207CHANNEL EXCAVATION

New Hampshire Department of Transportation Standard Specifications – 2016 Description

1.1This item shall consist of the excavation and disposal of all materials encountered in the construction of channels having a

bottom width of 10 ft. or more, except inlet and outlet ditches for multiple pipe culverts, as shown on the plans or as o rdered. Classification of Materials

2.1Common channel excavation shall consist of all excavation described above that is not classified as rock channel excavation.

Glacial till or boulder clay will be considered as common channel excavation.

2.2Rock channel excavation shall consist of all solid rock that can be removed only by blasting or ripping. It shall also consist

of boulders and parts of masonry structures when found to measure 1 cy or more.

2.3Unclassified channel excavation shall consist of all the channel excavation encountered.

Construction Requirements

3.1Channel excavation shall be removed to the limits shown or ordered.

3.1.1 When blasting is required, the provisions of 203.3.2 shall apply as though contained in this Section.

3.2All surplus material shall be incorporated in the work or disposed of as directed.

3.3No excavation shall be performed prior to cross-sectioning.

Method of Measurement

4.1Channel excavation will be measured by the cubic yard in accordance with 109.01. The upper limit shall be original ground

except as provided in 203.5.1.6. No allowance will be made for material excavated before measurements have been made or for material excavated beyond the required slope lines.

4.2Blast vibration control and monitoring, preblast condition surveys, postblast surveys, blasting precautions and other

protective measures will not be measured. Basis of Payment

5.1Channel excavation will be paid for at the Contract unit price per cubic yard complete for each class of channel excavation

included in the Contract. When common channel excavation is the only class included in the Contract, any rock encountered wi ll be paid for at a price equal to five times the Contract unit price for common channel excavation under Item 207.2.

5.2The cost of all blast vibration control and monitoring, preblast condition surveys, postblast surveys, blasting precautions and

other protective measures necessary to prevent damage and subsequent creation of claims in connection with blasting shall be subsidiary to Item 207.2 or Item 207.3. Pay items and units:

207.1Common Channel Excavation Cubic Yard

207.2Rock Channel Excavation Cubic Yard

207.3Unclassified Channel Excavation Cubic Yard

New Hampshire Department of Transportation Standard Specifications – 2016

Description

This work shall consist of furnishing and placing porous granular material at the locations shown on the plans or ordered.

Materials

The material shall consist of stones, rock fragments, and fine hard durable particles resulting from the natural disintegration

of rock. The material shall be free from harmful amounts of organic matter. The wear shall not exceed 60 percent. No more than 12 percent of the mat erial passing the No. 4 sieve shall pass the No. 200 sieve, and the material shall conform to the following gradations: 2.1.1 Granular backfill (sand) shall consist primarily of particles with 100 percent passing the 3” sieve and 70 to 100 percent passing the No. 4 sieve. 2.1.2 Granular backfill (gravel) shall consist of a mixture of stones or rock fragments and particles with 95 to 100 percent passing the 3” sieve and 25 to 70 percent passing the No. 4 sieve. 2.1.3 Granular Backfill (Bridge). When this item is specified the material shall meet the gradation requirements of Item 304.2. 2.1.4 Granular Backfill. When this item is specified, the gradation shall conform to 2.1.1 or 2.1.2.

Concrete class F, flowable fill may be requested in writing as a substitute for granular backfill. Approval shall be in

consideration of, but not limited to, differential frost heaving due to dissimilar materials, unit weight, structural requirements, lack of permeability, and damming resulting from water flow cut off. Construction Requirements

Granular backfill of the specified or ordered gradation shall be placed in layers at the locations shown or ordered. Backfil l

shall be placed in the manner detailed in the appropriate section in which the backfill is specified. The backfill layers shall not exceed 8” of compacted depth unless otherwise directed. Density shall meet the requirements of 203.3.8. Method of Measurement

Granular backfill will be measured by the cubic yard in accordance with 109.01 . When granular backfill is specified as

included in another item, no separate measurement will be made for the backfill furnished in connection with that item.

Backfill of over-excavated areas beyond or below the lines and grades shown or ordered will not be measured for payment.

4.3For pipe having an inside diameter of less than 48” no deduction will be made from granular backfill of the volume occupied

by the pipe constructed under 603 when granular backfill is ordered as bedding material.

4.4Granular backfill (bridge) will not be measured, but shall be the cubic yard final pay quantity in accordance with 109.11 for

compacted material required within the limits shown on the plans. Basis of Payment

The accepted quantity of granular backfill, of the type specified, will be paid for at the Contract unit price per cubic yard

complete in place.

Granular backfill (bridge) is a final pay quantity item and will be paid for at the Contract unit price per cubic yard complete

in place in accordance with 109.11.

5.3Concrete class F, flowable fill substituted for granular backfill will be paid for at the Contract unit price for granular backfill

of the type specified. Pay items and units:

209.1Granular Backfill Cubic Yard

209.20X Granular Backfill (Bridge) (F) Cubic Yard

209.3Granular Backfill (Sand) Cubic Yard

209.4Granular Backfill (Gravel) Cubic Yard