NOTE ** This section is based on products nationally manufactured under license from Anchor Wall Systems, Inc., which is located at the following address:
NOTE ** 6101 Baker Road, Suite 201
NOTE ** Minnetonka, MN 55345
NOTE ** Tel: (800) 473-4452 or (612) 933-8855
NOTE ** FAX: (612) 933-8833
NOTE **
NOTE ** Call for the location of the manufacturer nearest you.
NOTE **
NOTE ** "Anchor Vertica7," "Anchor Vertica Pro7," "Anchor Diamond7" and "Anchor Diamond Pro7" modular concrete wall units ensure proper alignment and precise set-back without need for mortar or pins due to their integral alignment feature.
NOTE **
NOTE ** SECTION 02834 - MODULAR CONCRETE RETAINING WALLS, Copyright 1998, The Architect's Catalog, Inc.
PART 1 GENERAL
1.1 SECTION INCLUDES
A. Modular concrete retaining wall units to the lines and grades designated on the construction drawings and as specified herein.
1.2 RELATED SECTIONS
NOTE ** Delete any sections below not relevant to this project; add others as required.
A. Section 02300 - Earthwork: Excavating, backfilling and compacting.
B. Section 02900 - Planting.
C. Section 02620 - Subdrainage.
1.3 UNIT PRICES
A. Measurement of segmental retaining wall shall be on an installed square foot basis computed on the total face area of installed wall. Face area is from bottom of base course to top of wall.
B. Payment for retaining wall will be made on a square foot basis at the Contract Unit Price.
1. Payment shall be considered full compensation for labor, materials, equipment, and testing required to install retaining wall in accordance with drawings and these specifications.
2. Quantities may vary from that shown on drawings, depending on existing topography; change to total quantity of wall face area will be paid or withheld at the Contract Unit Price.
1.4 REFERENCES
NOTE ** Delete references from the list below that are not actually required by the text of the edited section.
A. ASTM C 90 - Standard Specification for Load-Bearing Concrete Masonry Units.
B. ASTM C 140 - Test Methods of Sampling and Testing Concrete Masonry Units.
C. ASTM C 666 - Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing.
D. ASTM D 448 - Standard Classification for Sizes of Aggregate for Road and Bridge Construction.
E. ASTM D 698 - Standard Test Method for Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400 ft-lbf/ft3 (600 kN-m/m3)).
F. ASTM D 1557 - Test Method for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3 (2,700 kN-m/m3)).
1.5 DEFINITIONS
A. Backfill: Soil used as fill behind drainage aggregate and within the reinforced soil mass, if applicable.
B. Drainage aggregate: Material used around and directly behind concrete wall units.
C. Foundation soil: Soil mass supporting the leveling pad and reinforced zone of the retaining wall system.
D. Geosynthetic reinforcement: Material specifically fabricated for use as a soil reinforcement.
E. Wall fill: Free-draining aggregate material used within and around concrete retaining wall units.
1.6 SUBMITTALS
A. Submit under provisions of Section 01300.
B. Product Data: Manufacturer's printed product literature, including installation instructions.
C. Shop Drawings: Retaining wall system design including wall heights, geosynthetic reinforcement and drainage provisions.
1. Prepared and signed by a registered Professional Engineer retained by the Installer and licensed in the State of wall installation.
NOTE ** Delete the following paragraph if samples are not required.
D. Samples:
1. Furnish one unit in the color and face pattern specified; approved unit may be used in the work.
2. 12 inches square or larger piece of geosynthetic reinforcing specified.
E. Test Reports: Submit test reports from an independent laboratory demonstrating compliance of concrete units with reference standards.
1. Water absorption and compressive strength tested in accordance with ASTM C 140, Sections 6,8, and 9.
1.7 DELIVERY, STORAGE, AND HANDLING
A. Inspect the materials upon delivery to assure that specified products have been received.
B. Deliver and handle materials in manner that will prevent damage.
1. Store above ground on wood pallets or blocking.
2. Remove damaged or otherwise unsuitable material, when so determined, from the site.
3. Faces of the modular concrete units shall be free of chips, cracks and stains.
C. Prevent wet cement, epoxy, excessive mud, etc., from coming in contact with the materials.
NOTE ** Select one of the following Articles or delete both Articles if extra materials are not required.
