Section 636 Section 636 636-C: Electric Cable, Aerial Supported, Type, AWG ___, ___ Conductor - per linear foot 636-D: Electric Cable, Aerial Supported in Conduit, Type, AWG ___, ___ Conductor - per linear foot 636-E: Electric Cable, Underground in Conduit, Tracer Cable - per linear foot 636-F: Electric Cable, Repair - per linear foot 636-G: Underground Cable and Conduit, Removed - per linear foot 636-H: Underground Cable and Conduit, Removed and Relaid - per linear foot SECTION 637 - TRAFFIC SIGNAL CONDUIT AND PULL BOXES
637.01 Description . This work consists of furnishing all component materials required
to install enclosures and conduit in conformity with these specifications and at the locations and grades indicated on the plans or as dir ected. Enclosures shall house and protect equipment such as splice cases, exce ss cable and pull box equipment.
637.02 Materials .
637.02.1 Pull Box / Enclosures . Grade level pull box, enclosures, structural junction
boxes and covers shall meet the requirements of Subsection 722.06 and shall conform to the specific requirements set out hereunder. For grade level pull boxes and enclosures only, ANSI/SCTE 77 Tier 15 (15,000-pound design load, 22,500-pound test load) and Tier 22 (22,500-pound design load, 33,750-pound test load) enclosures with mi nimum size dimensions as shown in the detail drawings on the plans shall be installed for use in traffic signal construction. Enclosure boxes shall be open bottom. The cover supplied shall have a design load equal to that of the enclosure box. When multiple “Tiers” are specified the boxes must physically accommodate and structurally support compatible covers while possessing the highest Tier rating. In no assembly can the cover design load exceed the de sign load of the encl osure box. Stainless steel hex bolts and nuts shall be provided to secure the cover. Bolts and nuts shall withstand a minimum torque of 35 foot-pounds and a minimum of 750 pounds straight pull-out as a means to secure the cover to the box. Th e inside of the cover and the box shall be permanently marked (by impress or ink) with manufacturer’s name or logo, ANSI/SCTE Tier level and model number. If required by the Engineer, independent third party verification or test reports stamped by a registered Professional Engin eer certifying that all test pr ovisions of this specification have been met will be submitted with each subm ittal. All covers sha ll be provided with legend “Traffic Signal”, or as specified in pl ans, and the appropriate ANSI/SCTE Tier level embossed on their surface. Surface mounted junction boxes shall meet the requirements of Subsection 722.06 and shall conform to the specific requirements set out hereunder. Boxes shall be of size and characteristics as indicated on the plans.
637.02.02 Conduit. All conduits shall meet the requirements of Subsection 722.05 and
shall conform to the specific requirements set out hereunder. Furnishing and installing plastic and steel conduit shall be in accor dance with these specifications and close conformity with the lines shown on the pl ans or as established by the Engineer. The Contractor may, at no additional cost to the Department, use larger size conduit, in which case it shall be for the entire length of the run with no reducing couplings permitted. Conduits for fiber optic cable shall be clear of obstructions. Water based lubricants shall be used to reduce the potential for outer sheath corrosion.
637.03 Construction Requirements .
637.03.1 Pull box/Enclosures. All enclosures shall be installed in accordance with the
manufacturer’s recommendations and as shown on the plans. Enclosures shall not be located in the roadway, side walk, driveway or other path way surfaces unless specifically required on the plans. Enclosures shall not be located in drainage collection areas and locations where drainage runoff occurs should be avoided whenever possible. The final grade of enclosure covers shall be flush with adjacent material when they must be installed within sidewalks, islands or barrier walls. The final grade of enclosure covers located in soil or sodded areas shall be approximately one (1) inch higher than adjacent earth or sodded areas. Enclosures located in soil or sodded areas shall be inst alled with a supporting poured concrete collar, as shown by details on the plans. Enclosures installed in driveways, sidewalks or similar areas shall also be insta lled with a poured concrete collar between the edge of the enclosure and the edge of the adjacent excavated material. When practical, enclosures shown in the near vicinity of concrete curbing shall be placed adjacent to the back of the curb. Positions of grade-level encl osures are shown on the plans in their relative positions only and if needed shall be repositioned with the approval of the Engineer. A minimum 1-foot depth of crushed gravel underlayment material shall be installed underneath all open bottom enclosures in acco rdance with details shown in the plans. Underlayment materials may be required in other installations if shown with details in the plans. All enclosure covers shall be secured to the enclosure box using bolts as indicated in detailed drawings in the plans. All pull boxes provided shall be of the following minimum dimensions for each respective pull box type. Pull Box Type Nominal Minimum Dimensions Width (inches) x Length (inches) x Depth (inches) Type 1 11” x 18” x 12” Type 2 13” x 24” x 18” Type 3 17” x 30” x 24” Type 4 24” x 36” x 24” Type 5 30” x 48” x 24”
