31_70_00_Amendment_0004.pdf

Boardman Dam Removal and River Restoration

SECTION TABLE OF CONTENTS

DIVISION 31 - EARTHWORK

SECTION 31 70 00

ARTICULATED BLOCK

PART 1 GENERAL

1.1 DESCRIPTION

1.2 REFERENCES

1.3 DELIVERY, STORAGE, AND HANDLING

1.4 SUBMITTALS

1.5 PROJECT CONDITIONS

PART 2 PRODUCTS

2.1 PRODUCTS

PART 3 EXECUTION

3.1 CONSTRUCTION METHODS

3.2 INSTALLATION

3.3 QUALITY CONTROL

3.4 REPAIR/RESTORATION

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SECTION 31 70 00 Page 1

SECTION 31 70 00

ARTICULATED BLOCK

PART 1 GENERAL

1.1 DESCRIPTION

A. This Section specifies requirements for the installation of the auxiliary spillway articulated block armoring. The work covered herein includes the supply of all labor, tools, equipment, and materials necessary to furnish and install articulated block armoring in accordance with the lines, grades, design, and dimensions shown on the drawings and as specified herein, including, but not limited to:

1. Articulated block installation.

2. Mechanical Anchors.

3. Concrete block seams.

4. Aggregate drainage layer.

B. Articulated concrete block is required to control erosion problems in the application of an emergency auxiliary spillway during the dewatering process of Boardman Impoundment. The gross area of each individual block shall be no less than one square foot and maintain direct contact with the geotextile, which is placed directly onto the subgrade. Contractor to verify applicability and design of the articulated concrete block structure.

1.2 REFERENCES

A. The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only.

ASTM INTERNATIONAL (ASTM)

ASTM C476 Grout for Masonry

ASTM D4491 Standard Test Methods for Water Permeability of Geotextiles by Permittivity

ASTM D4533 Standard Test Method for Trapezoid Tearing Strength of Geotextiles

ASTM D6684 Materials and Manufacture of Articulating Concrete Block (ACB) Revetment Systems

ASTM D4716 Standard Test Method for Determining the (In-plane) Flow Rate per Unit Width and Hydraulic Transmissivity of a Geosynthetic Using a Constant Head

ASTM D4632 Standard Test Method for Grab Breaking Load and Elongation of Geotextiles

ASTM D4632 Standard Test Method for Grab Breaking

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ASTM D4751

ASTM D4833

Load and Elongation of Geotextiles

Standard Test Method for Determining Apparent Opening Size of a Geotextile

Standard Test Method for Index Puncture Resistance of Geomembranes and Related Products

Standard Practice for Installation of ACB Revetment Systems

American Association of State Highway and Transportation Officials

M288

1.3

Geotextiles

DELIVERY, STORAGE, AND HANDLING

A. Materials delivered to the site shall be inspected for damage, unloaded and stored with the minimum of handling. Materials shall be kept free of dirt and debris.

B. Deliver articulated block and associated materials to Project site in such quantities and at such times to ensure continuity of project. Handle and store articulated block materials at Project site to prevent physical damage. Synthetic geotextiles that are not to be installed immediately shall be protected from the direct sunlight and in accordance with the applicable portions of the Section entitled "Geotextiles".

1.4 SUBMITTALS

SD-01 Preconstruction Submittals

A. Procedure and Sequencing

1. Procedures and sequence for review and acceptance by the Government.

SD-02 Shop Drawings

B. Shop Drawings; G-DR

1. Shop drawings shall be submitted to the COR for review. No equipment shall be delivered or installed before this submittal package has been reviewed and commented on by the COR. Submittal package shall include:

a. Shop Drawings. Submit shop drawings for the layout and details of the articulated block mats. The articulated block mats layout shall be to the lines and grades shown on the Drawings. The shop drawings shall include layout, layout sequence, anchor details, mat junction details, anchor to mat connection details, details for grade change, and details of concrete seam connections.

