The construction requirements and material specifications shall conform to the latest edition of Indiana Department of Transportation and Construction and Material Specifications in addition to the following:
(A) Trench excavation.
(1) Open no more trench in advance of pipe laying than is necessary to expedite the work. Excavate trenches to a width that will provide adequate working space, but not more than the maximum design width. Do not undercut trench wall. Excavate trenches below the pipe invert a sufficient distance to provide space for the pipe bedding carry trenches in ledge rock, compact rocky or gravelly soil, or other unyielding materials below the bottom of the pipe at least one-fourth of the outside diameter at the pipe or six inches, whichever is greater. Refill the space beneath the pipe with bedding material as specified for first class bedding.
(2) Excavate pipe bell holes at each joint to provide full-length barrel support of the pipe and to prevent point loading at the bells or couplings.
(3) Unless trench banks above the top of the pipe are cut back on a stable slope, sheet and brace trenches as necessary to prevent saving or sliding to provide protection for workmen and the pipe and to protect adjacent structures and facilities. Do not remove trench sheeting unless the pipe strength is sufficient to support the external loads, including the weight of a prism of earth above the top of the pipe with trench width measured to the bank of the sheeting. Do not brace sheeting against pipe; knit brace it so that no concentrated loads or horizontal thrusts are transmitted to the pipes.
(4) In all cases over five feet in depth, trenches must be braced, or an acceptable cage inserted, or the ditch must be laid back to the angle of repose to protect the people working in the excavation. In existing street rights-of-way, permission must be obtained front the City Engineer to lay back the slopes in a public right-of-way
(B) Pipe bedding.
(1) Standard pipe bedding shall be first class bedding. The pipe shall be bedded in crushed stone or rounded gravel-bedding material placed on the trench bottom. The bedding material shall have 95% passing a 3/4-inch sieve and 95% retained in a No. 4 sieve. The bedding shall have a minimum thickness beneath the pipe of six inches or one-fourth of the outside diameter of the pipe, whichever is greater, and shall extend up the sides of the pipe to the horizontal centerline. Backfill from pipe horizontal centerline to a level not less than 12 inches above the top of the pipe shall be of the bedding material. Hand placed backfill shall be finely divided materials free from debris, organic material and stones.
(2) Carefully prepare bedding so that the pipe, after installation, will be true to line and grade. Surface grade will material or trench subgrade beneath the pipe to provide a uniform and continuous support beneath the pipe at all points between bell holes or pipe joints with approved bedding material beneath the pipe. After each pipe has been brought to grade, aligned, and placed in final position, deposit and densify sufficient bedding material under the haunches and on each side of the pipe to hold the pipe in proper position during subsequent pipe jointing, bedding and backfilling operations. Deposit bedding material uniformly and simultaneously on each side of the pipe to prevent lateral displacement.
(3) Place pipe that is to be bedded on a concrete cradle or encased in concrete in proper position on temporary supports consisting of pre-shaped wood blocks or bricks with wood edges when necessary, rigidly anchor or weight the pipe to prevent floatation when the concrete is placed.
(4) Place concrete for cradles, arches, or encasement uniformly on each side of the pipe and deposit at approximately its final position. Do not move concrete more than five feet from its point of deposit. Concrete placed beneath the pipe shall be sufficiently workable so that the entire space beneath the pipe can be filled without excessive vibration.
(C) Pipe laying.
(1) Grade stakes shall be required prior to laying any pipeline and either laser alignment or batter boards shall control grade.
(2) Protect pipe during handling against impact, shock, and free fall. Do not permit hooks to come in contact with pre-molded joint surfaces. Handle pipe having premolded joint rings or attached couplings so that no weight, including the weight of the pipe itself, will bear on or be supported by the jointing material. Take care to avoid dragging the spigot ring on the ground or allowing it to be damaged by contact with gravel, crushed stone, or other hard objects. After delivery alongside the trench, carefully examine each piece of pipe for roundness and specification compliance. Acceptable pipe may be marked with paint or other permanent marking material, so that the marks are plainly visible after installation in the trench and before the pipe is covered. Clean joint contact surfaces immediately prior to jointing. Use lubricants, primers, or adhesives as recommended by the pipe or joint manufacturer. Unless otherwise required, lay all pipe straight between changes in alignment and at uniform trade between changes in trade. Excavate bell holes for each pipe joint. When jointed in the trench the pipe shall form a true and smooth line. Keep trenches dry during pipe laying. Divert surface water from the trench area to the greatest extent practicable without causing damage to the adjacent property. Before pipe laying is started, remove all water that may have entered the trench. Whenever practicable start pipe laying at the lowest point and install the pipe so that the spigot ends point in the direction of flow.
