469 SECTION 894
894.01 Sign Backing Material
A.Flat Sheet Aluminum. Provide flat sheet aluminum that is an alloy meeting ASTM B 209 Alloy 6061 T6, or 5052-H38.
B.Extruded Aluminum Panels. Provide Extruded Aluminum Panels that meet ASTM B 221 Alloy 6063 T6. Furnish the panels in 12 inch and 6 inch sections. Provide panels that are flat and straight.
C.Shop Surface Preparation and Processing. Prepare sign sheeting and panels to conform with the reflective sheeting manufacturer’s warranty requirements. Shop drill holes. Do not field drill any holes required in the sign backing.
894.02 Retroreflective Sheeting Materials
A.General.
1.Materials. When submitting the certificate of compliance for retroreflective sheeting, submit manufacturer warranties and guarantees for materials, parts, workmanship, or performance. Apply retroreflective sheeting according to manufacturer’s recommendations. Treat the surface of the barricade rails , drums, or cones as recommended by the sheeting manufacturer before applying the reflective sheeting.
2.Silk Screen Printing. Use retroreflective sheeting within one year from the manufactured date. Mark the packaging cartons or roll goods with the manufacturer’s lot numbers and manufacture date.
3.Digital Printing. Fabricate digitally printed signs using equipment, materials and processes that have been certified by the sheeting manufacturer. Submit a copy of the certification to the Engineer with cer tificate of compliance. Follow the sheeting manufacturer’s quality control process during the manufacture process. Apply a UV -protective clear overlay to the entire face of the sign supplied by the reflective sheeting manufacturer.
B.Type III Retroreflective Sheeting Provide Type III retroreflective sheeting that meets ASTM D 4956, Type III.
C.Type IV Retroreflective Sheeting. Provide Type IV retroreflective sheeting that meets ASTM D 4956, Type IV.
D.Type VI Retroreflective Sheeting. Provi de Type VI retroreflective sheeting that meets ASTM D 4956, Type VI.
E.Type XI Retroreflective Sheeting. Provide Type XI retroreflective sheeting that meets ASTM D 4956, Type XI.
894.03 Posts and Hardware for Signs
Galvanize all materials requiring galvanization according to Section 854, “Galvanizing” .
A.Hardware for Signs.
1.General. Coat aluminum bolts, nuts, U -bolts, lockwashers, and washers with a minimum of a 0.002 inch anodic coating, followed by a chromate seal. Galvanize all steel bolts, nuts, U -bolts, lockwashers, and washers. The Engineer may approve the use of substitute alloys in lieu of the specified hardware alloy for signs upon submission of Certific ate of Compliance that the proposed substitute alloy that meets or exceeds the applicable specifications to the designated alloy.
2.Bolts. Fabricate aluminum panel bolts to meet ASTM B 211, Alloy 2024 T4 or 6061 T6. Use steel panel bolts and machine bol ts that meet ASTM A 307.
3.Nuts. Fabricate aluminum nuts, hex nuts, and vandal -resistant nuts of aluminum alloy to meet ASTM B 211, Alloy 6061 T6. Use steel hex nuts that meet ASTM A 307. Use a torque control nut system or torque wrenches to obtain the required torques for fuse joints and slip base used in the breakaway system. Use a torque control nut system that provides automatic torque control, consistently -controlled preload, vibration resistance, high strength, easy installation, simple inspectio n, and resistance to weather effects. Use a torque control nut that is designed to mate with standard high strength bolts meeting ASTM F 3125 Grade A 325. Use nuts with a minimum stripping strength of the threads that is equal to or exceeds the strength level of the mating bolts. If using torque control nuts, provide a Certificate of Compliance. Provide self-locking nuts that meet Federal Specification MIL-DTL -32258. Install according to the manufacturer’s recommendations.
4.Washers. 471 Fabricate: - aluminum lockwashers to meet ASTM B 209, Alloy 7075 T6; - aluminum flat washers to meet ASTM B 209, Alloy 2024 T4; - steel lockwashers to meet ANSI B 27.1; - steel flat washers to meet ASTM A 307; and - plastic washers to the sheeting manufacturer’s specifications.