1.8 EXTRA MATERIALS
A. Furnish Owner with matching replacement units comprising 1 percent of those installed on the Project.
B. Furnish Owner with three replacement units identical to those installed on the Project.
PART 2 PRODUCTS
2.1 MANUFACTURERS
A. Provide products fabricated under license from Anchor Wall Systems, Inc., 6101 Baker Road, Suite 201, Minnetonka, MN 55345; ASD. Tel: (800) 473-4452 or (612) 933-8855, FAX: (612) 933-8833.
2.2 MATERIALS
NOTE ** Delete one of the following two sets of paragraphs headed "Modular Concrete Retaining Wall Units." The first is for Anchor Vertica and Vertica Pro; the second is for Anchor Diamond and Diamond Pro.
A. Modular Concrete Retaining Wall Units: High strength, high density concrete units, freeze-thaw resistant with top locator providing a 4 degree set back from plane with each course.
NOTE ** Delete one of the following two paragraphs.
1. Acceptable Product: "Anchor Vertica Pro Retaining Wall Units".
2. Acceptable Product: "Anchor Diamond Pro Retaining Wall Units".
3. Comply with ASTM C 90 except provide minimum compressive strength of 3,000 psi and maximum water absorption of 7.0 percent.
4. Provide units with an integral concrete shear connection flange along the lower rear edge.
NOTE ** Delete one of the following two paragraphs.
5. Minimum exposed face area (Anchor Diamond units): 0.67 square feet.
6. Minimum exposed face area (Anchor Diamond Pro units): 0.94 square feet.
7. Unit height: Not more than plus or minus 1/16 inch variation from that specified.
NOTE ** Delete one of the following two paragraphs.
8. Face geometry: Beveled.
9. Face geometry: Straight.
NOTE ** Delete one of the following two paragraphs.
10. Texture: Smooth.
11. Texture: Split rock face.
12. Color: As selected by Architect from manufacturer's standard selections.
C. Geosynthetic Reinforcement: Woven polyester fiber geogrid, expanded polyethylene sheet geogrid, or woven polypropylene geotextile.
D. Base:
NOTE ** Delete 2 of the 3 following paragraphs.
1. Drainage aggregate.
2. Sand, specified in Section _____.
3. Concrete, specified in Section 03300.
E. Drainage Aggregate: Free-draining, coarse aggregate complying with ASTM 448, size no. 57, 67, 6, 7 or 8.
NOTE ** Delete the following paragraph if neither Anchor Vertica nor Anchor Vertica Pro units are used.
F. Unit Fill: Same materials as drainage aggregate.
NOTE ** Normally, the project engineer or geotechnical consultant determines whether the soil is suitable for backfill purposes. Soil types that are not suitable for modular retaining walls include USCS Classifications CH, OH, MH, OL, PT, and CL soils with a Plasticity Index greater than 25.
G. Backfill: On-site soils unless otherwise indicated on the drawings; where additional backfill is required, submit sample and specifications to project Geotechnical Engineer for approval.
NOTE ** Delete the following paragraph if drain tile is to be installed under another specification section. For Anchor Diamond, drains are normally required; for Anchor Vertica, they may not be.
H. Foundation Drain: Perforated or slotted PVC pipe or corrugated HDPE pipe, covered with geotextile filter fabric.
PART 3 EXECUTION
3.1 EXAMINATION
A. Examine the areas and conditions under which retaining walls are to be erected.
1. Notify the Architect in writing of conditions detrimental to the proper and timely completion of the work.
2. Notify the Architect in writing of site conditions which may affect wall performance or may require reevaluation of wall design.
B. Do not proceed with the work until unsatisfactory conditions have been corrected.
3.2 EXCAVATION
A. Excavate to the lines and grades shown on the drawings. Over-excavation will not be compensated for and replacement with compacted fill or wall system components will be required at Contractor's expense. Take care not to disturb base beyond the lines shown.
3.3 FOUNDATION PREPARATION
A. Excavate as required for footing or base dimension shown on the drawings, unless otherwise directed.
B. Obtain the Geotechnical Engineer's approval of subgrade to ensure that the actual soil strength meets or exceeds that required.
C. Remove soil not meeting the required strength, and replace with acceptable material.
D. Fill over-excavated areas with compacted backfill material.
NOTE ** Retain the following paragraph for Vertica.
