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Appendix C. Sample Trenchless Technology Specifications

This appendix contains sample specifications from many cities and states that have been used in practice and have proven successful. Although continual improvement is desirable, these samples have proven to be useful to those agencies that developed them. Some of these specifications are in draft format, but have been used on a limited basis.

City of Houston Standard Specification - Section 02441 - 01 July 1997.

Section 02441

MICROTUNNELING AND PIPE-JACKED TUNNELS

PART 1 G E N E R A L

1.01 SECTION INCLUDES

A. Tunnel construction of sewers by one-pass methods with or without man entry. The construction methods involve jacking pipe following a hand-shield excavation or a tunnel boring machine (TBM) or micro-tunnel boring machine (MTBM), with the pipe serving as both the tunnel liner during construction and the sewer pipe after completion of construction.

B. Contractor may select centrifugally-cast fiberglass pipe (FRP), vitrified clay pipe (VCP), reinforced concrete pipe (RCP) for storm or sanitary sewers. Use plastic-lined RCP for sanitary sewers. Unlined RCP or RCP lined with a liner other than that specified in Section 02427 ‑ Plastic Liner for Large-diameter Concrete Sewers and Structures will not be allowed for sanitary sewers.

1.02 MEASUREMENT AND PAYMENT

A. Unit Prices.

1. The length of the sewer installed will be measured by linear foot along the center line of the completed sewer from center line to center line of manholes, as designated on the Drawings; and to the end of stubs or the termination of the pipe; and to the inside face of lift station and treatment plant works. The installation of the sewer within the limits of a structure other than manholes will not be considered for measurement and payment at the unit price bid.

2. Payment will include and be full compensation for labor, equipment, materials, and supervision for construction of the sewer and excavation, complete in place including disposal of excess materials, sheeting, shoring or bracing, dewatering, utility adjustments, connections to existing sewers, grouting (if required), tests, backfilling, clean-up, and other related work necessary for construction as specified or as shown on the Drawings.

3. Payment for the installation of the sewer will be authorized by the City Engineer in two parts. Pay estimates for partial payments will be made as measured above according to the following schedule:

a. 95 percent payment will be made for jacked pipe installed but not yet grouted, in cases where grouting is specified.

b. 100 percent payment will be authorized on a linear foot basis for the amount of jacked sewer pipe installed, including grouting when specified.

4. Monitoring will be paid for at the lump sum price for installations, observations, and reporting.

B. Stipulated Price (Lump Sum): If the Contract is a Stipulated Price Contract, payment for work in this Section is included in the Total Stipulated Price.

1.03 REFERENCE STANDARDS

A. American Railway Engineering Association (AREA) Manual for Railway Engineering.

B. American Association of State Highway and Transportation Officials (AASHTO).

C. Occupational Safety and Health Administration (OSHA).

D. National Electrical Code - (NFPA 70).

1.04 DEFINITION

A. Jacked Pipe. A method for installing sewer pipe that serves as initial construction lining and tunnel support, installed for stability and safety during construction, and as the sewer pipe. The pipe is shoved forward, or jacked, as the tunnel is advanced.

B. Microtunneling. A method of installing pipe by jacking the pipe behind a microtunnel boring machine which is connected to and shoved forward by the pipe being installed, generally precluding man entry.

C. Tunnel Boring Machine (TBM). Mechanized excavating equipment that is a steerable, guided and articulated, connected to and shoved forward by the pipe being installed, with man entry.

D. Microtunnel Boring Machine (MTBM). Mechanized excavating equipment that is remotely-controlled, steerable, guided and articulated, connected to and shoved forward by the pipe being installed, usually precluding man entry.

E. Tunneling Methodology. A written description, together with supporting documentation that defines Contractor's plans and procedures for the microtunneling or pipe jacking operations.

F. Zone of Active Excavation. Area located within a radial distance about a surface point immediately above the face of excavation equal to the depth to the bottom of the excavation.

G. Critical Structure. Any building, structure, bridge, pier, or similar construction partially or entirely located within a zone of active excavation.

1.05 TUNNEL SUBMITTALS

A. Submittals shall be made in accordance with Section 01330 - Submittal Procedures.

B. The following submittals are required:

1. Tunneling Methodology. A brief description of proposed tunnel methodology for review. The description should be sufficient to convey the following:

a. Proposed method of tunnel construction and type of face support.

b. Manufacturer and type of tunneling equipment proposed; type of lighting and ventilation systems.

c. Number and duration of shifts planned to be worked each day.

d. Sequence of operations,

e. Locations of access shafts and work sites.

f. Method of spoil transportation from the face, surface storage and disposal location.

g. Capacity of jacking equipment and type of cushioning.

h. Identify critical utility crossings and special precautions proposed.

2. Drawings and Calculations: Submit for record purposes, drawings, and calculations for any tunnel support system designed by the Contractor. Drawings shall be adequate for construction, and include installation details. For pipe jacking and microtunneling, show pipe and pipe joint detail. Documents must be signed and sealed by a Professional Engineer registered in the State of Texas. Calculations shall include clear statement of criteria used for the design as described in Paragraph 1.06, Design Criteria.

3. Quality Control: Submit for review a brief description of quality control methods including:

a. Method and frequency of survey control.

b. Example of tunnel daily log.

4. Geotechnical Investigation: When geotechnical investigations are conducted by the Contractor, submit results to the City Engineer for record purposes.

5. Monitoring Plans:

a. Instrumentation Monitoring Plan: Submit for review, prior to construction, a monitoring plan that includes a schedule of instrumentation design, layout of instrumentation points, equipment installation details, manufacturer's catalog literature, and monitoring report forms.

b. Surface Settlement Monitoring Plan. Submit a settlement monitoring plan for review prior to construction. The plan shall identify the location of settlement monitoring points, reference benchmarks, survey frequency and procedures, and reporting formats.

6. Structures Assessment. Preconstruction and postconstruction assessment reports shall be provided for critical structures, namely those located within the zone of active excavation from the proposed tunnel centerline. Photographs or a video of any existing damage to structures in the vicinity of the sewer alignment shall be included in the assessment reports.

7. The readings of all monitoring shall be submitted to the City Engineer.

8. Daily Reports: The shift log as defined in Paragraph 3.04, Pipe-jacked Tunneling Data, subparagraph 3.04A, shall be maintained by the Contractor, and must be made available to the City Engineer on request.

1.06 DESIGN CRITERIA

A. Contractor is responsible for selection of the appropriate pipe and pipe joints to carry the thrust of any jacking forces or other construction loads in combination with overburden, earth and hydrostatic loads. Design of any pipe indicated on the Drawings considers in‑place loads only and does not take into account any construction loads. The criteria for longitudinal loading (jacking forces) on the pipe and joints shall be determined by the Contractor, based on the selected method of construction.

B. The jacked pipe shall be designed to withstand the thrust from the MTBM, TBM or shield and pipe advance without damage or distortion. The propulsion jacks shall be configured so that the thrust is uniformly distributed and will not damage or distort the pipe.

C. Take into account loads from handling and storing.

D. The criteria to be used at railroad crossings shall be Cooper E-80 locomotive loading distributions in accordance with AREA specifications for culverts. In the design, account for additive loadings due to multiple tracks.

E. The criteria to be used for truck loading shall be HS-20 vehicle loading distributions in accordance with AASHTO.

F. Provide pipes of diameter shown on the Drawings. Substitution of pipe with larger diameter to suit MTBM or TBM equipment availability will only be permitted if the Contractor can demonstrate to the City Engineer's satisfaction that design flows and velocities can be achieved.

PART 2 PRODUCTS

2.01 SEWER PIPE

A. Contractor shall be responsible for selecting appropriate pipes and pipe joints to safely carry the loads imposed during construction, including jacking forces. Pipe joints shall be flush with the outside pipe face when the pipes are assembled. Pipe materials shall be selected by Contractor from the following:

B. Centrifugally-cast fiberglass pipe, joints, and fittings to be in accordance with Section 02504 - Centrifugally-Cast Fiberglass Pipe.

C. Vitrified clay pipe, joints and fittings to be in accordance with Section 02508 - Extra Strength Clay Pipe.

D. Plastic-lined reinforced concrete pipe with joints and fittings to be in accordance with Section 02615 - Reinforced Concrete Pipe and Section 02427 - Plastic Liner for Large-diameter Concrete Sewers and Structures. Plastic liner is not required for storm sewers.

E. Use pipe that is round with a smooth, even outer surface, and has joints that allow for easy connections between pipes. Pipe ends shall be designed so that jacking loads are evenly distributed around the entire pipe joint and such that point loads will not occur when the pipe is installed. Pipe used for pipe jacking shall be capable of withstanding all forces that will be imposed by the process of installation, as well as the final in-place loading conditions. Protect the driving ends of the pipe and joints against damage.

PART 3 EXECUTION

3.01 CONSTRUCTION OPERATIONS CRITERIA

A. Use methods for microtunneling and pipe-jacked tunneling operations that will minimize ground settlement. Select a method which will control flow of water and prevent loss of soil into the tunnel and provide stability of the face under anticipated conditions.

B. Conduct tunneling operations in accordance with applicable safety rules and regulations, OSHA standards and Contractor's safety plan. Use methods which include due regard for safety of workmen, adjacent structures, utilities, and the public.

C. Maintain clean working conditions wherever there is man access.

D. For tunneling under railroad embankments, highways, or streets, perform the installation so as to avoid interference with the operation of the railroads, highways, or streets, except as approved by the owner of the facility.

3.02 GROUND WATER CONTROL

A. Provide ground water control measures in conformance with Section 01578 - Control of Ground Water and Surface Water, when necessary to perform the Work.

3.03 EQUIPMENT

A. Full directional guidance of a shield, TBM, or MTBM is a prerequisite of this method of construction.

B. The Contractor shall be responsible for selection of tunneling equipment which, based on past experience, has proven to be satisfactory for excavation of the soils to be encountered.

C. The Contractor shall employ tunneling equipment that will be capable of handling the various anticipated ground conditions and is capable of minimizing loss of soil ahead of and around the machine and shall provide satisfactory support of the excavated face.

D. Tunnel Boring Machine (TBM). A TBM used for pipe-jacking shall conform to the shape of the tunnel with a uniform perimeter that is free of projections that could produce over- excavation or voids. An appropriately sized overcutting bead may be provided to facilitate steering. In addition it shall:

1. Be capable of full face closure.

2. Be equipped with appropriate seals to prevent loss of bentonite lubricant.

3. Be capable of correcting roll by reverse drive or fins.

4. Be designed to handle adverse ground conditions including ground water ingress.

5. Be equipped with visual display to show the operator actual position of TBM relative to design reference.

E. Tunnel Shield. If a hand shield is used for pipe-jacked tunneling (with or without attached mechanized excavating equipment), the shield must be capable of handling the various anticipated ground conditions. In addition, the shield shall:

1. Conform to the shape of the tunnel with a uniform perimeter that is free of projections that could produce over-excavation or voids. An appropriately-sized overcutting bead may be provided to facilitate steering.

2. Be designed to allow the face of the tunnel to be closed by use of gates or breasting boards without loss of ground.

F. Microtunneling Equipment. In the case of MTBM, use a spoil transportation system which:

1. Either balances the soil and ground water pressures by the use of a slurry or earth pressure balance system; system shall be capable of adjustments required to maintain face stability for the particular soil condition and shall monitor and continuously balance the soil and ground water pressure to prevent loss of slurry or uncontrolled soil and ground water inflow, or, in the case of a slurry spoil transportation system:

a. Provides pressure at the excavation face by use of the slurry pumps, pressure control valves, and a flow meter.

b. Includes a slurry bypass unit in the system to allow the direction of flow to be changed and isolated, as necessary.

c. Includes a separation process. Design it to provide adequate separation of the spoil from the slurry so that slurry with a sediment content within the limits required for successful tunneling can be returned to the cutting face for reuse. Appropriately contain spoil at the site prior to disposal.

d. Uses the type of separation process suited to the size of tunnel being constructed, the soil type being excavated, and the work space available at each work area for operating the plant.

e. Allows the composition of the slurry to be monitored to maintain the slurry weight and viscosity limits required.