5.Stringers. Use aluminum stringers made of aluminum alloy that meets ASTM B 221, Alloy 6061 T6 or ASTM B 308, Alloy 6061 T6. Use steel stringers that meet ASTM A 36.
6.Aluminum Alloy Castings. Use permanent mold castings or sand castings for brackets, post caps, and fuse plates. Use aluminum alloy permanent mold castings that meet ASTM B 108, Alloy SG70A F or SG80A T6. Use aluminum alloy sand castings that meet ASTM B 26, Alloy SG70A F or SG70A T6.
7.Steel Castings. Provide brackets, post caps, and fuse plates that meet AASHTO M 103, Grade 65-35.
8.U-Bolts. Fabricate aluminum U -bolts to meet ASTM B 211, Alloy 2017 T4. Fabricate steel U -bolts to meet ASTM A 307.
9.Attachment Clip and Plate. For attachment of steel panels use galvanized steel attachment clips and plates to meet ASTM A 283.
10.Fuse Joint Bolts. Fabricate aluminum fuse plate bolts and washers from aluminum meeting ASTM B 211, Alloy 2024 T4. Fabricate steel fuse plate bolts and w ashers to meet ASTM F 3125 Grade A 325. Use nuts with the capacity to develop the bolt strength. Use galvanized bolts, nuts, and washers.
11.Breakaway Base Bolts. Use steel bolts and washers that meet ASTM F 3125 Grade A 325, and nuts with the capacity to develop the bolt strength. Use galvanized bolts, nuts, and washers.
B.Posts.
1.General. Create welds on aluminum according to Section 6 and create welds on galvanized steel according to Section 5 of the AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals . 472 2. Aluminum Tubular Posts and Accessories. Material Specification Drawn Seamless Tubes and Extruded Round or Square Tubes ASTM B 210, Alloy 6061 T6 or ASTM B 241, Alloy 6061 T6 Extruded Structural Shapes ASTM B 221, Alloy 6061 T6 Breakaway Bases ASTM B 209, Alloy 6061 T6 Fuse Plates ASTM B 209, Alloy 6061 T6 Fuse Plate Bolts and Washers ASTM B 211, Alloy 2024 T4
3.Steel (Galvanized) Posts and Accessories. Use AASHTO M 270, Grade 36 for all steel posts and accessories.
4.Square Steel Telescoping Tubular Posts.
a.Material. Use steel posts that meet Grade 55 hot rolled carbon sheet steel, structural quality, ASTM designation A 1011.
b.Shape. Use a square tube post formed of 12 gauge (0.105 U.S.S. gauge) and 10 gauge (0.135
U.S.S. gauge) steel, carefully rolled to size and is welded directly in the corner by high frequency resistance welding and externally scarfed to agree with corner radii.
c.Finish. Provide signposts manufactured from hot-dipped galvanized steel according to ASTM A 653, with a G90 coating. Zinc coat the corner weld after scarfing. Coat the steel with a chromate conversion coating and a clear organic polymer topcoat. Galvanize both the interior and the exterior of the post.
d.Cross Section. Use perforated tube that meets the requirements of Tabl e 894-01 for the required size of tube. Table 894 -01 Size U.S.S. Gauge Weight (lbs/foot) Moment of Inertia In4 Cross Sect. Area In2 Section Modulus In3 1 1/2" × 1 1/2" 12 1.70 0.129 0.380 0.172 1 3/4” × 1 1/2” 12 2.06 0.231 0.485 0.264 2" × 2" 12 2.42 0.372 0.590 0.372 2 1/4" × 2 1/4" 12 2.77 0.561 0.695 0.499 2 1/2" × 2 1/2" 12 3.14 0.605 0.841 0.590 2 3/16" × 2 3/16" 10 3.43 0.804 0.803 0.643 2 1/2" × 2 1/2" 10 4.01 0.979 1.010 0.785
e.Holes. Punch holes that are: - 7/16 × 1/64 inches in diameter; - on one inch centers; - on all four sides; - down the entire length of the post; - on centerline of each side; - in true alignment; and - opposite each other directly and diagonally. Remove all metal from the holes.
f.Length. Provide post of lengths within 1/4 inch of the specified length.
g.Telescoping Properties. Provide square tubes that have the ability to telescope all consecutive sizes freely at least ten feet without the necessity of matching any particular face to an y other face. Provide holes and ends that are free of burrs. Provide ends that are square.
h.Tolerances.
