2522.01 DESCRIPTION.
This specification is for fabrication and construction of tower lighting systems, consisting of footings, towers, luminaires, and associated appurtenant items required by the contract documents. Section 2523 shall apply to other components of this system.

Each individual installation shall consist of a tubular steel tower of circular or other approved cross-section of the length indicated in the contract documents, an approved lowering device, a reinforced concrete footing, approved luminaires of the proper number, and the electrical system described in the contract documents.

2522.02 SHOP DRAWINGS.
The Contractor shall submit drawings in accordance with Article 1105.03, along with a statement that methods and materials to be used in fabrication are in accordance with the contract documents. All materials or methods for which specific requirements have not been previously stipulated shall be noted and identified.

1. Tower lighting equipment (if applicable)

a. Tower design data

b. Lowering device, showing wiring diagram and materials

c. Luminaires, including photometric data

2. Additional drawings may be required on a project specific basis in accordance with the contract documents.

The Contractor shall furnish an appropriate certification of compliance with all design requirements and copies of all calculations necessary for proper design of the tower shaft and component features of the tower assembly. The structural design shall be performed by a Professional Engineer licensed in the State of Iowa, and the Contractor's certification shall appear on the drawings. The Contractor shall furnish the base shear, base moments, and vertical loads on the bottom of the base plate.

Prior to the time any fabrication or assembly of parts is begun, the Contractor shall have received written concurrence from the Engineer for the various items involved.

2522.03 MATERIALS.
Copies of a certified mill analysis for each heat of steel used in the pole and pole assembly and certified test results for support cables shall be submitted to the Office of Materials for review for compliance before these materials are shipped to the project.

The Contractor's attention is directed to Article 2522.05 for welding requirements.

The Office of Materials shall be notified of the shop fabrication schedule.

To identify materials included in each shipment and to ensure that materials and fabricated materials may be used in the work promptly after delivery, one copy of a mill certification shall accompany each shipment to the project, and two copies shall be sent to the Office of Materials.

Final approval of all materials and fabricated materials will be based on a certification that methods and materials used in fabrication are in accordance with the contract documents, on satisfactory reports from random monitoring inspections performed during fabrication, and on verification of satisfactory compliance at the time of final inspection of the construction site.

2522.04 LIGHTING TOWER.
The structural design of the tower and its appurtenances shall meet requirements of AASHTO "Standard Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals," with the following clarifications:

A. The design wind velocity (V) shall be 90 mph (145 km/h).

B. The total wind force on luminaires shall be calculated on the basis of the sum of projected areas for each individual luminaire.

Projected area of individual luminaires shall be based on manufacturer's recommendations.

C. The steel tubular shape shall be a compact section.

D. Each anchor bolt shall be furnished with one leveling nut and two anchoring nuts. Anchor bolts shall meet the requirements of ASTM F 1554, Grade 105 (724 MPa), be full-length galvanized, and be high-strength low alloy steel. Unless otherwise specified, anchor bolts shall be the Unified Coarse Thread Series and have Class 2A tolerance. The end of each anchor bolt intended to project from the concrete shall be color coded in red to identify the grade. Washers shall be galvanized and shall meet the requirements of ASTM F 436. Nuts shall meet the requirements of ASTM A 563, DH, be heavy hex, and be galvanized. Nuts may be over-tapped in accordance with the allowance requirements of ASTM A 563. Galvanizing shall meet the requirements of ASTM A 153, Class C; or ASTM B 695, Class 50.

E. The pole base and anchor bolt system shall be designed to resist both tension and compression resulting from bending moments and direct loads. The pole base plate shall be a solid plate. The holes cut out in the base plate for utility lines shall be kept to a minimum, subject to approval of the Engineer.

F. The poles may be furnished in single, welded units or in telescoping sections. It shall be permissible to fabricate the tower by welding two or more shaft sections together. If the pole sections are welded together, all transverse pole splices shall be butt welded with full penetration welds. The method used for connecting the sections shall result in a smooth joint with no projections on the exterior of the shaft. Unless specifically authorized otherwise, all welded connections of shaft sections shall be made in the fabricator's shop. Where, because of hauling length restrictions, the tower shaft cannot be shop fabricated in one piece, a telescoped pole shall be provided.

If the pole sections are telescoped together, the overlapped splices shall be equal in strength and rigidity to that of welded splices, and shall not exceed four sections for poles up to and including 120 feet (35 m) in length and shall not exceed five sections for poles between 120 feet (35 m) and 160 feet (50 m) in length. The telescoping sections shall overlap a length which is the larger of 2 feet (0.6 m) or 1.5 times the nominal diameter of the shaft at the splice level. The overlap shall have full contact between faying surfaces.