2. In the case of a cased auger earth pressure balance system, the system shall be capable of adjustments required to maintain face stability for the particular soil condition to be encountered. Monitor and continuously balance the soil and ground water pressure to prevent loss of soil or uncontrolled ground water inflow.

a. In a cased auger spoil transportation system, manage the pressure at the excavation face by controlling the volume of spoil removal with respect to the advance rate. Monitor the speed of rotation of the auger flight, and the addition of water.

3. Remote Control System. Provide an MTBM which includes a remote control system with the following features:

a. Allows for operation of the system without the need for personnel to enter the tunnel. Has a display available to the operator, at a remote operation console, showing the position of the shield in relation to a design reference together with other information such as face pressure, roll, pitch, steering attitude, valve positions, thrust force, and cutter head torque; rate of advance and installed length.

b. Integrates the system of excavation and removal of spoil and its simultaneous replacement by pipe. As each pipe section is jacked forward, the control system shall synchronize all of the operational functions of the system.

4. Active Direction Control. Provide an MTBM which includes an active direction control system with the following features:

a. Controls line and grade by a guidance system that relates the actual position of the MTBM to a design reference (e.g., by a laser beam transmitted from the jacking shaft along the pipe to a target mounted in the shield).

b. Provides active steering information which shall be monitored and transmitted to the operating console.

c. Provides positioning and operation information to the operator on the control console.

5. Use generator which is suitably insulated for noise ("hospital" type) in residential or commercial areas.

G. Pipe Jacking Equipment. Provide a pipe jacking system with the following features:

1. Has the main jacks mounted in a jacking frame located in the starting shaft.

2. Has a jacking frame which successively pushes a string of connected pipes following the tunneling excavation equipment towards a receiving shaft.

3. Has sufficient jacking capacity to push the tunneling excavation equipment and the string of pipe through the ground. Incorporates intermediate jacking stations, if required.

4. Has a capacity at least 20 percent greater than the calculated maximum jacking load.

5. Develops a uniform distribution of jacking forces on the end of the pipe by use of spreader rings and packing, measured by operating gauges.

6. Provides and maintains a pipe lubrication system at all times to lower the friction developed on the surface of the pipe during jacking.

7. Jack Thrust Reactions. Use reactions for pipe jacking that are adequate to support the jacking pressure developed by the main jacking system. Special care shall be taken when setting the pipe guide rails in the jacking shaft to ensure correctness of the alignment, grade, and stability.

H. Air Quality. Provide equipment to maintain proper air quality of manned tunnel operations during construction in accordance with OSHA requirements.

I. Enclose lighting fixtures in watertight enclosures with suitable guards. Provide separate circuits for lighting, and other equipment.

J. Electrical systems shall conform to requirements of National Electrical Code - NFPA70.

3.04 PIPE-JACKED TUNNELING DATA

A. Maintain shift logs of construction events and observations. The City Engineer shall have access to the Contractor's logs with regard to the following information:

1. Location of boring machine face or shield by station and progress of tunnel drive during shift.

2. Hours worked per shift on tunneling operations.

3. Completed field forms for checking line and grade of the tunneling operation, showing achieved tolerance relative to design alignment. Steering control logs will generally be acceptable.

4. Maximum pipe jacking pressures per drive.

5. Location, elevation and brief soil descriptions of soil strata.

6. Ground water control operations and piezometric levels.

7. Observation of any lost ground or other ground movement.

8. Any unusual conditions or events.

9. Reasons for operational shutdown in the event a drive is halted.

3.05 EXCAVATION AND JACKING OF PIPE

A. Tunnel Excavation.

1. Keep tunnel excavation within the easements and rights-of-way indicated on the Drawings and to the lines and grades designated on the Drawings.

2. Perform tunneling operations in a manner that will minimize the movement of the ground in front of and surrounding the tunnel. Prevent damage to structures and utilities above and in the vicinity of the tunneling operations.

3. Open-face excavations:

a. Keep the face breasted or otherwise supported and prevent falls, excessive raveling, or erosion. Maintain standby face supports for immediate use when needed.

b. During shut-down periods, support the face of the excavation by positive means; no support shall rely solely on hydraulic pressure.

4. Closed-face excavation:

a. Carefully control volume of spoil removed. Advance rate and excavation rate to be compatible to avoid over excavation or loss of ground.

b. When cutting head is withdrawn or is open for any purpose, keep excavated face supported and stabilized.

5. Excavated diameter should be a minimum size to permit pipe installation by jacking with allowance for bentonite injection into the annular space.

6. Whenever there is a condition encountered which could endanger the tunnel excavation or adjacent structures, operate without intermission including 24-hour working, weekends and holidays, until the condition no longer exists.

7. The Contractor shall be responsible for damage due to settlement from any construction-induced activities.

B. Pipe Jacking

1. Cushion pipe joints as necessary to transmit the jacking forces without damage to the pipe or pipe joints.

2. Maintain an envelope of bentonite slurry around the exterior of the pipe during the jacking and excavation operation to reduce the exterior friction and possibility of the pipe seizing in place.

3. If the pipe seizes up in place and the Contractor elects to construct a recovery access shaft, obtain approval from the City Engineer. Coordinate traffic control measures and utility adjustments as necessary prior to commencing work.

4. In the event a section of pipe is damaged during the jacking operation, or joint failure occurs, as evidenced by inspection, visible ground water inflow or other observations, the Contractor shall submit for approval his methods for repair or replacement of the pipe.

C. Grouting. Grouting requirements are defined in Section 02431 - Tunnel Grout.

3.06 CONTROL OF LINE AND GRADE

A. Construction Control.

1. The City Engineer will establish the baselines and benchmarks indicated on the Drawings. Contractor shall check baselines and benchmarks at the beginning of the Work and report any errors or discrepancies to the City Engineer.

2. Use the baselines and benchmarks established by the City Engineer to establish and maintain construction control points, reference lines and grades for locating tunnel, sewer pipe, and structures.

3. Establish construction control points sufficiently far from the work so as not to be affected by ground movement caused by pipe-jacked tunneling operations.

B. Bench Mark Movement. The Contractor shall ensure that if settlement of the ground surface occurs during construction which affects the accuracy of the temporary benchmarks the Contractor shall detect and report such movement and reestablish temporary bench marks. The locations of the permanent City of Houston monumentation benchmarks are indicated on the Drawings. Advise the City Engineer of any settlement affecting the permanent monumentation benchmarks.

C. Line and Grade.

1. Check and record the survey control for the tunnel against an above-ground undisturbed reference at least once for each 250 feet of tunnel constructed.

2. Record the exact position of the MTBM or TBM or shield after each shove to ensure the alignment is within specified tolerances. Make immediate correction to alignment before allowable tolerances are exceeded.

3. When excavation is off line or grade, make alignment corrections to avoid reverse grades in gravity sewers.

4. Acceptance criteria for the sewer pipe shall be plus or minus 6 inches in horizontal alignment from the theoretical at any point between manholes, including the receiving end, and plus or minus 1-1/2 inches in elevation from the theoretical.

5. Pipe installed outside tolerances and subsequently abandoned shall first be fully grouted.

3.07 MONITORING

A. Instrumentation Monitoring. Instrumentation requirements are shown on the Drawings. Instrumentation specified shall be accessible at all times to the City Engineer. Readings shall be submitted promptly to the City Engineer.

1. Install and maintain an instrumentation system to monitor and detect movement of the ground surface and adjacent structures. Establish vertical control points at a distance from the construction areas that avoids disturbance due to ground settlement.

2. Installation of the instrumentation shall not preclude the City Engineer, through an independent contractor or consultant, from installing instrumentation in, on, near, or adjacent to the construction work. Access shall be provided to the work for such independent installations.

3. Instruments shall be installed in accordance with the Drawings and the manufacturer's recommendations.

B. Surface Settlement Monitoring

1. Establish monitoring points on all critical structures.

2. Record location of settlement monitoring points with respect to construction baselines and elevations. Record elevations to an accuracy of 0.01 feet for each monitoring point location. Monitoring points should be established at locations and by methods that protect them from damage by construction operations, tampering, or other external influences.

3. Ground surface elevations shall be recorded on the centerline ahead of the tunneling operations at a minimum of 100-foot intervals or at least three locations per tunnel drive. For sewers greater than 60-inch diameter, also record similar data at approximately 20 feet each side of the centerline. Settlement monitoring points must be clearly marked by studs or paint for ease of locating.

4. Railroads. Monitor ground settlement of track subbase at centerline of each track.

5. Utilities and Pipelines. Monitor ground settlement directly above and 10 feet before and after the utility or pipeline intersection.

C. Reading Frequency and Reporting. The Contractor shall submit to the City Engineer, records of readings from the various instruments and survey points.

1. Instrumentation monitoring results to be read at the frequency specified and unless otherwise specified, shall be started prior to the zone of active excavation reaching that point, and shall be continued until the zone of active excavation has passed and until no further detectable movement occurs.

2. Surface settlement monitoring readings shall be taken:

a. Prior to the zone of active excavation reaching that point,

b. When the tunnel face reaches the monitoring point (in plan), and

c. When the zone of active excavation has passed and no further movement is detected.

3. All monitoring readings shall be submitted promptly to the City Engineer.

4. Immediately report to the City Engineer any movement, cracking, or settlement which is detected.

5. Following substantial completion but prior to final completion, make a final survey of all monitoring points.

3.10 DISPOSAL OF EXCESS MATERIAL

A. Remove spoil in accordance with Section 01576 - Waste Material Disposal.

3.11 ACCEPTANCE TESTING

A. Acceptance testing is to be carried out by methods described in Section 02533 - Acceptance Testing For Sanitary Sewer.

Florida DOT Draft Trenchless Technology Specifications

This is a draft version of the Florida DOT specifications, and as such, many of the final details such as section cross-references and other items have not yet been completed.

"EXPLANATION OF PROPOSED SPECS DOCUMENT"

The following specifications: SECTION 555 - DRAFT DIRECTIONAL BORING,

SECTION 556 - DRAFT JACK AND BORE, and

SECTION 557 - DRAFT VIBRATORY PLOWING,

are being made available for your review and comment on the FDOT Web Site before any formal process is begun (http://www.dot.state.fl.us/rddesign/utilities/files/utilities.htm). This is a chance for anyone to have input at the earliest possible time. Later, as "OFFICIAL DRAFTS" are developed, they will be re-published with a revision date for continued review and comment.

The Florida Department Of Transportation recently published the NEW 1999 Edition of the Standard Specifications. The language format was changed from the passive to active voice. The active voice is more direct and tends to be shorter. However, the draft specs mentioned above were pulled together using older specs and materials developed by the 1999 Statewide Value Engineering Boring Task Team. The Team was not concerned with any particular voice. For the purpose of beginning this spec development, it is believed these drafts will suffice solely for the initial "Un-Official" review of content.

The final specs must be re-written in the active voice final form. In order to expedite the review process and minimize re-writes associated strictly with voice, the intent is to first get reasonable agreement on the content. Afterwards we will concern ourselves with the voice and formatting issues. So you will know ahead of time there are other things that will need to be changed or included in final form are as follows:

1. Dual units (English and Metric) which are not contained herein must be added.

2. The Section called "SCOPE" will be eliminated and rolled more or less into the "Description" Section in accordance with the AASHTO specs development guidelines.

These proposed specs include some new issues and eliminate others. For example:

1. They do not contain a lot of material found in the old 1993 Utility Accommodation Manual such as permitting documentation requirements, and internal processes even though that was part of the old official spec. Internal processes still must be followed but they will be addressed in separate documentation.

2. Only construction documentation requirements are in the new specs.

3. Some new issues include better defined construction documentation, flagging of utilities, as-builts, making utilities traceable by electronic means, defining alignment tolerances, and responsibilities previously left to question.

Please submit any comments by July 3, 2000, through regular mail to Kenneth Weldon, State Utilities Engineer, Florida Department Of Transportation, 605 Suwannee St. - MS 32, Tallahassee, Fl. 32399-0450 or via the Internet to: Kenneth.Weldon@DOT.STATE.FL.US. Your comments will be considered in developing the first "OFFICIAL DRAFT " which will follow and be submitted to the Industry for review and comment in August 2000.

