defective section to verify the defect and ascertain its cause.
 
          B.This warranty shall not cover defects attributable to causes or occurrences beyond the Manufacturer's control and unrelated to the manufacturing process, including, but not limited to, abuse, misuse, mishandling, neglect, improper storage, improper installation, improper alteration, or improper application.
 
          C.In no event shall the Manufacturer be liable for any special, indirect, incidental, or consequential damages for the breach of any express or implied warranty or for any other reason, including negligence, in connection with the GEOWEB geocell system.
 
          PART 2PRODUCTS
 
          2.1MANUFACTURERS
 
          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: http://www.prestogeo.com
          ** 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.
 
          2.2CELLULAR CONFINEMENT SYSTEM (GEOWEB)
 
          A.Manufacturing Certification: The Manufacturer shall have earned a certificate of registration, which demonstrates that its quality-management system for its GEOWEB cellular confinement system is currently registered to the ISO 9001:2015 and CE quality standards.
 
          B.Basis of Design: Geoweb Cellular Confinement System. For Earth Retention Retaining Walls.
 
          C.Bas Materials:
          1.Polyethylene Stabilized with Carbon Black:
          a.Density: 58.4 to 60.2 lbs per cu ft (0.935 to 0.965 grams per cu cm) in accordance with ASTM D1505.
          b.Environmental Stress Crack Resistance (ESCR): 5000 hours in accordance with ASTM D1693.
          c.Resistance to Oxidation: 50 years in accordance with EN ISO 13438.
          d.Strip Tensile Strength: 100 percent of original strip tensile strength to be retained following exposure to accelerated weathering in accordance with EN 12224.
          e.Ultra-Violet light stabilization with carbon black.
          f.Carbon Black Content: 1.5 to 2 percent by weight, through addition of a carrier with certified carbon black content.
          g.Carbon black shall be homogeneously distributed throughout material.
          h.The manufacturer must have an in-place quality control to prevent irregularities in strip material.
          ** 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: 58.4 to 60.2 lbs per cu ft (0.935 to 0.965 grams per cu cm) in accordance with ASTM D1505.
          b.ESCR: 5000 hours in accordance with ASTM D1693.
          ** NOTE TO SPECIFIER ** Select the desired wall color.
          c.Color: Tan.
          d.Color: Green.
          e.Colorants: Non-heavy metal types homogeneously distributed throughout material.
          f.Ultra-Violet Light Stabilization: With HALS.
          g.HALS Content: 1.0 percent by weight, through addition of a carrier with a certified HALS concentrate.
          1)HALS: Homogeneously distributed throughout material.
 
          D.Cell Properties: GW30V.
          1.Individual cells are uniform in shape and size when expanded.
          2.Individual cell dimensions (nominal) shall be plus or minus 10.
          a.Length: 10.5 inches (267 mm).
          b.Width: 13.0 inches (330 mm).
          c.Nominal Area: 68.3 sq inches (440 sq cm) plus or minus 1 percent.
          d.Nominal Depth: 6 inches (150 mm).
 