E. Proof-roll foundation soil prior to fill and geosynthetic reinforcement placement.
3.4 BASE COURSE PREPARATION
NOTE ** Show base depth and width on the Drawings. Standard minimum base thickness is 6 inches. Edit the following paragraph, if necessary.
NOTE **
NOTE ** At Contractor's option, designs using reduced depth of aggregate and 1 to 2 inch concrete toppings may be used. Concrete shall be lean, unreinforced and a maximum of 2 inches thick. Where a reinforced footing is required, place below the frost line. Show any such footings on the Drawings.
A. Place granular base materials as indicated on the Drawings, but not less than 6 inches thick.
B. Place and compact base materials to the depths and widths indicated on the drawings.
C. Place base materials upon undisturbed soils or on foundation soils properly backfilled.
D. Compact base material to a level, hard surface on which to place the first course of units.
NOTE ** Edit the following paragraph if required compaction differs from 95 percent.
1. Compact to 95 percent standard proctor (ASTM D 698).
E. Prepare base materials to ensure complete contact of retaining wall unit with base material. Do not allow gaps.
3.5 ERECTION
A. Erect units in accordance with manufacturer's recommendations and as specified herein.
B. Place first course of concrete wall units on the prepared base material. Check units for level and alignment. Ensure that the top of all units in base course are at the same elevation.
C. Ensure that concrete wall units are in full contact with base.
D. Place concrete wall units side by side for full length of wall alignment. Alignment may be done by using a string line or offset of wall line.
E. Fill all voids between and within concrete wall units with drainage aggregate.
NOTE ** Delete 1 of the 2 following paragraphs.
NOTE **
NOTE ** Anchor Vertica and Anchor Diamond units require 12 inches of drainage fill.
NOTE ** Anchor Vertica Pro units may require as little as 6 inches of drainage fill.
F. Place at least 12 inches of free-draining aggregate behind the concrete wall units.
G. Place at least 6 inches of free-draining aggregate behind the concrete wall units.
H. Install drain tile at lowest elevation possible to maintain gravity flow of water to outside reinforced zone. "Daylight" drainage collection pipe to an approximate location away from wall system at each low point or at 50 foot intervals along wall.
I. Remove excess fill from top of concrete wall units and install next course. Ensure that drainage aggregate and backfill are compacted before installation of next course.
NOTE ** Delete 1 of the 2 following paragraphs.
NOTE **
NOTE ** Retain only the first for Anchor Vertica and Anchor Vertica Pro units.
NOTE ** Retain only the second for Anchor Diamond and Anchor Diamond Pro units.
J. Install each succeeding course so the side slots are in contact with the locator. Pull the units forward until the side slot of the unit touches the back of the locator of the previous course.
K. Pull each unit forward as far as possible until the locating surface of the unit contacts the locating surface of the unit in the preceding course.
L. Backfill as each course is completed.
M. Install geosynthetic reinforcement in accordance with retaining wall manufacturer's design recommendations and as indicated on drawings.
3.6 BACKFILL PLACEMENT
A. Place, spread, and compact reinforced backfill in a manner to minimize slack in reinforcement.
B. Place and compact fill in the reinforced zone.
1. Lifts not exceeding 6 to 8 inches in loose thickness where hand-operated compaction equipment is used.
2. Lifts not exceeding 12 inches in loose thickness where heavy, self-propelled compaction equipment is used.
C. Compact fill placed in reinforced zone to minimum 95 percent of soil's standard Proctor density (per ASTM D 698) or as recommended by project Geotechnical Engineer.
D. Allow only lightweight hand-operated equipment within 4 feet of back of retaining wall units, or one-half the wall height, whichever is greater.
NOTE ** Retain the following Article if applicable.
3.7 CAP UNIT INSTALLATION
A. Apply construction adhesive to the top surface of the unit below and place the cap unit into desired position.
B. Cut cap units if necessary to obtain the proper fit.
C. Backfill and compact to finish grade.
3.8 FIELD QUALITY CONTROL
A. Retain a qualified independent third party to verify correct installation of materials in accordance with drawings and these specifications.
B. Owner, at his own expense, may retain a qualified professional to perform random quality assurance checks.
C. Correct work found deficient and not in accordance with drawings and these specifications.
D. Retaining wall will not be considered complete until accepted by Architect or duly appointed representative of the Owner.
3.9 ADJUSTING AND CLEANING
A. Replace damaged units prior to Substantial Completion.
