05_02271 RipRap.docx

PART 1 - GENERAL

1.1. DESCRIPTION

A. This section covers materials and procedures for the installation of riprap and riprap bedding.

B. Riprap bedding may not be required at all riprap locations.

C. Thickness of riprap and bedding shall be as indicated on the Drawings.

1.2. QUALITY CONTROL

A. Quality assurance testing of riprap delivered to the site, consisting of the same tests and test requirements specified in Article 2.2, may be conducted by an independent testing laboratory retained by the Contracting Officer.

B. If additional tests are necessary to ensure continuous compliance with the specifications, in the opinion of the Contracting Officer, such tests shall be made by an independent laboratory retained by the Contractor.

C. The Contracting Officer shall have the authority to select the load of material to be sampled.

1.3. REFERENCES

A. AASHTO T 85-91 Specific Gravity and Absorption of Coarse Aggregate B. AASHTO T 103-91 Soundness of Aggregates by Freezing and Thawing C. ASTM C 40-04 Standard Test Method for Organic Impurities in Fine Aggregates for Concrete D. ASTM C 123-04 Standard Test Method for Lightweight Particles in Aggregate E. ASTM C 127-04 Standard Test Method for Density, Relative Density (Specific Gravity), and Absorption of Coarse Aggregate F. ASTM C 142-97(2004) Standard Test Method for Clay Lumps and Friable Particles in Aggregates G. ASTM C 535-03 Standard Test Method for Resistance to Degradation of Large-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine H. ASTM D 75-03 Standard Practice for Sampling Aggregates I. ASTM D 422-63(2002) Standard Test Method for Particle-Size Analysis of Soils J. ASTM D 1140-00 Standard Test Methods for Amount of Material in Soils Finer Than the No. 200 (75-um) Sieve K. ASTM D 4992-94(2001) Standard Practice for Evaluation of Rock to be Used for Erosion Control L. ASTM D 5312-04 Standard Test Method for Evaluation of Durability of Rock for Erosion Control Under Freezing and Thawing Conditions

PART 2 – PRODUCTS

2.1. MATERIALS

A. General

1. Stone used for riprap shall be hard, durable, angular in shape; resistant to weathering and to water action; free from overburden, spoil, shale and organic material; and shall meet the gradation requirements for the class specified.

2. Neither the width nor thickness of a single stone should be less than one-third its length.

3. Rounded stone or boulders will not be accepted.

4. Shale and stone with shale seams are not acceptable.

5. The minimum weight of the stone shall be 155 pounds per cubic foot as computed by multiplying the specific gravity (bulk-saturated-surface-dry basis, AASHTO T

85) by 62.4 pounds per cubic foot.

B. Riprap

1. The location and size of riprap to be placed at each location shall be as shown on the Drawings.

2. Each load of riprap shall be reasonably well graded from the smallest to the largest size specified.

3. Sand and rock dust will not be permitted in an amount exceeding five percent (5%) by weight of each load.

4. Control of gradation will be by visual inspection.

5. The Contractor shall provide a sample of at least five (5) tons, meeting the gradation for each class specified.

6. A sample of each class shall be located at the construction site near the location where the riprap is to be placed.

7. The sample shall be used as a frequent reference for judging the gradation of the riprap supplied.

8. The samples shall be in place and acceptable to the Contracting Officer before placement begins.

9. Any difference of opinion between the Contracting Officer and the Contractor concerning gradation shall be resolved by dumping and checking the gradation of two random truckloads of stone.

10. Mechanical equipment, a sorting site, and labor needed to assist in checking gradation shall be provided by the Contractor at no additional cost to the Government.

11. Classes of riprap and gradation requirements shall be as follows unless otherwise acceptable to the Contracting Officer.

Class 12 d50 12”

Class 24 d50 24”

2.1. PRELIMINARY REVIEW

A. General

1. The Contracting Officer's acceptance of the source and quality of riprap and riprap bedding blanket materials shall be obtained before the riprap work is started.

2. For such acceptance, certified reports prepared by an independent testing laboratory retained and paid for by the Contractor shall be submitted to the Contracting Officer.

3. Acceptance given on the basis of these reports will be a general acceptance only and continued compliance with all contract provisions will be required.

B. Riprap

1. The sources from which the stone will be obtained shall be selected well in advance of the time when the stone will be required in the work.

2. The acceptability of the stone shall be determined by tests.

3. Suitable samples of stone shall be taken in the presence of the Contracting Officer at least seven (7) days in advance of the time when the placing of riprap is expected to begin.

4. The acceptance of some rock fragments from a particular quarry site shall not be construed as constituting the acceptance of all rock fragments taken from that quarry.

5. Documented service records of the proposed material will be considered by the Contracting Officer in determining the acceptability of the stone.

6. Riprap materials shall meet the following requirements when tested in accordance with the specified procedures.

RIPRAP REQUIREMENTS

SECTION 02271 RIPRAP

Measel Spring and Leo Reservoir Repair RIPRAP

02271-2

PART 3 – EXECUTION

3.1. PLACEMENT

A. Riprap shall be placed on slopes and in other areas indicated on the Drawings.

B. Slopes shall be trimmed and dressed to conform to the slope lines indicated on the Drawings prior to riprap placement.

C. Where the trimmed slope is below the allowable minus tolerance limit, the slope shall be brought to grade by filling with bedding at the expense of the Contractor with no allowable unit adjustment.

D. The surface of the finished layer shall be uniform and free from mounds or windrows.

E. Stone for riprap shall be placed in a manner which will produce a well graded mass of stone with the minimum practicable percentage of voids.

F. The entire mass of stone shall be placed in conformance with the lines, grades, and thicknesses indicated on the Drawings.

G. Riprap shall be placed to its full course thickness in one operation and in such a manner as to avoid displacing the underlying material.

H. Placing of riprap in layers, or by dumping into chutes, or by similar methods likely to cause segregation will not be permitted.

I. The use of a backhoe working from the crest or a dragline with a clamshell will be acceptable.

J. The larger stones shall be well distributed and the entire mass of stone shall conform to the gradation specified.

K. All material placed as riprap protection shall be so placed and distributed that there will be no large accumulations of either the larger or smaller sizes of stone.

L. The final appearance shall be that of a dumped riprap rather than that placed by individual pieces.

M. A somewhat non-uniform rough surface is desired such that no individual rock fills a void from the blanket to the final grade.

N. Any holes in the mass shall be filled with rock spalls in the four-inch (4”) to two-inch (2”) size to ensure no open channels exist which may cause erosion of the riprap bedding.

O. No holes shall exist which show the riprap bedding after placement of the riprap.

P. The placement of riprap in existing channels or irrigation ditches shall be done in such a manner as to have the top of the place riprap meet the existing channel geometry.

Q. When placed in existing channels or irrigation ditches the placement of riprap shall not decrease the existing channel cross-sectional area.

***** END OF SECTION *****

Measle Spring and Leo Reservoir Repair RIPRAP

02271-4