1、Standard Specification for Steel Welded Wire Reinforcement, Deformed, for Concrete AASHTO Designation: M 221M/M 221-09 (2013) ASTM Designation: A497/A497M-07 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-4g M 221
2、M/M 221-1 AASHTO Standard Specification for Steel Welded Wire Reinforcement, Deformed, for Concrete AASHTO Designation: M 221M/M 221-09 (2013) ASTM Designation: A497/A497M-07 1. SCOPE 1.1. This specification covers welded wire reinforcement made from cold-worked drawn or rolled deformed wire, or a c
3、ombination of deformed and nondeformed wires, to be used for the reinforcement of concrete. Note 1Welded wire for concrete reinforcement has been described by various terms: welded wire fabric (WWF), fabric, and mesh. The wire reinforcement industry prefers the term “welded wire reinforcement” (WWR)
4、 as being more representative of the range of products being manufactured. Therefore, the term “welded wire fabric” has been replaced with the term “welded wire reinforcement” in this specification and in related specifications. 1.2. This specification is applicable for orders in either SI units (M
5、221M) or in inch-pound units (M 221). SI units and inch-pound units are not necessarily equivalent. Inch-pound units are shown in brackets in the text for clarity, but they are the applicable values when the material is ordered to M 221. Combining values from the two systems may result in nonconform
6、ance with the standard. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 32M/M 32, Steel Wire, Plain, for Concrete Reinforcement M 225M/M 225, Steel Wire, Deformed, for Concrete Reinforcement 2.2. ASTM Standard: A700-05, Standard Practices for Packaging, Marking, and Loading Methods for Steel Produc
7、ts for Shipment (withdrawn 2014) 2.3. Military Standard: MIL-STD-129, Marking for Shipment and Storage 2.4. Federal Standard: Fed. Std. No. 123, Marking for Shipments (Civil Agencies) 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a
8、 violation of applicable law.TS-4g M 221M/M 221-2 AASHTO 3. TERMINOLOGY 3.1. Description of Terms Specific to This Standard: 3.1.1. convoluted wirewhen wire for welded wire reinforcement is shaped into a sinusoidal wave shape, it is commonly referred to as “convoluted wire.” The wire is used in the
9、manufacture of cages for certain applications of concrete pipe reinforcing. Only nondeformed wire is normally subject to convolution. 3.1.2. welded wire reinforcementas used within the scope and intent of this specification, welded wire reinforcement designates a material composed of cold-worked ste
10、el wire, fabricated into sheets or rolls by the process of electric-resistance welding. The finished material shall consist essentially of a series of longitudinal and transverse wires arranged substantially at right angles to each other and welded together at points of intersection. 4. ORDERING INF
11、ORMATION 4.1. Orders for material to this specification should include the following information: 4.1.1. Quantity (mass or square area); 4.1.2. Name of material (deformed welded wire reinforcement for concrete reinforcement); 4.1.3. Wire spacing and sizes; 4.1.4. Minimum yield strength if Supplement
12、 S1 of M 225M/M 225 applies; and minimum yield strength if wire conforming to M 32M/M 32 is to be used and Supplement S1 of M 32M/M 32 applies; 4.1.5. Exclusion of oversteeling, if required (Section 9.4.1); 4.1.6. Length and width of sheets or rolls; 4.1.7. Packaging (Section 16); and 4.1.8. AASHTO
13、designation and year of issue. Note 2A typical ordering description is as follows: 930 m2welded deformed wire reinforcement for concrete reinforcement, 150 300-D6 D2 in flat sheets 2.4 m wide by 6.1 m long, in secured lifts, to M 221M-_. 10,000 ft2welded deformed wire reinforcement for concrete rein
14、forcement, 6 12-D6 D2 in flat sheets 96 in. wide by 240 in. long, in secured lifts, to M 221-_. 5. MATERIALS 5.1. The wire used in the manufacture of welded wire reinforcement shall conform to M 225M/M 225 and its Supplement S1, if so ordered, either solely or in combination with wire conforming to
15、M 32M/M 32 and its Supplement S1. 5.2. Welded wire reinforcement shall be furnished either in flat sheets, or in rolls, as specified by the purchaser. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4
16、g M 221M/M 221-3 AASHTO 6. MANUFACTURE 6.1. The wires shall be assembled by automatic machines or by other suitable mechanical means that will assure accurate spacing and alignment of all wires of the finished welded wire reinforcement. 6.2. Longitudinal and transverse wires shall be securely connec
17、ted at every intersection by a process of electrical-resistance welding, which employs the principle of fusion combined with pressure. 6.3. Wire of proper grade and quality when fabricated in the manner herein required in this specification shall result in a strong, serviceable, mat-type product hav