1.Outside Size Tolerances. Nominal Outside Dimensions Outside Tolerances at all sides at Corners 1 1/2" × 1 1/2" 0.006" 1 3/4” × 1 1/2” 0.008” 2" × 2" 0.008" 2 1/4" × 2 1/4" 0.010" 2 1/2" × 2 1/2" 0.010" 2 3/16” × 2 3/16” 0.010" Measure the outside dimensions at least 2 inches from the end of the tube. 474 (2) Wall Thickness Tolerances. Provide a wall thickness that is no less than 0.008 inches from the specified thickness and no more than 0.011 inches greater than the specified thickness.
3.Convexity and Concavity. Provide posts with a convexity and concavity of less than 0.010 inches. Determine by measuring the convexity and concavity from the center of the flat sides to the corner.
4.Squareness of Sides and Twist. Nominal Outside Dimensions Squareness Tolerance Twist Permissible in 3 Feet Length 1 1/2" × 1 1/2" 0.009" 0.050" 1 3/4” × 1 1/2” 0.010” 0.062” 2" × 2" 0.012" 0.062" 2 3/16" × 2 3/16" 0.014" 0.062" 2 1/4" × 2 1/4" 0.014" 0.062" 2 1/2" × 2 1/2" 0.015" 0.075" Provide posts that have sides that are 90 degrees to each other within the squareness tolerance listed above.
5.Straight Tolerance. Provide posts with a variation in straightness of less than 1/16 of an inch in 3 feet.
6.Corner Radii. Provide posts with a standard outside corner radius of 5/32 of an inch within a tolerance of 1/64 inch.
i.Installation. Do not m odify the square end of the post or provide a pointed square end. Provide a square end that is capable of being driven into the ground with the use of an approved driving cap.
j.Slip Base Assembly. Provide manufacturer certification that the chemistry, geometry, and mechanical properties are the same as those used in the tests and that the assembly will meet FHWA change-in -velocity requirements.
5.Accessories.
a.Anchor Plates. Use anchor plates that meet ASTM A 36, 10 gauge galvanized according to ASTM A 653 with a G90 coating.
b.Safety Retainer -Spacer Strap. Use steel straps that meet AISI 1020. 475 c. Nuts and Bolts. Use steel bolts that meet ASTM A 354, Grade BD, case hardened. Use nuts that meet AASHTO M 291, Grade DH. Use lockwashers th at are heavy -duty external type. Use nuts and bolts that are cadmium plated that meet ASTM A 165, Type 05, except when using clear chromate.
d.Fabrication. Provide machine straightened finished posts that have a uniform finish, free from defects affecting its strength, durability, or appearance. Provide holes and ends that are free of burrs. Punch the sign posts and stringers on the center line with 7/16 inch diameter holes on one inch centers for the entire length. Punch the base posts on center line with a minimum of 12 holes that are 7/16 inch diameter on one inch centers. Punch the first hole one inch from the top. Provide posts with a pointed bottom. Provide sign post, base posts, retainer -spacer, and anchor plates that are galvanized.
6.Structural Steel Posts. Provide structural steel posts that are fabricated from material conforming to Section
834.01 A, “Structural Carbon Steel” that are galvanized after fabrication.
894.04 Delineators
A.Posts. Provide steel posts that meet ASTM A 702. Provide galvanized steel posts or provide aluminum posts that meet ASTM B 308, Alloy 6061- T6. If providing galvanized steel posts, provide posts galvanized as specified in Section 854, “Galvanizing” .
B.Reflectors. Use reflective sheeting that meets Section 894.02 E, “Type XI Retroreflective Sheeting” that is white or yellow adhesive coated and permanently adhered to aluminum or galvanized steel. If using galvanized steel, provide steel galvanized as specified in Section 854, “Galvanization” . Use backing material that meets Section 894.01 A, “Flat Sheet Aluminum” .
