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. Overhead Sign Structures Art. 1094.05 Table 1 Base Metal Filler Metal 3003 to 3003 ER1100 3004 to 3004 ER4043 3003 to 6061 ER5183 or 5356 6061 to 6061 ER5356 * 6063 to 6063 ER5356 * A356-T61 or A444-T4 to 3003 ER4043 or 4145 A356-T61 or A444-T4 to 6061 ER4043 or 4145 A356-T61 or A444-T4 to 6063 ER4043 A356-T61 to A356-T61 ER4043 A444-T4 to A444-74 ER4043 * ER5356 and ER5556 may be used interchangeably for these base metals. Filler metals shall be kept covered and stored in a dry place at relatively uniform temperatures. Original rod or wire containers shall not be opened until time to be used. Rod and wire shall be free of moisture, lubricant, or other contaminants. Spools of wire temporarily left unused on the welding machine shall be kept covered to avoid contamination by dirt and grease collecting on the wire. If a spool of wire is to be unused for more than a short length of time, it shall be returned to the carton and the carton tightly resealed.
d.Shielding Gases. Shielding gas for gas metal-arc welding shall be argon, helium, or a mixture of the two (approximately 75 percent helium and 25 percent argon). Shielding gas for gas tungsten-arc welding done with alternating current shall be argon. Shielding gas for tungsten-arc welding done with direct current, straight polarity, shall be helium. Hose used for shielding gases shall be made of synthetic rubber or plastic. Natural rubber hose shall not be used. Hose that has been previously used for acetylene or other gases shall not be used.
e.Preparation of Materials. Joint details shall be according to design requirements and detail drawings. The locations of joints shall not be changed without the approval of the Engineer. Edge preparation shall be by sawing, machining, clipping, or shearing. Cut surfaces shall meet the American Standards Association's surface roughness rating value of 1,000. Oxygen cutting shall not be used. Surfaces and edges to be welded shall be free from fins, tears, and other defects that would adversely affect the quality of the weld. Art. 1094.05 Overhead Sign Structures Dirt, grease, forming or machining lubricants, or any organic materials shall be removed from the areas to be welded by cleaning with a suitable solvent or by vapor degreasing. The oxide shall be removed from all edges and surfaces to be welded just prior to welding by wire brushing or by other mechanical methods, such as rubbing with steel wool or abrasive cloth, scraping, filing, rotary planing, or sanding. If wire brushing is used, the brushes shall be made of stainless steel. Hand or power driven wire brushes and other mechanical devices that have been used on other materials shall not be used on aluminum. Where mechanical methods of oxide removal are found to be inadequate, a standard chemical method shall be used. Welding shall be done within 24 hours after chemical treatment. When gas tungsten-arc welding with direct current, straight polarity, is being used, all edges and surfaces to be welded shall have the oxide removed by a standard chemical method. Welding shall not be done on anodically treated aluminum unless the condition is removed from the joint area to be welded.
