DRAINAGE AGGREGATE

PART 1: GENERAL

1.01	Description

Work includes providing and installing all drainage aggregate materials to the lines and grades designated on the project construction plans.

1.02 Related Work

    A. Section - Segmental Retaining Wall Units

    B. Section  - Geosynthetic Wall Reinforcement

    C. Section - Site Preparation

    D. Section  - Earthwork

1.03 Reference Standards

A. ASTM D 3034 - Specification for Polyvinyl Chloride (PVC) Plastic Pipe

B. AASHTO T-27 - Test Method for Gradation Limits Fine Filter Material

C. ASTM D 1248 - Specification for Corrugated Plastic Pipe

D. 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 drainage aggregate meets the requirements of this specification.

1.05 Delivery, Storage and Handling

A. Plastic Pipe shall be stored in accordance with the manufacturer's recommendations to prevent damage and deleterious materials from becoming affixed. 

B. Drainage aggregate shall be stored to prevent contamination with other site and/or fill soils.

1.06 Measurement and Payment

A. Measurement of the drainage aggregate is on a cubic yard basis.

B. Payment shall cover drainage aggregate supply and installation.

C. Quantity of drainage aggregate 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 drainage aggregate will be paid for per cubic yard of net quantities shown on the construction drawings. Waste and overfill are incidental. Payment will be made under:

Pay Item                                            Pay Unit

Drainage Aggregate                          Cubic Yard

PART 2: MATERIALS

2.01 Definitions

A. Drainage collection pipe shall be a perforated/slotted PVC or corrugated HDPE pipe. The pipe may be covered with a knitted or nonwoven geotextile sock specifically designed to function as a filter.

B. Drainage aggregate shall be a free draining material, relative to the surrounding soil, so as to prevent build up of hydrostatic pressure.

C. Drainage geotextile shall have the following minimum properties or as recommended by the Design Engineer.

AOS                      ASTM D 4751         70-100

Grab Tensile          ASTM D 4632          110 lb.

Trap Tear              ASTM D 4533           40 lb.

Water Flow            ASTM D 4491           75 gpm/f t.

Puncture                ASTM D 4833           40 lb.

2.02 Products

A. Drainage aggregate shall be a clean, 1-inch minus crushed stone or granular fill meeting the following gradation (sieve size/% passing): 
l inch/100-75%, 3/4 inch/50-75%, No.4/0-60%, No.40/0-50%, No.200/0-5%

B. Drainage pipe shall be manufactured in accordance with ASTM D 3034 and/or ASTM D 1248.

C. Geotextile placed around the drainage aggregate or drain pipe shall be as outlined in Section 2.01 as recommended by the Design Engineer.

PART 3: EXECUTION

3.01 Drainage Collection Pipe

A. Install the drainage collection pipe according to the line, grades and sections shown in the project construction plans.

B. Install the drainage collection pipe to maintain gravity flow of water to outside the reinforced soil zone. Daylight the drainage collection pipe at a storm sewer manhole or along a slope at an elevation lower than the lowest point of the pipe within the reinforced soil mass.

C. The main collection drain pipe just behind the segmental units shall be a minimum of 3 inches in diameter. Any secondary collection drain pipe can gravity flow independently or tie into the main collection drain pipe with laterals at a maximum 50 foot spacing along the wall face.

3.02 Drainage Aggregate

A. Install the drainage aggregate to the line, grades and sections shown on the project construction plans.

B. Place the drainage aggregate to a minimum finished thickness and widths shown on the details herein, or as directed by the Engineer.

C. When a blanket drain is installed, a nonwoven geotextile should be installed prior to aggregate placement in accordance with the details provided on the drawings.

END OF SECTION