18、ing substantially square or rectangular openings. It shall be fabricated and finished in a workmanlike manner, shall be free of injurious defects, and shall conform to this specification. Note 3A variation of manufacturing includes the application of one or more longitudinal convoluted wires at one
19、edge of welded wire reinforcement for concrete pipe reinforcing cages. This shape allows the cage ends to be expanded to a larger diameter to accommodate the bell-shaped ends of concrete pipe. 7. MECHANICAL PROPERTY REQUIREMENTS 7.1. TensileWire for the production of welded wire reinforcement, defor
20、med, is described in M 225M/M 225. Tensile tests may be made on wire cut from the welded wire reinforcement and tested either across or between the welds; no fewer than 50 percent shall be across welds. Tensile tests across a weld shall have the welded intersection located approximately at the cente
21、r of the wire being tested and the cross wire forming the welded joint shall extend approximately 25 mm 1 in. beyond each side of the welded joint. Note 4Tensile and bend testing are normally done at the time wire is drawn. The manufacturers finished product still must satisfy the mechanical propert
22、ies when tested after fabrication. 7.2. Bend TestThe wire shall withstand the bend test as described in M 225M/M 225 and shall be performed on a specimen taken from between the welds. 7.3. Weld Shear StrengthThe weld shear strength between longitudinal and transverse wires shall be tested as describ
23、ed in Section 8. The minimum average shear value in newtons shall not be less than 241, multiplied by the nominal area of the large wire in square millimeters or in pounds-force, shall not be less than 35,000, multiplied by the nominal area of the larger wire in square inches, where the smaller wire
24、 is not less than MD25 D4 and has an area of 40 percent or more of the area of the larger wire. 7.3.1. Welded wire reinforcement having a relationship of larger and smaller wires other than that covered in Section 7.3 shall meet an average weld shear strength requirement of not less than 3.6 kN 800
25、lbf provided that the smaller wire is not smaller than MD25 D4. 7.3.2. Weld shear tests for determination of conformance to the requirements of Section 7.3 shall be conducted using a fixture as described in Section 8. 7.3.3. Four welds selected at random from the specimen described in Section 11.2 s
26、hall be tested for weld shear strength. The transverse wire of each test specimen shall extend approximately 25 mm 1 in. on each side of the longitudinal wire. The longitudinal wire of each test specimen shall be of such length below the transverse wire so as to be adequately engaged by the grips of
27、 the testing machine. It shall be of such length above the transverse wire that its end shall be above the center line of the upper bearing of the testing device. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applica
28、ble law.TS-4g M 221M/M 221-4 AASHTO 7.3.4. The material shall be deemed to conform to the requirements for weld shear strength if the average of the four samples complies with the value stipulated in Section 7.3. If the average fails to meet the prescribed value, all the welds across the specimen sh
29、all then be tested. The welded wire reinforcement will be acceptable if the average of all weld shear test values across the specimen meets the prescribed minimum value. 8. WELD SHEAR TEST APPARATUS AND METHODS 8.1. As the welds in welded wire reinforcement contribute to the bonding and anchorage va
30、lue of the wires in concrete, it is imperative that the weld acceptance tests be made in a jig that will stress the weld in a manner similar to which it is stressed in concrete. In order to accomplish this, the vertical wire in the jig must be stressed in an axis close to its center line. Also, the
31、horizontal wire must be held closely to the vertical wire, and in the same relative position to prevent rotation of the horizontal wire. When the welded wire reinforcement is designed with different wire sizes, the larger diameter wire is the “vertical wire” when tested. (See Figure 1.) Figure 1Weld
32、ed Wire Reinforcement Weld Tester 8.2. Figure 1 shows the details of a typical testing jig together with two anvils, which make it possible to test welds for wire up to 16 mm 0.625 in. in diameter. This testing jig can be used in most tension testing machines and should be hung in a ball-and-socket
33、arrangement at the center of the machine. This, or a similarly effective fixture designed on the same principle, is acceptable. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4g M 221M/M 221-5 AASHTO