f.Welding Procedure. All butt welds requiring 100 percent penetration, except those produced with the aid of backing, shall have the root of the initial weld chipped or machined out to sound metal before welding is started from the second side. Butt welds made with the use of backing shall have the weld metal thoroughly fused with the backing. Where accessible, backing for welds that are subject to computed stress or which are exposed to view on the completed structure and which are not otherwise parts of the structure shall be removed and the joints ground or machined smooth. In tubular members, butt welds subjected to computed stresses shall be made with the aid of permanent backing rings or strips. The procedure used for production welding of any particular joint shall be the same as used in the procedure qualification for the joint. All welding operations, either shop or field, shall be protected from air currents or drafts so as to prevent any loss of gas shielding during welding. Adequate gas shielding shall be provided to protect the molten metal during solidification. The work shall be positioned for flat position welding whenever practicable. In both shop and field, all weld joints shall be dry at time of welding. The size of the electrode, voltage and amperage, welding speed, gas or gas mixture, and gas flow rate shall be suitable for the thickness of the material, design of joint, welding position, and other circumstances influencing the work, and shall be shown on the approved Weld Procedure Specification (WPS). Gas metal-arc welding shall be done with direct current, reverse polarity. Overhead Sign Structures Art. 1094.05 Gas tungsten-arc welding shall be done with alternating current or straight polarity direct current. The Contractor shall submit to the Engineer, at his request, two weld samples for destructive testing and macroetching. These samples shall be welded according to the procedures that will be used in production welding. The Contractor shall submit to the Engineer for approval, the procedure to be used for the test samples and production welding. Should test of these samples indicate unsatisfactory welding, additional samples shall be furnished without cost to the Department. Poor workmanship as noted by visual inspection shall be sufficient cause for rejection. Where preheat is needed, the temperature of preheat shall not exceed 350 F (177 C) for nonheat-treated alloys. The temperature shall be measured by temperature indicating crayons, contact or accurate [±3.6 °F (±2 °C)] non-contact pyrometric equipment. Heat-treated alloys shall not be held at or near the maximum preheat temperature for more than 35 minutes.
g.Welding Quality. Regardless of the method of inspection, the acceptance or rejection of welds shall comply with the AWS D1.2/D1.2M Structural Welding Code – Aluminum and the following conditions. Welds having defects exceeding the levels of acceptance specified shall be considered as rejected unless corrected according to Article 1094.05(i). Undercut shall not be more than 0.01 in. (0.25 mm) deep when its direction is transverse to the primary stress in the part that is undercut. Undercut shall not be more than 1/32 in. (0.80 mm) deep when its direction is parallel to the primary stress in the part that is undercut. When undercut is present, the affected area shall be ground to a smooth transition.
h.Nondestructive Examination/Nondestructive Testing (NDE/NDT). To determine compliance with these specifications, all welds shall be visually inspected and, in addition, complete joint penetration welds subjected to computed stress shall be inspected by radiographic testing (RT) for butt welds and ultrasonic testing (UT) for T and corner joints. RT shall utilize aluminum edge blocks and location marks similar to those specified for steel in Article 505.04 in addition to the AWS D1.2/D1.2M Structural Welding Code - Aluminum requirements. The dye penetrant testing (DPT) shall be performed according to ASTM E 165, Standard Methods for Liquid Penetrant Inspection, Method B, Procedure B-2 or B-3. DPT shall be used on partial joint penetration and fillet welds as follows: 100 percent of the top and bottom cantilever truss chords to connection and gusset plates near column; 25 percent of top connection plate to collar; 100 percent of simple span splice flanges to main chords; and random 10 percent of main chords to diagonals, horizontals, and verticals as directed by the Engineer. If rejectable defects are found in 10 percent of welded connections between main chords and diagonals, horizontals, and verticals, another 10 percent of the welded connections between main chords and diagonals, horizontals, and verticals shall be Art. 1094.05 Overhead Sign Structures checked. If rejectable defects are found in the second 10 percent of welded connections between main chords and diagonals, horizontals, and verticals, 100 percent of the remaining connections between these members shall be checked. Dye penetrant inspection may be omitted, provided the inspector examines each layer of weld metal with a magnifier of 3X minimum before the next successive layer is deposited. Required NDE/NDT shall be the responsibility of the Contractor and its cost shall be included in the fabrication.
i.Corrections. In lieu of rejection of an entire member containing welding that is unacceptable, the corrective measures may be permitted by the Engineer, if the extent of repairs will not adversely affect the structure's serviceability. Defective welds shall be corrected by removing and replacing the entire weld or as permitted by AWS D1.2/D1.2M Structural Welding Code - Aluminum. Copper or tungsten inclusions shall be completely removed. Before rewelding, the joint shall be inspected to ensure all of the defective weld has been removed. If dye penetrant has been used to inspect the weld, all traces of penetrant solutions shall be removed with solvent, water, heat, or other suitable means before rewelding. Repaired areas shall be 100 percent inspected by RT, UT, or DPT as applicable.
