206STRUCTURE EXCAVATION

New Hampshire Department of Transportation Standard Specifications – 2016 FOR PIPES AND OTHER MINOR STRUCTURES Description

1.1This work shall consist of the excavation and backfill or disposal when necessary of all materials required to be removed to

complete the work as shown on the plans or as ordered. Excavation for the following shall be included under this item: berm ditches, inlet ditches and outlet ditches, sand drains, drainage pipes, multiple pipe structures, manholes, catch ba sins, drop inlets, cattle passes, headwalls, overhead traffic sign bases and the like, water and sewer pipes, pipe sleeves, conduits, and chan nels with less than a 10 ft -bottom width. Excavation for roadway ditches not adjoining roadway excavation will be included in this item unless otherwise specified. Classification of Materials

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

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

2.2Rock structure 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, except as provided in 604.5.2.2.

2.3Unclassified structure excavation shall consist of all structure excavation encountered.

Construction Requirements

3.1All excavation shall be removed to the limits shown or ordered and the excavated material incorporated in the work or

disposed of as directed. Berm ditches shall be constructed at the top of cut slopes as shown on the plans or as ordered.

3.2Excavated areas, including unsuitable material, below structures and pipes in ro ck shall be removed to the limits specified

and backfilled to the bottom of the pipe or structure with approved material. (See also 603.3.1.)

3.3Excessive widths of trench in excavation for pipes will not be permitted. Below the level of the tops of the pipes, the walls

of trenches shall be kept as nearly vertical as practicable. Trenches shall be shored in accordance with OSHA Regulations. (See also 603.3.1.7.)

3.4When blasting is required, the provisions of 203.3.2 shall apply as though contained in this Section.

Method of Measurement

4.1Structure excavation will be measured by the cubic yard in accordance with 109.01.

4.1.1 The lower limits shall be as shown on the plans, as designated in Figure 1 in 603, or as provided below. The upper limits shall be the original ground except as provided in 203.5.1.6. All excavation for p ipes and other structures that are to be installed by others will be measured for payment; otherw ise, the first 9 ft. of common structure excavation for pipes, manholes, catch basins, and drop inlets even when ordered in addition to those shown on the plans, shall be subsidiary except as follows:

ordered is wider than the specified payment limits in 4.1.2, the extra excavation will be measured in accordance with Figure 1 -D of 603.

below the 1 ft. limit will be measured for payment. 4.1.2 Unless otherwise shown on the plans, the horizontal limits shall be as follows for pipes: Inside Diameter Total Width Up to 12” 36” 12 to 24” I.D. + 24” Over 24” 2 x I.D. 4.1.3 The horizontal limits for end sections shall be the same as the pipes to which they are attached. 4.1.4 The horizontal limits for structures such as manholes, catch basins, headwalls, and the like will be 1 ft. outside of the base of the masonry and parallel or concentric thereto.

4.2All material classified as rock encountered within the neat lines established under this Section will be measured. No payment

will be made for any overbreakage below or beyond the limits specified.

4.3In case a conflict of horizontal limits exists in payment lines, as where a pipe enters a headwall, the greater limit will be used

for computing the quantity.

New Hampshire Department of Transportation Standard Specifications – 2016

4.4Unclassified structure excavation for exploratory purposes will be measured as provided under the applicable provisions of

206.4.1. Basis of Payment

5.1The accepted quantity of structure excavation will be paid for at the Contract unit price per cubic yard complete in place.

5.2Granular material specified or ordered will be paid for under Section 209.

5.3When common structure excavation is the only class included in the Contract, any rock encountered will be paid for at a

price equal to five times the unit price for common structure excavation under Item 206.2.

5.4When structure excavation items a re included in the Contract, but no items for exploratory purposes are in the Contract,

payment for excavation made for investigations or exploratory purposes will be paid for under Item 206.19 at five times the u nit price for the class of excavation encountered.

5.5If neither Item 206.1 nor Item 206.2 nor an item for exploratory purposes is included in the Contract, any structure excavation

encountered, including excavation for investigation or exploratory purposes, will be paid in accordance with 109.04 .

5.6No separate payment will be made for pre-blast and post-blast surveys or blasting monitoring work.

Pay items and units:

206.1Common Structure Excavation Cubic Yard

206.19Common Structure Excavation – Exploratory Cubic Yard

206.2Rock Structure Excavation Cubic Yard

206.39Unclassified Structure Excavation – Exploratory Cubic Yard

New Hampshire Department of Transportation Standard Specifications – 2016

Description

This 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

Common 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.

Rock 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.

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

Construction Requirements

Channel 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.

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

No excavation shall be performed prior to cross-sectioning.

Method of Measurement

Channel 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.

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

protective measures will not be measured. Basis of Payment

Channel 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.

The 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