          E.Strip Properties and Assembly:
          ** NOTE TO SPECIFIER ** Perforated textured strips are used for interior wall sections. Non-perforated textured strips are used for the front wall fascia. Both sections below are necessary. Contact Presto Geosystems for assistance.
          1.Perforated Textured Strip/Cell:
          a.Strip Sheet Thickness, Before Surface Disruption: 0 mil (1.27 mm), minus 5 percent, plus 10 percent in accordance with ASTM D5199.
          b.Polyethylene strips are surface textured with a multitude of rhomboidal (diamond shape) indentations.
          c.Textured Sheet Thickness: 60 mil plus or minus 6 mil (1.52 mm plus or minus 0.15 mm).
          d.Indentation Surface Density: 140 to 200 per sq inch (22 to 31 per sq cm).
          e.Strips perforated with horizontal rows of 0.4 inch (10 mm) diameter holes.
          f.Perforations Within Each Row: 0.75 inches (19 mm) on-center.
          g.Horizontal Rows: Staggered and separated 0.50 inches (12 mm) relative to hole centers.
          h.Edge of Strip to Nearest Edge of Perforation: A minimum of 0.3 inches (8 mm).
          i.Centerline of Spot Weld to Nearest Edge of Perforation: A minimum of 0.7 inches (18 mm).
          j.Slot: 3/8 by 1-3/8 inch (10 by 35 mm) in center of non-perforated areas and at center of each weld.
          2.Non-Perforated Textured Strip/Cell:
          a.To only be used on front face of earth retention systems.
          b.Strip Sheet Thickness: 50 mils (1.27 mm), minus 5 percent, plus 10 percent in accordance with ASTM D5199. Determine thickness flat, before surface disruption.
          c.Textured Sheet Thickness: 60 mils plus or minus 6 mils (1.52 mm plus or minus 0.15 mm).
          d.Polyethylene Strips: Textured surface with a multitude of rhomboidal (diamond shape) indentations.
          e.Indentation Surface Density: 140 to 200 per sq inch (22 to 31 per sq cm).
          f.Thickness of Textured Sheet: 60 mil plus or minus 6 mil (1.52 mm plus or minus 0.15 mm) determined in accordance with ASTM D5199.
          3.Assembly of Cell Sections:
          a.Fabricate using strips sheet polyethylene 142 inches (3.61 m) long and a width equal to cell depth.
          b.Connect strips using full depth ultrasonic spot-welds aligned perpendicular to longitudinal axis of strip.
          c.Ultrasonic Weld: Melt-pool width to be 1.0 inch (25 mm) maximum.
          d.Weld Spacing for GW30V Cell Sections: 17.5 inches plus or minus 0.10 inch (445 mm plus or minus 2.5 mm).
 
          F.GW30V Section Types and Sizes:
          ** NOTE TO SPECIFIER ** Select the desired GEOWEB® section length. The design may include more than one section length. Contact Presto Geosystems for assistance.
          1.Section Length: Wall configuration shall be as shown in the Contract Documents.
          a.3-cells long. 2.63 ft (0.80 m).
          b.4-cells long: 3.50 ft (1.07 m).
          c.5-cells long: 4.38 f (1.33 m).
          2.Section Width for All Lengths: 8.67 ft (2.64 m).
          3.Face Area for all Sections: 4.33 sq ft (0.40 sq m).
 
          G.Cell Seam Strength Tests
          1.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 Engineer at time of submittals.
          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: Uniform over full depth of cell.
          2)Minimum Seam Peel Strength: 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 E41.
          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 lbs (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 to support a 140 lbs (63.5 kg) load for test period.
          d.Internal Junction Efficiency: 100 percent or greater.
          1)Determined as ratio of junction performance to perforated strip performance, as determined by EN ISO 13426-1 and EN ISO 10319, respectively.
          e.Mechanical Junction Efficiency: 100 percent or greater.
          1)Determined as ratio of junction performance to perforated strip performance, as determined by EN ISO 13426-1 and EN ISO 10319, respectively.
          2)Connection Type: To be with integral components as designated by Manufacturer.
          f.Seam Peel-Strength Test: 10,000 hours.
          1)Provide data showing high-density polyethylene resin used to produce GEOWEB sections has been tested using an appropriate number of seam samples and varying loads to generate data indicating seam peel strength will survive a loading of 160 lbf (73 kg) for 10,000 hours.
 
          2.3INTEGRAL COMPONENTS
          ** NOTE TO SPECIFIER ** Select all components that apply and delete the others. 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. Staples may also be used.
 
          2.4Contact Presto Geosystems for assistance.
 
          A.ATRA Clips / Anchors:
          1.The ATRA Clip: Molded, high-strength polyethylene device available in standard 0.5 inch and metric (10 to 12 mm) versions.
          2.ATRA Anchors: 0.5 inch or metric (10 to 12 mm) steel reinforcing rod with an ATRA Clip attached as an end cap.
          3.ATRA Anchors: Assembled by inserting ATRA Clip onto reinforcing rod so the end is flush with top of the ATRA Clip. Prior to attaching the ATRA Clip, reinforcing rod to be free from all burrs and beveled.
 
