555-1 Description.
555-1.1 Scope of Work: The work specified in this Section documents the approved
construction methods and procedures for directional boring, also commonly called horizontal directional drilling (HDD).
555-1.2 General: HDD is a trenchless method for installing a product that serves as a
carrier pipe for transporting solids, liquids or gasses (under pressure or gravity flow), or serves as a conduit, casing, or duct for a carrier pipe, cable, or wire line products. It is a multi -stage process consisting of site preparation and restoration, equipment setup, and drilling a pilot bore along a predetermined path and then pulling the product back through the drilled space. When necessary, enlargement of the pilo t bore hole may be necessary to accommodate a product larger than the pilot bore hole size. This process is referred to as back reaming and is done at the same time the product is being pulled back through the pilot bore hole. Accomplish alignment of the bore by proper orientation of the drill bit head as it is being pushed into the ground by a hydraulic jack and determine orientation and tracking of the drill bit. In order to minimize friction and prevent collapse of the bore hole, introduce a soil stabilizing agent (drilling fluid) into the annular bore space from the trailing end of the drill bit. Select or design drilling fluids for the site specific soil and ground water conditions. Confine free flowing (escaping) slurry or drilling fluids at the gr ound surface during pull back or drilling. Remove all residual slurry from the surface and restore the site to preconstruction conditions.
555-2 Construction Site Requirements.
555-2.1 Pedestrian Traffic : When and where installations temporarily disrupt u se of a
pedestrian way , provide a safe alternate route in accordance with Standard Plans, Indexes 102- 600 and 102 -660.
555-2.2 Site Conditions:
1.Carry out excavation for entry, exit, recovery pits, slurry sump pits, or any other excavation as specifie d in Section 120. Sump pits are required to contain drilling fluids if vacuum devices are not operated throughout the drilling operation, unless approved by the Engineer.
2.Within 48 hours of completing installation of the product, clean the work site o f all excess slurry or spoils. Take responsibility for the removal and final disposition of excess slurry or spoils. Ensure that the work site is restored to pre -construction conditions or as identified on the plans.
3.Provide MOT in accordance with the Standard Plans and the MUTCD when and where the former is silent.
4.Exposure of product shall be limited to 3 feet and 14 consecutive days unless approved by the Engineer.
555-2.3 Damage Restoration: Take responsibility for restoration for any damage caused
by heaving, settlement, separation of pavement, escaping drilling fluid (frac -out), or the directional drilling operation, at no cost to the Department.
555-2.3 1 Remediation Plans: When required by the Engineer, provide detailed
plans which show how damage to any roadway facility will be remedied. These details will FY 2023-24 Return to Table of Contents become part of the As -Built Plans Package. Remediation plans must follow the same guidelines for development and presentation of the as -built plans. When remediation plans are required , they must be approved by the Engineer before any work proceeds.
555-3 Quality Control.
555-3.1 General: Take control of the operation at all times. Have a representative who is
thoroughly knowledgeable of the equipment, boring and Department procedures , present at the job site during the entire installation and available to address immediate concerns and emergency operations. Notify the Engineer 48 hours in advance of starting work. Do not begin installation until the Engineer is present at the job site and agrees that proper preparations have been made.
555-3.1 1 Product Testing: When there is any indication that the installed
product has sustained damage and may leak, stop all work, notify the Engineer and investigate the damage. The Engineer may requ ire a pressure test and reserves the right to be present during the test. Perform pressure test within 24 hours, unless otherwise approved by the Engineer. Submit the test results to the Engineer for review and approval. The Engineer is allowed up to 72 hours to approve or determine if the product installation is not in compliance with the specifications. The Engineer may require non -compliant installations to be fille d with excavatable flowable fill.
555-3.1 2 Testing Methods: Testing may consist of one of the following methods
and must always meet or exceed the Department’s testing requirements:
1.Follow the product manufacturer’s pressure testing recommendation s.
2.Ensure carrier pipes installed without a casing meet the pressure requirements set by the owner. If the owner does not require pressure testing, the Engineer may require at least one test.
3.A water tight pipe and joint configuration where the product is installed beneath any pavement (including sidewalk) and front shoulders is required. The Engineer will determine when and where water tight joint requirements will be applied to the ultimate roadway section for future widening. When a product i s located elsewhere, the pipe and joint configuration must meet or exceed soil tight joint requirements. Conduct tests for joint integrity for one 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.