894.05 Structures for Overhead Signs
A.General. Galvanize all materials requiring galvanization according to Section 854, “Galvanizing” after fabrication. Submit work drawings for all structures for overhead signs according to Sections 105.08 A.3, “Additional Section 600 Work Drawing Submittal Requirements ”. 476 1. Welding.
a.General. Perform all steel welding according to the specifications for welding of steel structures in the AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals.
b.Treatment of Welded Areas. Punch a minimum 3/4 inch hole into chords to facilitate galvanizing the struts and diagonal tubes. Provide two 1/2 inch holes at the top and bottom of the chords on the capped end to facilitate galvanizing. Provide on the end tower vertical columns two 1/4 inch holes in the base plate and two 3/4 inch holes at the top of each column to facilitate galvanizing.
c.Repair Galvanization. Repair damaged galvaniz ation according to Section 854, “Galvanizing” .
2.Grating and Handrail. If grates require splicing, make the splice at the center of the support. The rail may be in one or more pieces with a post assembly at each end of each piece of rail. Provide aluminum grating that meets ASTM B 221, Alloy 6063 T6. Provide aluminum grating that resists a point load of 500 pounds and has a deflection of 1/4 inch or less when loaded with a uniform load of 100 pounds per linear foot. Base the deflec tion on a simple span, 5 feet in length. Provide U -bolts, bolts, washers, nuts, and clips of austenitic stainless steel. Provide aluminum railing composed of 1.25 inch nominal diameter Schedule 40 pipe and fittings, with flush surfaces. Weld and grind smooth joints between the pipe and fittings. Fabricate railings in sections of adequate size that allow the sections to be raised and lowered by one person from one end of each section.
B.Free Standing Overhead Signs.
1.Round Tubes and Standard Pipe. Provide steel galvanized round tubes and standard pipe members that meet AASHTO M 270 Grade 36, or ASTM A 53 (Grade B Steel) .
2.Round-Tapered or Octagonal-Tapered Tubes. The Engineer will allow the overhead sign structure to be designed and fabricated from round-tapered or octagonal -tapered steel tubes instead of round and standard pipe. Retain major dimensions, such as truss cross section and length, and end towers vertical dimensions. If this option is chosen, furnish to the Engineer all necessary calculations and drawings used in designing these structures. Design the structures according to the latest issue of the AASHTO publication of Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals . Use a wind velocity of 90 mph to compute the wind pressures on the signs and structures. 477 Submit work drawings after the above design has been submitted and reviewed. Use round-tapered or octagonal -tapered tube members that have a minimum yield strength of 50,000 psi after fabrication. Design the shaft to have no more than one longitudinal weld. Provide a galvanized shaft.
3.Flat Bars. Provide galvanized flat bar members that meet the requirements in AASHTO M 270 Grade 36.
4.Flange. Use flange, base plate, clamps, and plate material that is of the same material used in fabricating columns and truss chords.
5.Truss. Provide galvanized steel shapes that meet AASHTO M 270 Grade 36.
6.Hardware. Fabricate galvanized steel bolts to meet ASTM F 3125 Grade A 325. Fabricate steel U - bolts from round steel bars. Thread the U -bolts on both ends meeting ASTM A 307 and galvanize the U -shaped bolts.
