- 896 - SECTION 1058 -- HIGH TENSILE BOLTS, NUTS, AND WASHERS
1058.01 Description
1.All high strength bolts s hall meet the requirements in ASTM A 325/A 325M and the modification in this Section.
2.All high strength nuts shall meet the requirements in ASTM A 563/A 563M, or ASTM A 194 and the modifications in this Section.
3.Hardened steel washers shall meet the requirements in ASTM F 436/F 436M and the modifications in this Section.
4.All bolts, nuts, and washers shall be plain (uncoated) unless otherwise specified.
5.Other fasteners or fastener asse mblies not referenced in this Specification, such as those conf orming to the requirements of ASTM F 1852, may be used subject to the appr oval of the Engineer and must be tested and approved by the Departm ent before use provided that:
a.They meet materials, manufacturing, and chemical composition requirements of AASHTO M 164 (ASTM A 325).
b.They meet mechanical pr operty requirements of the same specification in full-size tests.
c.The body diameter and bear ing areas under the head and nut, or their equivalent, shall not be less than those provided by a bolt and nut of the same nominal dimensions describ ed in Section 6 of the AASHTO LRFD Bridge Design Specifications.
1.Such alternate fasteners may differ in other dimensions from those of the bolts, nuts, and wa shers specified in Section 6 of the AASHTO LRFD Bridge Design Specifications.
1058.02 Material Characteristics
1.Bolts:
a.The maximum tensile strength for bolts with a diameter that is equal to or less than 1 inch (25 mm) shall be 150,000 psi (1034 MPa). Bolts with diameters that are larger than 1 inch (25 mm) shall have a maximum tensile strength equal to 120,000 psi (827 MPa).
b.Type 3 bolts, nuts, and washers must be used to assemble "weathering" steel structures. When stru ctures are painted, the bolts and the compatible nuts and washers may be Type 1 or Type 3.
2.Nuts:
a.If nuts are to be galvanized (hot dip or mechanically galvanized), they shall be heat treated grade 10S or 10S3 (2H, DH, or DH3).
b.Plain (uncoated) nuts shall be grades 8S or 8S3 (2, C, D, or C3) with a minimum Rockwell hardness of B89 (Brinell hardness of 180), or heat treated grades 10S or 10S3 (2H, DH, or DH3).
c.If nuts are to be galvanized, they shall be tapped oversize the minimum amount required for proper as sembly. The amount of overtap in the nut shall be so the nut assemble s freely on the bolt in the coated condition and shall meet the me chanical requirements of ASTM Specifications as indicated for nuts in Subsection 1058.01 above. High Tensile Bolts, Nuts, and Washers 1058.03 - 897 - d. Galvanized nuts shall be lubric ated with a lubricant containing a dye of any color that contrasts with the color of the galvanizing.
3.Marking: All bolts, nuts, and washers shall be marked according to the appropriate ASTM Specifications.
1058.03 Acceptance Requirements
1.Bolts:
a.Proof load tests (ASTM F 606/F 606M, Method 1) are required. The minimum frequency of tests shall be as specified in ASTM A 325/A 325M.
b.Wedge tests on full size bolts (ASTM F 606/F 606M) are required. If bolts are to be galvanized, tests shall be performed after galvanizing. The minimum frequency of testing shall be as specified in ASTM A 325/A 325M.
c.If galvanized bolts are specif ied, the thickness of the zinc coating shall be checked by taking measurements on the wrench flats or on top of the bolt head.
d.The Contractor may use eit her English or metric bolts in accordance with Table 1058.01.
1058.03 High Tensile Bolts, Nuts, and Washers
- 898 - Table 1058.01 Metric/English Bolt S ubstitution Table ** Equivalent * Bolt Sizes Metric (millimeters) English (inches) M6 1/4 M8 5/16 M10 7/16 M12 1/2 M14 9/16 M16 5/18 M20 3/4 M22 7/8 M24 1 M27 1 1/8 M30 1 1/4 M36 1 1/2 M42 1 3/4 M48 2 M56 2 1/4 M64 2 1/2 M72 2 3/4 M80 3 1/4 M90 3 1/2 M100 4 * All bolts on any structure must be all English or all Metric. Mixing is not allowed. ** The maximum bolt hole sizes shall be as described in Section 6 of the AASHTO LRFD Bridge Design Specifications.
