(A) The utility, if possible, is to be supported by diaphragms between the first interior stringers so as not to be visible from below when approaching the structure.
(B) Bridge vertical clearance must be reduced. Entire installation including supporting brackets, etc., must be above the bottom of the highest adjacent stringer. On-site drilling of bridge concrete or welding to existing steel will not be allowed. Provisions for expansion and contraction of the facility must be compatible with the expansion and contraction design of the bridge. Sleeving will usually not be required, but carrier pipes may have to have either heavier wall thickness than usual or for steel pipe have a higher yield strength by using a design factor 20% lower than that required by the US DOT Pipeline Safety Standards to provide more safety factor. Support rollers, saddles, and hangers may require padding or coating to minimize vibration noise and wear. Coating systems for utilities must be compatible with the life expectancy of coating systems of bridge members, where applicable. Metallic conduits are to have adequate positive grounds.
(C) Gas mains up to 100 psi operating pressure.
(1) General. If there is no cut off valve on the pressure side of the main within 200 feet of the bridge, the County Roads Department may require the installation of a valve closer to the bridge.
(2) On structures.
(a) In sidewalks. On new structures and rehabilitated structures (new decks), gas mains may be placed within the sidewalk area, provided suitable methods acceptable to the County Roads Department can be devised to vent the sidewalk. If encasement is used, casing pipes are to be extended through sleeves in the back walls. Carrier pipes at a distance of at least 10 feet outside the extremities of the structure. Casing pipes shall be vented to the atmosphere through a screened vent. This vent is to be located outside the shoulder line behind the guardrail.
(b) Between beams.
1. Where the encased carrier pipe is too large to be placed in the sidewalk, it is to be placed between beams. In this case, the casing pipe may be omitted, but the area between beams shall be vented by suitable openings whose design does not allow deck concrete and steel to be attacked by deicing salts. Casing pipes are to be vented to the atmosphere through screened vents. Vents are to be located so that no gas will be trapped in pockets between beams and diaphragms.
2. Gas mains are to be supported by existing diaphragms where possible. Additional supports between diaphragms are to be placed as required. On existing structures these additional supports are to be attached to the beams by bolting. Welding to existing steel beams will not be permitted. Where a gas main must be hung below the diaphragm, it is to be supported by hangers specially designed for this use.
3. Attachments to concrete structures, if permitted, must conform to the general structure, aesthetic and other specific requirements for steel structures but the details thereof shall be determined on a case by case basis.
4. Expansion joints in the gas main shall be compatible with the expansion and contraction design of the bridge.
5. Sleeves through the back walls are to be caulked to prevent seepage of water through the back walls.
6. The gas main is to be protected as much as possible from electrolysis caused by stray electric current.
(c) Underground in vicinity of structures.
1. Gas mains installed underground are to be encased in steel pipes where they lie within the right-of-way. The casing pipe is to be extended to the right-of-way lines and is to be sealed to the carrier pipe at each end. It is to be vented to the atmosphere through screened vents located at the right-of-way lines. The casing pipe may be installed by jacking, or tunneling, or where permitted, by open cut.
2. Casing pipes are to be designed to accommodate all externally applied loads. Where the gas main is installed by tunneling beneath the roadway and tunnel liner plates are installed, a solid steel casing pipe must also be used to contain and safely vent any gas escaping from the carrier pipe.
(D) Water and sewer piping.
(1) General. A cutoff valve is to be placed just off the bridge in the pipeline on the pressure side of the structure. Concrete buttresses are to be placed as appropriate at each end of the structure.
(2) On structures.
(a) Water mains and sewer lines on structures are usually placed between beams, preferably between the fascia beam and the first interior beam. This will permit placing the pipe in the shoulder on the approaches to the bridge. Piping is to be supported, if possible, by the existing diaphragms. Additional supports may be placed as required. They must be attached to the existing beams by bolts. Welding to existing beams will not be allowed. The piping may be placed on top of the diaphragms with U bolts or other suitable means to hold the pipe in place. Hangers, if used, shall be of a type especially designed for this use. Expansion joints for the piping shall be compatible with the expansion and contraction design of the bridge. The piping shall be fitted with dresser couplings, or approved equal, to enable adjustments for expansion, contraction, and deflection. A crows-foot restraining device placed at each joint of sufficient length to facilitate removal of any section of pipe without damage or removal of an adjacent section is recommended.
