(A) Clearing the right-of-way. Where cleaning of the right-of-way is necessary, it shall be completed prior to the start of trenching. Trees and brush shall be cut as near to the surface of the ground as practicable and piled for disposal. The contractor shall observe all federal and state laws relating to fire permits and local regulations related to burning such materials. Under no conditions shall excavated materials be permitted to cover brush or trees prior to cleaning and disposal. Existing trees or tree limbs whether on public or private property, are not to be removed without permission from the Town Engineer or Superintendent or as designated on the plans.
(B) Obstructions. This item refers to obstructions which may be removed and do not require replacement. Obstructions to the construction of the trench such as, but not limited to, stumps, abandoned piling, abandoned concrete structures, logs, rubbish, and debris of all types shall be removed by the contractor at his or her own expense. The Town Engineer or Superintendent will, if requested by the contractor, make changes in the alignment to avoid major obstructions if such alignment changes can be made without adversely affecting the intended function of the facility.
(C) Asphaltic concrete pavement removal and replacement.
(1) All bituminous and concrete pavements, regardless of thickness, shall be cut prior to excavation of trenches. Width of the pavement cut shall be at least six inches greater than the required width of the trench at ground surface at each side. Pavement removed during excavation shall be piled separately from the earth spoil and removed from the site and shall not be used in backfilling the trench.
(2) Undercut pavement shall be cut at least six inches greater than the trench wall.
(3) After the trench has been backfilled and compacted according to the specifications, the contractor shall bring the trench to a smooth even grade at the proper depth below the existing surface to provide the required depth of pavement. The contractor shall cut the existing pavement to a straight line and remove any pavement that has been damaged.
(4) The entire existing paved surface shall be cleaned before resurfacing is begun.
(5) The contractor shall apply a prime coat of asphalt tack coat to the edges of the existing pavement and to the cast iron manhole frames below the grade. He or she shall then place the asphaltic concrete over the prepared trench. The finished surface of the new pavement shall conform to the grade, crown, and slope of the existing pavement.
(6) Pavement replacement within all streets shall be at least two lifts one and one-half inch thickness each for a total asphaltic concrete thickness of three inches but shall not be less than existing pavement thickness. Pavement thickness greater than three inches shall be placed in layers not greater than two and one-half.
(D) Blasting. Blasting of excavation shall be permitted only after securing approval of the Town Engineer or Superintendent and only when proper precautions are taken for the protection of persons and property. Any damage caused by the blasting shall be repaired by the contractor at his or her own expense. The contractor’s methods of procedure and blasting shall conform to state laws, county laws, and municipal ordinances.
(E) Trench width. Minimum width of unsheeted trenches in which pipe is to be laid shall be 18 inches greater than the inside diameter of the pipe, except by permission of the Town Engineer or Superintendent. The maximum width of the trench shall be limited to the pipe outside diameter exclusive of the bells plus 24 inches. Trench width required where CDF is used, as the entire backfill shall be as shown on the plans or as directed by the Town Engineer or Superintendent. In all cases, trench width shall be confined to dedicated right-of-way for public thoroughfares or within areas of which construction easements have been obtained, unless special arrangements have been made with the affected property owners.
(F) Grade. The bottom of the trench shall be carried to the lines and grades shown on the plans or as established by the Town Engineer or Superintendent, with proper allowance for pipe thickness and for gravel bedding. Any part of the trench excavated below grade shall be corrected with material of the type specified in § 152.02(B)(1), for the full width of the trench and thoroughly compacted layers not to exceed six inches, to the established grade. Unless otherwise specified, service laterals shall be laid at a slope of one-fourth inch per foot.
(G) Shoring, sheeting, and grading of trenches. Whenever necessary to prevent caving during excavation of gravel, sandy soil, or other unstable material, the trench shall be adequately sheeted and braced. Where sheeting and bracing are used, trench widths shall be increased accordingly. Trench sheeting shall remain in place until pipe has been placed, backfilled at the pipe zone, tested for defects, and repaired, if necessary.