The pole sections to be telescoped together shall be factory test fit to insure straightness of the pole and accuracy of the mating surfaces and shall be match marked for accurate field assembly. In the field, the telescoping sections shall be mechanically fitted using factory supplied equipment. The Contractor shall submit field assembly procedures for the Engineer's review and concurrence.

G. Longitudinal seam welds for pole sections shall have 60% minimum penetration, except for the following areas:

1. Longitudinal seam welds within 6 inches (150 mm) of circumferential welds, which are complete penetration butt welds, shall be complete penetration welds.

2. Longitudinal seam welds, on both sections of telescopic (slip type) field splices of high level lighting (pole type) supports, shall be complete penetration welds for a distance of the nominal splice length plus 6 inches (150 mm).

3. When designated in the contract documents, 100% of the full penetration sections of longitudinal seam weld shall be radiographically inspected, and a random 10% of the partial penetration section of the longitudinal seam welds shall be inspected by the magnetic particle method.

H. For poles with welded transverse splices, all backing plates for transverse welds shall be beveled. For poles with telescoped lap joints, the lower section of the joint shall be beveled. The beveling is required to prevent possible interference with the operation of the lowering device.

I. An opening for a minimum 10 inches by 30 inches (250 mm by 750 mm) handhole to allow for servicing and maintenance of the lowering devices shall be provided in the pole. The handhole shall be reinforced to maintain the design strength of the pole and shall be gasketed to make it weatherproof. The gasket shall be made of neoprene or silicone rubber. Samples of the gaskets shall be provided to the Engineer prior to acceptance. Foam adhesive-back rubber gaskets are unacceptable. The door shall be hinged and fabricated from the same type of steel as the poles. The securing hardware shall be stainless steel. Provisions shall be made to bolt the door securely shut.

J. Intentionally left blank.

K. Prior to welding, the pole base plate shall be ultrasonically tested using a Straight Beam Search Unit, meeting requirements of the current AWS D1.1, Structural Welding Code, to determine the extent of laminar type discontinuities in the plate.

After welding the pole to the base plate, there shall be no laminar tears in the base plate, as determined by ultrasonic testing described above.

L. The shaft, base plate, and integral shaft components shall be fabricated with steel meeting requirements of ASTM A 709 Grade 50 (345 MPa), with a minimum yield strength of 50,000 psi (345 MPa). All steel required to be ASTM A 709 Grade 50 (345 MPa) shall meet impact requirements specified for main members in Article 4152.02. When approved by the Engineer, certain components of the tower assembly may be fabricated from steel meeting requirements of ASTM A 709 Grade 36 (250 MPa).

Pole shafts, anchor bolts, base plate, washers, nuts, and all steel items shall be fully galvanized inside and outside after fabrication in accordance with ASTM A 123 or ASTM A 153 as appropriate and shall be of uniform color and appearance.

2522.05 WELDING.
Welding and fabrication of steel structures shall be in accordance with Article 2408.13 except that gas, metal arc, and flux cored arc welding processes will be permitted.

A list of approved brands of electrodes may be obtained from the Office of Materials.

All fillet welds accessible for inspection shall be examined by magnetic particle inspection in accordance with ASTM E 709. This shall be done by the Contractor at no cost to the Contracting Authority.

All transverse butt welds and all specified 100% penetration longitudinal butt welds on the pole shall be examined 100% by ultrasonic inspection according to requirements of Article 2408.13. All longitudinal butt welds shall be examined by 100% visual inspection. The visual inspection shall be supplemented by magnetic particle inspection on all areas of questionable visual results. If defects are found in the area tested, additional inspection shall be performed for a minimum of 5 feet (1.5 m) on each side of the defect. The cost of these inspections shall be paid by the Contractor and shall be considered incidental to other items in the contract.

2522.06 LUMINAIRE LOWERING DEVICE.
This device shall consist of a luminaire frame, support cables, electrical cable, head frame, winch, and associated appurtenant devices. The lowering device shall properly transport the luminaire to a position within 5 feet (1.5 m) of the ground for maintenance, and maintain their alignment when raised to the operational position.

The luminaire frame shall be attached to two or three lift cables. A multiple conductor electrical cable shall be attached to the luminaire frame with a double weave, stainless steel, grip type, strain relief connection. All cables shall pass through a head frame assembly mounted at the top of the tower shaft, as shown in the contract documents, and shall pass freely through the shaft during raising and lowering operations.

The support cables shall be anti-rotational aircraft type stainless steel with a minimum diameter of 3/16 inch (4.8 mm) and having a safety factor of 5, shall be spaced 120 degrees apart where attached to the luminaire frame, and shall be attached to a terminating device within the tower shaft. The terminator shall provide a means of equalizing tension of the lift cables. Raising and lowering of the assembly shall be done with a stainless steel, anti-rotational aircraft type winch cable with 1/4 inch (6.4 mm) minimum diameter, with a safety factor of 3 attached to the terminator. An approved safety device shall be included to stop upward motion of the terminator at any time, in case of winch cable failure. A torque limiting device shall be included with the winch or power unit. The electrical cable shall be attached to the terminator with a strain relief device as used at the luminaire frame. Electrical connectors for the power and control circuits shall be rigidly attached to the terminator.

