and Signal Assemblies
639.1General Description
This work includes furnishing and erecting overhead sign and signal support strain poles and steel wire strand cable according to this specification and the plans. Make concrete or steel strain poles at any one location within the project from the same material unless the plans designate a particular type for that location. Use timber strain poles only where designated on the plans. 639.1.01 Definitions General Provisions 101 through 150. 639.1.02 Related References
ASTM A 27 / A 27 M ATSM A 36 / A 36 M ASTM A 123 / A 123 M ASTM A 153 / A 153 M ASTM A 242 M ASTM A 595 ASTM A 709 (A 709 M) AASHTO LRFD Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals, with interims 639.1.03 Submittals Submit to the Engineer shop drawings for steel and prestressed concrete strain poles for review and approval. Submission should be made electronically in a portable document format (pdf) and include an index. Format all drawings to fit 11 in. x 17 in. (279 mm x 432 mm) paper. Present calculations to fit 8.5 in. x 11 in. (216 mm x 297 mm) paper. The submission shall be prepared and stamped by the Design Engineer who shall be registered as a Professional Engineer in the State of Georgia. 1125 1125 1125 1125 1125
The Engineer will distribute submitted documents to the Bridge Engineer (SLTS@dot.ga.gov) for review and provide the State Traffic Operations Engineer with a copy of the transmittal letter. For installations governed only by a permit, and not a GDOT contract, drawing and calculation submission should be made directly to the Bridge Engineer with a copy to the District Permit Engineer. Design Strain poles shall be designed to the following wind speeds using a 1700 Mean Recurrence Interval (MRI) for the listed counties: • 150 mph: Bryan, Camden, Chatham, Effingham, Glynn, Liberty, McIntosh • 140 mph: Brantley, Bulloch, Charlton, Evans, Long, Screven, Tattnall, Wayne • 130 mph: Appling, Bacon, Brooks, Burke, Candler, Clay, Clinch, Decatur, Early, Echols, Emanuel, Grady, Jeff Davis, Jenkins, Lowndes, Miller, Pierce, Seminole, Thomas, Toombs, Ware • 120 mph: For all counties not listed above Strain poles shall be designed using the following criteria: • Fatigue Category 1 • Truck induced gusts included (required only for mast arm poles) • Galloping included (required only for mast arm poles)
639.2Materials
Ensure that materials meet the requirements of the following Specifications: Material Section Class A Concrete 500 Class B Concrete 500 Class AAA Concrete 500 Timber Poles 861.2.02 Seasoning and Preservative Treatment 863.2.01 Steel Wire Strand Cable 915.2.02 Guys and Anchors Per Plans 1126 1126 1126 1126 1126
Use shafts for steel strain poles fabricated of steel that conforms to one or more of the following: • ASTM A 242/A 242 M • ASTM A 709 Grade 50W (A 709 M Grade 345W) • ASTM A 595 • AISI 1015 • AISI 1020 • SAE: 1015 Ensure that the steel characteristics or strength do not change significantly from welding.
Use the appropriate shape of shaft which is a continuous taper and is constructed of corrosion resistant steel, unless otherwise specified, to the dimensions required for the specified classification type. Form the shaft from one piece with one electrically welded longitudinal joint and no intermediate horizontal joints.
Use a pole with a mill certified yield strength of at least 48,000 psi (331 MPa). After forming and welding the pole, the shaft may be longitudinally cold rolled under enough pressure to flatten the shaft to conform to the required yield strength. For Type IV steel strain poles, ensure that the wall thickness is at least 3 gauge or 0.25 in. (6 mm).
Assemble traffic signal strain poles as follows:
the base.
provide a weatherproof wire inlet close to the attachment. Conceal the other wiring to and from the controllers within the pole. For traffic signal strain poles with mounted controller cabinets, provide a 2 in. (50 mm) half coupling wire inlet to mount the controller cabinet on the designated pole. Ensure that the location where cable enters the wire inlets at the top of the traffic signal strainpoles has a neat design and appearance. Do not use junction boxes at the top of poles to facilitate cable entrances.
Provide a 0.5 in (13 mm) approved grounding connector in the shaft. Equip the top of the shaft with a removable cap held securely in place. Hot-dip galvanize the shaft according to ASTM A 123/A 123 M unless otherwise specified.
Secure to the lower end of the shaft a one-piece cast steel base or a one-piece flat plate base that meets the requirements of ASTM A 27, Grade 65-35/A27 M Grade 450-240, or A 36/ A 36 M, as required.
resist bending.
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Furnish each pole with four anchor bolts of the size required in the manufacturer’s Shop Drawings. Ensure that the anchor bolts meet the requirements of Subsection 852.2.02. Galvanize the threaded portions according to ASTM A 153/A 153 M and the Plan details.
Use shafts for these poles that comply with Subsection 865.2.01.B, except give the poles a steel trowel finish on the unformed side and any required pointing to eliminate air and water holes left by the steel forms. Use Class AAA concrete. Use a marking tool to identify the pole class and height or cast it with a die in the front face of the pole to produce letters and numbers at least 2 in. (50 mm) high and wide.