SECTION 555

DIRECTIONAL BORING

555 Scope.

The work specified in this Section documents the approved construction methods, procedures, and materials for Directional Boring, also commonly called Horizontal Directional Drilling (HDD).

555-1 Description.

HDD is a trenchless method for installing a product that serves as a direct conduit for liquids or gases, or as a duct for pipe, cable, or wire line products. It is a multi-stage process consisting of drilling a pilot bore along a predetermined path and then pulling the desired product back through the drilled space. The vertical profile of the bore alignment is typically in the shape of an inverted arc. When necessary, enlargement of the pilot bore hole to accommodate a product larger than the pilot bore cross section is accomplished by back reaming. This is done at the same time the product is being pulled back through the pilot bore space. Steering the bore is accomplished by proper orientation of the drill bit head as it is being pushed along an alignment by an above ground hydraulic jack. Orientation and tracking of the drill bit is determined by an above ground radio detection device which picks up a signal generated from a radio transmitter contained within the drilling bit. This radio signal is translated into depth and alignment. In order to minimize friction and provide a soil stabilizing agent, a drilling fluid is introduced into the annular space created during the boring operation. The rotation of the bit in the soil wetted by the drilling fluid creates slurry. This slurry acts to stabilize the surrounding soil and prevents collapse of the bore hole and loss of lubrication. Drilling fluids must be designed for the soil and ground water conditions. In order to confine any free flowing slurry at the ground surface during pull back or drilling, sump areas are created to contain any escaping slurry that might damage or be hazardous in surrounding areas. All residual slurry shall be removed from the surface and the site restored to preconstruction conditions.

555-2 Materials.

Materials must meet or exceed the following standards:

Material Standards for HDD Installation
Material Type Non-Pressure Pressure
Polyethylene (PE) ASTM D 2447 ASTM 2513ASTM D 2447
High Density Polyethylene ASTM D 2447ASTM D 3350ASTM F714 ASTM D 2447ASTM D 3350ASTM F714ASTM 2513
Polyvinyl-Chloride (PVC) ASTM F 789 N/A
Steel ASTM A139 Grade B(1) API 2B(2) AWWA C200API 2B(2)

(1) No hydrostatic test required

(2) Dimensional tolerances only

555-3 Construction Site Requirements

(a) Excavation for entry, recovery pits, slurry sump pits, or any other excavation shall be carried out as specified in Section 120. Sump areas are required to contain drilling fluids.

(b) After completing installation of the product the work site shall be restored . The work site shall be cleaned of all excess slurry left on the ground. Removal and final disposition of excess slurry or spoils as the product is introduced, shall be the responsibility of the boring contractor.

(c) Excavated areas shall be restored in accordance with the Standard Specifications for Road and Bridge Construction and Roadway and Traffic Design Standards. The cost of restoring damaged pavement, curb, sidewalk, driveways, lawns, storm drains, landscape, and other facilities is borne by the Contractor / Permittee.

(d) The provisions of Chapter 556, FS must be complied with. Methods to be used for marking Utilities shall minimize impact on other construction or maintenance activities, including mowing operations, which may be conducted throughout the project on a cyclic basis. In order to accomplish this, marking by painting is preferred but not required. When and where flagging of existing Utilities is required, these facilities shall not be flagged through an area for a length ahead of what construction can be accomplished in 14 consecutive days unless approved by the Engineer.

555-4 Quality Control

(a) A representative of the Contractor / Permittee must be in control of the operation at all times. The representative must have a thorough knowledge of the equipment and the procedures to be performed, and is present at the job site during the installation.

(b) The Department must be notified 48 hours in advance of starting work. The installation shall not begin until the Department's representative is present at the job site and agrees that proper preparations have been made.

555-5 Specific Requirements

555-5.1 Drilling Fluids & Reamer Hole Diameter

A mixture of bentonite clay or other approved slurry and potable water shall be used as the cutting and soil stabilization fluid. The viscosity shall be varied to best fit the soil conditions encountered. Water shall be clean and fresh, with a minimum pH of 6.

No other chemicals or polymer surfactant is to be used in the drilling fluid without the written consent of the Engineer and after a determination is made that the chemicals to be added are not harmful or corrosive to the facility and are environmentally safe.

555-5.2 Testing

When there is any indication a pipe has sustained damage and may leak, the work is to be stopped and the damage investigated. The Engineer may require a pressure test. The testing may consist of one of the following methods but shall always meet or exceed Department testing requirements:

(a) Manufacturer's pressure testing recommendations for the type of pipe being installed are followed. The Department's Engineer shall be notified and at his option be present during the test for review of the test results for compliance. The pressure test shall be performed within 24 hours. A copy of the test results shall be furnished to the Department's Engineer. If the pipe is not in compliance with specifications, the Engineer may require it to be filled with flowable fill.

(b) Product carrier pipes installed without a casing must meet pressure requirements set by the Owner. If the Owner does not require pressure testing, the Engineer may require at least one test. A copy of the test results shall be furnished to the Department's Engineer. If the pipe is not in compliance with specifications the Engineer may require it to be filled with flowable fill.

(c) The Department requires that conduit or pipe must meet or exceed soil tight joint requirements when leakage would not cause failure or adversely affect the integrity of the roadway pavement or shoulders. Where leakage could adversely affect pavement or shoulder integrity, a water tight joint is required. Tests for joint integrity shall be conducted for 1 hour. The test for a soil tight joint allows up to 0.1 gallon of water leakage at a sustained pressure of 2 PSI. The water tight joint criteria allows no leakage at all for a sustained pressure of 5 PSI.

555-5.3 Locating and Tracking

The Contractor / Permittee shall describe the method of locating and tracking the drill head during the pilot bore. The Department recognizes walkover, wire line, and wire line with surface grid verification (i.e. True-Trac), or any other system as approved by the Engineer, as the accepted methods of tracking directional bores. The locating and tracking system shall be capable of ensuring that the proposed installation is installed as intended. If an area of radio signal interference is expected to exceed 5 feet, the Engineer may specify the use of a suitable tracking system.

The locating and tracking system shall provide information on:

(a) Clock and pitch information.

(b) Depth.

(c) Transmitter temperature.

(d) Battery status.

(e) Position (x,y).

(f) Azimuth, where direct overhead readings (walkover) are not possible (i.e. subaqueous or limited access transportation facility.)

(g) Before commencement of a directional drilling operation, proper calibration of the equipment (if required) shall be undertaken.

(h) Alignment readings or plot points shall be taken and recorded every five feet.

All facilities shall be installed in such a way that their location can be readily determined by electronic designation after installation. For non-conductive installations this shall be accomplished by attachment of a continuous conductive material either externally, internally, or integrally with the product. Either a copper wire line or a coated conductive tape for this material may be used. Any break in the conductor must be connected by electrical clamp of brass or solder and coated with a rubber or plastic insulator to maintain the integrity of the connection from corrosion.

555-5.4 Drilling Fluids

The Contractor / Permittee shall identify the source of fresh water for mixing the drilling mud. Approvals and permits are required for such sources as streams, rivers, ponds, or fire hydrants. Any water source other than potable water may require a pH Test.

Monitoring of the drilling fluids such as the pumping rate, pressures, viscosity, and density is required during the pilot bore, back reaming, and pipe installation stages, to ensure adequate removal of soil cuttings and the stability of the borehole. Relief holes can be used as necessary to relieve excess pressure down hole. To minimize heaving during pullback, the pull back rate is determined in order to maximize the removal of soil cuttings without building excess down hole pressure. Excess drilling fluids shall be contained at entry and exit points until they are recycled or removed from the site. Entry and exit pits shall be of sufficient size to contain the expected return of drilling fluids and soil cuttings.

The Contractor / Permittee shall ensure that all drilling fluids are disposed of or recycled in a manner acceptable to the appropriate local, state, or federal regulatory agencies. When drilling in suspected contaminated ground, the drilling fluid shall be tested for contamination and disposed of appropriately. Any excess material shall be removed upon completion of the bore.

Restoration for damage to any transportation facility or non-transportation facility caused by heaving, settlement, escaping drilling fluid (fracout) or the directional drilling operation, is the responsibility of the Contractor / Permittee. Any pavement heaving or settlement damage requires restoration/replacement of the pavement per Standard Index 307. Sidewalk or Turnouts will be reconstructed per Standard Index 310 and 515 respectively.

Maximum Back-Ream Hole Diameter
Nominal Inside Pipe Diameter (Inches) Back-Ream Hole Diameter (Inches)
2 4
3 6
4 8
6 10
8 12
10 14
12 and greater Maximum Product OD plus 6"

555-5.5 Equipment Requirements

The Contractor / Permittee shall ensure that appropriate equipment is provided to facilitate the installation as follows:

HDD Equipment
System Description Pipe (1) Diameter (m) Bore Length (feet) Torque (ft/lbs) Thrust / Pullback (lbs)
Maxi-HDD 18 & greater 1000 + 10,000 + 70,000 +
Midi-HDD Up to 16 Up to 1000 1,900 to 9,999 20,001 to 69,999
Mini-HDD Up to 6 Up to 600 Up to 1,899 Up to 20,000

Equipment shall be matched to the size of pipe being installed. Installations differing from the above chart must be approved by the Engineer. The Contractor / Permittee ensures that the drill rod can meet the bend radius required for the proposed installation.

Multiple pipe or conduit installations shall not exceed the total outside pipe diameters stated above.

555-6 Documentation Requirements

555-6.1 Boring Path Report

The Contractor / Permittee shall furnish a Bore Path Report to the FDOT within 14 days of the completion of each bore path. The completed As-Built-Plans shall be submitted to the Engineer within 30 calendar days. No payment will be made for directional boring work until the Bore Path Report has been delivered to the Department. The report shall contain:

(a) Location of project and financial project number including the Permit No. when assigned.

(b) Name of person collecting data, including title, position, and company name.

(c) Investigation site location (contract plans station number or reference to a permanent structure within the project right of way).

(d) Identification of the detection method used.

(e) As-built placement drawings showing roadway plan and profile, cross section, boring location and subsurface conditions as defined in Bore Path Drawings below. Plan elevations shown shall be referenced to a FDOT Bench Mark when associated with an FDOT project, otherwise to a USGS grid system and datum, or to the top of an existing FDOT head wall. These drawings shall be done to the same scale in black ink on white paper, of the same size and weight and as the contract plans. Submittal of electronic plans data in lieu of hard copy plans may be approved by the Engineer if compatible with the Department software.

555-6.2 Boring Path Drawings

Boring Path Drawings shall be dimensionally correct copies of the contract plans. Notes shall be included on each drawing stating the final bore path diameter, facility diameter, drilling fluid composition, composition of any other materials used to fill the annular void between the bore path and the facility or facility placed out of service. If the facility is a casing, this shall be noted, as well as the size and type of carrier pipes to be placed within the casing as part of the contract work. The drawings shall be produced as follows:

(a) The contract plan view shall show the center-line location of each facility, installed or installed and placed out of service to an accuracy within 1 inch at the ends and other points physically observed. They show the remainder of the horizontal alignment of the center line of each facility installed or installed and placed out of service, and note the accuracy with which the installation was monitored.

(b) As directed by the Engineer, either a profile drawing for each bore path, or a cross section of the roadway at a station specified by the Engineer, or a roadway centerline profile, shall be provided. They shall show the ground or pavement surface and the crown elevation of each facility installed, or installed and placed out of service, to an accuracy within 1 inch at the ends and other points physically observed. It shall show the remainder of the vertical alignment of the crown of each facility installed, or installed and placed out of service, and notes the accuracy with which the installation was monitored. On profile drawings for bore paths crossing the roadway the contract plans stationing of the crossing shall be shown. On the profile drawings for bore paths paralleling the roadway the contract plans stationing are also shown. If the profile drawing for the bore path is not made on a copy of one of the contract profile or cross section

sheets, a 10 to 1 vertical exaggeration shall be used.