7.Anchor Bolts, Nuts, and Washers. Provide anchor bolts made of medium carbon, hot rolled steel bars meeting AASHTO M 314 Grade 55 and that meet the requirements in Table 894-02. Table 894 -02 Yield Strength 55,000 psi Ultimate Strength 75,000 to 95,000 psi Elongation (2 -inch gage), min 21%1 Reduction in Area, min 30%2 Longitudinal Charpy V -Notch, min 15 ft-lbs at 40°F 1 Elongation (eight ‐inch gage), minimum18 percent for bolts tested full section. 2 Bolts over 2 to 2 ‐1/2 inch, 22 percent min; over 2 ‐1/2 to 3 inch, 20 percent min. Perform notch toughness tests on specimens according to Test Frequency P of ASTM A 673 and the orient the notch perpendicular to the longitudinal axis of the anchor bolt. It may be necessary to heat the steel in order to meet the Charpy V -Notch impact requirements. Use galvanized anchor bolts, nuts, and washers. Provide threads on the anchor bolts that are 8UN series as specified in ANSI B1.1 and have Class 2A tolerances before coating. After coating, the maximum limit of pitch and major diameters may exceed the Class 2A limit by 0.021 inch for bolts 1 inch and smaller, and by 0.031 inch for bolts larger than 1 inch in diameter. Anchor bolt threads may be cut or rolled into the round bar stock. Use nuts for anchor bolts that meet ASTM A 563, Grade A, heavy hex. Provide threads that are 8UN series that meet ANSI B 1.1 Class 2B tolerances, and tapped oversize after 478 coating by not more than 0.021 inch for nuts 1 inch and smaller, or more than 0.031 inch for nuts larger than 1 inch. Lubricate the nuts as specified in Supplementary Requirement S1 of ASTM A 563. Use circular washers that meet ASTM F 436 Provide a Certificate of Compliance for all bolts that includes the results of yield strength, tensile strength, elongation, reduction of area, and charpy tests, and identification to the heat number of the steel, and to furnace lot number if heat treated. Stamp anchor bolts for cantilever and truss sign supports to identify them to a specific test report before sampling the bolts for testing. Stamp anchor bolts in the end of the hook to identify them to a specific heat number. Stamp anchor bolts in the threaded end cross section to identify them to a specific test report. The Engineer will sample anchor bolts (i ncluding nuts and washers) for destructive testing at the following frequency: − Cantilever sign supports - 1 bolt per cantilever per heat; − Truss sign supports - 1 bolt per truss assembly per heat; and − Other uses - 1 bolt per heat per project. Order additional bolts for sampling.
C.Overhead Signs on Bridge Structures.
1.Plates. Use brackets and reinforcing plates that meet ASTM B 209, Alloy 6061 T6.
2.Angles, I-Beams, and Channels. Use aluminum shapes that meet ASTM B 308, Alloy 6061 T6.
3.Bolts, Nuts, Washers, and Lockwashers. Provide nuts, bolts, washers, and lockwashers used in the erection and fabrication of the overhead sign structures on bridges made of austenitic stainless steel. Fabricate the bolts used for the attachment to the bridge according to ASTM F 3125 Grade A 325 and galvanize the bolts. Section 895 479 SECTION 895 HIGHWAY LIGHTING
895.01 Description
Furnish material that meets the requirements of the Institute of Electrical and Electronics Engineers, Underwriters Laboratories, and the Institute of Transportation Engineers.
895.02 Conduit
Submit a certificate of compliance for conduit.
A.Steel Conduit. Provide corrosive-resistant steel conduit meeting UL 6.
B.Nonmetallic Conduit.
1.PVC. Provide PVC conduit that meets the requirements of UL 651 suitable for direct burial applications and has a minimum wall thickness equivalent to Schedule 40 as defined by ASTM D 1785.
2.HDPE. Provide HDPE conduit that meets the requirements of UL 651 and ASTM D 3035 that is suitable for direct burial applications. Use HDPE conduit that has a minimum wall thickness equivalent to DR 15.5 as defined by ASTM D 3035.
895.03 Conductors
A.Feeders. If using conductors as feeders provide either a single conductor or multiple stranded conductors formed into a cable. Provide underground phase and neutral conductors that are insulated to meet the requirements for direct burial cable, rated at 600 volts, and that meet ASTM B 3 and B 8.
1.Single Conductor. Use single conductor marked with Style “RHW-USE” and the required AWG size on the sheath. Use stranded No. 6-AWG -Type THW or THHN/THWN for grounding conductor. Rubber insulation specifically listed for that purpose by UL does not require an outer cover.
2.Multiple Conductor. Provide Style USE for multiple conductor that meets NEMA Standards WC -70, rated at 0 through 600 volts, modified as follows:
a.Provide multiple conductors insulated with either cross -linked thermosetting polyethylene (XLP), or butyl.
b.Use multiple conductors that have circuit identification. Assemble conductors into a cable of circular cross section with filler, binder, armor, and an overall outer cover.
c.Use armor that is a bronze tape meeting ASTM B 130 with a minimum thickness of 10 mils and a spiral overlap of not less than 1/4 inch. Use an outer cover on the
Source: North Dakota Standard Specifications for Road and Bridge Construction, 2022 Edition. Pages 504–513 of 550.