SD-03 Product Data

C. Representative Samples; G-DR:

1. The sources from which the Contractor proposes to obtain materials shall be selected well in advance of the time when the materials will be required in the Work. Product literature and suitable samples of the articulated block mats, cable, fittings, anchors and filter fabric shall be submitted to the COR for approval, prior to delivery of any such material to the site of the Work. All samples shall be obtained by the Contractor and delivered at his/her expense to a point designated by the Government at least 10 days in advance of the time

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ASTM D6884

when the placing of the articulated block mats is expected to begin.

The Contractor shall submit the articulated block revetment system Manufacturer's certification that the revetment system and components meet the requirements of this specification.

SD-05 Design Data

D. Calculations; G-DR

1. Provide calculations to Engineer for review that show the Articulated

Concrete Block design is capable of handling the 10yr (10%) flow event.(maximum velocity of approximately 23 ft/s based on the design presented in the Drawings)

E. Engineer Qualifications. Submit name and experience of engaged consultant/supplier of articulated block mats, anchors, and masonry grout.

F. Product Data; G-DR. Submit manufacturer's product data, test reports, and material certifications as required.

G. Qualification Data: For qualified Installer.

1.5 PROJECT CONDITIONS

A. Coordinate articulated block installation with all other work to avoid delays. Including dewatering progress.

B. The work area shall have sediment controlled in accordance with water discharge and erosion control permits as required.

PART 2 PRODUCTS

2.1 PRODUCTS

A. Articulated Block

1. Shall be manufactured in conformance with the requirements of ASTM D

6684 "Materials and Manufacture of Articulating Concrete Block (ACB) Revetment / Systems", except that, unless otherwise specified, freeze-thaw requirements shall not apply.

B. Mechanical Anchors as specified by articulated block manufacturer.

C. Articulated Concrete Block Seams.

1. 4000 psi grout, concrete, or approved equal. Grout shall be as per

ASTM C476.

D. Geogrid as specified by articulated block manufacturer, but can be any triaxial type that has a 1 inch minimum aperture size.

E. Woven Geotextile Filter Fabric

1. The filtration geotextile should be woven and may be composed of multifilament yarns or monofilament yarns. Woven slit film (monofilament or multifilament) geotextiles should not be used as a filter beneath ACBs.

There are several additional general criteria to address durability during construction and survivability during operation of the filtration geotextile. These along with the retention and permeability requirements are summarized below:

Woven Geotextile Specifications:

Criteria Specifications Standard

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Retention (O95) < 6.5 mm #4 sieve ASTM D4751 Permeability (KGTX) >= 2x10-2 cm/s ASTM D4491 Percent Open Area (POA) >= 4% ASTM D4716 Grab Strength >= 90 lbs ASTM D4632 Elongation >= 15 % ASTM D4632 Puncture Strength >= 80 lbs ASTM D4833 Trapezoidal Tear >= 50 lbs ASTM D4533 Survivability Class 1 or 2 AASHTO M288

1. AASHTO #1 and #2 Bedding Stone, or approved equal.

Coarse Aggregate Drainage Layer Specifications:

Criteria Specifications ASTM Standard Permeability (KDRN) >= 1x10-2 cm/s D 2434 Thickness >= 6 in - D50 >= Aperture Size of Geogrid (typ. 1 in min) D 422

PART 3 EXECUTION

3.1 CONSTRUCTION METHODS

A. Areas on which filter fabric and articulated block are to be placed shall be constructed to the lines and grades shown on the Drawings. The subgrade for the articulated block mats shall be free of voids, pits or depressions and shall be proof-rolled to a minimum of 90% of the ASTM D 698 density. Voids, pits or depressions shall be brought to grade by backfilling in accordance with the applicable portions of the project specifications. All obstructions, such as roots and projecting stones larger than 1 inch remaining on the surface, shall be removed and all of the soft or low density pockets of material removed must be filled with selected material and compacted to a minimum of 90% of the ASTM D 698 density.

B. EXCAVATION AND PREPARATION

1. Shall be done in accordance to the lines, grades and dimensions shown on the Drawings and in accordance with Section 31 23 00 "Earthwork."

