**Construction Specification 761---Rock Riprap**

**1. Scope**

The work shall consist of the construction of rock riprap revetments and
blankets, including filter or bedding where specified.

**2. Material**

Rock for loose rock riprap shall conform to the requirements of Section
814, Riprap Materials, of the latest edition of the Alabama Department
of Transportation Standard Specifications for Highway Construction.
Gradation shall be as specified in Section 7.

Prior to delivery of rock, the Contractor shall designate in writing the
source from which he intends to obtain the rock and information
satisfactory to the Contracting Officer that the material meets the
requirements of the contract. The Contractor shall provide the Engineer
free access to the source for the purpose of obtaining samples for
testing.

**3. Subgrade preparation**

The subgrade surface on which the rock riprap, filter, bedding, or
geotextile is to be placed shall be cut or filled and graded to the
lines and grades shown on the drawings. When fill to subgrade lines is
required, it shall consist of approved material and shall conform to the
requirements of the specified class of earthfill.

Rock riprap, filter, bedding, or geotextile shall not be placed until
the foundation preparation is completed and the subgrade surface has
been inspected and approved.

**4. Equipment-placed rock riprap**

The rock riprap shall be placed by equipment on the surface and to the
depth specified. It shall be installed to the full course thickness in
one operation and in such a manner as to avoid serious displacement of
the underlying material. The rock for riprap shall be delivered and
placed in a manner that ensures the riprap in place is reasonably
homogeneous with the larger rocks uniformly distributed and firmly in
contact one to another with the smaller rocks and spalls filling the
voids between the larger rocks. Some hand placing may be required to
provide a neat and uniform surface.

Rock riprap shall be placed in a manner to prevent damage to structures.
Hand placing is required as necessary to prevent damage to any new and
existing structures.

**5. Filter or bedding**

When the contract specifies filter, bedding, or geotextile beneath the
rock riprap, the designated material shall be placed on the prepared
subgrade surface as specified. Compaction of filter or bedding aggregate
is not required, but the surface of such material shall be finished
reasonably smooth and free of mounds, dips, or windrows.

**6. Measurement and payment**

***Method 1---***For items of work for which specific unit prices are
established in the contract, the quantity of each type of rock riprap
placed within the specified limits is computed to the nearest ton by
actual weight. The volume of each type of filter or bedding aggregate is
measured within the specified limits and computed to the nearest cubic
yard by the method of average cross-sectional end areas. For each load
of rock riprap placed as specified, the contractor shall furnish to the
COTR a statement-of-delivery ticket showing the weight to the nearest
0.1 ton.

Payment is made at the contract unit price for each type of rock riprap,
filter, or bedding. Such payment is considered full compensation for
completion of the work.

***Method 2---***For items of work for which specific unit prices are
established in the contract, the quantity of each type of rock riprap
placed within the specified limits is computed to the nearest 0.1 ton by
actual weight. The quantity of each type of filter or bedding aggregate
delivered and placed within the specified limits is computed to the
nearest 0.1 ton. For each load of rock riprap placed as specified, the
contractor shall furnish to the engineer a statement-of-delivery ticket
showing the weight to the nearest 0.1 ton. For each load of filter or
bedding aggregate, the contractor shall furnish to the COTR a
statement-of-delivery ticket showing the weight to the nearest 0.1 ton.

Payment is made at the contract unit price for each type of rock riprap,
filter, or bedding. Such payment is considered full compensation for
completion of the work.

***Method 3---***For items of work for which specific unit prices are
established by the contract, the volume of each type of rock riprap and
filter or bedding aggregate is measured within the specified limits and
computed to the nearest cubic yard by the method of average
cross-sectional end areas.

Payment is made at the contract unit price for each type of rock riprap,
filter, or bedding. Such payment is considered full compensation for
completion of the work.

***Method 4---***For items of work for which specific unit prices are
established by the contract, the volume of each type of rock riprap,
including filter and bedding aggregate, is measured within the specified
limits and computed to the nearest cubic yard by the method of average
cross-sectional end areas.

Payment is made at the contract unit price for each type of rock riprap,
including filter and bedding. Such payment is considered full
compensation for completion of the work.

***Method 5---***For items of work for which specific unit prices are
established by the contract, the quantity of each type of rock riprap
placed within the specified limits is computed to the nearest ton by
actual weight. For each load of rock for riprap placed as specified, the
contractor shall furnish to the COTR a statement-of-delivery ticket
showing the weight to the nearest 0.1 ton.

Payment is made at the contract unit price for each type of rock riprap,
including geotextile used for filter or bedding. Such payment is
considered full compensation for completion of the work.

***Method 6---***For items of work for which specific unit prices are
established by the contract, the volume of each type of rock riprap is
measured within the specified limits and computed to the nearest cubic
yard by the method of average cross-sectional end areas.

Payment is made at the contract unit price for each type of rock riprap,
including geotextile used for filter or bedding. Such payment is
considered full compensation for completion of the work.

***All methods---***The following provision applies to all methods of
measurement and payment. Compensation for any item of work described in
the contract, but not listed in the bid schedule, is included in the
payment for the item of work to which it is made subsidiary. Such items
and the items to which they are made subsidiary are identified in
section 8.

No separate payment is made for testing the gradation of the test pile.
Compensation for testing is included in the appropriate bid item for
riprap.

**7. Items of work and construction details**

Items of work to be performed in conformance with this specification and
the construction details therefore are:

[Bid Item 19, Loose Rock Riprap]{.underline}

(1) This item shall consist of furnishing and installing rock riprap
    required for the inlet, and the two outlet basins on the site as
    shown on the drawings.

(2) Riprap may be equipment placed with hand work to fill voids and
    provide uniformity. Hand placement of the rock will be required
    adjacent to the outlet pipes. A layer of geotextile will be secured
    around the outlet end of the 18 in. diameter pipes prior to
    installing the rock riprap on the upstream slope of the two outlet
    basins.

(3) Riprap gradation shall conform to the requirements of Class 2
    Riprap, Alabama Highway Department Standard Specification of Highway
    Construction, Section 814. Stone for Class 2 riprap shall consist of
    reasonably well graded durable rock with a median stone size of 80
    pounds and not more than 10 percent smaller than 10 pounds and not
    over 10 percent larger than 200 pounds. There shall be sufficient
    small stones and spalls to approximately fill the voids between the
    larger stones.

(4) Measurement and payment shall be by Method