(c) If during installation an obstruction is encountered which prevents installation of the pipe in accordance with this specification, the pipe may be taken out of service and left in place at the discretion of the Engineer, and shall immediately be filled with flowable fill. A new installation procedure and revised plans must be submitted to and approved by the Engineer before work can resume. If a bore path is abandoned without installing a facility, the drawings shall show the abandoned bore path along with the final bore path. The abandoned bore path shall be noted as "Abandoned Bore Path." They shall also show the location and length of the drill head and any drill stems not removed from the bore path. If conditions warrant removal of the materials installed in the abandoned bore path, as determined by the Department, during construction or in the future, the cost and responsibility shall be born by the permittee.

(d) On all the drawings, show the crown elevation, diameter and material type of all utilities encountered and physically observed during the subsoil investigation. For all other obstructions encountered during a subsoil investigation or the installation, show the type of material, horizontal and vertical location, top elevation and lowest elevation observed, and note if the obstruction continues below the lowest point observed.

555-7 Method Of Measurement

Fees paid the Contractor / Permittee shall be based on the actual length of the installation, measured in place along the surface of the ground, complete and accepted. No additions or deductions will be made for sweeps in either the vertical or horizontal direction to complete the installation.

555-8 Basis Of Payment.

Payment will be made under Item XXX-02-XXX Horizontal Directional Drilling per lineal foot of bore diameter, where:

555-XX-X01 < than 6 inches bore diameter

555-XX-X02 6.0 inches to < 12.0 inches bore diameter

555-XX-X03 12.0 inches to < 18.0 inches bore diameter

555-XX-X04 18.0 inches to < 24.0 inches bore diameter

555-XX-X05 24.0 inches to < 30.0 inches bore diameter

555-XX-X06 30.0 inches and greater bore diameter

No payment shall be made for abandoned bore paths, taken out of service or incomplete installations.

Payment to the Contractor / Permittee shall be full compensation for all work specified in this section. This includes all installations, from plan point of beginning to plan point of ending (i.e. pull box) at plan depth, removal of excavated materials and spoils, removal and disposal of drilling fluids, backfilling, and complete restoration.

SECTION 556

JACK AND BORE

556 Scope.

The work specified in this Section documents the approved construction methods, procedures, and materials for Jack And Bore (J&B), also known as auger boring. Micro tunneling (MT) is considered to be a hybrid of Jack and Bore for purposes of specifications.

556-1 Description.

J&B is a method for installing a product (often called a casing) that may serve as a direct conduit for liquids or gases, or as a duct for pipe, cable, or wire line products. It is a multi-stage process consisting of constructing a temporary horizontal jacking platform and a starting alignment track in an entrance pit at a desired elevation. The product is then jacked by manual control along the starting alignment track while simultaneous excavation of the soil is accomplished by a rotating cutting head operating in the leading edge of the product's annular space. The ground up soil (spoil) is transported back to the entrance pit by helical wound auger flights rotating inside the product. J&B typically provides limited tracking and steering as well as limited support to the excavation face.

MT is conducted similar to J&B with the exception it is a remotely controlled, guided pipe jacking process that provides continuous support to the excavation face. The guidance system usually consists of a laser mounted in the tunneling drive shaft which communicates a reference line to a target mounted inside the MT machine's articulated steering head. The MT process provides the ability to control the excavation face stability by applying mechanical or fluid pressure to counterbalance the earth and hydrostatic pressures.

The removal of excess material is the responsibility of the boring contractor as well as restoration of the site to the condition which existed prior to construction. The method for removal or final disposition of spoils is not covered under this specification. However, the cost of removal or final disposition shall be considered included in the cost of the boring.

556-2 Materials.

Materials approved for installation within the R/W shall be selected based on their suitability for the construction method as defined in the following table. After determining product suitability, individual material standards as contained in the subsequent table shall apply.

Product Suitability By Construction Method
Type Pipe / Casing Installation Mode Suitable Pipe/Casing
J&B Jacking Steel
MT Jacking DI, FRPM, PC, PCCP, RCCP, RCP, Steel, VCP
Material Standards Acceptable for J&B and MT Installations
Material Type Non-Pressure Pressure
Ductile Iron (DI) AWWA C150/C151ASTM A716, A747 AWWA C150/C151
Fiberglass Reinforced Polymer Mortar (FRPM) ASTM D 3262 ASTM D 3517AWWA C950
Polymer Concrete (PC) DIN 54815-1 & 2 N/A
Prestressed Concrete Cylinder Pipe (PCCP) N/A AWWA C300
Reinforced Concrete Cylinder Pipe (RCCP) N/A ASTM C361
Reinforced Concrete Pipe (RCP) ASTM C 79ASCE xx-97 ASTM C 361AWWA C300/C302
Steel ASTM A139 Grade B(1)API 2B(2) AWWA C200API 2B(2)
Vitrified Clay Pipe (VCP) ASTM C1208EN 295-7 N/A

(1) No hydrostatic test required (2) Dimensional tolerances only

556-2.1 Steel Pipe Casing

The size of the steel casing shall be at least 6 inches larger than the largest outside diameter of the carrier pipe. The casing pipe shall be straight seam pipe or seamless pipe. All steel pipe may be bare inside and out, with the manufacturers' recommended minimum nominal wall thicknesses to meet installation and loading requirements. Coatings to extend the service life may be permitted. All steel casing pipe shall be square cut and have dead-even lengths which are compatible with the J&B equipment.

All steel pipe casings and welds shall meet or exceed the thickness requirements to achieve the service life requirements noted in the FDOT Drainage Manual Chapter 6. For purposes of determining service life, casings installed under roadways will be treated as cross drains and casings under driveways will be treated as side drain pipe installations. For purposes of material classification, steel pipe casing will be considered structural plate steel pipe. Steel pipe casing of insufficient length shall achieve the required length through fully welded joints. Joints shall be air-tight and continuous over the entire circumference of the pipe with a bead equal to or exceeding that required to meet the thickness criteria of the pipe wall. All welding shall be performed by a qualified welder.

556.2.2 Reinforced Concrete Pipe Casing

In addition to the above concrete pipe standards, the pipe shall comply with the following minimum requirements:

(a) 5,000-psi concrete compressive strength.

(b) Class III, IV, or V as required by load calculations, with a C-wall.

(c) Full circular inner and/or outer reinforcing cage.

(d) Multiple layers of steel reinforcing cages, wire splices, laps and spacers are permanently secured together by welding in place.

(e) Straight outside pipe wall with no bell modification.

(f) No elliptical reinforcing steel is allowed.

(g) Single cage reinforcement with a 1-inch minimum cover from the inside wall.

(h) Double cage reinforcement with a 1-inch minimum cover from each wall.

(i) Joints are gasket type.

(j) Additional joint reinforcement.

Upon installation, the Engineer may at his discretion require the contractor to perform concrete wiping or injection of the joints if it is believed the joints have not maintained their water tightness during the jacking operation. No additional payment will be made for this operation.

556-3 Construction Site Requirements

556-3.1 Excavation and Restoration

(a) Excavation for entry, recovery pits, or any other excavation shall be carried out as specified in Section 120. Sump areas are required to contain drilling or auguring fluids.

(b) After completing installation of the product, the work site shall be restored . The work site shall be cleaned of all excess slurry left on the ground. Removal of excess slurry or spoils as the product is introduced, shall be the responsibility of the boring contractor.

(c) Excavated areas shall be restored in accordance with the Standard Specifications for Road and Bridge Construction and Roadway and Traffic Design Standards. The cost of restoring damaged pavement, curb, sidewalk, driveways, lawns, storm drains, landscape, and other facilities is borne by the Contractor / Permittee.

(d) The provisions of Chapter 556, FS must be complied with. Methods to be used for marking Utilities shall minimize impact on other construction or maintenance activities, including mowing operations, which may be conducted throughout the project on a cyclic basis. In order to accomplish this, marking by painting is preferred but not required. When and where flagging of existing Utilities is required, these facilities shall not be flagged through an area for a length ahead of what construction can be accomplished in 14 consecutive days unless approved by the Engineer.

556-3.2 Ground Water Control

(a) When ground water level must be controlled, the system is compatible with the properties, characteristics, and behavior of the soils as indicated by the soil investigation report.

(b) Ground water may be controlled from sumps constructed inside the excavated areas (pits). When sump pumps are not sufficient to control the ground water, de-watering is required as specified in Section 455.28 and other local, state or federal regulations.

556-4 Quality Control

(a) A representative of the Contractor / Permittee must be in control of the operation at all times. The representative must have a thorough knowledge of the equipment and the procedures to be performed, and is present at the job site during the installation.

(b) The Department must be notified 48 hours in advance of starting work. The installation shall not begin until the Department's representative is present at the job site and agrees that proper preparations have been made.

556-5 Specific Requirements

556-5.1 Specific Micro-Tunneling Requirements

Continuous pressure shall be provided to the face of the excavation to balance groundwater and earth pressures. Shafts shall be of sufficient size to accommodate equipment, the pipe selected, and to allow for safe working practices. Entry and exit seals shall be provided at shaft walls to prevent inflows of groundwater, soil, slurry, and lubricants. Thrust blocks shall be designed to distribute loads in a uniform manner so that any deflection of the thrust block is uniform and does not impart excessive loads on the shaft itself, or cause the jacking frame to become misaligned.

The Micro-Tunneling boring machine (MTBM) shall meet the following minimum performance requirements:

(A) Capable of providing positive face support regardless of the MTBM type.

(B) Articulated to enable controlled sheeting in both the vertical and horizontal directions to a tolerance of plus or minus 1 inch from design alignment.

(C) All functions are controlled remotely from a surface control unit.

(D) Capable of controlling rotation. This is accomplished by a bi-directional drive on the cutter head or by using anti-roll fins or grippers.

(E) Capable of injecting lubricant around the exterior of the pipe being jacked.

(F) Capable of controlling heave and settlement to acceptable tolerances as indicated in the contract documents.

The main control system of the MTBM shall provide the following information to the operator as the minimum required for successful operation of the MTBM:

(A) Deviation of the MTBM from the required line and grade of the pipeline (normally by reference to a laser beam.)

(B) Grade and roll of the MTBM.

(C) Jacking load.

(D) Torque and RPM of the cutter head.

(E) Instantaneous jacking rate and total distance jacked.

(F) Indication of steering direction.

For slurry systems, the following is also required:

(G) The volume of slurry flow in both the supply and return side of the slurry loop.

(H) Indication of slurry bypass valve position.

(I) Indication of pressure of the slurry in the slurry chamber.

The jacking system shall have the capability of pushing the MTBM and pipe through the ground in a controlled manner and compatible with the anticipated jacking loads and pipe capacity. The jacking force applied to the pipe shall be monitored and not exceed the pipe manufacturer's recommendations.

The pipe lubrication system shall be functional at all times and sufficient to reduce jacking loads. Pipe lubrication systems shall include a mixing tank, holding tank and pumps to convey lubricant from the holding tank to application points at the rear of the MTBM. Sufficient fluids shall be maintained on site so as not to allow loss of lubrication.

Power Distribution System shall be identified under the contract or permit provisions as well as any noise constraints.

Spoil removal capability and method shall be identified so as not to create a hindrance to other activities which may be necessary in the area.

556-5.2 Testing

Upon completion of any casing or non-casing carrier installation, the Engineer may require a pressure test. If there is any obvious damage or problems noted during the installation such as jacking obstructions which had to be cleared and may have altered the shape or alignment of the product in any way, testing is always required. The testing may consist of one of the following methods but shall always meet or exceed Department testing requirements:

(a) Manufacturer's pressure testing recommendations for the type of pipe being installed are followed. The Department's Engineer shall be notified and at his option be present during the test for review of the test results for compliance. The pressure test shall be performed within 24 hours. A copy of the test results shall be furnished to the Department's Engineer. If the pipe is not in compliance with specifications, the Engineer may require it to be filled with flowable fill.

(b) Product carrier pipes installed without a casing must meet pressure requirements set by the Owner. If the Owner does not require pressure testing, the Engineer may require at least one test. A copy of the test results shall be furnished to the Department's Engineer. If the pipe is not in compliance with specifications the Engineer may require it to be filled with flowable fill.

