SECT-33_BORING_&_JACKING.docx

SECTION 33 - BORING AND JACKING

Item No. Title

33.1 GENERAL

33.3 PIPE HANDLING

33.4.5 Miscellaneous Requirements

33.4.6 Directional Boring

33.1 GENERAL

The installation of a casing pipe by the method of boring and jacking shall be covered by these specifications. The overall work scope shall include, but not be limited to, boring and jacking pits and equipment, sheeting, steel casing pipe, carrier pipe, skid, steel straps, coatings, location signs as required, miscellaneous appurtenances to complete the entire WORK as shown on the STANDARD DRAWINGS, and restoration. Boring and jacking operations shall be performed within the right-of-way and/or easements shown on the DRAWINGS. Hydraulic pushing of casing pipe is prohibited.

33.2 PIPE MATERIAL

33.2.1 STEEL CASING

Steel casings shall conform to the requirements of ASTM Designation A139 (straight seam pipe only) Grade "B" with a minimum yield strength of 35,000 psi. The casing pipes shall have the minimum nominal diameter and wall thickness as shown on the following table:

Field and shop welds of the casing pipes shall conform with the American Welding Society (AMS) standard specifications. Field welds shall be complete penetration, single-bevel groove type joints. Welds shall be airtight and continuous over the entire circumference of the pipe and shall not increase the outside pipe diameter by more than 3/4-inch.

33.2.2 CARRIER PIPE

The carrier pipe for potable water, reuse water, and sanitary sewer shall be minimum Pressure Class 150 ductile iron pipe with individually restrained joints. Interior and exterior DIP wall surfaces shall receive required coating treatments per plan-set standard drawings that apply to potable water, reuse water, and sanitary sewer utilities. PVC for gravity and force main sewers shall be a minimum of AWWA / C900 / RJ / DR18, with individually restrained joints using “Certa-Loc” by Certainteed, or approved equal. DIP or PVC pipe shall comply with all areas of these specifications and plan-set standard drawings.

33.2.3 INSPECTION

All casing pipe to be installed may be inspected at the site of manufacture for compliance with these specifications by an independent laboratory selected and paid for by the CITY. The manufacturer's cooperation shall be required in these inspections.

All casing pipe shall be subjected to a careful inspection prior to being installed. If the pipe fails to meet the specifications it shall be removed and replaced with a satisfactory replacement at no additional expense to the CITY.

33.3 FIRE HANDLING

Care shall be taken in loading, transporting, and unloading to prevent injury to the pipe or coatings. Pipe shall not be dropped. All pipe shall be examined before laying, and no piece shall be installed which is found to be defective. Any damage to the pipe or coatings shall be repaired to the satisfaction of the CITY.

33.4 CONSTRUCTION REQUIREMENTS

33.4.1 WORK COORDINATION

It shall be the CONTRACTOR'S responsibility to perform the boring and jacking work in strict conformance with the requirements of the City of St. Cloud and/or other agency in whose right-of-way or easement the work is being performed. Any special requirements of said agencies such as insurance, flagmen, etc., shall be strictly adhered to during the performance of WORK. The special requirements shall be performed by the CONTRACTOR at no additional cost to the CITY.

33.4.2 DEWATERING

Dewatering through the casing during construction shall not be permitted. All dewatering methods shall be approved by the CITY before construction work begins.

33.4.3 CARRIER PIPE SUPPORT

The carrier pipes shall be supported within the casing pipes so that the pipe bells do not rest directly on the casing. The load of the carrier pipes shall be distributed along the casing-by-casing spacers. Casing spacers shall be bolt on style split shells made of either T-304 stainless steel or fusion-coated steel (a minimum 0.010" thick coating of PVC shall be provided over the entire band). The shell shall be lined with a PVC liner 0.090" thick with 85-90 Durometer. All nuts and bolts shall be high strength, low alloy meeting AWWA C111. Runners shall be made of a high molecular weight polymer with inherent high abrasion resistance and a low coefficient of friction.

