Art. 1093.01 Sign Supports SECTION 1093. SIGN SUPPORTS
1093.01 Structural Steel Supports. The structural steel shall have a silicone
content suitable for galvanizing.
a.Breakaway. All structural steel shall be according to AASHTO M 270 (M 270M). After fabrication, the post, fuse plate, base plate, and upper 6 in. (150 mm) of the stub post shall be galvanized according to AASHTO M 111. Bolts and nuts on the fuse plates may be plated according to ASTM B 633 (B 633M) SC3 and then painted with an approved zinc rich paint. All high strength bolts, nuts, and washers shall be according to
Article 1006 — 08(b).
b.Tubular. Hollow structural steel tubing shall be according to ASTM A 500 Grade B or ASTM A 501. After fabrication, the post, base plate, and upper 6 in. (150 mm) of the stud post shall be galvanized according to AASHTO M 111. All high strength bolts, nuts, and washers shall be according to
Article 1006 — 08(b).
c.Telescoping. The post shall be a square tube formed of 12 gauge steel according to the standard specification for cold rolled carbon steel sheets commercial quality ASTM A 1008 (A 1008M). The post shall be formed to size and, if necessary, shall be welded in such a manner that weld or flash shall not interfere with telescoping. Holes 7/16 ± 1/64 in. (11 ± 0.4 mm) will be spaced on 1 in. (25 mm) centers on at least two opposite sides. The holes shall align to accept a 3/8 in. (10 mm) bolt through the post at any location. The post shall have a smooth galvanized finish applied either before or after forming. The following tolerances will be permitted. The nominal outside dimension will not vary more than ±0.008 in. (± 0.2 mm) [± 0.10 in.(± 2.5 mm) for the 2 1/4 in. (57 mm) size] from the dimension stipulated. The wall thickness will not vary more than +0.011 to -0.008 in. (+0.28 to -0.20 mm) from the standard 12 gauge plate thickness. The maximum allowable twist in a 3 ft (1 m) length and the permissible variation in squareness shall be as shown in the following table. Post Size Squareness Twist 1 3/4 x 1 3/4 in. ±0.010 in. 0.062 in. 2 x 2 in. ±0.012 in. 0.062 in. 2 1/4 x 2 1/4 in. ±0.014 in. 0.062 in. Overhead Sign Structures Art. 1094.03 Post Size Squareness Twist 44 x 44 mm ± 0.25 mm 1.7 mm 51 x 51 mm ± 0.30 mm 1.7 mm 57 x 57 mm ± 0.35 mm 1.7 mm The posts shall be straight and have a smooth uniform finish. It shall be possible to telescope all consecutive sizes of posts freely and for at least 10 ft (3.0 m) of their length without the necessity of matching any particular face to any other face. All holes and ends shall be free from burrs and ends shall be cut square. The posts shall be hot-dip galvanized according to AASHTO M 111, or given triple coated protection by in-line application of hot-dip galvanized zinc per AASHTO M 111 followed by a chromate conversion coating and a cross- linked polyurethane acrylic exterior coating. The inside surfaces shall be given corrosion protection by in-line application of a full zinc base organic coating after fabrication, tested in accordance with ASTM B 117. If a weld process is performed after galvanizing, the weld shall be zinc-coated after the scarfing operation.
1093.02 Base for Telescoping Sign Support. The base shall be cast from
iron meeting the requirements of ASTM A 126, Class A. The finished casting shall be free from burrs, cracks, voids, or other defects. Castings shall be galvanized by either the hot-dip process according to AASHTO M 232 or mechanical plating method according to ASTM B 695, Class 50 with a maximum coating of 3.5 oz/sq ft (1077 g/sq m). The nominal inside dimension of the square hole shall not vary more than 1/16 in. (2 mm) from the dimension shown on the plans.
1093.03 Reserved.
SECTION 1094. OVERHEAD SIGN STRUCTURES
1094.01 General. Materials used in the fabrication of overhead sign structures,
including their supports and walkways, shall be according to the specifications set forth in the plans and the following.
1094.02 Anchor Rods, Nuts, and Washers. Anchor rods shall be according
to Article 1006.09, Grade 105 (Grade 725) and galvanized for the entire length shown on the plans.
1094.03 Conduit. All conduit furnished shall be 3 in. (75 mm) nominal size and
shall comply with ANSI C 80.1 or 80.5. The interior and exterior surfaces of steel conduit shall be galvanized. Art. 1094.04 Overhead Sign Structures
1094.04 Mounting Hardware. Carbon steel bolts, nuts, and washers shall be
according to ASTM A 307, Grade A and shall be hot-dip galvanized according to AASHTO M 232, Class D.
1094.05 Structural Aluminum. The aluminum alloys to be welded under these
specifications may be any of the following ASTM designations.
a.Aluminum Fabrication. Aluminum shall be assembled, welded, and inspected according to AWS D1.2/D1.2M Structural Welding Code- Aluminum, except as herein modified.
b.Load-carrying Elements. All primary load carrying elements shall be evaluated as cyclically loaded structures according to AWS D1.2/D1.2M Structural Welding Code-Aluminum. Wrought nonheat-treatable alloys: Alloy 3003 and Alloy 3004. Wrought heat-treatable alloys: Alloy 6061 and Alloy 6063. Cast heat-treatable alloys: ASTM B 108, Alloy A 356.0-T61 for permanent mold castings; ASTM B 26, Alloy 520.0-T4 or A356.0-T6 for sand castings; or ASTM B 618, Alloy 520.0-T4 or A3256.0-T6 for investment castings. All castings shall have a radiographic discontinuity level according to Grade C, 1/4 in. (6 mm) section thickness. Material used for permanent backing shall be at least equivalent in weldability to the base metal being welded.
c.Welding Processes. These specifications include provisions for welding by the gas metal-arc process and the gas tungsten-arc process. Other processes shall not be used, except as permitted by the Engineer. Tungsten electrodes for the gas tungsten-arc process shall be according to the Specification for Tungsten-Arc Welding Electrodes, AWS A 5.12. Filler metals to be used with particular base metals shall be as shown in Table 1. Other filler metals may be used as approved by the Engineer or as specified in the plans.
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Source: Illinois Standard Specifications for Road and Bridge Construction, 2022 Edition. Pages 1099–1101 of 1,217. View official source ↗