          B.ATRA Key: Constructed of polyethylene. Provides a high strength connection with pull-through of 275 lbs (125 kg).
          1.Used to connect GEOWEB panels together at each interleaf and end-to-end connection for all applications, including front face of walls.
 
          C.Staples: May also be used for connections. To be 1/2 inch (13 mm), Stanley Bostitch, SL5035.
 
          2.5CELL INFILL MATERIALS
          ** NOTE TO SPECIFIER ** Specify desired infill material. Contact Presto Geosystems for assistance. Typical infill materials include; but are not limited to:
 
          2.6Free draining granular material such as sand, gravel, crushed rock, or fine grained cohesive soils.
 
          2.7Vegetated Wall: Infill outer cells with screened topsoil that supports vegetation.
 
          2.8Non-Vegetated Wall: Infill outer cells with granular material, gravel, crushed rock, grout, or concrete.
 
          A.Front fascia infill Material: _________ as specified in the Contract Documents.
 
          B.GEOWEB infill Material: _________ as specified in the Contract Documents.
 
          C.Infill Material behind GEOWEB: _________ as specified in the Contract Documents.
 
          D.Infill Material: Free of any foreign material.
 
          E.Not Acceptable Infill Material: Clays, silts, and organic soils.
 
          F.Infill Material: Free-flowing and not frozen when placed in GEOWEB sections.
 
          2.9SURFACE TREATMENTS
          ** NOTE TO SPECIFIER ** Specify the desired surface treatment. Contact Presto Geosystems for assistance. Degradable revegetative blankets may be used to wrap GEOWEB® sections to prevent loss of infill material from the outer cells. Concrete and surface grouts may be applied to the outer cells in a stacked channel.
 
          A.Surface treatment includes one or a combination of the following:
          1.Vegetation.
          2.Degradable revegetative blankets.
          3.Concrete
          4.Surface grouts.
          5.Other.
 
          2.10ADDITIONAL COMPONENTS
          ** NOTE TO SPECIFIER ** Specify the desired components. Contact Presto Geosystems for assistance.
 
          A.Drainage System: As specified in Contract Documents.
 
          B.Geotextile Separation Layer: As specified in the Contract Documents.
          ** NOTE TO SPECIFIER ** Delete the following section if a gravity wall is desired.
 
          C.Geogrid Reinforcement: As specified in the Contract Documents.
 
          PART 3EXECUTION
 
          3.1EXAMINATION
 
          A.Verify site conditions are as indicated on the drawings. Notify the Engineer if site conditions are not acceptable. Do not begin preparation or installation until unacceptable conditions have been corrected.
 
          B.Verify layout of structure is as indicated on the drawings. Notify the Engineer if layout of structure is not acceptable. Do not begin preparation or installation until unacceptable conditions have been corrected.
 
          3.2PREPARATION
 
          A.Prepare subgrade as specified and install earth retention system in accordance with Manufacturer's instructions.
          ** NOTE TO SPECIFIER ** Delete section if on-site installation assistance is not desired. If required, specify the numbers of days.
 
          B.On-site time for installation assistance by the Manufacturer's field representative shall be ____ days with one trip. All travel and expense costs for Manufacturer's field representative installation assistance shall be included in the base bid price.
 
          C.Subgrade Preparation:
          1.Excavate, shape or fill foundation soils to elevations indicated on drawings.
          2.Ensure foundation soil meets minimum strength requirements through proof rolling or other conventional method and is approved by the Engineer. If unacceptable foundation soils are encountered, excavate affected areas, and replace with suitable quality material as directed by the Engineer.
 
          3.3INSTALLATION
          ** NOTE TO SPECIFIER ** Delete section if a geotextile separation layer is not required.
 