33.4.4 JACKING PITS

Excavation adjacent to the roads shall be performed in a manner to adequately support the roads. Bracing, shoring, sheeting or other supports shall be installed in accordance with the FLORIDA TRENCH SAFETY ACT. The CONTRACTOR shall install suitable reaction blocks for the jacks as required. Jacking operations shall be continuous and precautions shall be taken to avoid interruptions, which might cause the casing to "freeze" in place. Within 72 hours of completion of jacking operations, the reaction blocks, braces, and all other associated construction materials shall be completely removed from the site.

33.4.5 MISCELLANEOUS REQUIREMENTS

Correct line and grade shall be carefully maintained. Earth within the casing shall not be removed too close to the cutting edge in order to prevent the formation of voids outside the casing. If voids are formed, they shall be satisfactorily filled with grout by pumping.

The sections of steel casing shall be field welded in accordance with the applicable portions of AWWA C206 and AWS D7.0 for field welded pipe joints. The CONTRACTOR shall wire brush the welded joints and paint with Inertol Quick-Drying Primer 626 by Koppers Company or approved equal. After completion of jacking, the CONTRACTOR shall clean the interior of the Casing of all excess material.

The annular space between the carrier pipe and casing shall be filled with clean sand if required in the bore and jack permit. Masonry plugs are to be installed at each open end of the casing. Plugs shall be suitable for restraining the earth load while allowing drainage of the casing.

33.4.6 DIRECTIONAL BORING

A. General Directional boring shall be permitted at the discretion of the City Manager’s designated Engineer. Horizontal directional boring has become an accepted method of underground utility construction. Its use in water, sewer and reuse piping has become possible with the introduction of restrained joint PVC piping, in sizes ranging from 4" to 12" and a 150 psi working pressure rating. Directional boring will be considered by the City Manager’s designated Engineer based upon a set of three (3) controlling parameters: economics, service requirements, and jurisdiction.

B. Materials Piping material for directional boring use shall be PVC or HDPE. PVC shall conform to AWWA C900/ for restrained joint installations, be DR-18 or stronger, and shall be Certainteed, Certa-Loc, or approved equal. HDPE shall be a minimum DR-11 with butt fused joints and manufactured by Plexico, CSR Poly, or approved equal. The engineer of record is responsible for determining the correct material for the installation. The City may require certified engineering calculations showing that installation procedures will not exceed manufactures recommendations for the pipe.

C. Workmanship Directional boring work shall be performed by contractors that specialize in such work only. Prior to undertaking any directional bore work, the Contractor must supply the City Manager’s designated Engineer with written evidence that confirms minimum experience requirements of either two (2) continuous years, or a minimum of fifty (50) installations of the pipe size and length of bore to be installed. No work will be authorized until the City Manager’s designated Engineer has approved the boring contractor's credentials.

All operations connected with directional boring installations, including burp holes, machine pits, drilling mud, and surface restoration shall be considered a part of the directional boring contractor's work. Any areas that are uplifted by the contractor's operations (mud blowouts, etc.) shall be fully restored to original condition. Pipe deflections shall not exceed manufacturers' and/or AWWA limitations in any direction. The installation shall be fully pressure tested at the completion of installation to the standards of Section 45, Section 51, and/or Section 54, whichever is applicable.

Directional boring work shall conform to the lines and/or grades indicated on the plans. The Contractor shall utilize boring/pulling machinery of sufficient capacity for the pipeline size and length of bore. Once a pullback has begun, it shall be continuous with no more than 30-minute intervals between sectional installations. Progress of the initial bore shall be closely and continuously monitored with an electronic tracking device that is capable of pinpointing both the horizontal and vertical positions of the bore head within six (6) inches. The bore head shall be configured so as to allow changes in both the horizontal and vertical directions should electronic tracking dictate such changes. The locations of all existing underground utilities must be clearly identified prior to commencing work, and the vertical clearance requirements of the City’s standard details must be strictly adhered to. Pipe shall be installed a minimum of 3 feet and a maximum of 6 feet below existing facilities unless approved otherwise. Contractor shall provide a boring log to the City upon completion of the installation.

SECTION 33 - BORING AND JACKING