- 923 - SECTION 1071 -- POSTS AND FASTENERS FOR HIGHWAY SIGNING
1071.01 Description
1.This Section covers galvaniz ed or painted enamel steel posts, flexible posts, and zinc or cadmium plated fasteners for use in highway signing for other than Type A and Type B signs.
1071.02 Material Characteristics
1.a. Sign posts shall be a st andard "U" or channel shape. The posts shall be flange type, and the length shall be shown in the contract. The posts may be light or heavy duty.
b.Steel posts for signs shall be made from hot-wrought carbon steel or rail steel conforming to t he requirements specified in ASTM A-702 (Steel B).
c.All holes shall be at least 3/8 inch (9.5 mm) diameter. They shall be punched or dril led in each post and spaced 1 inch (25 mm) from center to center, ±1/16 in ch (+1.5 mm), beginning with the first hole at 1 inch (25 mm) from the top of the post. Punchi ng shall be done so that there will be no cracks or burs radiating from the holes.
d.(1) Painted posts shall be cleaned of all loose scale before finishing and painted with one or more coats of weather resistant enamel (black or green, as specified).
2.The finish shall produce a glossy appearance with satisfactory elastic and adhering properties.
3.The paint film thickne ss shall not be less than 1.5 mils (38 m).
4.After drying, the finish shall not crack or chip from the metal when struck a light blow with a hammer.
5.The paint coating shall show no appreciable change in adhesion or appearance when immersed in water at room temperature for a period of 72 hours.
e.Galvanized posts shall be ho t-dip galvanized after fabrication in accordance with ASTM A 123.
f.Painted posts which have been heavily scratched or marred in shipment and galvanized posts which have their galvanizing damaged shall be rejected.
g.(1) Light-duty post shall be at least 2 inches (50 mm) and not more than 2 1/2 inches (38 mm) wide on the side of the post to which the sign is to be fastened.
2.The post's weight shall be at least 1.12 lb/ft (1.6 kg/m), and the post shall have at least 15 and not more than 20 holes.
3.Light-duty posts shall be painted black or dark green.
h.(1) Heavy-duty posts shall be at least 3 inches (75 mm) and not more than 3 1/2 inches (90 mm) wide on the side of the post to which the sign is to be fastened.
2.The post's weight sha ll not be less than 2.5 lb/ft (3.75 kg/m), and the post shall have at leas t 50 and not more than 60 holes.
1071.02 Posts and Fasteners for Highway Signing
- 924 - (3) Heavy-duty posts may be painted black, green, or be galvanized.
3.a. Fasteners shall be round or pan head machine screws meeting the dimensional requirements of ASTM F 568 Property Class 4.6 with metric coarse threads meeting the dimensional requirements of ANSI/ISO.
b.The diameter of the fastener shall be shown in the contract.
c.The minimum thread length is shown in Table 1071.01. Table 1071.01 Thread Length Length of Fastene r Minimum Length of Thread 2 inches (50 mm) and under Entire Length Over 2 inches (50 mm) 1 3/4 inches (44 mm)
4.a. Nuts shall be square, hex, or hex machine nuts meeting the requirements of ASTM A 563M, Property Class 5.
b.Threads shall be ANSI metric coarse.
5.Plain washers shall be Type A meeting the requirements of ANSI 18.22M and have the dimensions shown in Table 1071.02. English Table 1071.02 Washer Dimensions Washer Inside Diameter (inches) Outside Diameter (inches) Thickness (inches) 3/16 0.245 to 0.265 0.557 to 0.577 0.036 to 0.065 1/4 0.307 to 0.327 0.727 to 0.749 0.051 to 0.080 5/16 0.370 to 0.390 0.868 to 0.905 0.064 to 0.104 3/8 0.433 to 0.453 0.993 to 1.030 0.064 to 0.104 Metric Table 1071.02M Washer Dimensions Bolt Inside Diameter (millimeters) Outside Diameter (millimeters) Thickness (millimeters) M5 6.22 to 6.73 14.15 to 14.66 0.91 to 1.65 M6 7.80 to 8.31 18.47 to 19.02 1.30 to 2.03 M8 9.40 to 9.91 22.05 to 22.99 1.63 to 2.64 M10 11.0 to 11.51 25.22 to 26.16 1.63 to 2.64
6.a. Lock washers shall be re gular helical spring steel of a compatible size for the required fastener.
b.Lock washers shall meet the dimensional requirements of ANSI B18.21.1.
c.Lock washers shall have a Rockwell Hardness of C45 to C51. Posts and Fasteners for Highway Signing 1071.03 - 925 - 7. The machine screws, nuts, and washers shall have a zinc or cadmium coating with a minimum thickness of 0.31 mils (8 m), with a Type III treatment conforming to AST M B 633 Class Fe/Zn 8 or ASTM B 766 Class 8, respectively.
8.Fasteners for delineators sha ll be at least 3/16 inch (5 mm) diameter pan or round head machine screws (length as shown in the contract) conforming to the requirements of ASTM F 568.
1071.03 Acceptance Requirements
1.Galvanized or painted enamel steel posts and zinc or cadmium plated fasteners will be accepted based on the requirements of this Specification and the requir ements in the Department’s Materials Sampling Guide . - 926 - SECTION 1072 -- REFLECTORS
1072.01 Description
1.Authorized reflectors are described in this Section.
1072.02 Material Characteristics
1.The reflector shall consist of a round retroreflecting lens permanently bonded and hermetically sealed to its back.
2.The back may be either acrylic plastic or metal foil. a. The foil back reflectors must have a minimum of 0.018 inch (0.46 mm) thick alum inum housing.
b.The acrylic plastic back reflectors do not require an aluminum housing.
3.The reflector shall have a mount ing hole in the center with a diameter of not less than 3/16 inch (5 mm).
4.The reflector shall have a visible reflective area of not less than 6.5 square inches (4200 mm
2.when mounted.
5.The lens shall consist of a smooth front surface free from projections or indentations other than the central mounting hole and manufacturer's identification.
6.The rear surface shall be a pris matic configuration such that it will cause total internal reflection of light.
7.The prism arrangement in the lens shall be su ch that the lens will have a segmented appearance with at least 2 and not more than 6 segments in each unit.
8.The unit shall be permanently sealed against dust, water, and water vapor.
9.Fasteners for delineators sha ll be at least 3/16 inch (5 mm) diameter pan or round head machine scr ews (length shown in the contract) conforming to the requirements of ASTM F 568.
1072.03 Specific Intensity
1.The reflectors shall meet specif ic intensity requirements shown in Table 1072.01. Table 1072.01 Reflector Requirements Observation Angle, (degrees) Entrance Angle, (degrees) Minimum Specific Intensity (Candlepower per foot-candle) (Candela per lux) White Yellow Red Blue 0.1 0 120 (11.1) 72 (6.7) 30 (2.8) 12 (1.1) 0.1 20 48 (4.5) 29 (2.7) 12 (1.1) 4.8 (0.4) 0.33 0 20 (1.9) 12 (1.1) 5 (0.5) 2.0 (0.2) 0.33 20 8 (0.7) 5 (0.5) 2 (0.2) 0.8 (0.08)
2.Failure to meet the minimum specific intensity requirements of more than two reflectors out of the 53 subjected to testing shall constitute failure of the lot.
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 957–959 of 1,048.