637.03.2 Conduit. All material installed shall follow the following guidelines.
Blank duct plugs shall be used to seal the ends of all conduits immediately upon conduit placement. This includes, but is not limited to, intermediate/incomplete sections of conduit prior to conduit splicing or termination in pull boxes and empty conduits in pull boxes prior to cable installation. All conduits shall either be sealed with blank duct plugs or filled with duct putty or sealant, as approved by the Engineer. Conduit shall be installed in a straight line horizontal path between pull boxes and/or foundations except where shown otherwise in the plans.
637.03.2 1--Conduit Duct Bank . Continuous flexible conduit installation in earth shall
be trenched, horizontal directional bored or drilled, or plowed at the Contractor’s discretion, unless otherwise noted on the plans, at a minimum depth of 24-inches from the top of the conduit. Conduit duct banks shall be installed by configuring individual continuous flexible conduits into a continuous duct bank from termination point to termination point as shown in the Standard Details and other contract documents. All continuous flexible conduit located under the paved roadway in the plans shall meet the following requirements.
a.The conduit shall be placed at a minimum depth of 30 inches.
b.Backfill shall meet Standards for a paved roadway.
c.All areas shall be completely restored daily according to the time frames set under the approved Traffic Control Plan. If a drainage or utility conflic t arises, the Contractor shall submit a plan for resolving the conflict to the Engineer for review and approval. Every effort shall be made to minimize coupli ng. Couplings will be permitted only with the Engineer’s prior approval. Bored or drilled conduit shall meet the following requirements:
a.All conduits under railroad tracks shall be horizontal directional bored or drilled at a minimum of ten (10) feet below the railroad bed. It is also the Contractor’s responsibility to determine any additional requirements from the railroad owner and shall meet those requirements in addition to those included in the plans and these Specifications. Any required steel casings or other materials needed to meet the railroad authority requirements shall be included in the cost of the conduit.
b.All conduits to be installed under streams shall be horizontal directional bored or drilled. No open trenching through an area deemed to be a current or wet weather stream will be allowed. All conduit bored under streams shall be a minimum depth of five (5) feet below the stream bed.
c.Bore Logs will be required for each bore location.
d.The Contractor shall submit a proposed bore log format to the Engineer for review and approval. Conduit shall be placed in the straightest orientation possible, reducing bends, twists, rises, and waves. Conduits shall be held in place during backfilling when necessary to keep straight and at the proper depth. Where field conditions require the trench to change direction and bends are necessary, the bends sha ll be formed in the trench and should be smooth and even and shall not have less than a 4-foot radius, as measured to the inside surface of the conduit. Every conduit shall be tested after the conduit is installed and before cable or pull tape is installed. Testing shall be performed on all conduit types in these Specifications, including but not limited to, each cell of multi-cell cond uits, each conduit in duct banks, and each conduit. All testing shall be performed using the procedures and mandrel size recommended by the conduit manufacturer. Testing shall be performed in the presence of the Engineer. Payment for all testing shall be included in the cost of the conduit.
637.03.2 2--Rigid Galvanized Steel Conduit . Structural and Exposed conduit runs shall
be 2-inch rigid galvanized steel unless otherwise required by the plans. All conduit runs on structures and poles shall be properly terminated into the respective device, or a duct seal shall be installed so as to seal the conduit from moisture, insects, rodents and other foreign material. The costs of the galvanized steel conduit, and all associated fittings shall be included in the cost other items. Bushings shall be installed in conduit at all exposed conduit terminations for protection of the conductors.
