A. 
Description.
(1) 
The work of this article includes, but is not limited to:
(a) 
Approach trench excavation.
(b) 
Installation of casing pipe.
(c) 
Installation of carrier pipe.
(2) 
Related work specified elsewhere.
(a) 
Trenching, backfilling and compacting: Article VII.
(3) 
Definitions: none.
(4) 
Applicable Standard Details: DT 02150-1 Casing Installation.[1]
[1]
Editor's Note: Said Standard Detail is included as an attachment to this chapter.
B. 
Quality assurance.
(1) 
Reference standards.
(a) 
Comply with applicable federal, state and local ordinances, codes, statutes, rules and regulations, and affected jurisdictional bodies.
(b) 
Pennsylvania Department of Transportation (PennDOT), latest revisions, Publication 408 Specifications.
(2) 
Contractor qualifications. Construction operations shall be undertaken only by an experienced contractor with a minimum of five operations of similar magnitude and condition.
C. 
Submittals.
(1) 
Submit history of previous work completed of equivalent nature and scope. Include qualification and experience of key personnel.
(2) 
Submit description of proposed construction methods, including methods to establish and maintain vertical and horizontal alignment.
(3) 
Manufacturers' literature. Submit manufacturers' catalog information for each type of pipe, fittings, couplings, adapters, gaskets, casing spacers, and assembly of joints for approval by the municipality. Include manufacturers' recommendations for deflection in pipe joints.
D. 
Certificates. Submit certifications for each type of pipe, fittings, gaskets, lubricants or other joint materials from the manufacturers attesting that each of these meets or exceeds specifications requirements.
E. 
Job conditions.
(1) 
Conduct operations so as not to interfere with, interrupt, damage, destroy, or endanger the integrity of surface or subsurface structures or utilities, and landscape in the immediate or adjacent areas.
(2) 
When boring or jacking under state highways and railroads, comply with applicable right-of-way occupancy permits.
(3) 
If boring is obstructed, relocate or jack or tunnel crossing as approved by the municipality.
A. 
Steel casing pipe.
(1) 
ASTM A53; 35,000 psi minimum yield strength, new materials only.
(2) 
Full circumference welded joints.
(3) 
Diameter and wall thickness as shown on the drawings.
(4) 
One mil thick standard bituminous coating, interior and exterior.
B. 
Casing spacers.
(1) 
Nonmetallic.
(a) 
High-density polyethylene (HDPE) with no metal bolts or attachments. Spacers shall strap onto carrier pipe and slide easily into casing but shall not move during installation.
(b) 
Spacers shall provide constant projections around entire circumference of carrier pipe. Projections must have minimum height to pipe bells, similar to RACI type spacers as manufactured by RACI Spacers of North America, Vernon, British Columbia, or approved equal.
(2) 
Stainless steel (bolt on). Stainless steel shell with PVC liner, stainless steel hardware, and UHMW polymer runners. Centered type as manufactured by Cascade Waterworks Manufacturing Company, Yorkville, Illinois, or equal.
(3) 
Timber skids. Pressure treated, cut to a cross-sectional size to allow placement of the carrier pipe in the casing and to support the barrel of the carrier pipe. Provide with notches to accommodate fastening. Treat notches at time of pipe installation.
C. 
Steel strapping: ASTM A36.
D. 
Sand (fine aggregate): Section 703.1, Publication 408 Specifications, Type A.
E. 
Grout: one part Portland cement (ASTM C150), and six parts mortar sand mixed with water to a consistency applicable for pressure grouting.
F. 
Flowable fill: as specified in Article VII.
A. 
Approach trench.
(1) 
Excavate approach trench using methods as site conditions require.
(2) 
Ensure pipe entrance face as near perpendicular to alignment as conditions permit.
(3) 
Establish a vertical entrance face at least one foot above top of casing or tunnel lining.
(4) 
Install adequate excavation supports as specified in Article VII.
B. 
Casing pipe installation methods.
(1) 
Boring.
(a) 
Install casing pipe with the determined vertical and horizontal alignment prior to installation of the carrier pipe.
(b) 
Push the pipe into the ground with a boring auger rotating within the pipe to remove the spoil. Do not advance the cutting head ahead of the casing pipe except for that distance necessary to permit the cutting teeth to cut clearance for the pipe. The machine bore and cutting head arrangement shall be removable from within the pipe. Arrange the face of the cutting head to provide a barrier to the free flow of soft material.
(c) 
Do not overcut excavation by more than one inch greater than the outside diameter of the casing pipe.
(d) 
If voids should develop greater than the outside diameter of the pipe by approximately one inch, grout to fill voids.
(2) 
Jacking.
(a) 
Construct adequate thrust wall normal to the proposed line of thrust.
(b) 
Impart thrust load to the pipe through a suitable thrust ring that is sufficiently rigid to ensure distribution of the thrust load on the pipe.
(3) 
Drilling and jacking:
(a) 
Use an oil-field-type rock roller bit or plate bit made up of individual roller cutter units solidly welded to the pipe which is turned and pushed for its entire length by the drilling machine to give the bit the necessary cutting action.
(b) 
Inject a high-density slurry (oil field drilling mud) to the head as a cutter lubricant. Inject slurry at the rear of the cutter units to prevent jetting action ahead of the pipe.
(4) 
Mining and jacking. Utilize manual hand-mining excavation from within the casing pipe as it is advanced with jacks, allowing minimum ground standup time ahead of the casing pipe.
C. 
Carrier pipe installation within casing pipe.
(1) 
All provisions regarding cleaning, inspection and handling specified under pipe material sections apply to this work.
(2) 
Place the carrier as shown on Standard Detail DT 02150-1.[1] Exercise care to prevent damage to pipe joints when carrier pipe is placed in casing.
[1]
Editor's Note: Said Standard Detail is included as an attachment to this chapter.
(3) 
Support pipeline within casing so that no external loads are transmitted to carrier pipe. Attach casing spacers to barrel of carrier pipe at six feet on centers, minimum two per pipe section.
(4) 
Close ends of casing by sealing with brick masonry bulkheads, water plug, or other approved hydraulic cement. The downstream bulkhead shall have a two-inch diameter stainless steel weephole.
(5) 
Completely fill annular space between carrier pipe and casing pipe with limestone screenings. If in a state highway right-of-way, fill annular space with flowable fill.
D. 
Carrier pipe installation without casing pipe.
(1) 
Bore the opening with a boring auger to the determined vertical and horizontal alignment.
(2) 
Do not overcut boring excavation by more than one inch greater than the outside diameter of the lateral pipe.
(3) 
Carefully guide the lateral pipe and joints through the opening, assembling joints prior to inserting into the boring.