2.Nuts:
a.Proof load tests (ASTM F 606/F 606M) are required. The minimum frequency of tests shall be as specified in ASTM A 563/A 563M, or ASTM A 194/A 194M. If nuts are to be ga lvanized, tests shall be performed after galvanizing, overtapping, and lubricating.
b.If galvanized nuts are specified, the thickness of the zinc coating shall be checked by taking measurements on the wrench flats.
3.Washers: Hardened steel washers shall be tested in accordance with ASTM F 436/F 436M. If galvanized washers are specified, hardness testing shall be performed after galvanizing. (The coating shall be removed before taking hardness measurements.)
4.Assemblies: a. Rotational capacity tests are required and shall be performed on all plain or galvanized (after galvanizing) bolt, nut, and washer assemblies by the manufacturer or distributor before shipping.
b.(1) Except as modified herein, the rotational capacity test shall be performed according to ASTM A 325/A 325M. High Tensile Bolts, Nuts, and Washers 1058.03 - 899 - (2) Each combination of bolt production lots, nut lots, and washer lots shall be tested as an assembly.
3.A rotational capacity lot number shall be assigned to each combination of lots tested.
4.The minimum frequency of testing shall be 2 assemblies per rotational capacity lot.
5.The bolt, nut, and washer assembly shall be assembled in a Skidmore-Wilhelm calibrator or an a cceptable equivalent device. For bolts that are too short to be assembled in the calibrator, see Subsection 1058.03, Paragraph 4.b.(9).
6.(i) The minimum nut rotation, from a snug-tight condition equal to 10% of the minimum bolt tension (minimum bolt tension is equal to 70% of the minimum tensile load), shall be:
a.240 degrees (2/3 turn) for bolt lengths less than or equal to 4 diameters.
b.360 degrees (1 turn) for bolt lengths greater than 4 diameters and less than or equal to 8 diameters.
c.480 degrees (1 1/3 turn) for bolt lengths greater than 8 diameters. (ii) During the tightening process, the Contractor should continuously monitor the fastener t ension on the calibration device, the bolt torque indicated on the torque wrench dial, as well as the relative rotation of the nut with respect to the snug-tight position. After snug-tightening the nut to the appropriate tension (shown in the tables below), the nut shall be rotated until the minimum bolt tension (as shown in the appropriate table) has been reached. The bolt torque reading should be recorded as close as possible to the minimum bolt tension. This torque must be less than or equal to the calculated torque obtained from the following formula: Torque Formula Tm < T c = 0.25 PD Where: T c = calculated torque in ft. lbs. (Newton-meters) T m = measured torque in ft. lbs. (Newton-meters) P = measured bolt tension in pounds (Newtons) D = bolt diameter in feet (meters) (values shown in tables below)
7.If the above torque-tension relationship has been satisfied, rotation of the nut should continue (past the rotation point where the minimum bolt tension-torque was taken) in the tightening direction to complete the minimum nut rotation shown in Paragraph 4.b.(6) of this Subsection. The tension reac hed at this rotation shall be equal to or greater than the turn test tension (equal to 1.15 times the minimum bolt tension). The snug tension, minimum bolt tension, and the turn test tension are shown in Table 1058.02.
1058.03 High Tensile Bolts, Nuts, and Washers
- 900 - Table 1058.02 Bolt Tension Requirements SI Standard Bolt Diameter (millimeters) Diameter (meters) 16 0.016 20 0.020 22 0.022 24 0.024 27 0.027 30 0.030 36 0.036 10% Snug Tension (kilonewtons) Minimum Bolt Tension (kilonewtons) Turn Test Tension (kilonewtons) US Standard Bolt Diameter (in) Diameter (ft) 1/2 0.042 5 /8 0.052 3/4 0.063 7/8 0.073 1 0.083 1 1/8 0.094 1 1/4 0.104 1 3/8 0.115 1 1/2 0.125 10% Snug Tension (kips) Minimum Bolt Tension (kips) Turn Test Tension (kips)
8.If the torque-tension relationship or the rotation-tension relationship as determined in Paragr aphs 4.b.(6) and 4.b.(7) of this Subsection does not meet requirements, the fastener assembly lot represented by these test samples sha ll not be used. However, if allowed by the Engineer, the complete fastener assembly lot represented by these failed test samples may be cleaned, relubricated, an d then resubmitted for evaluation.
