1、Standard Specification for Corrugated Sheet Steel Beams for Highway Guardrail AASHTO Designation: M 180-18 Technical Section: 4d, Safety Devices Release: Group 2 (June) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001T
2、S-4d M 180-1 AASHTO Standard Specification for Corrugated Sheet Steel Beams for Highway Guardrail AASHTO Designation: M 180-18 Technical Section: 4d, Safety Devices Release: Group 2 (June) 1. SCOPE 1.1. This specification covers corrugated sheet steel prepared for use as beams in highway guardrails.
3、 1.2. The values stated in SI units are to be regarded as the standard. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 111M/M 111, Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products M 232M/M 232, Zinc Coating (Hot-Dip) on Iron and Steel Hardware T 65M/T 65, Mass Weight of Coating on Iro
4、n and Steel Articles with Zinc or Zinc-Alloy Coatings 2.2. ASTM Standards: A307, Standard Specification for Carbon Steel Bolts, Studs, and Threaded Rod 60 000 psi Tensile Strength A563M, Standard Specification for Carbon and Alloy Steel Nuts (Metric) A653/A653M, Standard Specification for Steel Shee
5、t, Zinc-Coated (Galvanized), or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process A924/A924M, Standard Specification for General Requirements for Steel Sheet, Metallic Coated by the Hot-Dip Process A1046/A1046M, Standard Specification for Steel Sheet, Zinc-Aluminum-Magnesium Alloy-Coated
6、by the Hot-Dip Process B6, Standard Specification for Zinc B695, Standard Specification for Coatings of Zinc Mechanically Deposited on Iron and Steel E376, Standard Practice for Measuring Coating Thickness by Magnetic-Field or Eddy-Current (Electromagnetic) Testing Methods F568M, Standard Specificat
7、ion for Carbon and Alloy Steel Externally Threaded Metric Fasteners (withdrawn 2012) 2.3. ANSI Standards: B1.13M, Metric Screw Threads D M Profile B18.2.4.1M, Hex Nuts, Style 1, Metric B18.2.4.6M, Hex Nuts, Heavy, Metric 2018 by the American Association of State Highway and Transportation Officials.
8、 All rights reserved. Duplication is a violation of applicable law.TS-4d M 180-2 AASHTO 2.4. Federal Standard: TT-P-641, Type II Zinc Dust Primer for Steel or Galvanized Metal Surfaces 2.5. Military Standard: DOD-P-21035, Paint, High Zinc Dust Content, Galvanizing Repair (Metric) 3. CLASSIFICATION 3
9、.1. Six types and two classes of guardrail are provided as follows: 3.1.1. Types: Type IZinc-coated, 550 g/m2(1.80 oz/ft2) total both sides coating weight (mass) minimum single-spot. Type IIZinc-coated, 1100 g/m2(3.60 oz/ft2) total both sides coating weight (mass) minimum single-spot. Type IIIBeams
10、to be painted. Type IVBeams of corrosion-resistant steel. Type VZinc-6 percent aluminum-3 percent magnesium alloy coated, 245 g/m2(0.80 oz/ft2) total both sides coating weight (mass) minimum single-spot. Type VIZinc-6 percent aluminum-3 percent magnesium alloy coated, 305 g/m2(1.00 oz/ft2) total bot
11、h sides coating weight (mass) minimum single-spot. 3.1.2. Classes: Class ABase metal nominal thickness2.67 mm (0.105 in.). Class BBase metal nominal thickness3.43 mm (0.135 in.). 4. ORDERING INFORMATION 4.1. Orders for guardrail under this specification shall include the following information, as re
12、quired, to adequately describe the desired material: 4.1.1. Quantity (linear meter or number of pieces), 4.1.2. Class of guardrail, 4.1.3. Type of guardrail, 4.1.4. Effective length of beam section 3.8 or 7.6 m (12.5 ft or 25.0 ft), 4.1.5. Shape (W-beam or thrie beam), and 4.1.6. Exceptions to this
13、specification or special requirements, if any. 5. BASIS OF ACCEPTANCE 5.1. All material shall be subject to inspection and sampling at the fabricating plant, warehouse, or after delivery to the site of construction. 5.2. Acceptance by Sampling: 2018 by the American Association of State Highway and T
14、ransportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4d M 180-3 AASHTO 5.2.1. The engineer may take one piece of guardrail, a backup plate, and end or buffer section from each 200 pieces in a lot, or from each lot if less than 200 pieces are included therein,
15、 for determination of compliance with specification requirements. If one piece fails to meet the requirements, two other pieces shall be tested. If either of these pieces fails to conform to the requirements of this specification, the lot of material represented by these samples shall be rejected. A
16、 lot shall be considered that quantity of material offered for inspection at one time that bears the same heat and coating identification. 5.3. Acceptance by Brand Registration and Guarantee: 5.3.1. By mutual agreement between the fabricator and engineer, acceptance may be based on a brand registrat
