206Structure Excavation for Conduits and Minor Structures

206.01 Description . This work consists of the removal of material necessary for the

construction of foundations for box culverts, box bridges, underdrains, pipe culverts and headwalls, and other minor structures when authorized by the section covering their construction. It shall also include all neces sary pumping, bailing, drainage, cribbing or sheeting, other foundation work, and the backfilling and proper disposal of all excavated material as directed. Unless otherwise spec ified, excavation for pipe used as sidedrain will not be measured as structure excavation.

206.02 Blank .

206.03 Construction Requirements .

206.03.1 Excavation . No excavation shall be made until the Engineer has cross

sectioned and staked out the work. The Contract or shall exercise care to ensure that the adjacent natural ground is not unnecessarily disturbed or the foundation loosened below the bottom of the footing unless ad ditional excavation is required. When the plans indicate or the Engineer directs removal of material classified in the contract as muck excavation or special exca vation, the undercut shall be made and the area backfilled approximately one foot ab ove the flow line of the structure and compacted to the required density befo re structure excavation is performed. Foundation areas shall be excavated to the footing elevations and dimensions shown on the plans or as established. The right is reserved to make adjustments in the location or flow line to provide adequate drainage and to make dimension changes in the footings to obtain a satisfactory foundation. In addition to the requirements of this subs ection, excavation for pipe culverts will be performed in accordance with Subsection 603.03. Material encountered that is unsuitable for a stable foundation shall be excavated and backfilled as provided in Subsection 203.03.

206.03.2 Backfill . All backfilling shall be in acco rdance with the requirements and

provisions of Subsection 203.03. When the plans indicate or the Engineer orders removal of unsuitable material or other undercut below the normal grade line to provide a satisfactory foundation and further orders a specified depth of select material that may not be available from within the right- of-way or easement areas, the Contractor shall furnish a suitable backfill material such as sand, gravel, or other similar granular materials.

206.04 Method of Measurement . Structure excavation acceptably performed will be

measured as set forth herein. For structures other than pipe culverts, the area to be included in the measurement of structure excavation will be that area bounded by vertical planes one foot outside of the neat lines of the footing. For pipe culverts, the vertical planes will be one foot each side of the nominal inside diameter of the pipe or less for tile and pipe underdrains if indicated on the plans. The length to be allowed will be one foot beyond each end of the pipe, except when the pipe is joined to another structure for which paym ent for structure excavation will be made. In this case, the length will be limited to the poi nt of intersection of the centerline of the pipe with the boundary of structure excavation of joining structures. The depth allowed will be that actually removed between the natural ground line or the bottom of the graded section, whichever is lower, and the bottom of the footing or the bottom of the trench in the case of pipe. Measurement will not be made for excavation beyond the neat lines described which are made for the convenience or necessity of the Contractor’s operation. The volume of structure excavation allowed for payment will be the summation of the products of the widths, depths and lengths described. In case the Engineer orders additional excavation for foundation improvement below the depth indicated herein, this excavation within the designated neat lines will be measured as structure excavation. Unless otherwise specified, selected backfill material shown on the plans or directed by the Engineer to be produced from an area to be excavated under one of the classes of excavation set out in the contract will be measured and paid for under the applicable item of excavation. Any special ordered (select) material that is produced from excavation identified on the plans as E.S.F.E. will be measured for paymen t as contractor furnished select material. Select material ordered or authorized by Engineer to provide a satisfactory foundation for structures and conduit will be measured by the cubic yard (FM). Contractor furnished materials such as sand, gravel, granular materi als, timber, etc. for backfilling will be paid at the contract unit price of the material used or as extra work in accordance with Subsection 104.03 when the pay item for select material for undercuts is not set up in the contract. Haul necessary to supply the selected material, other than Contractor-furnished, will be measured as set out in Section 205. No measurement will be made for water or other liquids removed.

206.05 Basis of Payment . Structure excavation, measured as prescribed above, will be

paid for at the contract unit price per cubic yard which price shall be full compensation for the work. Special materials and/or methods of strengthening the foundation, ordered by the Engineer, will be paid for at the contract unit price for the material used; or, when no unit price is included in the contract, the work w ill be paid for as Extra Work in accordance with Subsection 104.03. Payment will be made under: 206-A: Structure Excavation - per cubic yard 206-B: Select Material for Undercuts, Contractor Furnished, FM - per cubic yard SECTION 207 - SETTLEMENT PLATE

207.01 Description. This work consists of furnishing all labor, materials, equipment,

and services necessary to install, protect, maintain, and monitor settlement plate(s) in order to determine and report total embankment settlement. Monitoring shall consist of the surveyed elevation of the top of the vertical interior standpipe at monitoring and reporting increments determined by the rate of embankment construction and/or the time increment specified on the site specific construction plan s and guidelines, as compared to the initial baseline survey to determine the total recorded settlement. 207.02--Materials. The required material lengths and quantities are the responsibility of the Contractor based on the embankment total height, plus surcharge height, if required, plus stick-up. The Contractor shall be responsible for verification of ground line at the time of construction and adjustment of quantities, as needed.

207.02.1 1-Inch Diameter Steel Pipe and Couplings. Pipe shall be 1-inch diameter,

ASTM A53, Schedule 40, black, threaded end, steel pipe with compatible steel couplings.

207.02.2 2-Inch Diameter Steel Pipe and Couplings. Pipe shall be 2-inch diameter,

ASTM A53, Schedule 40, black, threaded end, steel pipe with compatible steel couplings.

207.02.3 Steel Plate. The steel plate shall be a minimum ½-inch thick by 2-foot by 2-

foot ASTM A53, steel plate.

207.03 Construction Requirements.

207.03.1 Installation. The settlement plate(s) shall be assembled and placed at the

locations shown in the plans or as directed by the Engineer. Each settlement plate shall be placed on a level ground surface at or near the existing ground surface, subsequent to stripping, clearing and grubbing operations in preparation for embankment construction. Field weld-all-around a 1-inch threaded coupli ng to center of steel plate using a ¼-inch single bevel weld. Sections of the 1-inch and 2-inch steel pipe shall be added incrementally as the fill height is increased to maintain a 2-foot to 4-foot extension of the steel pipe above the embankment fill level at all times. The 1-inch diameter steel pipe shall be centered within the 2-inch diameter pipe to prevent any interference of movement between the two pipe sections and extend vertically at least 6-inches (or the estimated design settlement depth) above the 2-inch pipe. The 2-inch diameter steel pipe shall begin at an elevation approximately six inches (6”) above the elevation of the steel plate. In the event that damage to the settlement plate(s) occurs as the result of the Contractor’s operations and it is deemed by the Engineer to be unusable, the Contractor will be