9.Bolts that are too short to test in a Skidmore-Wilhelm calibrator may be tested in a steel joint using steel shims with proper hole size and thickness so as to place 3 to 5 exposed threads within the joint. The minimum turn-test tension requirement of Paragraph 4.b.(7) of this Subsection need not apply since there is no way of measuring tension. However, the torque value at proper installation rotation shall be determined as follows: The nut must be snug tightened using the same effort (or torque) required to reach the 10% snug tensio n as shown in the appropriate unit section of Table 1058.02. This "snug-torque" value may be determined by using longer bolts from the same lot that will fit in the ca librator. After match- marking the nut after snug-tightening, the nut shall be rotated to the minimum rotation required for turn-of-nut installation (equal to 1/2 of the High Tensile Bolts, Nuts, and Washers 1058.04 - 901 - rotation values shown in Paragraph 4.b. (6) of this Subsection). The torque value obtained at this installation ro tation must not exceed the torque as computed by the formula in Paragraph 4.b.(6) of this Subsection using a value of P equal to the turn test tens ion shown in the appropriate unit section of Table 1058.02.
5.Reporting: a. The results of all tests (including zinc coating thickness) required herein and in the appropriate AASHTO or ASTM Specifications shall be recorded on the appropriate document.
b.The location where tests ar e performed and the date of tests shall be reported on the appropriate document.
6.Witnessing: The tests need not be witnessed by an inspection agency. However, the manufacturer or distributor that perfo rms the tests shall certify that the results recorded are accurate. Recent calibration documentation (calibrations performed at least on a yearly basis) for testing machines, as well as torque and tension measuring equipment used for performing said tests, shall be provided upon request by the Engineer.
1058.04 Documentation
1.Mill Test Report(s) (MTR):
a.MTR shall be furnished for all mill steel used in the manufacture of bolts, nuts, or washers.
b.MTR shall indicate the place where the material was melted and manufactured.
2.Manufacturer Certifie d Test Report(s) (MCTR):
a.The manufacturer of the bol ts, nuts, and washers shall furnish test reports (MCTR) for the item furnished.
b.Each MCTR shall show the relevant information required according to Subsection 1058.03.
c.The manufacturer performing the rotational capacity test shall include on the MCTR:
1.The lot number of each of the items tested.
2.The rotational capacity lot number as required in Subsection 1058.03, Paragraph 4.b.(3).
3.The results of the tests required in Subsection 1058.03, Paragraph 4.b.
4.The pertinent information required in Subsection 1058.03, Paragraph 5.b.
5.A statement that the MCTR for the items meets this Specification and the appropriate ASTM Specification.
6.The location where the bolt assembly components were manufactured.
1058.04 High Tensile Bolts, Nuts, and Washers
- 902 - 3. Distributor Certified Test Report(s) DCTR:
a.The DCTR shall include MCTR for the various bolt assembly components.
b.The rotational capacity test may be performed by a distributor (in lieu of a manufacturer) and reported on the DCTR.
c.The DCTR shall show the results of the tests required in Subsection 1058.03, Paragraph 4.b.
1058.05 Shipping
1.Bolts, nuts, and washers from eac h rotational capacity lot shall be shipped in the same container. If there is only one production lot number for each size of nut and washer, the nuts and washers may be shipped in separate containers. The container shall be permanently marked with the rotational capacity lot number such that identification will be possible at any stage before installation.
2.The appropriate MTR, MCTR, or DCTR shall be supplied to the Engineer for acceptance before installation. - 903 - SECTION 1059 -- ZINC COATING ON HARDWARE
1059.01 Description
1.This Specification covers zi nc coatings applied on iron and steel hardware not otherwise covered, such as bolts, nuts, screws, nails, fittings, and other miscellaneous general hardware.
1059.02 Material Characteristics
1.Zinc coated hardware shall be hot dipped to conform to the requirements of ASTM A 153 or mechanically coated to conform with AASHTO M 298, Class 50.
1059.03 Acceptance Requirements
1.Acceptance will be based on requirements identified in this Specification and those in the Department’s Materials Sampling Guide .
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 930–936 of 1,048.