637.03.2 3--Aerially Suppor ted Traffic Signal Conduits . The following requirements
are applicable to aerially supported installations:
a.Conduit entering pull boxes shall terminate two inches inside of the box wall and not less than two inches above the bottom. Conduit entering through the bottom of a pull box shall be located as near the sides and ends as possible to leave the major portion of the box clear. Conduits shall ride freely through boxes for allowance of expansion and contraction.
b.Expansion fittings as detailed on bridge st ructure plans shall be installed where conduit crosses an expansion joint in the structure. Where it is deemed inadvisable to install expansion fittings in closely confined areas, the Engineer may permit the installation of approved bronze flexible tubing instead; expansion joints and tubing shall be th e same size as the conduit.
c.All assemblies on concrete structures sha ll be grounded through a bonding jumper to the rigid metal lighting conduit, which in turn shall be bonded to the steel superstructure or run to the ground.
d.All conduit, junction boxes, pull boxes, etc., must be attached to bridge structures by means of studs driven by approved methods.
e.Aerial conduit shall be supported by messenger cable suspended from approved supporting devices when shown on the plans or directed.
637.03.2 4--Marking Tape. As shown in the plans Standard Details, marking tape shall
be installed above all underground conduit installed by trenching or plowing. Marking tape shall be installed in continuous manufactured lengths. No splicing or overlapping will be permitted. A minimum of four (4) feet of marking tape shall be installed into pull boxes where trenched conduit is terminating. Marking tape shall enter under the lower edge of the pull box. Marking tape will not be required when conduit is bored or plowed.
637.03.2 5--Conduit Detection Wire. One (1) conduit detection wire is required with all
conduits installed by any installation method, including trenching, directional boring, or plowing. Conduit detection wire will be re quired with all conduits installed by any installation method, including trenching, directional boring, or plowing. Only one (1) conduit detection wire will be required per installed conduit segment regardless of the number of conduits installed in that segment. Conduit detection wire shall be installed in conduit. Conduit detection wire will not be required for structure mounted conduit, except where underground segments of structure mounted conduit are greater than 20 feet in length. Conduit detection wire will not be required for conduit segments between pull boxes and pole/sign structure foundations, except where c onduit segments are great er than 20 feet in length. The conduit detection wire shall be continuous and unspliced between pull boxes and shall enter the pull boxes at the same location as the conduit with which it is installed, entering under the lower edge of the pull box. Four (4) feet of conduit detec tion wire shall be coiled and secured in each pull box or vault. Testing, as requested by the Engineer, shall be as follows:
a.a continuity or tone test shall be perf ormed after installation to confirm that a continuous run of conduit detection wire was installed between pull boxes or vaults.
b.a test plan shall be prepared, supplying equipment, conducting the test and documenting the results. A test plan shall be submitted at least 15 working days prior to the desired testing date. Testing shall not begin until the Engineer has approved the test plan. All tests shall be c onducted in the presence of the Engineer.
637.03.2 6--Pull Tape. Pull tape shall be installed into each empty conduit and empty cell
within a multi-cell conduit. The pull tape shall be installed after conduit testing has been completed. Five (5) feet of slacked pull tape shall be installed and secured in each empty conduit or cell at each pull box. The pull tape shall be secured by tying it to the blank duct plug for the conduit in which it is installed.
637.03.2 7--Duct Plugs . Blank duct plugs shall be inst alled in each empty conduit that
enters a pull box, ground-mounted cabinet, pole foundation, hub, or building entrance. Cable duct plugs shall be installed in each conduit containing fiber optic or RDS communications cable that enters a pull box, ground-mounted cabinet, hub, or building entrance. Cable duct plugs shall not be used on conduits containing power service conductors.
