**Construction Specification 721---Excavation**

**1. Scope**

The work shall consist of the excavation required by the drawings and
specifications and disposal of the excavated materials.

**2. Use of excavated material**

To the extent they are needed, all suitable material from the specified
excavations shall be used in the construction of required permanent
earthfill or rockfill. The suitability of material for specific purposes
is determined by the engineer. The contractor shall not waste or
otherwise dispose of suitable excavated material.

**3. Disposal of waste materials**

All surplus or unsuitable excavated materials are designated as waste
and shall be disposed of at the locations shown on the drawings.

**4. Excavation limits**

Excavations shall comply with OSHA Construction Industry Standards
(29CFR Part 1926) Subpart P, Excavations, Trenching, and Shoring. All
excavations shall be completed and maintained in a safe and stable
condition throughout the total construction phase. Structure and trench
excavations shall be completed to the specified elevations and to the
length and width required to safely install, adjust, and remove any
forms, bracing, or supports necessary for the installation of the work.
Excavations outside the lines and limits shown on the drawings or
specified herein required to meet safety requirements shall be the
responsibility of the contractor in constructing and maintaining a safe
and stable excavation.

**5. Borrow excavation**

When the quantities of suitable material obtained from specified
excavations are insufficient to construct the specified earthfills and
earth backfills, additional material shall be obtained from the
designated borrow areas. The extent and depth of borrow pits within the
limits of the designated borrow areas shall be as specified in section
10 or as approved by the engineer.

Borrow pits shall be excavated and finally dressed to blend with the
existing topography and sloped to prevent ponding and to provide
drainage.

**6. Overexcavation**

Excavation in earth beyond the specified lines and grades shall be
corrected by filling the resulting voids with approved, compacted
earthfill. The exception to this is that if the earth is to become the
subgrade for riprap, rockfill, sand or gravel bedding, or drainfill, the
voids may be filled with material conforming to the specifications for
the riprap, rockfill, bedding, or drainfill. Before correcting an
overexcavation condition, the contractor shall review the planned
corrective action with the engineer and obtain approval of the
corrective measures.

**7. Measurement and payment**

For items of work for which specific unit prices are established in the
contract, the volume of each type and class of excavation within the
specified pay limits is measured and computed to the nearest cubic yard
by the method of average cross-sectional end areas or by methods
outlined in section 10 of this specification. Regardless of quantities
excavated, the measurement for payment is made to the specified pay
limits except that excavation outside the specified lines and grades
directed by the engineer to remove unsuitable material is included.
Excavation required because unsuitable conditions result from the
contractor\'s improper construction operations, as determined by the
engineer, is not included for measurement and payment.

***Method 1---***The pay limits shall be as designated on the drawings.

***Method 2---***The pay limits shall be defined as follows:

a\. The upper limit shall be the original ground surface as it existed
before the start of construction operations except that where excavation
is performed within areas designated for previous excavation or
earthfill, the upper limit shall be the modified ground surface
resulting from the specified previous excavation or earthfill.

b\. The lower and lateral limits shall be the neat lines and grades
shown on the drawings.

***Method 3---***The pay limits shall be defined as follows:

a\. The upper limit shall be the original ground surface as it existed
before the start of construction operations except that where excavation
is performed within areas designated for previous excavation or
earthfill, the upper limit shall be the modified ground surface
resulting from the specified previous excavation or earthfill.

b\. The lower and lateral limits shall be the true surface of the
completed excavation as directed by the engineer.

***Method 4---***The pay limits shall be defined as follows:

a\. The upper limit shall be the original ground surface as it existed
before the start of construction operations except that where excavation
is performed within areas designated for previous excavation or
earthfill, the upper limit shall be the modified ground surface
resulting from the specified previous excavation or earthfill.

b\. The lower limit shall be at the bottom surface of the proposed
structure.

c\. The lateral limits shall be 18 inches outside of the outside surface
of the proposed structure or shall be vertical planes 18 inches outside
of and parallel to the footings, whichever gives the larger pay
quantity, except as provided in d below.

d\. For trapezoidal channel linings or similar structures that are to be
supported upon the sides of the excavation without intervening forms,
the lateral limits shall be at the underside of the proposed lining or
structure.

e\. For the purposes of the definitions in b, c, and d, above, any
specified bedding or drainfill directly beneath or beside the structure
will be considered to be a part of the structure.

***All methods---***The following provisions apply to all methods of
measurement and payment.

Payment for each type and class of excavation is made at the contract
unit price for that type and class of excavation. Such payment will
constitute full compensation for all labor, materials, equipment, and
all other items necessary and incidental to the performance of the work
except that extra payment for backfilling overexcavation will be made in
accordance with the following provisions.

Payment for backfilling overexcavation, as specified in section 8 of
this specification, is made only if the excavation outside specified
lines and grades is directed by the engineer to remove unsuitable
material and if the unsuitable condition is not a result of the
contractor\'s improper construction operations as determined by the
engineer.

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 10 of this
specification.

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

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

[Bid Item 15, Excavation]{.underline}

(1) This item shall consist of excavation necessary to slope or shape
    areas for riprap placement, install pipe or drop inlets, strip areas
    to a suitable foundation for earthfill, excavate from borrow areas,
    and other excavation necessary to complete the work.

(2) Borrow areas shall be graded and finished as directed by the
    Engineer.

(3) Measurement and payment will be by Method .