New Mexico Administrative Code › Title 17 - PUBLIC UTILITIES AND UTILITY SERVICES › Chapter 4 - UTILITY RIGHTS OF WAY AND EASEMENTS › Part 2 - REQUIREMENTS FOR OCCUPANCY OF STATE HIGHWAY SYSTEM RIGHT-OF-WAY BY UTILITY FACILITIES › Section 17.4.2.14 - DEFINITIVE DESIGN REQUIREMENTS

Current through Register Vol. 35, No. 13, July 16, 2024
A.
Pipeline installations; location and alignment:
From the highway
				viewpoint, there are sound reasons for requiring pipeline crossings at right
				angles to the roadway alignment. Oblique angle highway crossing pipeline
				installations have many detrimental characteristics as they increase the
				interference with traffic during construction, are more liable to conflict with
				highway drainage and structures, upset distribution of live loads to the
				subgrade and across pavement joints, are considerably harder to control as to
				line and grade when boring or jacking the pipeline beneath the highway, and
				they usually create more damage to the pavement structure and subgrade on open
				cut installations. Diagonal crossings usually require more maintenance and
				repairs; therefore, all pipeline crossings shall be at or near ninety (900)
				degrees. Minor variations will only be considered on a case by case basis, upon
				justification submitted to the Department by the utility. Conditions which are
				generally unsuitable for pipeline crossings should be avoided, such as
				locations in deep cuts, across cuts and fills on steep slopes, near the
				footings of bridge piers, abutments, retaining walls and other structures,
				across interSections at grade or entrance and exit ramp terminals, at cross
				drains (transverse drop inlets) where flow may be obstructed, or in locations
				requiring extensive rock excavations to provide the minimum bury.
B.
Pipeline casings;
				encasement:
A carrier pipe is said to be cased (or encased) if it is
				installed freely inside in a larger diameter pipe. Encasement may also be
				complete or partial, designed to protect the carrier pipe, lighten its burden,
				facilitate its insertion and withdrawal and guarantee the integrity of the
				roadway structure or prism. Common types of casements are those carriers cased
				or sleeved inside a larger pipe, cradled by a continuous concrete seat fitting
				the pipe (cradling), walled by a continuous concrete sidefill (walling), boxed
				or jacketed by concrete completely surrounding the pipe (boxing), capped by a
				continuous concrete topping or slab (capping)), coated or wrapped by a
				substantial girdling cover (wrapping), grouted by mortar filling borehole
				annulus and overbreak (grouting), or tunneled by installation in a utility
				subway.
(1) Of these methods, only the
				casing, tunnel, utility subway or gallery provide the complete independence of
				the carrier pipe from the surrounding roadway structure, and adequate
				protection to the roadway from leakage of the pipeline. These methods also
				provide means for insertion and replacement of carriers without access or
				disturbance to through-traffic roadways.
(2) The following encasement methods do not
				provide all of the above benefits, but may be utilized subject to individual
				approvals, on substantiation submitted by the utility: Concrete cradling
				enhances the load supporting capability of rigid pipes, but accomplishes little
				else. Walling does the same for semi-rigid and flexible pipes. Capping
				strengthens both rigid and flexible pipes, and somewhat protects from highway
				operations penetrating the overfill. When applied to weak or brittle pipes,
				concrete boxing or jacketing provides protection to the pipe from earth loads,
				leakage, corrosion or abrasion to some degree. Adequate coating or wrapping
				prevents contact with corrosive water, soil or vapors. Grouting aids in
				restoring the continuity and integrity of the earth supporting the pavement
				structure.