Section 2102. Roadway and Borrow Excavation.

This work shall include removal of all materials as indicated in the contract documents and from borrow pits, exclusive of that designated as channel excavation. It shall also include removal of material necessary to provide suitable approaches from intersecting highways and private entrances. It shall include all shaping and sloping necessary for construction of the roadbed, slopes, gutters, and inlet and outlet ditches in accordance with these specifications and in conformance with the alignment, grade, and cross sections shown in the contract documents or established by the Engineer.

If impractical to remove utility poles before excavation or embankment construction, the Contractor will be required to work around the poles.

Before excavation is begun, grass, weeds, other herbaceous vegetation, and rubbish shall be removed as provided in Article 2101.02.

All roadway and borrow excavation will be classified as Class 10, Class 12, or Class 13 hereinafter defined and as indicated in the contract documents.

Boulders encountered in excavation shall be removed or buried. Surface collections of boulders, within the limits of the work, shall be removed where necessary for satisfactory completion of the work. After completion of excavation operations and as part of the finishing process, the Contractor shall collect all loose boulders, rocks, and pieces of broken Portland cement concrete, which have a vertical projection 4 inches (100 mm) or more above the surface of the ground or a minimum diameter of 6 inches (150 mm), that appear during the finishing operation. Boulders, except those handled in a way normal to Class 10 excavation, will be classified as Class 12 excavation. Unless otherwise specified, the Contractor shall place boulders in any of the following ways:

Boulders not placed as provided above may, with approval of the Engineer, be used for filling gullies, be racked in neat compact piles at locations designated by the Engineer within the right-of-way and accessible from the traveled way, or be buried within the right-of-way at locations designated by the Engineer.

Removal of unsuitable or unstable soil or placement of selected or special backfill material, or both, may be required in the contract documents or by the Engineer.

If the finished grade line leaves a subgrade of unsuitable or unstable soil, the Engineer may require the Contractor to remove that soil as below grade excavation and backfill to the finished grade line. Material encountered above the elevation of finished subgrade which cannot be properly consolidated in the embankment may be designated as unstable soil by the Engineer. If the surface on which the plans indicate that selected or special backfill shall be placed is such that it will be seriously distorted by hauling equipment, the Engineer may designate this material as unstable.

Removal of unsuitable or unstable soil and placement of selected or special backfill material shall be in accordance with the following requirements:

2102.05 ROCK CUTS.
When excavation to the finished grade line results in a roadbed surface consisting of loose or solid rock, the Contractor shall excavate 1 foot (0.3 m) below the finished grade of the roadbed and backfill to the required grade with suitable earth. Subject to approval of the Engineer, the earth backfill may be obtained from any point within the right-of-way where suitable backfill material is available. The Contractor shall conduct operations in such a way that the Engineer is given the opportunity to take cross sectional measurements required before backfill is placed.

When presplitting of rock cuts is required, the limits of the area and the procedure will be designated.

The contract documents may require that part or all of the Class 12 Excavation be crushed. When crushing is required, the contract documents will specify the size and/or gradation the rock shall be crushed to, and specify where the crushed material is to be stockpiled or used in the contract.

2102.06 BORROW.
Unless otherwise provided in the contract documents, when the quantity of material required for embankments is not available within the limits of the roadway cross sections or specific borrow areas as indicated, the Contractor shall make up the deficiency from borrow areas provided by the Engineer or furnish equivalent material from alternate borrow areas.

The following definitions apply to this specification:

Borrow areas provided by the Contractor shall be regular in cross section to permit accurate measurement. Care shall be taken to blend to natural land forms and avoid unnecessary damage to the land. The Contractor shall not turn natural drainage of surface water on to adjoining owners and shall use strict diligence in draining the surface water in its natural course or channel. Excavation shall be completed in a way as to be consistent with the existing natural drainage conditions.

Where a mandatory borrow area is designated in the contract documents, it is mandatory that borrow material be obtained from the borrow location designated unless permission is obtained from the Engineer to obtain borrow from another location.

Unless the contract documents designate borrow areas as mandatory borrow areas, borrow areas will be considered optional borrow areas. The Contractor has the option of either using the optional borrow areas or proposing to furnish equivalent material from alternate borrow areas.

The Contractor may be required to compensate the Contracting Authority for material removed from optional borrow areas. When required, the rate of compensation per cubic yard (cubic meter) to be charged will be shown in the contract documents. Compensation will not be required for topsoil that is removed and replaced. Compensation will be based on quantities shown in the contract documents, as corrected. However, when only a portion of the designated quantity is taken from the area, the quantity will be calculated from cross section measurements. When the contract documents do not identify an amount per cubic yard (cubic meter) for compensation, the material in the optional borrow area is available to the Contractor at no cost.

Slope Dressing Only: 1. Peat or Muck.
2. Soils with a plasticity index of 35 or greater.
3. A-7-5 or A-5 having a density less than 85 pcf (1350 kg/m3) (AASHTO T 99 Proctor Density).
Type C placement placed 3 feet (1 m) below top of subgrade in fills: 1. All soils other than A-7-5 or below subgrade A-5 having a density of 95 pcf (1500 kg/m3) or less (AASHTO T 99 Proctor Density).
2. All soils other than A-7-5 or A-5 containing 3.0% or more carbon.
Type B placement placed 5 feet (1.5 m) below top of subgrade in fills: 1. A-7-6 (30 or greater).
2. Residual clays (overlaying bedrock) regardless of classification.
Type A placement placed in layers 5 feet (1.5 m) below top of subgrade in fills: 1. Shale.
(Alternate layers shall be suitable Class 10 or Type C placement soils.) 2. A-7-5 or A-5 soils having a density greater than 86 pcf (1351 kg/m3) but less than 95 pcf (1500 kg/m3) (AASHTO T 99 Proctor Density).