555-3.1 3 Failed Bore Path: If conditions warrant removal of any materials
installed in a failed bore path, as determined by the Engineer, it will be at no cos t to the Department. Promptly fill all voids with excavatable flowable fill.
555-3.2 Product Locating and Tracking: The method of locating and tracking the drill
head during the pilot bore will be shown in the Plans. The Department recognizes walkover, wi re line, and wire line with surface grid verification, or any other system as approved by the Engineer, as the accepted methods of tracking directional bores. Use a locating and tracking system capable of ensuring 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 must provide information on:
1.Clock and pitch information
2.Depth
3.Transmitter temperature
4.Battery status
5.Position (x,y) FY 2023-24 Return to Table of Contents
6.Azimuth, where direct overhead readings (walkover) are not possible (i.e. subaqueous or limited access transportation facility)
7.Ensure proper calibration of all equipment before commencing directional drilling operation.
8.Take and record alignmen t readings or plot points such that elevations on top of and offset dimensions from the center of the product to a permanent fixed feature are provided. Such permanent fixed feature must have prior approval of the Engineer. Provide elevations and dimension s at all bore alignment corrections (vertical and horizontal) with a minimum distance between points of 100 feet. Provide a sufficient number of elevations and offset distances to accurately plot the vertical and horizontal alignment of the installed produ ct. A minimum of three elevation and plot points are required.
555-3.3 Product Bore Hole Diameter: Minimize potential damage from soil
displacement/settlement by limiting the ratio of the bore hole to the product size. The size of the back reamer bit or p ilot bit, if no back reaming is required, will be limited relative to the product diameter to be installed as follows: Table 555-1 Maximum Pilot or Back -Reamer Bit Diameter When Rotated 360 Degrees Outside Pipe Diameter Inches* Maximum Bit Diameter Inche s <8 Diameter + 4 8 to 24 1.5 x Diameter >24 Diameter + 12 *Use manufacturer’s recommendation for pipe with restrained joints.
555-3.4 Drilling Fluids: Use a mixture of bentonite clay or other approved stabilizing
agent mixed with potable water with a minimum pH of 6.0 to create the drilling fluid for lubrication and soil stabilization. Do not use any other chemicals or polymer surfactants in the drilling fluid without written consent from the Engineer. Certify to the Engineer in writing th at any chemicals to be added are environmentally safe and not harmful or corrosive to the facility. Identify the source of water for mixing the drilling fluid. Any water source used other than a potable water source may require a pH test.
555-4 Drilling Op erations:
555-4.1 Installation Process: Ensure adequate removal of soil cuttings and stability of
the bore hole by monitoring the drilling fluids such as the pumping rate, pressures, viscosity and density during the pilot bore, back reaming and pipe insta llation. Relief holes can be used as necessary to relieve excess pressure down hole. Obtain the Engineer’s approval of the location and all conditions necessary to construct relief holes to ensure the proper disposition of drilling fluids is maintained and unnecessary inconvenience is minimized to other facility users. To minimize heaving during pull back, the pull back rate is determined in order to maximize the removal of soil cuttings without building excess down hole pressure. Contain excess drilling fluids at entry and exit points until they are recycled or removed from the site or vacuumed during drilling operations. Ensure that entry and exit pits are of sufficient size to contain the expected return of drilling fluids and soil cuttings. Ensure th at 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 FY 2023-24 Return to Table of Contents contaminated ground, test the drilling fluid for contamination and appropriately dispose o f it. Remove any excess material upon completion of the bore. If in the drilling process it becomes evident that the soil is contaminated, contact the Engineer immediately. Do not continue drilling without the Engineer’s approval. When conditions warrant , as determined by the Engineer, back reaming for enlarging the bore diameter shall be accomplished by connecting the reamer to trailing drill stems at the exit pit of the pilot bore. The drill pipe shall remain in the bore hole until the final product is pulled into place. After the pilot bore is established, do not push anything from the entry pit to the exit pit. The timing of all boring processes is critical. Install a product into a bore hole within the same day that the pre -bore is completed to ensu re necessary support exists.
555-4.2 Boring Failure: If an obstruction is encountered during boring which prevents
completion of the installation in accordance with the design location and specification, the pipe may be taken out of service and left in pl ace at the discretion of the Engineer. Immediately fill the product left in place with excavatable flowable fill. Submit a new installation procedure and revised plans to the Engineer for approval before resuming work at another location. If, during construction, damage is observed to the FDOT facility, cease all work until resolution to minimize further damage and a plan of action for restoration is obtained and approved by the Engineer.