(H) Location of the excavated materials. During trench excavation, the contractor shall locate the excavated material so it will not completely obstruct a traveled roadway or street; and, unless otherwise approved by the Town Engineer or Superintendent, all streets and roadways shall be kept open to at least one-way traffic.
(I) Removal of water. The contractor shall provide and maintain ample means and devices with which to promptly remove and dispose of all water, including flow from existing sewer lines, entering the trench excavation during the time the trench is being prepared for the pipe laying, during the laying of the pipe, and until the backfill at the pipe zone has been completed. The contractor shall dispose of the water and sewage in accordance with state and local regulations.
(J) Foundation stabilization. When, in the opinion of the Town Engineer or Superintendent, the material in the bottom of the trench is unsuitable for supporting the pipe, the contractor shall excavate below the flow line as directed by the Town Engineer or Superintendent and backfill to the required grade with gravel of the type specified in § 152.02(B)(1).
(K) Trench backfill. The pipe zone shall be defined as extending from the spring line to the pipe to a point 12 inches above the outside of the pipe and for the full width of the trench, for all classes of backfill. In areas of rock or other areas designated by the Town Engineer or Superintendent, the entire pipe zone shall backfilled with three-fourths inch minus “crushed gravel”. In all other areas, the pipe zone shall be backfilled with materials not exceeding one and one-half inches in size selected from the specified trench backfill and thereafter placed and hand-tamped in six-inch layers.
(L) Trench backfill compaction.
(1) After the contractor has backfilled the pipe zone of the trench as required, he or she shall then backfill the balance of the trench, with the type backfill specified, in one-foot layers, mechanically compacted each layer to 95% of maximum density in roadways and 85% to 90% in all other areas.
(2) Any subsequent settlement of the trench or ditch during the guarantee period shall be considered to be the result of improper compaction and shall be corrected at no expense to the district.
(M) Trench backfill above pipe zone. The following types of backfill shall be used on the project in the areas shown on the plans. The class of backfill used for service connections will generally be the same as that used for the sewer line, which they are connected.
(1) Class “A” backfill. The entire trench above the pipe zone shall be backfilled with native excavated material and compacted in accordance with the specifications.
(2) Class “B” backfill. With the exception of the last ten inches, the trench above the pipe zone shall be backfilled with gravel or trench backfill and compacted according to the specifications. The top ten inches of the trench shall be backfilled and compacted in successive layers with eight inches of one and one-half inch minus “crushed gravel”, and two inches of three-fourths inch minus “crushed gravel”.
(3) Class “C” backfill. With the exception of the top 11 inches, the trench above the pipe zone shall be backfilled with gravel for trench backfill and compacted according to the specifications. The top 11 inches of the trench shall be backfilled and compacted in successive layers with eight inches of one and one-half inches minus “crushed gravel”, and two one and one-half inch layers of asphaltic concrete.
(4) Class “D” backfill. With the exception of the top three inches, the entire trench shall be backfilled with controlled density fill (CDF). Pipe base will not be required or used. Provision approved by the Town Engineer or Superintendent shall be made for fixing the pipe in place above the trench bottom as specified until the CDF has become firm. The top three inches of the trench shall be backfilled and compacted in successive layers with two, one and one-half inch layers of aspaltic concrete.
(N) Excess excavated material. All excess excavated materials shall be hauled and disposed of by the contractor. The contractor shall make his or her own arrangements for the disposal of the excavated material and shall bear all costs and retain any profit incidental to such disposal.
(O) Rock excavation. Before proceeding with rock excavation, the contractor shall have completed the common excavation to such depths that only rock excavation remains. At this time, the trench shall be made available to the Town Engineer or Superintendent and measurements will be taken to determine the amount of rock excavation remaining.
(Ord. passed - -)