A. 
Location of Existing Utilities.
Contractor shall verify the existence and location of all existing underground utilities along the route of the work.
B. 
Protection of Existing Utilities.
Contractor shall take the necessary precautions to protect all existing utilities from damage due to his operations. Any damage to the existing utilities will be repaired at the Contractor’s expense by qualified personnel. In order to protect existing utilities that are required to be exposed, Contractor’s operation shall be such that a sufficient distance back from the edge of the excavation is maintained to avoid overloading and to prevent slides or caving. No unnecessary excavation or exposing of existing underground utilities will be allowed.
C. 
Convenience to Public.
All trenching and excavating shall be performed in a manner that will cause as little inconvenience to the public as possible. All excavated material shall be kept trimmed such that minimum inconvenience is caused to the public or adjoining property owners. At street crossings, sidewalks and other points deemed necessary by the Engineer or the designated representative of the Engineer, trenches and excavations shall be bridged in a secure manner so as to prevent serious interruption of travel and to provide access to fire hydrants, public property, and private property. All bridging shall be preapproved by the Engineer or the designated representative of the Engineer.
D. 
Erosion Control:
The Contractor shall conform to the provisions described in technical specification Section 01560, Storm Water Pollution Prevention and any additional provisions for erosion control that may be shown on the plans or described in the technical specifications. All erosion control and storm water pollution prevention measures shall begin at the onset of the project and be maintained throughout the duration of the work until the disturbed area is stabilized at which time they shall be removed unless specifically required otherwise.
E. 
Traffic Control:
Provide and maintain traffic control in conformity with the applicable statutory requirements and within highway right-of-way as required by the authority having jurisdiction over the right-of-way. Adequate traffic control devices shall be in place prior to: 1) removal of any existing control devices, 2) construction equipment move in, and 3) any work within public right-of-way. Traffic control shall be in accordance with the latest version of the Texas Manual on Uniform Traffic Control Devices. The Contractor shall notify all emergency service providers in the event of a road closure or other activity that may impair the emergency travel of the emergency service provider.
1. 
Maintenance of Traffic.
Conduct work in a manner that will interfere as little as possible with public travel, whether vehicular or pedestrian, whenever it is necessary to cross, obstruct, or close roads, driveways, and walks, whether public or private. The Contractor shall, at his own expense, provide and maintain suitable and safe bridges, detours, or other temporary structures for the accommodation of public and private travel and shall give reasonable notice to owners of private drives before interfering with them; provided however, that such maintenance of traffic will not be required at any point where the Contractor has obtained permission from the owner and tenant of the private property involved, to obstruct traffic at any designated point thereon and for the duration of whatever period of time as may be agreed on.
2. 
Barricades, Lights, and Signs.
All streets, roads, highways, and other public thoroughfares that are closed to traffic shall be protected by means of effective barricades on which shall be placed acceptable warning signs. Barricades shall be located at the nearest intersection, public highway or street on each side of the blocked section. All open trenches or other excavations shall be provided with suitable barriers, signs, and lights to the extent that adequate protection is provided to the public. Obstructions, such as material piles and equipment, shall be provided with similar warning lights and signs. All barricades and obstructions shall be illuminated by means of warning lights. Materials stored upon or alongside public streets and highways shall be so placed, and the work conducted at all times, as to cause minimum obstruction and inconvenience to the traveling public.
(Ordinance 2007-106, App. B, adopted 3/20/07)
A. 
Excavation.
1. 
General:
Excavation shall include the removal of any trees, stumps, brush, debris or other obstacles that may obstruct the line of work, and the excavation and removal of all earth, rock or other material to the extent necessary to install the utility and all appurtenances in conformance with the line and grades shown on the plans or as specified herein.
2. 
Trench Width:
The sides of all trenches shall be cut as near vertical as possible. Whenever the prescribed maximum trench width is exceeded for pipe utilities, except as such excess may be required for compliance with plans or specifications, the pipe shall be cradled with 2,000 psi concrete at the expense of the Contractor. Unless shown or specified otherwise, the maximum and minimum trench widths for the associated utility shall be measured at 12-inches above the top of the utility line and shall be as follows:
a. 