(c) The Department requires that conduit or pipe meet or exceed soil tight joint requirements when leakage would not cause failure or adversely affect the integrity of the roadway pavement or shoulders. Where leakage would adversely affect pavement or shoulder integrity, a water tight joint is required. Tests for joint integrity shall be conducted for 1 hour. The test for a soil tight joint allows up to 0.1 gallon of water leakage at a sustained pressure of 2 PSI. The water tight joint criteria allows no leakage at all for a sustained pressure of 5 PSI.

556-5.3 Locating and Tracking

For all installations, the Contractor / Permittee shall submit sufficient information to establish his proposed strategy for providing:

(a) A positive indication of where the leading edge of the casing is located with respect to line and grade. This indication is provided with a water gauge (Dutch level), electronic transmitting and receiving devices, or other approved methods. The Contractor / Permittee indicates the intervals for checking line and grade, and a record is maintained at the job site.

(b) Equipment of adequate size and capability to install the project. This includes the equipment

manufacturer's information for all power equipment used in the installation.

(c) A means for controlling line and grade.

(d) A means for controlling over cut to a minimum, with the maximum limited to a 3/4-inch space around the circumference of the casing pipe.

(e) A means for centering the cutting head inside the borehole.

(f) Providing a positive means for preventing the rear of the cutting head from advancing in front of the leading edge of the casing by more than 1/3 times the casing diameter in stable cohesive conditions not to exceed 8 inches. In unstable conditions, such as granular soil, loose or flowable materials, the cutting head is retracted into the casing a distance that permits a balance between pushing pressure, pipe advancement and soil conditions to assure no voiding takes place.

(g) Adequate casing lubrication with a bentonite slurry or other approved techniques.

(h) An adequate band around the leading edge of the casing to provide extra strength, which in loose, unstable materials when the cutting head has been retracted into the casing reduces skin friction as well as provides a method for the slurry lubricant to coat the outside of the casing.

(i) At least 20 feet of full diameter auger at the leading end of the casing. Subsequent auger size may be reduced, but the reduced auger diameter must be at least 75% of the full auger diameter.

(j) Water to be injected inside the casing to facilitate spoil removal. The point of injection is be no closer than 2 feet from the leading edge of the casing.

All the above options are required for major installations unless the Engineer has agreed in writing that they are not necessary. For both major and minor installations, the Contractor / Permittee is responsible for submitting to the Engineer information indicating his proposed strategy for providing compatible materials and equipment.

All facilities shall be installed in such a way that their location can be readily determined by electronic designation after installation. For non-conductive installations this shall be accomplished by attachment of a continuous conductive material either externally, internally, or integrally with the product. Either a copper wire line or a coated conductive tape for this material may be used. Any break in the conductor must be connected by electrical clamp of brass or solder and coated with a rubber or plastic insulator to maintain the integrity of the connection from corrosion.

556-7 Documentation

556-6.1 Boring Path Report

The Contractor / Permittee shall furnish a Bore Path Report to the FDOT within 14 days of the completion of each bore path. The completed As-Built-Plans shall be submitted to the Engineer within 30 calendar days. No payment will be made for directional boring work until the Bore Path Report has been delivered to the Department. The report shall contain:

(a) Location of project and financial project number including the Permit No. when assigned.

(b) Name of person collecting data, including title, position, and company name.

(c) Investigation site location (contract plans station number or reference to a permanent structure within the project right of way).

(d) Identification of the detection method used.

(e) As-built placement drawings showing roadway plan and profile, cross section, boring location and subsurface conditions as defined in Bore Path Drawings below. Plan elevations shown shall be referenced to a FDOT Bench Mark when associated with an FDOT project, otherwise to a USGS grid system and datum, or to the top of an existing FDOT head wall. These drawings shall be done to the same scale in black ink on white paper, of the same size and weight and as the contract plans. Submittal of electronic plans data in lieu of hard copy plans may be approved by the Engineer if compatible with the Department software.

556-6.2 Boring Path Drawings

Boring Path Drawings shall be dimensionally correct copies of the contract plans. Notes shall be included on each drawing stating the final bore path diameter, facility diameter, drilling fluid composition, composition of any other materials used to fill the annular void between the bore path and the facility or facility placed out of service. If the facility is a casing, this shall be noted, as well as the size and type of carrier pipes to be placed within the casing as part of the contract work. The drawings shall be produced as follows:

(a) The contract plan view shall show the center-line location of each facility, installed or installed and placed out of service to an accuracy within 1 inch at the ends and other points physically observed. They show the remainder of the horizontal alignment of the center line of each facility installed or installed and placed out of service, and note the accuracy with which the installation was monitored.

(b) As directed by the Engineer, either a profile drawing for each bore path, or a cross section of the roadway at a station specified by the Engineer, or a roadway centerline profile, shall be provided. They shall show the ground or pavement surface and the crown elevation of each facility installed, or installed and placed out of service, to an accuracy within 1 inch at the ends and other points physically observed. It shall show the remainder of the vertical alignment of the crown of each facility installed, or installed and placed out of service, and notes the accuracy with which the installation was monitored. On profile drawings for bore paths crossing the roadway the contract plans stationing of the crossing shall be shown. On the profile drawings for bore paths paralleling the roadway the contract plans stationing are also shown. If the profile drawing for the bore path is not made on a copy of one of the contract profile or cross section sheets, a 10 to 1 vertical exaggeration shall be used.

(c) If during installation an obstruction is encountered which prevents installation of the pipe in

accordance with this specification, the pipe may be taken out of service and left in place at the discretion of the Engineer, and shall immediately be filled with flowable fill. A new installation procedure and revised plans must be submitted to and approved by the Engineer before work can resume. If a bore path is abandoned without installing a facility, the drawings shall show the abandoned bore path along with the final bore path. The abandoned bore path shall be noted as "Abandoned Bore Path." They shall also show the location and length of the drill head and any drill stems not removed from the bore path. If conditions warrant removal of the materials installed in the abandoned bore path, as determined by the Department, during construction or in the future, the cost and responsibility shall be born by the permittee.

(d) On all the drawings, show the crown elevation, diameter and material type of all utilities encountered and physically observed during the subsoil investigation. For all other obstructions encountered during a subsoil investigation or the installation, show the type of material, horizontal and vertical location, top elevation and lowest elevation observed, and note if the obstruction continues below the lowest point observed.

556-8 Method Of Measurement.

Fees paid the Contractor / Permittee shall be based on the actual length of the installation, measured in place along the surface of the ground, complete and accepted. No additions or deductions will be made for sweeps in either the vertical or horizontal direction to complete the installation.

556-9 Basis Of Payment.

Payment will be made under Item 556-01-XXX Jack & Bore- per lineal foot of bore diameter, where:

556-01-X01 < than 6 inches bore diameter

556-01-X02 6.0 inches to < 12.0 inches bore diameter

556-01-X03 12.0 inches to < 18.0 inches bore diameter

556-01-X04 18.0 inches to < 24.0 inches bore diameter

556-01-X05 24.0 inches to < 30.0 inches bore diameter

556-01-X06 30.0 inches and greater bore diameter

Payment will be made under Item 556-02-XXX Micro-tunneling- per lineal foot of bore diameter, where:

556-02-X01 < than 6 inches bore diameter

556-02-X02 6.0 inches to < 12.0 inches bore diameter

556-02-X03 12.0 inches to < 18.0 inches bore diameter

556-02-X04 18.0 inches to < 24.0 inches bore diameter

556-02-X05 24.0 inches to < 30.0 inches bore diameter

556-02-X06 30.0 inches and greater bore diameter

No payment shall be made for abandoned bore path, taken out of service or incomplete installations. Payment to the Contractor / Permittee shall be full compensation for all work specified in this section. This includes all installations, from plan point of beginning to plan point of ending (i.e. pull box) at plan depth, removal of excavated materials and spoils, removal and disposal of drilling fluids, backfilling, and complete restoration.

Texas DOT Boring and Tunneling Specification - 1993

ITEM 476

JACKING, BORING OR TUNNELING PIPE

476.1. Description. This Item shall govern for furnishing and in- stalling of pipe by the methods of jacking, boring or tunneling as shown on the plans and in accordance with this Item.

476.2. Materials. Pipe may be either corrugated metal pipe con- forming to Item 460, "Corrugated Metal Pipe", of the size, type, design and dimension shown on the plans, or reinforced concrete pipe, conforming to the special requirements for jacking, boring or tunneling of Item 464, "Reinforced Concrete Pipe", of the size, strength and dimension shown on the plans, or other types as may be specified by the Engineer or shown on the plans.

476.3. Construction Methods.

(1) General. If the grade of the pipe at the jacking, boring, or tunneling end is below the ground surface, suitable pits or trenches shall be excavated for the purpose of conducting the jacking, boring or tunneling operations and for placing end joints of the pipe. Excavations greater than five (5) feet in depth shall be protected as specified in Item 402, "Trench Excavation Protection" or Item 403, "Temporary Special Shoring".

Where pipe is required to be installed under railroad embankments, highways, streets, or other facilities by jacking, boring or tunneling methods, construction shall be made in such a manner that will not interfere with the operation of the railroad, street, highway, or other facility, and shall not weaken or damage any embankment or structure.

Pipe damaged in jacking, boring or tunneling operations shall be repaired in place to the satisfaction of the Engineer. Pipe damaged beyond repair will be removed and replaced. Repair or removal and replacement of damaged pipe will be done at the Contractor's expense.

The pits or trenches excavated to facilitate jacking, boring or tunneling operations shall be backfilled immediately after the installation of the pipe has been completed.

(2) Jacking. Heavy duty jacks suitable for forcing the pipe through the embankment shall be provided. In operating jacks, even pressure shall be applied to all jacks used. A suitable jacking head and suitable bracing between the jacks and the jacking head shall be provided so that pressure will be applied to the pipe uniformly around the ring of the pipe. Joint cushioning material of plywood or other material may be used as approved by the Engineer. Plywood cushioning material shall be 1/2 inch minimum thickness for pipe diameters 30 inches and less and 3/4 inch minimum thickness for pipe diameters greater than 30 inches. Cushioning rings may be made up of single or multiple pieces. A suitable jacking frame or back stop shall be provided. The pipe to be jacked shall be set on guides, properly braced together, to support the section of the pipe and to direct the pipe in the proper line and grade. The whole jacking assembly shall be placed so as to line up with the direction and grade of the pipe. In general, the embankment material shall be excavated just ahead of the pipe, the material removed through the pipe, and the pipe forced through the embankment with jacks, into the space thus provided.

The Contractor shall furnish for the Engineer's approval, a plan showing the proposed method of jacking. The plan shall include the design for the jacking head, jacking support or back stop, arrangement and position of jacks, pipe guides, etc., complete in the assembled position.

The excavation for the underside of the pipe, for at least one-third of the circumference of the pipe, shall conform to the contour and grade of the pipe. Over-excavation to provide not more than two (2) inches of clearance may be provided for the upper half of the pipe. This clearance shall be tapered to zero at the point where the excavation conforms to the contour of the pipe. Over-excavation in excess of one (1) inch shall be pressure grouted the entire length of the installation.

The distance that the excavation shall extend beyond the end of the pipe depends on the character of the material, but shall not exceed two (2) feet. This distance shall be decreased when directed by the Engineer.

Preferably, the pipe shall be jacked from the low or downstream end. The final position of the pipe shall not vary from the line and grade shown on the plans, or established by the Engineer, by more than one (1) inch in 10 feet. The variation shall be regular and in one direction and the final flow line shall be in the direction shown on the plans.

The Contractor may use a cutting edge of steel plate around the head end of the pipe extending a short distance beyond the end of the pipe with inside angles or lugs to keep the cutting edge from slipping back onto the pipe.

When jacking of pipe has begun, the operation shall be carried on without interruption, insofar as practicable, to prevent the pipe from becoming firmly set in the embankment.

(3) Boring. The boring shall proceed from a pit provided for the boring equipment and workmen. The location of the pit shall be approved by the Engineer. The boring shall be done mechanically either using a pilot hole or by the auger method.