555-5 Documentation Requirements.
555-5.1 Boring Path Report: Submit a Bore Path Report to the Engineer within seven
days of the completion of each bore path. Include the following in the report:
1.Location of project and financial project number including the Permit Number when assigned
2.Name of person collecting d ata, including title, position and company name
3.Investigation site location ( Plans station number or reference to a permanent structure within the project right of way)
4.Identification of the detection method used
5.Elevations and offset dimens ions as required in 555 -3.2
555-5.2 As-Built Plans: Provide the Engineer a complete set of as -built plans showing
all bores (successful and failed) within 30 calendar days of completing the work . As-built plans must be PDF files, in the same scale as the Plans. Ensure that the plans are dimensionally correct copies of the Plans and include roadway plan and profile, cross-section views, boring location and subsurface conditions as directed by the Engineer. The plans must show appropriate elevations referenced to a permanent FDOT feature (mast arm foundation, manhole inlet cover, head wall, etc). Specific plans content requirements include but may not be limited to the following:
1.The Contract plan view shows the center line location of each facility installed, or installed and placed out of service, to an accuracy of 1 inch at the ends and other points physically observed in accordance with the bore path report.
2.As directed by the Engineer, provide either a profile plan for each bore path, or a cross-section of the roadway at a station specified by the Engineer, or a roadway centerline profile. Show the ground or pavement surface and crown elevat ion of each facility installed, or installed and placed out of service, to an accuracy of within 1 inch at the ends and other exposed locations. On profile plans for bore paths crossing the roadway, show stationing of the crossing on the Plans. On the prof ile plans for the bore paths paralleling the roadway, show the Plans FY 2023-24 Return to Table of Contents stationing. If the profile plan for the bore path is not made on one of the Plans, use a 10 to 1 vertical exaggeration.
3.If, during boring, an obstruction is encountered which prevent s completion of the installation in accordance with the design location and specification, and the product is left in place and taken out of service, show the failed bore path along with the final bore path on the plans. Note the failed bore path as “Faile d Bore Path - Taken Out of Service”. Also show the name of the utility owner, location and length of the drill head and any drill stems not removed from the bore path.
4.Show the top 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 and lowest elevation observed, and note if th e obstruction continues below the lowest point observed.
5.Include bore notes on each plan stating the final bore path diameter, product diameter, drilling fluid composition, composition of any other materials used to fill the annular void between the b ore path and the product, or facility placed out of service. Note if the product is a casing as well as the size and type of carrier pipes placed within the casing as part of the Contract work.
555-6 Compensation.
No direct payment will be made for direct ional bore. Include the cost to perform this operation in the Contract price for the item being installed. No compensation will be made for failed bore paths, injection of flowable fill, products taken out of service, or incomplete installations. No compensation will be made for the pay item associated with the directional bore until a Bore Path Report has been submitted and accepted by the Engineer. FY 2023-24 Return to Table of Contents SECTION 556 JACK AND BORE
556-1 Description.
556-1.1 Scope of Work: 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 also included in the category of J&B for purposes of the Specifications.
556-1.2 General: 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 carrier (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 with simultaneous excavation of the soil being accomplished b y a rotating cutting head 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 steerin g as well as limited support to the excavation face. MT is conducted similar to J&B with the exception that it is remotely controlled, guided pipe jacking process that provides continuous support to the excavation face. The guidance system usually consis ts 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 mechanica l or fluid pressure to counterbalance the earth and hydrostatic pressures. Removal and disposition of excess material varies, is the responsibility of the boring contractor and is not covered under this Specification. However, the cost of removal or final disposition is included in the cost of the J&B operation. No J&B conduit may be left open ended without approval of the Engineer .
556-2 Materials.
Select materials approved for installation within the right -of-way based on their suitability for the co nstruction method as defined in Table 556-1. After determining product suitability, individual material standards as contained in Table 556-2 apply. Table 556-1 Product Suitability by Construction Method Type Pipe/Casing Installation Mode Suitable Pipe/C asing Jack and Bore Jacking Steel, Plastic Micro tunneling Jacking DI, FRPM, PC, PCCP, RCCP, RCP, Steel FY 2023-24 Return to Table of Contents
Source: Florida Standard Specifications for Road and Bridge Construction, 2024 Edition. Pages 787–791 of 1,299.