A top-latching system shall be used. Non-latching systems will not be allowed.

The latch barrels shall be cast, high strength, copper-free aluminum or cast stainless steel. Latching shall be accomplished by the alternate raising and lowering of the luminaire ring assembly using the winch and hoisting assembly. There shall be no moving latch parts or springs attached to the head frame assembly. The latch mechanism shall not be impaired by the formation of ice and shall not require adjustment after the original installation. Indicator flags shall be used to show when the luminaire supporting ring is in the latched or unlatched position.

Pulleys shall be stainless steel type designed for the respective types and sizes of cables used and shall be equipped with permanently lubricated, sealed bearings or oil impregnated bronze bushings mounted on stainless steel shafts. The head frame assembly shall be enclosed and shielded from the elements by means approved by the Engineer.

The electrical power cable shall be a multiple conductor cable complying with the requirements for flexible cord. It shall be designed to meet all physical requirements for satisfactory operation of the lowering device. All provisions for electrical disconnects shall be accessible from ground level.

Steel used for the luminaire frame and head frame assembly shall meet requirements of ASTM A 709 Grade 50 (345 MPa). For the purpose of Charpy V-notch toughness requirements, all steel required to be ASTM A 709 Grade 50 (345 MPa) will be considered main members. Miscellaneous appurtenant steel components may be constructed using ASTM A 709 Grade 36 (250 MPa) steel. All steel and the head frame dome shall be galvanized.

The luminaire frame shall be designed to accommodate the specified number of luminaires on mounts consisting of 2 inch (50 mm) slipfitters.

Conductors for connections from the power cable to the luminaires shall be protected by suitable raceways or shall be made with weatherproof cables securely anchored to the luminaire frame. A luminaire frame of hollow cross section may be used as a raceway. All connections shall be made in weather tight boxes or within the luminaire housings.

Lateral movement of the luminaire frame during raising or lowering operations shall be controlled by use of three or more spring loaded centering arms with rubber or nylon rollers, or by other approved means. The centering arms shall be interlocked with each other to retain the tower in a centered position.

The winch assembly shall consist of a worm gear speed reducer with either one or two output shafts with cable drum attached. The winch shall be securely anchored and capable of supporting five times the maximum lifted load. The winch shall include an integral drag brake to prevent unwinding, slipping or free spooling of the winch cable. The drum shall be provided with keepers to ensure that the cable will properly wrap onto the drum. The winch, when powered by the internal power unit, shall raise the luminaire ring at a minimum rate of 12 feet (4 m) per minute.

The terminator and attached components shall be shaped to prevent interference to the raising or lowering operation by irregularities on the interior surface of the tower shaft.

2522.07 TOWER LIGHTING LUMINAIRE.
The luminaire assembly shall consist of a rain tight aluminum housing and slipfitter with an internally mounted ballast and shall be designed for operation with the specified lamp.

As required, the optical system shall consist of a specular aluminum or prismatic glass reflector and a prismatic glass refractor or a clear lens.

Luminaires with open bottom optical systems shall have prismatic glass reflectors and refractors.

Luminaires with horizontal burning lamps shall have totally enclosed optical systems with prismatic glass refractors.

Specular aluminum reflectors shall have a protective coating of oxide applied by the anodic oxidation process. The manufacturer shall certify that the coating is not less than 6 milligrams per square inch (0.01 mg/mm²) and that the reflectivity of the specular surface is not less than 82%.

The lamp socket shall be mogul multiple and porcelain enclosed. Sockets for vertical burning lamps shall have a lamp gripping device.

All glassware shall be annealed, thermal-shock-resisting, borosilicate glass.

The slipfitter shall accommodate a standard two-inch (50 mm) pipe bracket and shall provide for leveling of the luminaire.

The light source shall be a high pressure sodium lamp of the size shown in the contract documents.

The ballast shall be of the regulated high-power-factor type with starting current lower than operating current. It shall maintain lamp wattage within ± 10% with a line voltage regulation of ± 10%, with not less than 90% power factor.

2522.08 FOOTINGS.
Footings shall be constructed as required in the contract documents at the specified locations. Unless specifically stated otherwise, methods and materials used for construction of footings shall be in conformance with current specifications. Placement of anchor bolts shall be in accordance with Article 2405.09, B. Placement of conduit and any other appurtenant or optional features of the footing shall be as shown in the contract documents.