17、ion and guarantee filed with the engineer by the fabricator. For acceptance of a brand, the fabricator shall furnish a brand registration and guarantee meeting the approval of the engineer and showing the brand name or designation, the manner in which it will appear on the fabricated beams, the typi
18、cal mechanical properties, chemical composition if specified, the class and type of guardrail, and other specified properties. The fabricator shall also guarantee that as long as material is furnished under that brand and designation, it will conform fully to the requirements of the specification an
19、d shall be replaced without cost to the engineer when found not in conformity with any of the specified requirements. The brand registration and guarantee shall be sworn to for the fabricator by a person having legal authority to bind the company. Upon approval of a brand registration and guarantee,
20、 that brand will be accepted without further certification. If, in subsequent actual field use, there is evidence of misbranding as determined by random sampling and detection of inadequate tensile strength, yield strength, elongation, improper coating, deficient thickness, or improper fabrication,
21、the material will be rejected and approval for further use withdrawn until subsequently reapproved. Samples for test of any material offered for use may be taken at any time deemed desirable by the engineer. 5.3.2. The manufacturer or fabricator shall make such tests and measurements as necessary to
22、 ensure that the material produced complies with all specification requirements. These tests and measurements shall be so identified by the identification symbols or code used on the beam that the manufacturer can produce specific reports showing these test results. Copies of reports of these tests
23、shall be kept on file and shall be submitted to the engineer on request. 5.3.3. The brand shall be removed or obliterated by the manufacturer or fabricator on all material where control tests, as outlined herein, do not show conformance to this specification. 6. MATERIALS 6.1. Base MetalThe beam, tr
24、ansition, end, and buffer sections shall consist of sheet produced from electric arc furnace or basic oxygen furnace steel and shall meet the mechanical properties specified in Section 8. The chemical composition of the base metal for Type IV beams shall be as approved by the engineer. 6.2. ZincThe
25、zinc used for the coating of Type I and II sections shall be as prescribed in ASTM B6, and shall be at least equal to the grade designated as “Prime Western.” 6.3. Zinc-Aluminum-Magnesium AlloyThe zinc-aluminum-magnesium alloy for Types V and VI shall contain 513 percent aluminum, 24 percent magnesi
26、um, and up to 1 percent total additional alloying elements (except iron), and the balance zinc as prescribed in ASTM A1046/A1046M Coating Bath Composition, Table 6 Type 1. 6.4. Bolts and Nuts: 6.4.1. Unless otherwise specified, bolts and nuts for Types I, II, and III beams shall conform to or exceed
27、 the requirements of ASTM A307 and shall be coated in accordance with Section 9.4. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4d M 180-4 AASHTO 6.4.2. Bolts and nuts for Type IV beams shall be o
28、f an approved corrosion resistant material and conform to or exceed the requirements of ASTM A307. 6.4.3. All connections or splices shall be formed with oval shoulder button headed bolts to minimize projections on the roadside of the guardrail. Splice and post bolts and nuts shall conform to one of
29、 the configurations shown in Figures 1 or 2. Either of the alternate configurations may be furnished unless otherwise specified by the engineer. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4d M 1
30、80-5 AASHTO Note: Oval shoulder shall have smooth radii and shall maintain an essentially full vertical height of the apex of the oval. All dimensions shown on Alternate Bolt No. 1 also apply to Alternate Bolt No. 2. All dimensions are subject to manufacturers tolerances except where allowable toler
31、ances are shown. Figure 115.88-mm (5/8-in.) Post or Splice Bolt and Nut 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4d M 180-6 AASHTO Notes: 1. The bolt shall have M16 2 threads as defined in ANS
32、I B1.13M for Grade 6 g tolerances. Bolt material shall conform to ASTM F568M (withdrawn 2012) for Class 4.6. Material for corrosion resistant bolts shall conform to ASTM F568M for Class 8.8.3 bolts. 2. Nuts shall have ANSI B1.13M M16 2 Grade 6H threads. The geometry of the nuts, with the exception o
33、f the recess shown in the drawing, shall conform to ANSI B 18.2.4.1M Style 1 for zinc-coated hex nuts, and ANSI B18.2.4.6M heavy-hex corrosion-resistant nuts shall conform to the requirements of ASTM A563M for Class 8S3. Zinc-coated nuts shall be tapped oversize as specified in ASTM A563M, except th