Storm sewers.
Minimum width: 16-inches plus O.D. of Pipe.
Maximum width: 24-inches plus O.D. of Pipe.
b. 
Sanitary sewers.
Minimum width: 16-inches plus O.D. of Pipe.
Maximum width: 24-inches plus O.D. of Pipe.
c. 
Water lines.
Minimum width: 16-inches plus O.D. of Pipe.
Maximum width: 24-inches plus O.D. of Pipe.
3. 
Trench Depth.
Unless shown or specified otherwise, trenches shall be excavated to a depth such that the following minimum depths of cover are maintained on the associated utility (as measured from final grade):
a. 
Water mains: 42-inches of cover.
b. 
Sewage force mains: 42-inches of cover.
4. 
Trench Bottom.
Accurately grade trench bottom such that uniform bearing and support is provided for the utility being installed. Trench bottom shall be such that the utility is supported along it’s entire length by undisturbed soil except where bell holes or depressions are required. When bell holes or depressions are required for the proper installation of a utility, the trench bottom shall be completely graded before the bell hole or depression is excavated. Bell holes or depressions shall be no larger than required for the proper installation of the utility. The following procedures shall be used when various types of trench subgrades are encountered:
a. 
Earth Subgrade.
Where a firm and stable foundation for the utility being installed can be obtained in the natural soil and where special embedment is not shown on the plan details or specified herein, the bottom of the trench shall be carefully trimmed to fit the lower portion of the utility line. Should the excavation be carried below grade, except when otherwise detailed on the plans or specified herein, the Contractor shall refill it with Class I embedment material and compact it until the bottom of the trench is firm and unyielding.
b. 
Rock Subgrade.
Where the bottom of the excavation for the utility line is in rock or other hard material, the rock or other hard material shall be removed to a depth not less than four (4") inches below subgrade and the bottom of the trench brought to true subgrade elevation by filling with Class I embedment or other suitable materials as approved by the Engineer. The fill shall be compacted until a firm and uniformly unyielding foundation is established for the utility line being installed.
c. 
Soft Subgrade.
Where a soft or spongy material is encountered in the excavation at subgrade level, it shall be removed only upon the direction of the Engineer or the designated representative of the Engineer. When directed, remove the soft material and replace it with Class I embedment or other suitable materials as approved by the Engineer or the designated representative of the Engineer. The fill replacing the soft material shall be compacted and shall be to a depth that will result in a true trench subgrade that provides a firm and uniformly unyielding foundation for the utility being installed.
5. 
Sheeting, Shoring, and Bracing.
Shore all excavations in accordance with OSHA Standards and the applicable section, or sections, of these specifications. When excavations are made adjacent to existing buildings or other structures, or in paved roadways, particular care shall be taken to adequately sheet, shore, and brace the sides of the excavation to prevent undermining of, or the settlement beneath, the structures or pavements. Underpinning of adjacent structures or pavement, and the costs associated with it, shall be the responsibility of the Contractor. All sheeting, shoring, and bracing shall be done in such a manner that will not cause any caving or sliding of banks and will not endanger any human life or damage any existing structures or property. Fill and compact all holes or voids left by the removal of sheeting, shoring or bracing with suitable materials. If for any reason, the Contractor, with the approval of the Engineer or the designated representative of the Engineer, elects to leave in place the sheeting, shoring or bracing, no payment will be allowed for such material left in place.
6. 
Dewatering Excavations.
Immediately remove all surface water, ground water or seepage water from sewers, drains, ditches, or other sources which may accumulate in the excavation during construction. Removal of water shall be done by pumping, bailing, draining, well pointing, or other approved methods. The Contractor shall have available, at all times, sufficient equipment in proper working order for dewatering excavations. Disposal of all water from excavations shall be in a legal and safe manner. All dewatering of excavations including pumping, bailing, draining, ditching, well pointing, underdrains, etc., is incidental work and will not be paid for separately.
7. 
Open Cut Excavations.