When the pilot hole method is used an approximate two (2) inch pilot hole shall be bored the entire length of the crossing and shall be checked for line and grade on the opposite end of the bore from the work pit. This pilot hole shall serve as the centerline of the larger diameter hole to be bored.

When the auger method is used, a steel encasement pipe of the appropriate diameter equipped with a cutter head to mechanically perform the excavation shall be used. Augers shall be of sufficient diameter to convey the excavated material to the work pit.

Excavated material shall be disposed of by the Contractor, as approved by the Engineer. The use of water or other fluids in connection with the boring operation will be permitted only to the extent necessary to lubricate cuttings; jetting will not be permitted.

In unconsolidated soil formations, a gel-forming colloidal drilling fluid consisting of at least 10 percent of high grade carefully processed bentonite may be used to consolidate cuttings of the bit, seal the walls of the hole, and furnish lubrication for subsequent removal of cuttings and immediate installation of the pipe.

Allowable variation from line and grade shall be as specified in Subarticle 476.3.(2). Overcutting in excess of one (1) inch shall be remedied by pressure grouting the entire length of the installation.

(4) Tunneling. Where the characteristics of the soil, the size of the proposed pipe, or the use of monolithic sewer would make the use of tunneling more satisfactory than jacking or boring; or when shown on the plans, a tunneling method may be used, with the approval of the Engineer.

When tunneling is permitted, the lining of the tunnel shall be of sufficient strength to support the overburden. The Contractor shall submit the proposed liner method to the Engineer for approval. Approval by the Engineer shall not relieve the Contractor of the responsibility for the adequacy of the liner method.

The space between the liner plate and the limits of excavation shall be pressure-grouted or mud-jacked.

Access holes for placing concrete shall be spaced at maximum intervals of 10 feet.

(5) Joints. If corrugated metal pipe is used, joints may be made by field bolting or by connecting bands, whichever is feasible. If reinforced concrete pipe is used, the joints shall be in accordance with Item 464, "Reinforced Concrete Pipe".

476.4. Measurement. This Item will be measured by the linear foot between the ends of the pipe along the flow line.

This is a plans quantity measurement Item and the quantity to be paid for will be that quantity shown in the proposal and on the "Estimate and Quantity" sheet of the contract plans, except as may be modified by Article 9.8. If no adjustment of quantities is required, additional measurements or calculations will not be required.

476.5. Payment. The work performed and materials furnished in accordance with this Item and measured as provided under "Measurement" will be paid for at the unit price bid for "Jacking or Boring Pipe", or "Jacking, Boring or Tunneling Pipe" of the type, size, and strength or design specified.

This price shall be full compensation for excavation, grouting, backfilling and disposal of surplus material; for furnishing all materials, including pipe liner materials required for tunnel operations; for all preparation, hauling and installing of pipe and pipe liner materials; and for all labor, tools, equipment and incidentals necessary to complete the work except that protection methods for excavations greater than five (5) feet in depth shall be measured and paid for as required under Item 402, "Trench Excavation Protection" or Item 403, "Temporary Special Shoring".

San Antonio Pipe Bursting Specification

San Antonio Water System Standard Specifications for Construction

ITEM NO. 900

RECONSTRUCTION OF SANITARY SEWER BY

PIPE BURSTING/CRUSHING REPLACEMENT PROCESS

900.1 DESCRIPTION:This specification includes requirements to rehabilitate existing sanitary sewers by the pipe bursting/crushing method. The pipe bursting/crushing process is defined as the reconstruction of existing sanitary sewers by the simultaneous insertion (breaking and expanding the old pipe) of liner pipe within the bore of the existing pipe. Also covered in this specification is pipe, pipe joining, manhole connections, connection of service laterals and stubs, point repairs, obstruction removals, television requirements, testing requirements, by-pass pumping criteria, site restoration, erosion control requirements, and warranty requirements.

The pipe bursting/crushing process involves the rehabilitation of deteriorated gravity sewer pipe by installing new pipe material within the enlarged bore created by the use of using a static, hydraulic, or pneumatic hammer "moling" device, suitably sized to break the existing pipe or by using a modified boring "knife" with a flared plug that crushes the existing sewer pipe. Forward progress of the "mole" or the "knife" may be aided by hydraulic equipment or other apparatus. Replacement pipe is either pulled or pushed into the bore. Sewer services are reconnected to the new pipe through small excavations from the surface. Sewage flows from the upstream line and from the services are pumped as required to prevent overflows and provide continual service. All excavations required for reconnecting and pumping service flows, entry pits, exit pits, obstruction removal, point repairs, among others, are to be kept to a minimum and all damage to surface and underground features, facilities, utilities and improvements are to be repaired.

900.2 MATERIALS

1. HIGH DENSITY POLYETHYLENE PIPE (HDPE) related to pipe bursting or pipe crushing for a sanitary sewer or related pipe line habilitation:

a. Solid wall HDPE pipe referred to as Drisco 1000, Drisco 8600, Quail Pipe, Poly Pipe, and Plexco Pipe that is in conformance with ASTM F714 and ASTM requirements stated herein are considered approved for this project. HDPE pipe on this project will further be required to have a minimum pipe stiffness of 46 psi for 12 inch to 48 inch diameter pipe and 115 psi for 8 inch to 10 inch diameters as required by SAWS and TNRCC.

PIPE MANUFACTURE: All pipe and fittings will be high density polyethylene pipe and made of virgin material. No rework except that obtained from the manufacturer's own production of the same formulation will be used. The liner material will be manufactured from a High Density High Molecular weight polyethylene compound which conforms to ASTM D 1248 and meets the requirements for Type III, Class C, Grade P-34, Category 5, and has a PPI rating of PE 3408.

b. The pipe produced from this resin will have a minimum cell Classification of 345434C (Inner wall will be light in color) under ASTM D 3350. A higher number cell classification limit which gives a desirable higher primary property, per ASTM D 3350 may also be accepted by the Engineer at no extra cost to SAWS. The value for the Hydrostatic Design basis will not be less than 1600 PSI (11.03 MPA) per ASTM D 2837. Pipe will have ultraviolet protection.

c. PIPE COLOR AND QUALITY: For television inspection purposes, the polyethylene pipe will have light-colored interior achieved with a homogenous, light-colored material throughout or with a fully bonded light-colored interior liner meeting specifications above indicated. All pipe will be free of visible cracks, holes, foreign material, foreign inclusions, blisters, or other deleterious or injurious faults or defects. Pipe and fittings shall be as uniform as commercially practical in color, opacity, density, and other physical properties.

For interior lined pipe, the liner will be a minimum of 10 mils thick and co-extruded. The bond between the layers will be strong and uniform. It will not be possible to separate the two layers with a probe or point of a knife blade so that the layers separate cleanly at any point, nor will separation of the bond occur, between layers, during testing performed under the requirements of this specification.

d. PIPE DIAMETER: Polyethylene Plastic Pipe will meet the applicable requirements of ASTM F 714 Polyethylene (PE) Plastic Pipe (SDR-PR) Based on Outside Diameter, ASTM D 1248, and ASTM D 3550. Internal diameter of the pipe indicated on the plans will be the minimum allowable pipe size.

e. PIPE DIMENSION RATIOS: The minimum wall thickness of the polyethylene pipe will meet the following, as based on the deepest portion of a particular pipe pull, typically between manholes:

Depth of Cover (Feet) Minimum SDR of Pipe

0 - 16.0 19

>16.1 17

Wall thickness shall be as indicated on the plans and will be in accordance with Chevron Plexco Industrial Piping System Pipe Data and Pressure Ratings Bulletin 301, or approved equal.

f. PIPE JOINING: Solid wall pipe shall be produced with plain end construction for heat-joining (butt fusion) conforming to ASTM D 2657.

The polyethylene pipe will be assembled and joined at the site using the thermal butt-fusion method to provide a leak proof and structurally sound joint. Threaded or solvent-cement joints and connections are not permitted. All equipment and procedures used will be used in strict compliance with the manufacturer's recommendations. Fusing will be accomplished by personnel certified as fusion technicians by a manufacturer of polyethylene pipe and/or fusing equipment.

The butt-fused joint will be true alignment and will have uniform roll back beads resulting from the use of proper temperature and pressure. The joint surfaces will be smooth. The fused joint will be watertight and will have tensile strength equal to that of the pipe. All joints will be subject to acceptance by the Engineers and/or his representative prior to insertion. All defective joints will be cut out and replaced at no cost to SAWS. Any section of the pipe with a gash, blister, abrasion, nick, scar, or other deleterious fault greater in depth than ten percent (10%) of the wall thickness, will not be used and must be removed from the site. However, a defective area of the pipe may be cut out and the joint fused in accordance with the procedures stated above. In addition, if in the opinion of the Engineers and/or his representative any section of pipe has other defects, including those hereinafter listed, that may indicate damaged, improperly manufactured, faulty, or substandard pipe, said pipe will be discarded and not used. Defects warranting pipe rejection include the following: concentrated ridges, discoloration, excessive spot roughness, and pitting; insufficient or variable wall thickness; pipe damage from bending, crushing, stretching or other stress; pipe damage that impacts the pipe strength, the intended use, the internal diameter of the pipe, internal roughness characteristics; or any other defect of manufacturing or handling.

Clamps and Gaskets: Clamps shall be stainless steel, including bolts and lugs as manufactured by JCM Industries Type 108 or equal. Furnish full circle, universal clamp couplings with a minimum 3/16-inch thick neoprene, grid-type gasket. Select clamps to fit outside diameter of pipe. Use minimum clamp length of 30" for replacement pipes O.D. of 10.75 inches (10 inch nominal) or greater, and 18 inches for replacement pipe O.D. less than 10.75 inches.

Terminal sections pipe that are joined within the insertion pit will be connected with a full circle pipe repair clamp. The butt gap between pipe ends will not exceed one-half (½) inch.

g. FORCE MAINS: Where applicable, solid wall pipe for sanitary sewer force mains shall have a minimum working pressure rating of 150 psi, and an inside diameter equal to or greater than the nominal pipe size indicated on the Drawings.

h. AUGERING PIPE: HDPE pipe is not approved in applications requiring augering of sewer pipe.

i. PIPE MARKING: Each standard and non-standard length of pipe or fitting shall be clearly marked with pipe size, pipe class, production code, material designation and other relevant identifying information.

j. PIPE INSPECTIONS: The Engineer reserves the right to inspect pipes or witness pipe manufacturing. Such inspection shall in no way relieve the manufacturer of the responsibilities to provide products that comply with the applicable standards and these Specifications. Should the Engineer wish to witness the manufacture of specific pipes, the manufacturer shall provide the Engineer with adequate advance notice of when and where the production of those specific pipes will take place. Approval of the products or tests is not implied by the Engineer's decision not to inspect the manufacturing, testing, or finished pipes.

900.3 CONSTRUCTION

1. PIT LOCATION: Location and number of insertion or launching pits will be chosen by the contractor, and will typically be located near existing or proposed manholes, P.I.'s in the line, at logical breaks in the construction phasing, or at locations to comply with access or maintenance requirements.

Pits shall be placed and located to minimize the total number of pulls and maximize the length of pipe replaced per pull, within the constraints of maintaining service and access and other requirements. Use excavations at point repair locations for insertion pits where possible.

2. OPERATIONS: The contractor shall provide equipment, planning, and job execution necessary to accomplish the work in an efficient manner and consistent with the objectives of this specifications, including preventing damage to existing infrastructure, maintaining pedestrian and vehicle access, and providing continual sewer service to customers.

Pipe shall be assembled and fused on the ground in sections equivalent to the length of the anticipated pull. During installation, all bending and loading the pipe shall be in conformance with manufacturers recommendations and shall not damage pipe.

Manholes shall be prepared so as to provide pipe installation at the lines and grades indicated on the plans. The invert in the manholes shall be removed as required to allow for pipe installation activities and to accommodate invert replacement. Manhole inverts shall be restored upon completion with 3000 psi grout so as to establish a minimum 4 inch thick bottom on the manhole after shaping per drawings.