j.Qualification of Procedures, Welders, and Welding Operators. Joint welding procedures that are to be employed under these specifications shall be qualified by tests prescribed in the AWS D1.2/D1.2M Structural Welding Code - Aluminum. The qualifications shall be at the expense of the Contractor. The Engineer may accept properly documented evidence of previous qualification of the joint welding procedures to be employed. All welders and welding operators shall be qualified by tests specified by the AWS D1.2/D1.2M Structural Welding Code - Aluminum. The Engineer may accept properly documented evidence of previous qualification of the welders and welding operators to be employed.
1094.06 Structural Steel. All structural steel pipe shall be ASTM A 53 Grade B
or A 500 Grade B or C. All structural steel plates and shapes shall be according to AASHTO M 270 Grades 36, 50, or 50 W (M 270M Grades 250, 345, or 345W); AASHTO M 223 Grade 50 (M 223M Grade 345); AASHTO M 222 (M 222M); or ASTM A 36 (A 36M). Stainless steel for shims and handhole covers shall be ASTM A 240 (A 240M), Type 302 or 304, or another alloy suitable for exterior exposure and acceptable to the Engineer. Steel to be hot-dip galvanized shall have a silicon content either less than 0.04 percent or between 0.15 percent and 0.25 percent. Pavement Markings Art. 1095.01 SECTION 1095. PAVEMENT MARKINGS
1095.01 Thermoplastic Pavement Markings. This material shall be a mixture
of resins and other materials providing an essentially nonvolatile thermoplastic compound especially developed for traffic markings.
a.Ingredient Materials.
1.Binder. The binder shall consist of a mixture of synthetic resins, at least one of which is solid at room temperature. The solid resin shall be a hydrocarbon or alkyd resin. The total binder content of the thermoplastic compound shall be well distributed throughout the compound. The binder shall be free from all foreign objects or ingredients that would cause bleeding, staining, or discoloration. The binder shall be 18 percent minimum by weight of the thermoplastic compound. The binder shall be characterized by an IR Spectra. Future shipments of binder will be checked by an IR Spectra to verify that the binder has not been changed.
2.Pigment. The pigment used for the white thermoplastic compound shall be a high-grade pure (minimum 93 percent) titanium dioxide (Ti0 2). The white pigment content shall be a minimum of ten percent by weight and shall be uniformly distributed throughout the thermoplastic compound. The pigments used for the yellow thermoplastic compound shall not contain any hazardous materials listed in the Environmental Protection Agency Code of Federal Regulations (CFR) 40, Section 261.24, Table 1. The combined total of RCRA listed heavy metals shall not exceed 100 ppm when tested by X-ray fluorescence spectroscopy. The pigments shall also be heat resistant, UV stable and color-fast yellows, golds, and oranges, which shall produce a compound which shall match Aerospace Material Specification Standard 595 33538 (Orange Yellow). The pigment shall be uniformly distributed throughout the thermoplastic compound.
3.Filler. The filler to be incorporated with the resins as a binder shall be a white calcium carbonate, silica, or an approved substitute. Any filler which is insoluble in 6N hydrochloric acid shall be of such particle size as to pass a No. 100 (150 µm) sieve.
4.Glass Beads. The glass beads used as intermix beads with the thermosplastic pavement marking material shall meet the requirements of Article 1095.07. The glass beads shall be uniformly mixed throughout the material at the rate of not less than 30 percent by weight of the thermoplastic compound, retained on a No. 100 (150 µm) sieve.
b.Thermoplastic Compound.
1.Characteristic Requirements.
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Source: Illinois Standard Specifications for Road and Bridge Construction, 2022 Edition. Pages 1101–1106 of 1,217. View official source ↗