C. INSPECTION AND APPROVAL

1. Immediately prior to placing the filter fabric and articulated block mats, the prepared area shall be inspected by the Government's Representative and approval obtained from the COR before any fabric or mats are placed thereon.

3.2 INSTALLATION

A. General: Articulated block mats shall be placed within the limits shown on the Drawings. The articulated block mats shall be placed on the filter fabric in such a manner as to produce a relatively planar surface.

No more than 200 linear feet of filter fabric shall be laid before being covered with articulated block, and any fabric installed more than 2 days shall be lifted and the surface of the slope inspected for any slope defects. The Government may require any uncovered fabric to be lifted after heavy rainfall to inspect for slope damage. Final acceptance and approval of the installation will be made by the COR. The Contractor shall hold the Owner harmless from liability of any kind arising from the use of any patented or non-patented invention used in the performance of this work.

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F. Aggregate Drainage Layer

B. Filter Fabric: Filter fabric shall be installed in accordance with manufacturer's specifications. Adjacent layers of filter fabric shall have a minimum of two feet of overlap. The geotextile filter fabric shall be placed so that the upstream strip of fabric overlaps the downstream strip, when applicable. The geotextile shall extend at least two (2) feet beyond the top and bottom revetment termination points. Fabric shall be secured with 6" x 1" x 6" steel pins or staples prior to placement of articulated block mats.

C. Placement of Aggregate Drainage Layer: An aggregate drainage layer consisting of 6 inches of AASHTO #1 and #2 bedding stone shall be placed directly on the geotextile filter fabric in such a way as it maintains intimate contact along the entire length of the revetment.

D. Placement of Prefabricated Mats: Articulated block mats shall be done with mats attached to a spreader bar or other approved device to aid in the lifting and placing of the mats in their proper position by the use of a crane or other approved equipment. The mats shall be placed side-by-side and/or end-to-end so that the mats abut each other. The maximum space or gap between mattresses shall be 3 inches, except that local wider gaps may be accepted if the length of the gap is less than 3 feet and the entire gap is grouted. No overlapping of mats will be accepted and no blocks shall project vertically more than 1 inch beyond the adjacent blocks. All placements of mats shall be in accordance with the manufacturer's recommendations and the Contractor's approved shop drawings. As adjacent mats are placed, they shall be secured to each other by fastening the protruding horizontal and vertical cable connections and end cable loops together along each side of the mats. The fastening shall be done with approved anchors.

E. Construct Articulated Concrete Block Seams: Grout, concrete, or approved equal seams shall be placed at the upstream and downstream ends of the articulated block mats forming the complete auxiliary spillway as detailed in the Drawings. The seams shall anchor the articulated block mats in place and prevent any undermining of the structure during flood flows. A minimum of two (2) individual articulated blocks from each mat in contact with the seams shall be incorporated into the concrete seam with a minimum of 1 foot of concrete extending below the articulated block mat.

F. Construct articulated block so as to keep the auxiliary spillway armored and protected from scour by flood waters flowing through the auxiliary spillway. Any and all damage caused by the failure of articulated block from any cause whatsoever shall be the responsibility of the Contractor.

3.3 QUALITY CONTROL

A. The Contractor shall inspect for compliance with contract requirements and record the inspection of all operations including but not limited to the following, as applicable:

1. Preparation of surface to receive articulated block mats.

2. Filter fabric soundness and free of defects.

3. Placement of aggregate drainage layer.

4. Mechanical anchors - breaking strength.

5. Assembly of individual articulated blocks bound by cables to form articulated block mats.

6. Placement of mats and filter fabric on the prepared subgrade.

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3.4 REPAIR/RESTORATION

A. Repair or replace, as acceptable to the Government, adjacent work or structures damaged or displace through installation, removal, or inadequacy of articulated block and anchors.

B. Repair site to a condition acceptable to the Government and similar to the existing site conditions prior to placement of articulated block.

This includes filling holes, pits, and depressions in a satisfactory manner.

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