3. EQUIPMENT: The Contractor shall utilize pipe bursting/crushing equipment with adequate pulling/pushing force to complete pulls in a timely manner. The contractor shall provide equipment on the pulling mechanism to verify the pulling/pushing force exerted on the pipe does not exceed the manufacturer's recommendation for allowable pulling force to prevent damage to the pipe. The pulling force may not exceed the following: 6 tons for 8.625" O.D.; 10 tons for 10.75"inch O.D.; 17 tons for 14" O.D.; 23 tons for 16 inch O.D.; 28 tons for 18 inch O.D. Allowable pulling force for all diameters shall be determined by the contractor depending on the pipe size, wall thickness, manufacturer, field conditions, pull distance, manhole integrity, bearing capacity of soils, adjacent infrastructure, related equipment and cable strength, and related considerations.

4. Equipment shall be configured with adequate knives or other appropriate devices to minimize interruptions in the installation process due to obstruction removal and other problems. Pipe shall be secured to the pulling/pushing device in accordance with standard practice. The diameter of the pulling/pushing head shall be equal or slightly greater than the pipe OD.

5. MINIMIZE NOISE IMPACT: Equipment used to perform the work will be located away from buildings so as not to create a noise impact. Provide silencers or other devices to reduce machine noise as required to meet requirements.

6. PROTECTION: The Contractor shall provide for the general safety of workers, pedestrians and traveling public throughout this project. Existing surface improvements and underground facilities and utilities shall also be protected. Damage caused by the Contractor shall be repaired at his own expense. Protection to be provided includes:

a. Provide barricades, warning lights and signs for excavations created by point repairs. Conform to requirements of TxDOT, City of San Antonio, and of contract documents.

b. Protection of Manholes: The Contractor will install all pulleys, rollers, bumpers, alignment control devices and other equipment required to protect existing manholes, and to protect the pipe from damage during installation. Lubrication may be used as recommended by the manufacturer. Under no circumstances will the pipes be stressed beyond their elastic limit.

c. Do not allow sand, debris, or runoff to enter sewer system.

d. Verify location of all underground utilities and facilities potentially impacted by rehabilitation related or other project activities and take necessary precautions to provide protection from damage. Damage caused by the Contractor shall be at his cost and responsibility.

e. Protect the new pipe and components during all phases of work, including hauling, installation, entry into the entry pit, and prevention of scarring or gouging of the pipe or components.

7. SEALING LINER IN MANHOLE:

a. Allow liner pipe to normalize to ambient temperatures as well as recover from imposed stretch before cutting to fit between manholes, sealing at manholes, and manhole invert shaping. Normalization usually takes at least 12 hours for polyethylene.

b. Cut liner so that it extends four inches into manhole. Make a smooth, vertical cut and slope area over top of exposed liner using non-shrink grout.

c. Seal the annular space between liner and sanitary sewer main at each manhole with a chemical seal and non-shrink grout. Place strips of oakum soaked in sealer (Scotchseal 5600 as manufactured by 3M Corporation, or equal) in a band to form an effective water-tight gasket in the annular space between liner and existing opening in manhole. Make width of the sealing band a minimum of eight inches or the thickness of the manhole wall, whichever is greater.

d. Finish seal with a non-shrink grout placed around annular space from inside manhole. Apply grout in a band not less than six inches wide.

e. Reshape and smooth the manhole invert. Form a smooth transition with a reshaped invert and a raised manhole bench to eliminate sharp edges of liner pipe, concrete bench, and channeled invert. Build up and smooth invert of manhole to match flow line of new liner.

8. FIELD TESTING

a. After the existing sewer is completely replaced, internally inspect with television camera and video tape as required. The finished tape will be continuous over the entire length of the sewer between two manholes and to be free from visual defects.

b. Defects which may affect the integrity or strength of the pipe in the opinion of the Engineer will be repaired or the pipe replaced at the Contractor's expense.

c. The Contractor shall smoke test to verify all sewer service connections.

d. The following items are excerpted from TNRCC Chapter 317 requirements for gravity sewer construction testing (§317.a.4). Compliance with these requirements is required unless the contractor obtains and provides written authorization from the TNRCC authorizing alternative testing and compliance procedures:

1. Testing of Installed Pipe: An infiltration, exfiltration or low-pressure air test shall be specified. Copies of all test results shall be made available to the executive director (TNRCC) upon request. Tests shall conform to the following requirements:

2. Infiltration or Exfiltration Tests: The total exfiltration as determined by a hydrostatic head test, shall not exceed 50 gallons per inch diameter per mile of pipe per 24 hours at a minimum test head of two feet above the crown of the pipe at the upstream manhole. When pipes are installed below the groundwater level an infiltration test shall be used in lieu of the exfiltration test. The total infiltration, as determined by a hydrostatic head test, shall not exceed 50 gallons per inch diameter per mile of pipe per 24 hours at a minimum test head of two feet above the crown of the pipe at the upstream manhole, or at least two feet above existing groundwater level, whichever is greater. For construction within the 25 year flood plain, the infiltration or exfiltration shall not exceed 10 gallons per inch diameter per mile of pipe per 24 hours at the same minimum test head. If the quantity of infiltration or exfiltration exceeds the maximum quantity specified, remedial action shall be undertaken in order to reduce the infiltration or exfiltration to an amount within the limits specified.

3. Low Pressure Air Test: The procedure for the low pressure air test shall conform to the procedures described in ASTM C-828, ASTM C-924, ASTM F-1417 or other appropriate procedures, except for testing times. The test times shall be as outlined in this section. For sections of pipe less than 36-inch average inside diameter, the following procedure shall apply unless the pipe is to be joint tested. The pipe shall be pressurized to 3.5 psi greater than the pressure exerted by groundwater above the pipe. Once the pressure is stabilized, the minimum time allowable for the pressure to drop from 3.5 pounds per square inch gauge to 2.5 pounds per square inch gauge shall be computed from the following equation:

T = time for pressure to drop 1.0 pound per square inch gauge in seconds

K = 0.000419'D'L, but not less than 1.0

D = average inside pipe diameter in inches

L = length of line of same pipe size being tested, in feet

Q = rate of loss, 0.0015 cubic feet per minute per square foot internal surface shall be used

Since a K value of less than 1.0 shall not be used, there are minimum testing times for each pipe diameter as follows:

4. Pipe Diameter Minimum Length for Time for

(inches) Time Minimum Longer Length

(seconds) Time (seconds)

(feet)

6 340 398 0.855(L)

8 454 298 1.520(L)

10 567 239 2.374(L)

12 680 199 3.419(L)

15 850 159 5.342(L)

18 1020 133 7.693(L)

21 1190 114 10.471(L)

24 1360 100 13.676(L)

27 1530 88 17.309(L)

30 1700 80 21.369(L)

33 1870 72 25.856(L)

5. The test may be stopped if no pressure loss has occurred during the first 25% of the calculated testing time. If any pressure loss or leakage has occurred during the first 25% of the testing period, then the test shall continue for the entire test duration as outlined above or until failure. Lines with a 27-inch average inside diameter and larger may be air tested at each joint. Pipe greater than 36 inch diameter must be tested for leakage at each joint. If the joint test is used, a visual inspection of the joint shall be performed immediately after testing. The pipe is to be pressurized to 3.5 psi greater than the pressure exerted by groundwater above the pipe. Once the pressure has stabilized, the minimum time allowable for the pressure to drop from 3.5 pounds per square inch gauge to 2.5 pounds per square inch gauge shall be 10 seconds.

6. Deflection Testing. Deflection tests shall be performed on all flexible pipes. For pipelines with inside diameters less than 27 inches, a rigid mandrel shall be used to measure deflection. For pipelines with an inside diameter 27 inches and greater, a method approved by the executive director shall be used to test for vertical deflections. Other methods shall provide a precision of ± two tenths of one percent (0.2 %) deflection. The test shall be conducted after the final backfill has been in place at least 30 days. No pipe shall exceed a deflection of five percent. If a pipe should fail to pass the deflection test, the problem shall be corrected and a second test shall be conducted after the final backfill has been in place an additional 30 days. The tests shall be performed without mechanical pulling devices. The design engineer should recognize that this is a maximum deflection criterion for all pipes and a deflection test less than five percent may be more appropriate for specific types and sizes of pipe. Upon completion of construction, the design engineer or other Texas Registered Professional Engineer appointed by the owner shall certify, to the Executive Director, that the entire installation has passed the deflection test. This certification may be made in conjunction with the notice of completion required in §317.1(e)(1) of this title (relating to General Provisions). This certification shall be provided for the Commission to consider the requirements of the approval to have been met.

7. Mandrel Sizing. The rigid mandrel shall have an outside diameter (O.D.) equal to 95% of the inside diameter (I.D) of the pipe. The inside diameter of the pipe, for the purpose of determining the outside diameter of the mandrel, shall be the average outside diameter minus two minimum wall thicknesses for O.D. controlled pipe and the average inside diameter for I.D. controlled pipe, all dimensions shall be per appropriate standard. Statistical or other "tolerance packages" shall not be considered in mandrel sizing.

8. --Mandrel Design. The rigid mandrel shall be constructed of a metal or a rigid plastic material that can withstand 200 psi without being deformed. The mandrel shall have nine or more "runners" or "legs" as long as the total number of legs is an odd number. The barrel section of the mandrel shall have a length of at least 75% of the inside diameter of the pipe. A proving ring shall be provided and used for each size mandrel in use.

9. --Method Options. Adjustable or flexible mandrels are prohibited. A television inspection is not a substitute for the deflection test. A deflectometer may be approved for use on a case by case basis. Mandrels with removable legs or runners may be accepted on a case by case basis.

900.4 MEASUREMENT AND PAYMENT:Measurement and payment for items included in this specification shall be in accordance with the pay items listed below. Work included in these items shall include and the price provided by the Contractor will be considered as full compensation for furnishing and placing of all materials, labor, tools, and equipment; cleaning, preparation, repairs, obstruction removal, inspection; and phasing, protecting, work execution and any other work necessary to complete the project.

1. INSTALLED PIPE: The inserted pipe will be paid for per linear foot of pipe installed using pipe-bursting/pipe crushing method for the pipe diameter, type, quantity, and depth specified and will include all pipe installation materials, all submittals, sealing materials at manholes and annulus (if required), launching pits, receiving pits, post testing, shoring, bedding, backfill, and all necessary, corresponding, and related work specified herein. (Item 900)

2. SERVICES: Locating and reconstruction of services and all connections of services will be paid for per each connection made, including fittings and pipe. Payment for abandoned services will be on a per each connection made basis. (Item 900.1)

3. POINT REPAIRS: Point repairs will be paid for on a per each basis, as needed. Extra length point repair will be paid based on the length of pipe replaced per repair beyond the length established for each single point repair item, as needed. Abandoned point repairs will be paid on a cubic yard basis, as needed. (Item 900.5)

4. OBSTRUCTION REMOVAL: Obstruction removal will be paid for on a per each basis, as needed. (Item 900.6)

5. STORM WATER POLLUTION PREVENTION AND EROSION CONTROL PLAN: Payment for this item will be based on the items and quantities of control measures included in the proposal on the basis indicated in the respective specification sections.

6. SITE RESTORATION: Except as associated with point repairs and obstruction removals, site restoration for all impacts to surface improvements will be on a linear foot basis of the rehabilitated line segment. For point repairs and obstruction removals, site repair will be on a per each basis.

7. TELEVISION INSPECTION: Payment will be made for television inspection of the sewer line prior to pipe rehabilitation in accordance with specifications Item 866 and cleaning will be in accordance with specification Item 868. There will be no additional or separate payment for "post-TV" video inspection, documentation, required submittals, and associated or related work.

8. BYPASS PUMPING: The cost of any necessary bypass pumping will be considered subsidiary to the appropriate pay items for pipe installation, television inspection, repair, or related work and will not be a separate pay item.