34、 8.3. Test specimens should be inserted through the notch in the anvil using the smallest notch available in which the vertical wire will fit loosely. The vertical wire shall be in contact with the surface of the free rotating rollers while the horizontal wire shall be supported by the anvil on each
35、 side of the slot. The bottom jaws of the testing machine shall grip the lower end of the vertical wire and the load shall be applied at a rate of stressing not to exceed 690 MPa/min 100 ksi/min. 9. DIMENSIONS 9.1. WidthThe width of welded wire reinforcement shall be considered to be the center-to-c
36、enter distance between outside longitudinal wires. The permissible variation shall not exceed 13 mm 0.5 in. than the specified width. In case the width of flat sheets or rolls is specified as the overall width (tip-to-tip length of cross wires), the width shall not vary more than 25 mm 1 in. from th
37、e specified width. When measurements involve a convoluted wire, the measurement shall be made to the approximate center of the sinusoidal wave shape. 9.2. LengthThe overall length of flat sheets, measured on any wire, may vary 25 mm 1 in., or 1 percent, whichever is greater. 9.3. Overhang of the tra
38、nsverse wires shall not project beyond the center line of each longitudinal edge wire more than a distance of 25 mm 1 in., unless otherwise specified. When transverse wires are specified to project a specific length beyond the center line of a longitudinal edge wire, the permissible variation shall
39、not exceed 13 mm 0.5 in. greater or less than the specified length. 9.4. The permissible variation in weight of any wire in the finished welded wire reinforcement shall conform to the tolerances prescribed for the wire before fabrication, in M 225M/M 225, with the following exceptions: 9.4.1. Unless
40、 otherwise precluded by the purchaser, the manufacturer will be permitted to apply oversized wire (not undersized). The size differential shall not exceed one “D” size increment on sizes D8 and smaller, and two “D” size increments on sizes larger than D8. In all cases in which such oversteeling is p
41、racticed, the producer shall identify the welded wire reinforcement with the style originally ordered. 9.5. The average spacing of wires shall be such that the total number of wires contained in a sheet or roll is equal to or greater than that determined by the specific spacing, but the center-to-ce
42、nter distance between individual members may vary not more than 6.4 mm 0.25 in. from the specified spacing. It is understood that sheets of welded wire reinforcement of the specified length may not always contain an identical number of transverse wires and, therefore, may have various lengths of lon
43、gitudinal overhang. 10. WORKMANSHIP 10.1. Wire of proper grade and quality, when fabricated in the manner herein required, shall result in a strong, serviceable, mat-type product having substantially square or rectangular openings. It shall be fabricated and finished in a workmanlike manner, as dete
44、rmined by visual inspection, and shall conform to this specification. 11. SAMPLING 11.1. Test specimens for testing mechanical properties shall be obtained by cutting from the finished welded wire reinforcement a full-width section of sufficient length to perform testing as described in Sections 7.1
45、 and 7.2. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4g M 221M/M 221-6 AASHTO 11.2. Test specimens for determining weld shear properties shall be obtained by cutting from the finished welded wire
46、 reinforcement a full-width section of sufficient length to perform testing as described in Section 7.3.3. 11.3. Measurements for conformance to dimensional characteristics shall be made on full sheets or rolls. 11.4. If any test specimen exhibits obvious imperfections, it may be discarded and anoth
47、er specimen substituted. 12. NUMBER OF TESTS 12.1. One test for conformance to tensile strength and bend requirements shall be made for each 7000 m275,000 ft2 of welded wire reinforcement or remaining fraction thereof. For testing prior to fabrication, one test for each 18 Mg 20 tons of wire shall b
48、e made. 12.2. One test for conformance to weld shear strength requirement shall be made for each 28 000 m2300,000 ft2 or remaining fraction thereof. 13. INSPECTION 13.1. The inspector representing the purchaser shall have free entry, at all times, while work on the contract of the purchaser is being
49、 performed, to all parts of the manufacturers works that concern the manufacture of the material ordered. The manufacturer shall afford the inspector all reasonable facilities to assure that the material is being furnished in accordance with this specification. 13.2. Except for yield strength, all tests and inspections shall be made at the place of manufacture prior to shipment, unless otherwise specified. Such tests shall be conducted so as not to interfere unnecessarily with the operation of the works. 1