2522.09 ERECTION.
After testing has been accomplished to the satisfaction of the Engineer, the tower may be erected on the foundation. The precise aligning and erecting of all components of the tower lighting system shall be considered essential. The tower shall be plumbed and verified in at least two directions, 90 degrees apart, with a transit. All plumbing shall be done during full cloud cover, prior to sunrise, or after sunset as approved by the Engineer to prevent thermal expansion effects on the steel tower due to heat from sunshine. All towers shall be plumbed within a tolerance of 50% of the pole top diameter. The void between the base plate and top of the foundation shall be covered as shown on the plans.

Other components of this system shall be constructed and all components shall be tested in accordance with Section 2523.

The procedure for tightening anchor bolt nuts on tower lighting, after tower has been plumbed, shall be as follows:

1) This work shall be performed only on days with winds less than 15 mph (25 km/h). All tightening of the nuts shall be done in the presence of the inspector. Once the tightening procedure is started it must be completed on all of the base plate nuts without pause or delay.

2) Properly sized wrenches and/or sockets designed for tightening nuts and/or bolts shall be used to avoid rounding or other damage to the nuts. Adjustable end or pipe wrenches will not be allowed.

3) Base plate, anchor rods and nuts shall be free of any dirt or debris.

4) Stick wax or bees wax shall be applied to the threads and bearing surfaces of the anchor bolt, nuts, and washers.

5) Top nuts shall be tightened so they fully contact the base plate. Leveling nuts shall be tightened to snug tight condition. Snug tight shall be defined as the full effort of one person on a wrench with a length equal to 14 times the bolt diameter but not less than 18 inches (460 mm). Full effort shall be applied as close to the end of the wrench as possible. Tightening shall be accomplished by leaning back and using entire body weight to pull firmly on the end of the wrench until the nut stops rotating. A minimum of two separate passes of tightening shall be used. Tightening shall be sequenced in each pass so that the nut on the opposite side, to the extent possible, is subsequently tightened until all of the nuts in that pass have been tightened.

6) Top nuts shall be tightened to snug tight as described for the leveling nuts.

7) The top nuts and base plate shall be match-marked using paint, crayon, or other approved means to provide a reference for determining the relative rotation of the nut and base plate during tightening. The top nuts shall be further tightened in two passes, as listed in the following table, using a striking or hydraulic wrench. A sequence of tightening in each pass shall be used so that the nut on the opposite side, to the extent possible, is subsequently tightened until all nuts in that pass have been turned. The leveling nut shall not be rotated during the top nut tightening.

Anchor Bolt Size	First Pass	Second Pass	Total Rotation
Less than or Equal to 1 1/2 inch (38 mm) diameter	1/6 turn	1/6 turn	1/3 turn
Greater than 1 1/2 inch (38 mm) diameter	1/12 turn	1/12 turn	1/6 turn

8) The jam nuts shall be lubricated, placed, and tightened to snug tight.

2522.10 TRANSPORTING TOWERS.
Transporting of the towers over the highways of the State of Iowa shall be subject to all applicable laws, rules, and regulations governing such movements. It is the Contractor's responsibility to obtain any required permits for such movements. Maximum overall length of the hauling unit and tower shall be 120 feet (35 m).

2522.11 MISCELLANEOUS.
A manufacturer's service engineer shall be present, on site, to advise the Contractor during the installation of at least one complete lowering system. Duties of the manufacturer's service engineer shall include directing all adjustments to the lowering system to insure positive latching and unlatching (a minimum of three complete raising and lowering cycles) and other necessary work. The Contractor shall provide three complete raising and lowering operations for the other towers, providing the same adjustment and commissioning as demonstrated by the manufacturer's service engineer on the first tower.

2522.12 METHOD OF MEASUREMENT.
Items of work involved in tower lighting, satisfactorily completed, will be measured for payment as follows:

A. Towers.
The Engineer will determine, by actual count, the number of towers installed for the various lengths specified in the contract documents.

B. Luminaires.
The Engineer will determine, by actual count, the number of luminaires installed on the project.

C. Footings.
Footings will be measured for payment as outlined in the following sections:

Piling Structural Concrete Reinforcement Excavation

Section 2501 Section 2403 Section 2404 Section 2402

2522.13 BASIS OF PAYMENT.
Payment to the Contractor for the various items of work involved in tower lighting will be as follows:

A. Towers.
For the number of towers installed of each specified length, the Contractor will be paid the contract unit price.

B. Luminaires.
For the number of luminaires installed, the Contractor will be paid the contract unit price.

C. Footings.
Footings will be paid for as outlined in the following sections:

Piling Structural Concrete Reinforcement Excavation

Section 2501 Section 2403 Section 2404 Section 2402

Payment for towers shall be full compensation for furnishing all materials, equipment, tools, and labor for construction of the towers complete, including an approved lowering device, and related equipment, anchor bolt assembly, and responsibility during the testing period.

Payment for other components of the tower lighting system will be as provided in Article 2523.23.