Surplus excavated material shall be placed as directed by the Engineer. It shall generally be used in widening adjacent embankments, to flatten sideslopes, or to construct berms in accordance with Article 2107.12.

Intercepting ditches and flumes shall be constructed as shown in the contract documents.

In cuts along side hills where there is a possibility of surface water causing damage to the backslope of the cut, intercepting ditches with appropriate flume outlets shall be constructed to intercept surface water. Where surface water or water from side ditches would otherwise follow the toe of the embankment slope, the water shall be directed away from the toe of slope by runout ditches.

When locating tile lines is required by the Engineer, trenching and backfilling shall be done at locations shown in the contract documents or as directed by the Engineer. The Contractor shall construct a continuous trench having a minimum depth of 5 feet (1.5 m) and a minimum width of 4 inches (100 mm). Trenching shall be outside the limits of the embankment. The Engineer shall examine the trench and excavated material to locate tile lines. Backfilling shall not be started without approval of the Engineer. All trenches shall be backfilled.

If necessary in prosecution of the work to interrupt or alter the natural flow of surface waters or flow of artificial drains, the Contractor shall provide temporary drainage facilities as are necessary to prevent damage to public or private property. The Contractor shall restore the original drainage facilities as soon as the work will permit. The Contractor shall be fully liable for all damages arising from action or inaction in providing for temporary drainage.

Trees and shrubs to be preserved shall be protected from injury during grading operations. The Engineer may require barricades or fences for this purpose.

Whenever the Contractor's operations encounter remains of prehistoric people's dwelling sites, burial sites, or artifacts of historical or archaeological significance, the operations shall be temporarily discontinued at the site. The Engineer, in conjunction with proper archaeological authorities of the State of Iowa, will promptly examine the exposure and determine the disposition.

When directed by the Engineer, the Contractor shall excavate the site in a manner to preserve the artifacts encountered and remove them for delivery to the custody of proper State authorities.

2102.11 FINISHING.
Excavation and embankment work, including borrow pits, shall be finished in a high quality manner to the specified or designed grade and cross section. On projects which do not involve a surface course other than a traffic compacted surface, the Engineer may waive the setting of finishing stakes if compliance with grade and cross section requirements has been obtained and appearance and riding qualities are satisfactory. Backslopes shall be kept neatly finished as construction progresses.

All finishing work shall be kept as close as possible to construction operations. This applies particularly to steep slopes and large areas which could result in pollution of streams by soil erosion. When erosion control items are a part of the contract, the contract documents may specify a completion date for specific areas. When these dates are not specified, the Contractor shall complete erosion control work on all finished areas within 5 working days after completion of finishing. The Contractor shall keep finishing operations current with other construction operations.

If the Contractor fails to maintain partly finished work in a satisfactory manner, when ordered in writing by the Engineer, all other work shall be discontinued until all finishing and maintenance work is in a satisfactory condition. Before final acceptance, the roadway shall be finished to the specified or designed line, grade, and cross section.

The degree of finish for grading slopes, shoulders, and ditches will be that ordinarily obtainable through use of power equipment operating under favorable conditions and operated by skilled workers. Hand methods of finishing will be required only when satisfactory results are not otherwise obtained.

All backslopes and foreslopes shall be finished to the extent that they conform to the cross section, and all bulges shall be removed and all sags filled. Unless specifically excluded, all backslopes and foreslopes on all projects shall be roughened as a final finishing operation except those which contain sufficient sand or rock to make roughening impractical. Roughening shall be to a minimum depth of 3 inches (75 mm) and shall be done by scarification, use of a heavy disk, or other suitable means.

Equipment used in roughening the surface shall operate in a direction substantially parallel with the toe of the slope. If the material being roughened is of such nature that an objectionable amount rolls down the slope, the Contractor shall start roughening operation at the toe of the slope and proceed in parallel strips up the slope.

Temporary water pollution control, shall be constructed in accordance with Section 2525.

On contracts for grading work to be done immediately prior to paving work covered by a separate contract, the grading Contractor shall build the rough grade to the full width of roadbed and with sufficient crown to provide surface drainage. The roadbed shall be constructed so that the surface elevation shall not be lower at any point than the elevation of the corresponding pavement subgrade and shall not be above this elevation by more than 3 inches (75 mm), except at structures or when required by the contract documents.

The operation of earth moving equipment with legal axle loads will be permitted on new pavements or resurfaced roads if the road is not open to general traffic. Operation of earth moving equipment will not be permitted on pavements or resurfaced roads open to general traffic.

The above restrictions will not be construed to prevent the Contractor from hauling across pavement with legal loads at locations designated by the Engineer, or to prohibit the Contractor from turning across pavement to the opposite shoulder when embankment height or ditch depth prevents turning in the opposite direction. All flaggers necessary for safe operations shall be furnished by the Contractor at no additional cost.

The work of roadway and borrow excavation will be measured as follows:

Removal of pipe culverts that are not encased in concrete will not be measured or paid for, but will be considered as incidental to excavation.

The work of roadway and borrow excavation will be paid for as follows:

When Type B compaction is specified, work performed at the direction of the Engineer to dry the material in excess of that obtained by the maximum number of diskings specified in Article 2107.06 shall be performed as extra work as provided in Article 1109.03, B.

Extra compensation will not be allowed for working around utilities.

For work performed in connection with preservation of archaeological salvage, the Contractor will be paid as provided in Article 1109.03, B.

If the contract does not include an item for Stripping, Salvaging, and Spreading Topsoil, Section 2105, such work ordered by the Engineer will be paid for at 1.5 times the contract unit price for Class 10 excavation.