Except where otherwise shown on the plans, all utility installations shall be accomplished by open cut. In all cases where open cuts are allowed through pavements, the methods of construction must meet the requirements of the appropriate regulating agency in all respects including deviations from these specifications or plans. Open cut excavations crossing paved or unpaved public roadways and driveways shall be done such that inconvenience to users is minimized. Repair all open cut pavements in accordance with the plan details or to the original condition, whichever is more stringent. Repair all open cut pavements in a timely fashion. Where a utility line is to be installed across a paved roadway by open cut, the Contractor, with the approval of the Engineer or the designated representative of the Engineer, may elect to install the utility by boring and in such case will be paid for the corresponding pavement repair if provided for in the bid form.
8. 
Boring, Jacking or Drilling.
When shown on the plans, the utility line shall be installed by boring, jacking or drilling under roadways, streets or railroads, or the line shall be installed in a casing that has been placed by boring, jacking or drilling in accordance with requirements of all regulating agencies.
9. 
Excavation of Appurtenances.
Excavate as required for appurtenances of the utility being installed. For manholes and other similar structures leave at least two (2) feet clear between the outer surfaces and the embankment or timber that may be used to hold or protect the banks. Any over excavating below appurtenances is not allowed. If over excavating of appurtenances occurs, the excavation will be refilled with cement stabilized sand or concrete. The cost for this refilling shall be the responsibility of the Contractor.
10. 
Explosives.
The use of explosives to aid excavation work is strictly prohibited.
B. 
Embedment.
All embedment for utilities shall be in accordance with the plan details and shall use the materials outlined in this specification. In general, the embedment zone of a utility line is 4-inches below the bottom of the utility to 12-inches above the top of the utility. All materials for the embedment of a utility being installed shall be placed in layers, or lifts, that do not exceed 6-inches in thickness unless otherwise indicated on the plans or herein. Compaction of embedment zone material shall be in strict accordance with the plan details.
C. 
Backfilling.
1. 
General.
The three (3) types of backfill that may be used include: cement stabilized sand, bank sand, and common backfill. Install the various types of backfill material in accordance with and at the locations detailed on the plans. Backfilling shall include the refilling and consolidation of the required fill in trenches/excavations from the top of the embedment zone of the utility being installed up to the surrounding ground surface or to the bottom limits of a required pavement repair as detailed on the plans.
2. 
Cement Stabilized Sand.
Installation of cement stabilized sand backfill shall be in conformance with the applicable paragraphs of technical specification Section 02240, Cement Stabilized Sand, and shall be installed in accordance with and at the locations shown on the plans.
3. 
Bank Sand.
Install approved bank sand backfill in accordance with and in the locations shown on the plan details. Place sand backfill in maximum 8-inch loose layers/lifts above the embedment zone and compact each layer to 95% Standard Proctor.
4. 
Common Backfill.
Unless specified or shown otherwise on the plan details, backfill all trenches with approved common backfill material from the trench excavation. Place common backfill in 8-inch layers/lifts above the embedment zone and compact each layer to 92% Standard Proctor.
5. 
Compaction and Consolidation of Backfill.
Compact each layer of backfill with mechanical equipment to the required density. As an option, the Contractor may elect to consolidate the backfill by jetting and flooding until full settlement has been reached. Jetting and flooding will not be allowed in any areas where the utility system is being installed under a paved section. If used, jetting shall be accomplished by pumping water through a pipe that is slowly inserted vertically into the backfill. The end of the pipe shall be lowered to a point near the top of the embedment zone, taking care not to disturb the bedding or cause the utility to float. The trench shall then be flooded in puddles until no more appreciable absorption of water into the backfill occurs.
6. 
Excess Material:
Excavated material unsuitable for backfilling and excess material shall be disposed of in a manner approved by the Engineer or the designated representative of the Engineer. Acceptable surplus spoil may be neatly distributed and spread on the right-of-way in open areas or pastures.[1]
[1]
Editor's Note: Original has this as Subsection 5.
(Ordinance 2007-106, App. B, adopted 3/20/07)
Restore surfaces at construction sites to a condition equal to condition prior to construction.
(Ordinance 2007-106, App. B, adopted 3/20/07)