GEOSYNTHETIC WALL
REINFORCEMENT
PART 1: GENERAL
1.01 Description
Work includes furnishing and installing geosynthetic reinforcement
to the lines and grades designated on the plans.
1.02 Related Work
A. Section - Segmental Retaining Wall Units
B. Section - Earthwork
C. Section - Drainage Aggregate
1.03 Reference Standards
A. ASTM D 4595 - Tensile Properties of Geotextiles by the Wide-Width
Strip Method
B. ASTM D 4632 - Tensile Properties of Geotextiles
C. ASTM D 52 - Tensile Creep Testing of Geosynthetics
D. GRI:GGl - Single Rib Geogrid Tensile Strength
E. NCMA SRWU-1- Determination of Connection Strength between Geosynthetics and Segmental
Concrete Units
F. NCMA - Design Manual for Segmental Retaining Walls
G. Where specifications and reference documents conflict, the Architect/Engineer shall
make the final determination of applicable document.
1.04 Certification
A. Contractor shall submit a notarized manufacturer's
certification, prior to start of work, stating that the geosynthetic reinforcement
meets the requirements of this specification.
1.05 Delivery, Storage and Handling
A. Contractor shall check the geosynthetic reinforcement upon
delivery to assure that the proper grade and type of material has been received. A product
certification should be provided with each shipment.
B. The geosynthetic reinforcement shall be stored above -20�F.
C. Rolled geosynthetic material shall be stored in accordance with manufacturer's
recommendations.
1.06 Measurement and Payment
A. Measurement of the geosynthetic reinforcement is on a square yard
basis.
B. Payment shall cover geosynthetic reinforcement supply and installation.
C. Quantity of geosynthetic reinforcement as shown on drawings may be increased or
decreased at the direction of the Architect/ Engineer based on construction procedures and
actual site conditions.
D. The accepted quantities of geosynthetic reinforcement will be paid for per square yard
of net quantities shown on the construction drawings. Waste and overlaps are incidental.
Payment will be made under:
Pay Item
Pay Unit
Geosynthetic Reinforcement
SQ. YD.
PART 2: MATERIALS
2.01 Definitions
A. Geosynthetic reinforcement shall be a polymer product
specifically manufactured as a soil reinforcement element that meets the requirements of
this specification.
B. Concrete segmental retaining wall (SRW) units are as detailed on the drawings and
specified under Section - Segmental
Retaining Wall Units.
C. SRW Unit pins are as detailed on the drawings and specified under Section SRW Units.
D. Leveling pad material is sand or gravel as specified under Section - SRW Units or
low-strength unreinforced concrete.
E. Reinforced backfill (infill soil) is the soil used within reinforced soil mass.
F. Retained backfill or common backfill is the soil behind the reinforced soil mass and
leveling pad.
2.02 Geosynthetic Reinforcement Properties
A. The geosynthetic reinforcement shall possess the following
minimum design properties, determined by product specific testing as deffined in the NCMA
Design Manual for Segmental Retaining Walls (Section 3.5).
LTDS Ci
Cds
Geogrid Type "A"
(1000 lb/ft) (0.7 )
(0.7)
Geogrid Type "B"
(if required)
PART 3: EXECUTION
3.01 Foundation Soil Preparation
A. Foundation soil preparation shall be as specified in Section -SRW
Units.
3.02 Wall Erection
A. Wall erection shall be as specified in Section SRW Units.
3.03 Geosynthetic Reinforcement Installation
A. The geosynthetic reinforcement shall be installed at the wall
height, horizontal location, and to the extent as shown the project construction plans, or
as directed by the Architect/ Engineer.
B. The geosynthetic reinforcement shall be laid horizontally on compacted reinforced
backfill and connected to the concrete SRW units. Embedment detail shall be consistent
with the SRW manufacturer's recommendations.
C. Correct orientation (roll direction) of the geosynthetic reinforcement shall be
verified by the Contractor.
D. Place segmental unit and fill in accordance with Section - SRW Units.
E. The geosynthetic reinforcement shall be pulled taut and free of wrinkles prior to
placement of soil fill. The geosynthetic may be secured in place with staples, pins,
sandbags, or fill as required by fill properties, fill placement procedures, or weather
conditions, or as directed by the Architect/ Engineer.
F. For constructability
considerations, maximum spacing between geogrid layers shall be 2.0 vertical feet.
|