(A) Tunneling.
(1) All streets are to be bored or tunneled unless otherwise approved by the Director of General Services.
(2) Tunnelling is often necessary where pipe or conduit passes under curb, or other underground facilities. The permittee shall not do any tunneling except by permission of the Director of General Services. Where tunneling has been resorted to, the permittee shall bed the pipe or conduit as specified in division (C) below. The remainder of the space from top of this fill to the roof of the tunnel shall be completely filled with 1:4:8 concrete of suitable consistency, thoroughly tamped to fill the entire space, and to afford a rigid support for the tunnel roof for its entire area. The complete backfilling of the tunnel shall be performed to pass the approval of the Director of General Services.
(3) In the installation of small service pipes, it is suggested that the pipe be jacked through or that a hole of sufficient size be bored. In such cases, charge for inspection and issuance of permit only will be made for that portion of street over services installed.
(B) Trenching (including utility repairs).
(1) Whenever culverts, sewers, manholes, valve chambers, catch basin connections, water mains, gas pipe, electric conduits, or house connections thereto, or any type of subsurface facilities are exposed in excavating, the permittee shall, at his or her own expense, protect them from damage.
(2) The length, width, and location of the trench or street cut, also the manner in which the work is done, shall be under the direction of the Director of General Services. Every precaution shall be taken to safeguard the work, and to inconvenience the public as little as possible.
(3) The permittee shall carefully saw cut and remove the paving and base course materials and store them in piles separated from the excavated earth. Excavated material shall be placed so as not to obstruct gutters or drains and in such manner as will cause minimum inconvenience to the public. If necessary, temporary covers for gutters shall be installed to insure adequate drainage. In special cases, it may be necessary to remove part or all of the excavated material from the street.
(4) Openings shall be properly sheeted and braced where necessary to prevent caving, slipping, or cracking of sides. Sheeting and bracing used to support the sides of the opening shall be carefully removed as the backfilling of the trench progresses, but if considered, by the Director of General Services, necessary for the protection of the banks, the sheeting and bracing shall be cut off two feet below the surface of the subgrade and left in place. If pavement along the sides of the opening is, or becomes undermined and unsupported, permittee shall, at his or her own cost and expense, break down and remove the undermined pavement and the foundation thereof and shall also remove loose earth and replace with earth properly compacted or low strength mortar backfill in the manner provided under division (C) below.
(C) Backfilling and restoration.
(1) Backfill and restoration of pavement and sod areas shall conform to the following specifications:
(a) Low-strength mortar backfill material. Description: This work shall consist of the placement of a flowable mixture of Portland cement, fly ash and sand for backfilling conduits under public roadways.
(b) Materials shall be:
1. Cement 801.01;
2. Fly ash shall meet ASTM C-618;
3. Fine aggregate shall be natural sand or sand manufactured from stone, gravel, or aircooled slag. The gradation of the sand shall meet the requirements of 804. The sand shall be fine enough to stay in suspension in the mixture to the extent required for proper flow. The Director of General Services reserves the right to reject the sand if a flowable mixture cannot be produced.
4. Water used for mortar backfill shall be free from oil, acid, strong alkalies or vegetable matter.
(c) Mortar mix proportioning. The initial trial mixture shall consist of the following quantities of materials per cubic yard:
Class LSM - O | |
Cement | 50 lbs. |
Fly ash | 250 lbs. |
Sand | 2910 lbs. |
Water (Target) | 500 lbs. adjustments of the proportions may be made by the Director of General Services providing the total absolute volume of the materials is maintained. |
(d) Mix adjustment. The supplier shall make one or more one-cubic yard trial batches at different water contents to insure a flowable mortar. Mixture is too dry when cracks develop in the mortar as it flows into place.
(e) To expedite settlement of the mortar, it will be necessary for bleed water to appear on the surface immediately after the mortar is struck off. A delay in bleeding indicates there are too many fines in the mixture, so the fly ash quantity shall be reduced in increments of 50 pounds until the mixture is bleeding freely. Approximately 60 pounds of sand shall be added to replace each 50 pound increments of fly ash to maintain the original yield.
(f) Mixing mortar. The mortar shall be delivered to the site of the work and discharge shall be completed within two and one-half hours.
(g) Placing mortar. Flowable mortar shall be discharged from the mixer by any reasonable means into the space to be filled. The fill material shall be brought up uniformly to the fill line shown on the plans or as directed by the Director of General Services. Placing of material over low-strength mortar backfill may commence as soon as the surface water is gone or as directed.
(h) Before placing the flowable mortar as backfill for a storm sewer conduit, the permittee shall secure the conduit to prevent it from floating during placement of the flowable mortar. The permittee's proposed method of backfill placement and proposed method of holding the conduit at the plan grade and flowline elevations should be discussed prior to construction.
(2) Excavation material for compacted backfill. Any material from excavation of trenches which is desired to be used for backfill above pipes, which is to be compacted, shall be clean and shall be of such composition that said material can be compacted to 95% relative density with near optimum water content.
(3) Seeding and protection. All grass areas disturbed by construction shall be restored by seeding and mulching as per KTC Item 212.03.
(4) Full-depth pavement sawing. All existing pavement to be removed shall be sawed full depth at the limits of removal, using a diamond saw blade to provide a uniform edge and prevent damage to the pavement that is to remain in place. All pavement sawing should be performed at right angles whenever possible.
(5) Item 403 - sealing edges. All edges of the asphalt concrete surface course constructed under this contract shall be sealed with asphalt cement meeting the same specifications as used in Item 403. Sealing edges shall be done neatly and without more than one-half inch of the sealant being visible on the surface. Any extra sealant applied to visible surfaces shall be carefully and thoroughly removed by the permittee.
(6) Responsibility for dust, dirt, and appearance. The permittee shall do everything possible to minimize dust and dirt, and to keep the appearance of the area surrounding the street opening in good order. The permittee shall use calcium chloride or equal to keep dust to a minimum. After the close of each working day, the permittee shall see that the surrounding area around the opening is swept up, and as clean as possible. At no time will it be permissible to leave piles of excavated dirt in the street or sidewalk. If necessary, the area will be washed with water. The permittee shall do whatever the Director of General Services deems necessary to clean up the area.
(7) The typical detail sections, attached to Ordinance No. O-4-04, passed March 1, 2004, shall be utilized for all restoration work based upon the existing conditions and improvements.
(Ord. O-4-04, passed 3-1-04)