(D) Joints. In all jointing operations, the trench shall be dry. Before making pipe joints, all surfaces of the pipe shall be clean and dry. Lubricants, primers, adhesives, and other joint preparation material shall be used as recommended by the pipe or joint manufacturer’s specifications. One or more of the following joints may be used:
(1) Compression joints. Compression joints shall conform to ASTM specifications C443 for concrete pipe and ASTM 0425 for vitrified clay pipe.
(2) Bituminous joints, mastic type. After the tongue and groove or bell and spigot have been brushed and wiped clean and dry, and before the pipe is placed in position, both tongue and groove or bell and spigot shall be coated with bituminous plastic cement. The bituminous plastic cement shall be used in sufficient quantity to completely fill the joint when the pipe is placed in final position. After the pipe has been placed in position and is set to its true alignment and grade and blocked, all surplus bituminous plastic cement within the pipe shall be removed and the joints painted or wiped. The joints on the outside of the pipe shall be completely filled and beveled from bell to barrel on bell and spigot pipes.
(3) Coupling bands for corrugated steel pipe. Unless otherwise specified, field joints shall be made with bands. Bands shall be at least 0.064 inches in thickness and at least 10 1/2 inches wide. Band sheets shall be made from the same base metal as the pipe and shall have the same coating. Bands shall have two corrugations 7 5/8 inches center to center to conform to the inner corrugations of the rerolled ends of the pipe. Bands 12 inches through 42 inches in diameter shall be one-piece bands, greater than 42 inches diameter shall be two piece. Bands shall be secured with a bar, bolt, and strap connector.
(E) Backfilling trenches.
(1) Unless other protection work is directed, backfill trenches immediately after the pipe is laid. In the case of concrete cradle bedding, delay backfilling until the concrete has set sufficiently to support the backfill load. Except for unusual circumstances (such as sub-aqueous installation) permit no water to rise in un-backfilled trenches after the pipe is in place. Backfill material to be placed above pipe bedding shall be free of brush, debris and junk. Unless specifically authorized, place no brick or rock excavation or other detritus material in the upper 18 inches of the trench. Place no rock or stones having a dimension larger than six inches within three feet of the top of the pipe. Large stones may be placed in the remainder of the trench backfill only if well separated and arranged so that no interference with backfill settlement will result. Use pounding, jetting, or water flooding for consolidating backfill material only when approved by the City Engineer, particularly prone to water damage are sewers laid in heavy clay soils or during cold winter months. Water flooding or jetting in porous sand or gravel during warm periods may be recommended. In general, limit the addition of water during backfill to provide optimum moisture content for tamping procedure.
(2) All backfill for storm sewers, sanitary sewers or water mains in roadway areas or that will be under curbs, or within five feet of pavement or curb, shall be made with approved granular material. In all other areas the backfill material may consist of on-site material but the pipe must be covered with tamped bedding material to a depth of one foot over the highest point of the pipe.
(F) Headwalls.
(1) Unless waived in writing by the City Engineer, concrete with steel reinforced headwalls are required on all stormwater pipe outlets. As a minimum, a half headwall is required. A full headwall is required to stabilize grade slopes. The top of a full headwall shall be parallel to final grade.
(2) Full headwalls are required on both the inlet and outlet of stormwater pipes under driveways and other roadways which expose the pipe to possible crushing by vehicle traffic.
(G) Pipe material specification.
(1) Corrugated metal. All corrugated metal pipe shall be aluminum coated, welded seam and conform to INDOT (only permitted with city approval and located outside of pavement or sidewalks).
(2) Concrete pipe. Unless waived by the City Engineer, all storm pipe under a public roadway 24 inches in diameter or less shall be concrete pipe with steel reinforcement and conform to INDOT.
(3) PVC pipe. PVC pipe may be used upon approval of the City Engineer. PVC may not be used under roadway, parking, or another paved area. PVC pipe shall be the highest quality, high strength. PVC pipe such as A-2000 corrugated PVC pipe or approved equivalent approved by the city.
(4) HDPE pipe. HPPE liner pipe shall be used in accordance with current INDOT specifications, AASHTO M252 and M294 and ASMR 2306.
(H) Other requirements. All easements shall be acquired and recorded. A recorded copy of the easements shall be submitted with the as-built drawing.
(I) As-built. At the completion of construction, the contractor shall supply the city with an as-built survey. This plan shall show all improvements indicating location, materials used, sizes, distances, elevations and access or utility easements. The as-built plan shall include any and all deviation from the construction plan verified by an actual post-construction certified survey. The plan shall be submitted on mylar and digitally in a format acceptable to the city.
(Ord. - -, passed - -03; Am. Ord. 16-2020, passed 12-7-20)