          A.Install geotextile separation layer as shown in the Contract Documents. Ensure outer edges of geotextile are buried a minimum of 6 inches (150 mm) and install in accordance with the Manufacturer's instructions.
 
          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.
          a.Maximum Particle Size: 2 inches (50 mm).
          b.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. 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 the drawings. The 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.
          ** NOTE TO SPECIFIER ** Delete this section if a Gravity GEOWEB® Retaining Wall is not desired. Contact Presto Geosystems for assistance.
 
          D.Installation of Gravity GEOWEB Retaining Wall System:
          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 on all connections including the front fascia panels. Staples may also be used. 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 ft (1 m) 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.
          ** NOTE TO SPECIFIER ** Specifier Note: Delete this section if a Reinforced GEOWEB® Retaining Wall is not desired. Contact Presto Geosystems for assistance.
 
          E.Installation of Reinforced GEOWEB Retaining Wall System:
          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. Staples may also be used. ATRA keys are the most expedient connection method.
          4.Place precut sections of reinforcement at specified elevations as indicated on the drawings and temporarily hold in-place with pins or fill. The reinforcement shall be placed horizontally, with high-strength axis perpendicular to wall face.
          5.Extend outer edges of reinforcement to within 6 inches (150 mm) of the front face of in-place GEOWEB sections and extend horizontally into the backfill zone.
          6.Overfill cells with granular material and level surface approximately 2 inches (50 mm) above cell walls.
          7.Compact cell infill material to a minimum 95 percent Standard Proctor with a walk-behind-compactor. Avoid using heavy compaction equipment within 3 ft (1 m) of the front face of the wall.
          8.Manually tension reinforcement layer by pulling it away from back of GEOWEB sections so it is taut. If necessary, pin reinforcement to eliminate loose folds during placement of backfill over reinforcement. Lay reinforcement layer flat when pulled back perpendicular to back of GEOWEB section.
          9.Do not operate tracked equipment directly on top of reinforcement layer until a minimum thickness of 6 inches (150 mm) of backfill has been placed over reinforcement layer. Rubber-tired equipment may drive on top of reinforcement at slow speeds. Exercise care and avoid sudden stops and sharp turns.
          10.Place backfill within reinforced zone in maximum lifts of 8 inches (200 mm) and compact to a minimum 95 percent Standard Proctor. Ensure excessive displacement of reinforcement does not occur during fill placement. Place backfill near GEOWEB section and spread toward back of reinforced soil zone. Shape and compact backfill level with GEOWEB section before placing subsequent layers of reinforcement.
          11.Place and compact retained soils, for fill situations, behind reinforced soil zone in approximate lifts of 8 inches (200 mm) and compact to a minimum 95 percent Standard Proctor.
          12.When topsoil or special infill materials are specified for exposed face cells of GEOWEB sections, confirm filling procedures with the Engineer prior to construction. These may include, but are not limited to:
          a.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.
          b.Partial spillage of internal infill material into outer cells may be permitted depending on tolerance of special outer cell infill material. Dressing of outer cells can be a separate procedure following installation of several GEOWEB section layers.
          13.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.
 
          F.Surface Treatment
          ** NOTE TO SPECIFIER ** Specifier Note: Delete the sections that do not apply.
          1.Vegetation shall be as specified in the Contract Documents and installed immediately after the GEOWEB cell infill is placed and protected with mulch.
          2.Degradable revegetative blankets shall be as specified in the Contract Documents and installed during installation of the GEOWEB wall sections. Place the appropriate length of blanket under the GEOWEB layer leaving material length such that once the GEOWEB layer is infilled and compacted, the blanket is wrapped up and over the front wall section, sandwiching the GEOWEB layer between the blanket. Repeat this process for each subsequent layer. If vegetation is specified, it must be applied in the outer cells prior to wrapping the fascia with the blanket.
          3.Concrete shall be as specified in the Contract Documents and installed immediately after the GEOWEB cell infill is placed.
          4.Surface grout shall be as specified in the Contract Documents and installed immediately after the GEOWEB cell infill is placed.
 
         
END OF SECTION