Use hardware for steel and concrete strain poles with these features:
chemically to applicable ASTM specifications.
• If diameters are less than 0.5 in. (13 mm), the hardware is passivated stainless steel that meets the requirements of AISI 300, commercial grade. • If diameters are 0.5 in. (13 mm) and larger, the hardware conforms to ASTM physical and chemical qualifications that ensure strength commensurate with the parts being connected. Galvanize the hardware according to ASTM A 153/A 153 M.
otherwise specified. Ensure that galvanizing has a coating of at least 2 oz/ft.² (610 g/m²) according to ASTM A 153/A 153 M.
Provide poles for supporting CCTV, VDS, and microwave radar detection devices that meet the following design specifications: • Limited to a live horizontal deflection at the top equal to or less than 1% of pole height in a 50 mph wind, with a design load of four static cameras and one movable camera. • Torsional deflection limited to a 1 degree, maximum. Install mounting brackets, as illustrated on the plans, which are galvanized steel and are compatible with the mounting design of the specified cameras and pan/tilt devices and are affixed to the pole to prohibit rotation. Install all wiring internal up to the camera mounting bracket with no external conduit on the pole. Provide a weatherproof wiring access point or handhole on the pole. 639.2.01 Delivery, Storage, and Handling General Provisions 101 through 150.
639.3Construction Requirements
639.3.01 Personnel General Provisions 101 through 150. 639.3.02 Equipment General Provisions 101 through 150. 639.3.03 Preparation General Provisions 101 through 150. 1128 1128 1128 1128 1128
639.3.04 Fabrication General Provisions 101 through 150. 639.3.05 Construction
Construct the following according to the plan:
Hold the pole in its out-of-plumb position until the cavity around the pole is filled with Class B or better concrete and is set and cured for at least 7 days. Then, apply tension to the pole.
Construct the foundations for steel poles as follows:
directed by the Engineer.
these securely by a template to ensure proper position in the completed foundation. NOTE: Never attempt to realign the anchor bolts after pouring the foundation.
displacement.
as specified.
below finished grade, according to Subsection 500.3.05.AB.4, Type III—Special Surface Coating Finish.
Drill round holes or dig square holes for prestressed concrete poles.
portions of Section 500 and Plan details.
them after erecting.
Install ground rods for steel and prestressed concrete strain poles adjacent to the strain pole base as follows:
the finished ground.
wire to the grounding nut of the strain pole base.
center-to-center in a horizontal pattern and at least 12 in. (300 mm) below the finished ground. 11291129112911291129
Join the rods and connect them to the grounding nut of the pole base with No. 6 AWG solid copper wire and
ground rod clamps.
Use the proper rake to erect the pole so that the pole will be plumb after the load is applied.
Follow these steps to erect the cable:
if necessary.
639.3.06 Quality Acceptance
General Provisions 101 through 150.
639.3.07 Contractor Warranty and Maintenance
General Provisions 101 through 150.
639.4Measurement
Highway signs are measured and paid for under Section 636.
Treated timber poles of the class and length specified are measured by the number of units installed, including
guys, anchors, and hardware.
Steel cable of the specified size are measured by the linear foot (meter), complete in place.
Steel strain poles are classified and measured for payment by each unit and by type according to the
following table:
Type Span Length
I Less than 60 ft. (18 m)
II 60 to 95 ft. (18 m to 29 m)
III Greater than 95 ft. (29 m)
IV Traffic signal strain pole
Prestressed concrete strain poles are measured for payment by each unit and pole type as specified in the
above table.
639.4.01 Limits
General Provisions 101 through 150. 11301130113011301130
639.5Payment
Treated timber poles of the class and length specified will be paid for at the Contract Price bid per each. Payment
is full compensation for poles, concrete encasements, excavation for pole and anchor holes, temporary pole
alignment, bracing, guys, and items to complete the Work.
Steel strain poles of the type specified, complete in place and accepted, including foundation, backfill, erection,
and necessary re-grassing will be paid for at the Contract Unit price bid for each pole of each type.
Prestressed concrete strain poles of the type specified, complete in place and accepted, including foundation,
backfill, erection, and necessary re-grassing will be paid for at the Contract Unit Price bid for each pole of
each type.
When neither concrete nor steel strain poles are specified, either type is acceptable. Measurement is specified in
Subsections 639.4.C. or 639.4.D. The payment item is Strain Poles, Type___.
Steel cable complete in place and accepted will be paid for at the Contract Unit Price bid per linear foot (meter) of
each specified diameter. Payment is full compensation for furnishing and erecting the cable and for providing
hardware including thimbles, but not hardware that is a part of the pole.
Payment will be made under:
Item No. 639 Treated timber pole class___, __ ft. (m) Per each
Item No. 639 Steel strain pole, type____ Per each
Item No. 639 Prestressed concrete strain pole, type___ Per each
Item No. 639 Strain Poles, Type___ Per each
Item No. 639 Steel strand wire cable___in. (mm) Per linear foot (meter)
639.5.01 Adjustments
General Provisions 101 through 150.. 1131 1131 1131 1131 1131
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