34、at a diametrical allowance of 510 mm shall be used instead of 420 mm. 3. Dimensional tolerances not shown or implied are intended to be those consistent with the proper functioning of the part, including its appearance and accepted manufacturing practices. Figure 216-mm Post or Splice Metric Bolt an
35、d Nut 6.5. Washers and Backup Plates: 6.5.1. Washers shall be rectangular as shown in Figure 3. Washers for Types I, II, III, V, and VI beams shall be galvanized in accordance with Section 9. Washers for Type IV beams shall be of an approved corrosion-resistant steel. Backup plates if specified for
36、use at non-splice points shall consist of 305-mm (1-ft) sections of beams and shall be of the same class and type specified for the full-length beams. 6.6. End or Buffer Sections: 6.6.1. End or buffer sections shall be of the same or greater thickness of the metal and the same type as the beam to wh
37、ich it is attached, or the engineer may specify the minimum thickness of the metal and type. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4d M 180-7 AASHTO 7. MANUFACTURE 7.1. The beams and end or
38、 buffer sections shall be shaped and punched in conformance with the requirements shown in Figures 3 and 4. Transition sections shall be fabricated in accordance with Figure 5 and shall provide a smooth and uniform transition between beams. They shall be ready for assembly when delivered. Only drill
39、ing or cutting necessary for special connections and for sampling will be permitted in the field. Warped or deformed beams will be rejected. Beams to be erected on a radius of 46 m (150 ft) or less shall be shop-curved to the appropriate curvature of the installation. 8. MECHANICAL PROPERTIES 8.1. T
40、he mechanical properties of the base metal shall conform to the following requirements: 8.1.1. Beams and Transition Sections: Yield point, minimum, 345 MPa (50,000 psi); Tensile strength, minimum 483 MPa (70,000 psi); and Elongation, in 50 mm (2 in.), minimum, 12 percent. 8.1.2. End and Buffer Secti
41、ons: Yield point, minimum, 227 MPa (33,000 psi); and Tensile strength, minimum 310 MPa (45,000 psi). 8.1.3. Test specimens for mechanical properties shall be prepared and tested as specified in ASTM A924/A924M. Correction for thickness of specimens shall be as follows: Table 1Coating Thickness Corre
42、ction Weight of Coating Minimum Single-Spot Correctiona,bMinimum Single-Spot Minimum Triple-Spot Type g/m2oz/ft2g/m2oz/ft2mm in. I 550 1.80 610 2.00 0.08 0.0030 II 1100 3.60 1220 4.00 0.15 0.0060 V 245 0.80 275 0.90 0.04 0.0016 VI 305 1.00 350 1.15 0.05 0.0020 agalvanized coating mass : thickness (7
43、.14 g/m2= 1.00 m) (1.00 oz/ft2= 1.68 mils) bzinc-aluminum-magnesium alloy coating mass : thickness (6.01 g/m2= 1.00 m) (1.00 oz/ft2= 2.00 mils) 9. COATING REQUIREMENTS 9.1. Type I and II Beams: 9.1.1. The beams may be galvanized before or after fabrication. Beams galvanized before fabrication shall
44、be coated in accordance with ASTM A653/A653M. Beams galvanized after fabrication shall conform to the requirements of M 111M/M 111. Coating and testing requirements listed under M 180 shall govern. Sampling and testing not listed under M 180 shall be conducted in accordance with the referenced coati
45、ng specification. 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4d M 180-8 AASHTO 9.1.2. The mass of coating shall conform to the requirements prescribed in Table 2 for the types specified. The mas
46、s of coating is the total amount of galvanizing on both sides of a sheet or beam, expressed as grams per square meter (ounces per square foot) of the sheet or beam. Table 2Weight of Coating Weight of Coating Min Check Limit Single-Spot Test Min Check Limit Triple-Spot Test Type g/m2oz/ft2g/m2oz/ft2I
47、 550 1.80 610 2.00 II 1100 3.60 1220 4.00 Note: The “Spot” in Spot Test shall be a randomly selected location on the finished beam or sheet. The “Weight” of coating in Table 2 is deemed to be the combined weight on both sides of the beam or sheet at that spot. 2018 by the American Association of Sta
48、te Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4d M 180-9 AASHTO Notes: 1. All dimensions are subject to manufacturers tolerances except where allowable tolerances are shown. 2. All dimensions shown in millimeters unless otherwise noted.
49、 (All parenthetical values are in inches unless otherwise noted.) 3. Rectangular plate washers are optional only in the transition sections. They are not to be used in the main sections of strong-post guardrail. Figure 3W-Beam 2018 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4d M 180-10 AASHTO Notes: 1. All dimensions are subject to manufacturers tolerances except where allowable tolerances are