637.04 Method of Measurement. Pull Box Enclosures of the type specified will be
measured as unit per each. Conduit of the type specified will be measured per linear feet to the nearest foot. All conduit types shall be measured along the conduit by the following:
a.From center of pull box to center of pull box this includes any vertical conduit runs as indicated on plans.
b.From center of pull box to three (3) feet from a foundation or cabinet. Conduit inside foundation and three (3) feet from a foundation or cabinet shall be included with the foundation.
c.Continuous Flexible Conduit (Conduit Duct Bank) will be measured by the linear foot for each type of conduit bank indicated after installation and shall include the type and number of conduit indicated below. Conduit Bank: Three (3) – 2-inch Continuous Flexible Conduits 2” Conduit: One (1) – 2-inch Continuous Flexible Conduit or PVC Schedule 40 Conduit. 2” Conduit w/Bank: One (1) – 2-inch Continuous Flexible Conduit installed in the same trench as the related Conduit Bank Type as specified in the Plan Sheet. Conduit Bank Bored: Three (3)– 2-inch Continuous Flexible Conduits 2” Conduit Bored: One (1) – 2-inch Continuous Flexible Conduit
d.Messenger cable and other supporting devices for aerial supported signal conduit will not be measured for separate payment but shall be incidental to and included in the contract unit price for traffic signal conduit, aerial supported. Note: Separate encasement for borings is not required unless necessary for proper installation due to poor soil conditions. If encasement is needed in those situations the cost of the encasement shall be included in the cost of the conduit.
637.05 Basis of Payment . Pull Box Enclosures, measured as prescribed above, will be
paid for at the contract unit price per each , which price shall be full compensation for furnishing all materials including the cover, installing, crushed gravel underlayment, poured concrete collars, replacement of sod or existing grassing, final clean-up and for all equipment, tools, labor and incident als necessary to complete the work. Conduit / Duct Bank, measured as prescribed above, will be paid for per linear feet, which price shall be full compensation for all materials, equipment, labor, trenching, installing, backfilling trench, plowing, directional boring, restoration, marking tape, pull tape, duct plugs, fittings, conduit detection wire, testing, bore logs, and all other incidentals necessary for the installation of the conduit system. Rigid Galvanized Steel, measured as prescrib ed above, will be paid for per linear feet, which price shall be full compensation for all materials, equipment, labor, all related materials including but not limited to couplings, mounting straps, bonding to ground, etc., that is installed on sign structures, poles or be tween the pull boxes, and all other incidentals necessary for the installation of the conduit system. Equipment cabinets will be included in the cost of other items and will not be measured separately. Marking Tape, Conduit Detection Wire, Pull Tape, Duct Plugs and Sealant will be included in the cost of the conduit and will not be measured separately. Payment will be made under: 637-A: Pull Box Enclosure, Type, Tier - per each 637-B: Pull Box Enclosure, Structure Mounted, Type - per each 637-C: Traffic Signal Conduit, Underground, Type, Size - per linear foot 637-D: Traffic Signal Conduit, Underground Drilled or Jacked, Type, Size - per linear foot 637-E: Traffic Signal Condu it, Structural Conduit, Type, Size - per linear foot 637-F: Traffic Signal Conduit, Aerial Supported, Type, No, Size - per linear foot 637-G: Traffic Signal Conduit, Underground Encased in Concrete, Type, Size - per linear foot 637-H: Traffic Signal Conduit Bank, Underground, Type, No., Size - per linear foot 637-I: Traffic Signal Conduit Bank, Underground Drilled or Jacked, Type, No., Size - per linear foot 637-J: Traffic Signal Conduit Bank, Structural Conduit, Type, No., Size - per linear foot SECTION 638 - FLASHER ASSEMBLIES
638.01 Description. This work consists of furnishing all components and materials
required to assemble flasher assemblies and School Zone Flasher Beacon assemblies, including options for solar powered applications, in accordance to these specifications and the details shown on the plans.
638.01.1 Operational Specifications. The two flashers on the flasher assembly shall
alternate on and off when recei ving a signal from the traf fic controller. The flasher assembly shall have beacons that flash at a rate of not less than 50 or more than 60 times per minute. The illuminated period of each flas h shall not be less th an 50% of the dwell time. The yellow signals shall be flashed a lternately. The beacons shall have a night dimming feature.
Source: Mississippi Standard Specifications for Road and Bridge Construction, 2017 Edition. Pages 573–578 of 1,113.