Wichita, Kansas Microtunneling Specification

SECTION 808

MICROTUNNELING INSTALLATION OF PIPE

808.1 DESCRIPTION

The Contractor shall furnish and install pipe by microtunneling as indicated and in conformity with this specification. The work includes, but shall not be limited to traffic control, excavation, dewatering, removal of all materials encountered in microtunneling operations, disposal of all material not required in the work, grouting, bulkheads, backfilling and site restoration.

The Contractor shall provide a microtunneling process which uses a remotely operated shield machine for installing pipes or pipe linings underground without the use of ground stabilization techniques. The intent of the process is to minimize surface disruption and allow installation of pipe without many of the constraints imposed by trenching or conventional tunneling methods.

808.2 MATERIALS

a)Pipe -Carrier pipe shall conform to the Supplemental Specification for Jacking Pipe of the size, type, materials, thickness and class indicated.

b)Grout -Grout for voids shall consist of 1 part Portland Cement and 4 parts fine, clean sand mixed with water.

808.3 EQUIPMENT

General:

The microtunneling system shall consist of five major, independently controlled components:

a) Microtunnel Boring Machine (MTBM)

b) Jacking system

c) Spoil removal system

d) Guidance and control system

e) Pipe lubrication system.

Description of the System:

a) The Contractor shall provide a microtunneling system for installing pipe behind a remotely controlled, steerable, guided, articulated Microtunnel Boring Machine (MTBM). The MTBM shall be connected to and followed by the pipe which is installed by jacking and shall be capable of fully controlling the rate at which the material is being excavated at all times.

b) The minimum depth of cover to the pipe being installed using the microtunneling process is normally six (6) feet or 1.5 times the outer diameter of the pipe being installed, whichever is the greater. With special precautions, and approval by the Engineer, this depth of cover may be decreased.

c) Microtunneling work shall be executed so as to minimize settlement or heave. Overcut shall not exceed 1" on the radius of the pipe being installed without the approval of the Engineer. The annular space created by the overcut may be filled with the lubrication material that is used to reduce the friction drag of the soil on the pipe.

Micro Tunnel Boring Machine (MTBM):

a) The MTBM shall be capable of controlling rotation or roll by means of bi-directional drive on the cutter head or by the use of fins or grippers. The MTBM shall be articulated to enable remotely controlled steering of the shield.

b) A display showing the position of the shield in relation to a design reference shall be available to the operator at an operation console together with other information such as face pressure, roll, pitch, steering attitude and valve positions.

c) The MTBM shall have a cutter face capable of supporting the full excavated area at all times, and may have the capability of setting a calculated earth balancing pressure and positively measuring the earth pressure at the face.

d) When soil conditions dictate, the tunnel shall be capable of removing cobbles and boulders. The excavation system shall be fully capable of excavating all material that it will encounter.

Automated Spoil Transportation:

a) The automated spoil transportation system shall match the excavation rate to the rate of spoil removal, maintaining settlement or heave within tolerances specified herein.

b) The balancing of ground water pressures shall be achieved by the use of a slurry pressure or auger earth pressure balance system. The system shall be capable of any adjustment required to maintain face stability for the particular soil condition to be encountered on the project. The system shall monitor and continuously balance the ground water pressure.

c) If a slurry spoil transportation system is used, the ground water pressure may be managed by use of the slurry pumps (which may be of variable speeds), pressure control valves and a flow meter. A slurry bypass unit shall be included in the system to allow the direction of flow to be changed and isolated, as necessary.

d) A separation process shall be provided when using the slurry transportation system. The process shall be designed to provide adequate separation of the spoil from the slurry so that the clean slurry can be returned to the cutting head for reuse. The Contractor shall identify the type of separation process to be used.

If an Auger spoil transportation system is utilized, the ground water pressures may be managed by controlling the volume of spoil removal with respect to the advance rate (Earth Pressure Balance Method) and the application of compressed air. In soils with excessive ground water, approval of the Engineer may be required for earth pressure balance auger systems. Approval will be based on the evaluation of the equipments ability to balance soil and water pressures at the face, stability of the soils and the significance of the ground water present.

Pipe Jacking Equipment:

a) The main jacks shall be mounted in a jacking frame and located in the drive (starting) shaft. The jacking frame successively pushes the MTBM followed by a string of connected pipes toward a receiving shaft. The jacking capacity of the system shall be sufficient to push the MTBM and the string of pipes thorough the ground.

b) The main jacking equipment installed shall have a capacity greater than the anticipated jacking load. The hydraulic cylinder extension rate shall be synchronized with the excavation rate of the MTBM, which is determined by the soil conditions.

c) Intermediate jacking stations shall be provided by the Contractor when the total anticipated jacking force needed to complete the installation exceeds the designed maximum jacking force of the pipe or 80% of the capacity of the main jacks.

d) The jacking system shall develop a uniform distribution of jacking forces on the end of the pipe by the use of spreader rings and packing.

Pipe Lubrication System:

A pipe lubrication system may be utilized when anticipate jacking forces on the pipe are expected to exceed the capacity of the main jacks or exceed the pipe design strength with the appropriate safety factor. An approved lubricant shall be injected at the rear of the MTBM and, if necessary, through the pipe walls to lower the friction developed on the surface of the pipe during jacking and thereby reduce the jacking forces.

Remote Control System:

a) A Remote Control System shall be provided that allows for the operation of the system without the need for personnel to enter the microtunnel.

b) In man entry sized pipes, intermittent entry of personnel will be permitted into the pipe for maintenance during the drive and for removal of equipment once the pipe installation is complete.

c) The control equipment shall integrate the method of excavation and removal of soil and its simultaneous replacement by the pipe. As each pipe section is jacked forward, the control system shall synchronize excavation and jacking speeds. The system shall provide complete and adequate ground support at all times.

Active Direction Control:

a) Line and grade shall be controlled by a guidance system that relates the actual position of the MTBM to a design reference (e.g. by a laser beam transmitted from the jacking shaft along the center line of the pipe to a target mounted in the shield). The microtunneling system shall be capable of maintaining grade to within plus or minus 1" and alignment to within plus or minus 1.5", unless otherwise approved by the Engineer.

b) The active steering information shall be monitored and transmitted to the operation console. The minimum steering information available to the operator on the control console shall include the position relative to the design reference, roll, indication, attitude, rate of advance, installed length, thrust force, and cutter head torque.

808.4 CONSTRUCTION METHODS

General:

The Contractor shall provide and maintain adequate microtunneling equipment, install support systems as required, provide and install carrier pipe, and faithful execution of work using microtunneling and installing pipe simultaneously. The Contractor shall have sole responsibility for safety of microtunneling operations and for persons engaged in the work.

The Contractor shall furnish shop drawings showing his proposed method of microtunneling, including design for microtunneling head, installation of microtunneling supports or back stop, arrangement and position of microtunneling machinery, pipe guides, grouting plan, intended disposal of excavated material, and a project safety plan for the Engineer's review.

Jacking and Receiving Shafts:

Shafts shall be of a size commensurate with safe working practices. The Contractor shall provide shop drawings showing the shaft locations for approval by the Engineer.

The design of the shafts shall ensure safe exit from the driving shaft and entry into the receiving shaft of the MTBM.

Shafts and jacking pit shall be adequately ventilated. Air monitoring of the shafts or pits shall be conducted by the Contractor on a continuous basis in accordance with the Contractor's Safety Plan.

Before beginning construction at any location, the Contractor must adequately protect existing structures, utilities, trees, shrubs and other permanent objects where visible or shown on the drawings.

The Contractor shall furnish and install equipment to keep the jacking shaft free of excess water. The Contractor shall also provide surface protection during the period of construction to ensure that surface runoff does not enter the driving shaft.

A thrust block is required to transfer jacking loads into the soil. The thrust block shall be designed to support the maximum jacking pressure developed by the main jacking system. Special care shall be taken when setting pipe guide rails in the jacking shaft to ensure correctness of the alignment, grade, and stability. If a concrete thrust block or treated soil zone is utilized to transfer jacking loads in to the soil, the MTBM is not to be jacked until the concrete or other material have attained the required strength.

During construction operations and until pits are backfilled, barricades and lights to safeguard traffic and pedestrians shall be furnished and maintained conforming to the Manual Uniform Traffic Control Devices (MUTCD).

When grade of pipe at microtunneling end is below ground surface, suitable pits or trenches shall be excavated for the purpose of conducting the microtunneling operations and for joining pipe. Work shall be sheeted securely and braced to prevent earth caving and to provide a safe and stable work area. Minor lateral or vertical variations in final position of pipe from line and grade established by Engineer will be permitted at the discretion of Engineer provided that such variations shall be regular and only in one direction and that final grade of flow line shall be in direction indicated.

If trench bottom is unstable or excessively wet or when installation of water and wastewater pipe will result in cover less than six (6) feet or 1.5 times the outer diameter of the pipe being installed, whichever is the greater, the Contractor shall notify the Engineer. The Engineer may require the Contractor to install a concrete seal, cradle, cap or encasement or other appropriate action.

As soon as possible after carrier pipe(s) are completed, pits or trenches excavated to facilitate these operations shall be backfilled. The backfill in the street ROW shall be compacted to not less than 95 percent of the density conforming to ASTM D698. At the Contractor's option, flowable excavatable fill may be used up to three feet below the finished surface grade.

Where the characteristics of soil or size of proposed pipe would make use of tunneling more satisfactory that microtunneling, a tunneling method may be submitted for acceptance by Engineer.

Tunneling shall conform to the requirements of the Standard Specifications.

Jacking Pipe:

In general, pipe used for jacking shall be round, have a smooth, even outer surface, and with joints that allow for easy connections between pipes. Pipe ends shall be square and smooth so that jacking loads are evenly distributed around the entire pipe joint, such that point loads are minimized when the pipe is jacked. Pipe used for pipe jacking shall be capable of withstanding all forces that will be imposed by the process of installation, as well as the final in place loading conditions. The driving ends of the pipe and intermediate joints shall be protected against damage as specified by the manufacturer. The detailed method proposed to cushion and distribute the jacking forces shall be described by the Contractor for each particular pipe material.

Pipe showing signs of failure may be required to be jacked through to the reception shaft and removed. Other methods of repairing the damaged conduit may be used, as recommended by the manufacturer and subject to approval by the Engineer. Repair or replacement of damaged pipe shall be performed by the Contractor at no additional cost to the City.

The pipe manufacturer's design jacking loads shall not be exceeded during the installation process. The pipe shall be designed to take full account of all temporary installation loads. Jacking pipe is specified in other supplemental Specifications.

Installation:

Suitable pits or trenches shall be excavated for the purpose of conducting the jacking operations and for placing end joints of the pipe. Such work shall be sheeted securely and braced in a manner to prevent earth caving and to provide a safe, stable work area.

The microtunneling shall proceed from a pit provided for the microtunneling equipment and workmen. The location of the pit shall meet the approval of the Engineer. Excavated material shall be removed from the working pit and disposed of properly. The use of water or other fluids in connection with the boring operation will be permitted only to the extent to lubricate cuttings. Jetting shall not be permitted.

In unstable soil formations, water or processed drilling fluid, containing colloidal material such as bentonite, may be used to consolidate the drill cuttings, seal the walls or the hold and furnish lubrication to facilitate removal of the cuttings from the bore. Water jetting shall not be permitted.

808.5 SUBMITTALS

The following material shall be submitted by the Contractor to the Engineer for review:

a) Manufacturer's literature describing in detail the microtunneling system to be used. Detailed description of projects on which this system has been successfully used.

b) Method of spoil disposal.

c) Anticipated jacking loads.

d) Method(s) of controlling ground water at shafts and by the MTBM.

e) Shaft dimensions, locations, surface construction, profile, depth, method of excavation, shoring bracing and thrust block design.

f) Verification that the pipe complies with the project specifications.

This shall include literature describing the microtunneling pipe to be used on this project. The literature shall include allowable safe jacking loads with a safety factor of at least 2.5. A list of names, addresses, and telephone numbers of contacts on successfully completed microtunneling projects shall be provided for verification.

g) Proposed shaft locations and sizes.

h) Project Safety Plan.

All contractor submittals requiring structural design shall be signed and sealed by a Registered Professional Engineer in Kansas.

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Updated: 09/18/2014
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