(b) Attachments to a concrete structure, if permitted, must conform to the basic structural, aesthetic and other specific requirements for steel structures but the details must be tailored to the particular concrete structure.
(c) The piping is to pass through sleeves in the back walls. These are to be caulked to prevent seepage of water through the back walls. Piping up to 12 inches in diameter is to be covered with insulation to prevent freezing. No portion of the piping or its support is to project below the bottom flange of the highest adjacent beam.
(3) Underground vicinity of structures.
(a) Underground piping shall be placed in casing pipes where pipe size and soil materials are such that flow from a broken main would jeopardize bridge supports.
(b) Casing pipes are to extend for the full width of the right-of-way sufficiently beyond footings so that water from a broken main will be safely discharged away from the footing. The casing pipe shall be sealed to the carrier pipe at the high end and open into a manhole at the low end. The casing may be either steel or reinforced concrete, and shall be designed for all externally applied loads and for the internal pressure from a ruptured carrier pipe. A valve is to be installed on the pressure side of the right-of-way. The piping is to be located at least 10 feet from the nearest bridge footing, and the casing pipe is to be installed in 10-foot maximum lengths. As each length is installed, it is to be backfilled and thoroughly tamped before additional excavation is performed. The open ends of the casing pipe are to be closed at the end of each working day.
(E) Power and communication lines.
(1) General.
(a) Power and communication lines to be attached to structures must be installed in conformance to National Electric Code and National Safety Code requirements. Electrical lines with voltage in excess of 98 kilovolts rms to ground will not be installed on structures.
(b) For the safety of persons using the bridge; signing to warn all users of the voltage shall be provided as set forth herein under this section.
(2) On structures.
(a) In sidewalks (or parapets). On new structures and rehabilitated structures, the power or communication lines placed in conduits may be installed within the sidewalk or parapet area. On an existing structure, removal and replacement of existing sidewalk and/or parapet to accommodate the lines in these areas may be acceptable, should this be the feasible alternative without cost to the county and with minimal inconvenience to traffic. Installations in the sidewalk or parapet areas shall conform, to the extent applicable, with Division of Bridge Development Structural Standards Nos. BR-SS-6.09, 79-70 sheets 1 and 2 of 2 and BR-SS-0.01, 75-13 sheets 1 and 2 of 2, latest revision.
(b) Between beams.
1. Power and communication lines to be installed on structures are to be placed in conduits. Conduits are to be supported by existing diaphragms where possible. When additional supporting members are required, they are to be attached to the beams by bolts. No welding to existing steel will be permitted. Conduits are to be placed between fascia and first interior beam, if possible. Telephone and other low voltage (50 volts or less) lines may be placed in plastic, fiberglass, or PVC conduits. High voltage lines must be placed in steel conduits. Conduits are to have expansion/deflection joints that are compatible with the design of the bridge. No part of the installation shall project below the bottom flange of the highest adjacent beam.
2. Metal sleeves through the abutment back walls are to be provided for passage of the conduits. These are to be caulked to prevent leakage of water through the back wall.
3. Attachments to a concrete structure, if permitted, must conform to the general intent of the basic structural, aesthetic, and other specific requirements for steel structures but the details will be tailored to suit the particular concrete structure.
(F) General requirements for all utilities.
(1) No utility installation is to be placed on the outside of a structure where it will be visible.
(2) When a utility passes through a back wall, spaces around the metal sleeved penetration are to be filled with non-shrink grout, and then caulked to prevent leakage of water.
(3) To comply with the requirement that no part of an installation may project below the bottom of the highest adjacent stringer, it may be necessary to raise or replace existing diaphragms with smaller diaphragms, and to place additional ones as necessary to support the installation and to equal the strength of the diaphragms removed. Removal and replacement shall be carried out progressively. All connections shall be bolted. Welded connections are not permitted.
(4) Casing pipes should have provisions to drain condensate.
(Ord. —, passed 6-30-2009) Penalty, see § 54.99