« PreviousContinue »
203(10) Linear grading
204.01 Haul shall consist of the transporting of the material obtained as excavation from its original location to its final location in the work, except Borrow Case 2, foundation fill, and backfill material.
Method of Measurement
204.02 In determining what constitutes authorized haul, it will be assumed that material taken from excavation will be deposited in embankment after having been hauled the minimum distance. The haul distance for material moved from outside the roadway will be measured along the shortest route determined by the Engineer to be feasible and satisfactory unless otherwise provided. The haul distance for material obtained within the roadway limits and placed in the immediate roadway will be measured along the centerline of the roadway.
Haul will be the product obtained by multiplying the number of units of excavation removed from its original position by the mean distance such excavation is hauled. The distance between the center of volume of the excavation and the center of volume of the embankment will be the haul distance in the units specified. Haul may be computed by mass diagram or analytical methods, as determined by the Engineer.
Basis of Payment 204.03 If included in the bid schedule, the quantity of haul measured as provided above will be paid for at the
contract price. If pay items from the list below are not included in the bid schedule, no direct payment for haul will be made, but payment therefor will be considered as included in the bid price for other items of the contract.
Payment will be made under: Pay item
Pay unit 204 (1) Haul
Station yard. 204 (2) Haul
Cubic-yard-mile. 204 (3) Haul
205.01 Overhaul shall consist of authorized hauling in excess of the free-haul distance.
Free-haul distance is the specified distance that excavated material shall be hauled without additional compensation. Unless otherwise provided in the contract documents, the free-haul distance shall be 2,000 feet.
Method of Measurement
205.02. The limit of free-haul will be determined from a mass diagram by fixing on the volume curve, two points, one on each side of the neutral grade point, one in excavation and the other in embankment, such that the distance between them equals the free-haul distance, and the included quantity of excavation and embankment are in balance. All materials within the free-haul limit will be eliminated from further consideration. The distance between the center of volume of the remaining mass of excavation and of the remaining mass of embankment minus the free-haul distance will be the distance to be multiplied by the number of units of excavation removed from the original location and hauled beyond the free-haul distance. Analytical methods may be used for computing overhaul in lieu of the mass diagram method described herein.
Basis of Payment
205.03 If included in the bid schedule, the quantity of overhaul measured as provided above will be paid for at the contract price.
Payment will not be made for overhaul of Borrow Case 2, foundation fill, and backfill material.
If pay items from the list below are not included in the bid schedule, no direct payment for overhaul will be made, but payment therefor will be considered as included in the bid price for other items of the contract.
Payment will be made under: Pay item
Pay unit 205 (1) Overhaul
Station yard. 205(2) Overhaul
Cubic-yard-mile. 205(3) Overhaul
Section 206.—STRUCTURE EXCAVATION
206.01 General. This work shall consist of the necessary excavating for the foundations of bridges, culverts, underdrains, and other structures not otherwise provided for in the specifications. Except as otherwise provided for pipe culverts, the backfilling of completed structures, and the disposal of all excavated material shall be in accordance with these specifications and in reasonably close conformity with the plans or as established by the Engineer.
This work shall include necessary bailing, pumping, draining, sheeting, bracing, and the necessary construction of cribs and cofferdams, and furnishing the materials therefor, and the subsequent removal of cribs and cofferdams and the placing of all necessary backfill.
This work shall also include the furnishing and placing of approved granular backfill material to replace unsuitable material encountered below the foundation elevation of structures.
No allowance will be made for classification of different types of material encountered.
206.02 Clearing and Grubbing. Prior to starting excavation operations in any area all necessary clearing and grub
bing in that area shall have been performed in accordance with section 201.
(a) General, all structures.—The Contractor shall notify the Engineer sufficiently in advance of the beginning of any excavation so that cross-sectional elevations and measurements may be taken of the undisturbed ground. The natural ground adjacent to the structure shall not be disturbed without permission of the Engineer.
Trenches or foundation pits for structures or structure footings shall be excavated to the lines and grades or elevations shown on the plans or as staked by the Engineer. They shall be of sufficient size to permit the placing of structures or structure footings of the full width and length shown. The elevations of the bottoms of footings, as shown on the plans, shall be considered as approximate only and the Engineer may order, in writing, such changes in dimensions or elevations of footings as may be deemed necessary, to secure a satisfactory foundation.
Boulders, logs, and any other objectionable material encountered in excavation shall be removed.
After each excavation is completed, the Contractor shall notify the Engineer to that effect, and no footing, bedding material or pipe culvert shall be placed until the Engineer has approved the depth of excavation and the character of the foundation material.
(b) Structures other than pipe culverts.—All rock or other hard foundation material shall be cleaned of all loose material and cut to a firm surface, either level, stepped, or serrated as directed by the Engineer. All seams or crevices shall be cleaned and grouted. All loose and disintegrated rock and thin strata shall be removed. When the footing is to rest on material other than rock, excavation to final grade shall not be made until just before the footing is to be placed. When the foundation material is soft or mucky or otherwise unsuitable, as determined by the Engineer, the Contractor shall remove the unsuitable material and backfill with approved granular material. This foundation fill shall be placed and compacted in 6-inch layers up to the foundation elevation.
When foundation piles are used, the excavation of each pit shall be completed before the piles are driven and any placing of foundation fill shall be done after the piles are driven. After the driving is completed all loose and displaced material shall be removed, leaving a smooth, solid bed to receive the footing.
(c) Pipe culverts.—The width of the pipe trench shall be sufficient to permit satisfactory jointing of the pipe and
thorough tamping of the bedding material under and around the pipe.
Where rock, hardpan, or other unyielding material is encountered, it shall be removed below the foundation grade for a depth of at least 12 inches or one-half inch for each foot of fill over the top of pipe, whichever is greater, but not to exceed three-quarters of the vertical inside diameter of the pipe. The width of the excavation shall be at least one foot greater than the horizontal outside diameter of the pipe. The excavation below grade shall be backfilled with selected fine compressible material, such as silty clay or loam, and lightly compacted in layers not over 6 inches in uncompacted depth to form a uniform but yielding foundation.
Where a firm foundation is not encountered at the grade established, due to soft, spongy, or other unstable soil, such unstable soil under the pipe and for a width of at least one diameter on each side of the pipe shall be removed to the depth directed by the Engineer and replaced with approved granular material properly compacted to provide adequate support for the pipe, unless other special construction methods are called for on the plans.
The foundation surface shall provide a firm foundation of uniform density throughout the length of the culvert and, if directed by the Engineer, shall be cambered in the direction parallel to the pipe centerline.
Where pipe culverts are to be placed in trenches excavated in embankments, the excavation of each trench shall be performed after the embankment has been constructed to a plane parallel to the proposed profile grade and to such height above the bottom of the pipe as is shown on the plans or directed by the Engineer.
206.04 Utilization of Excavated Materials. All excavated material, so far as suitable, shall be utilized as backfill or embankment. The surplus material, whether or not temporarily allowed to be placed within a stream area, shall be disposed of finally in such manner as not to obstruct the stream or otherwise impair the efficiency or appearance of the structure. No excavated material shall be deposited at any time so as to endanger the partly finished structure.
206.05 Cofferdams. Suitable and practically watertight cofferdams shall be used wherever water-bearing strata are encountered above the elevation of the bottom of the excavation. Upon request, the Contractor shall submit drawings showing his proposed method of cofferdam construction, as provided under subsection 105.02.
Cofferdams or cribs for foundation construction shall, in general, be carried well below the bottoms of the footings and shall be well braced and as nearly watertight as prac