1、Standard Method of Test for Helical Lock Seam Corrugated Pipe AASHTO Designation: T 249-03 (2016) Release: Group 2 (June 2016) American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-4b T 249-1 AASHTO Standard Method of Te
2、st for Helical Lock Seam Corrugated Pipe AASHTO Designation: T 249-03 (2016) Release: Group 2 (June 2016) 1. SCOPE 1.1. This method of test is to be followed in ascertaining the quality of the seam of a helical lock seam corrugated pipe. VISUAL METHOD 2. PROCEDURE 2.1. Determine lock seam quality by
3、 examining samples of the lock seam cross section sawed from the pipe. See Figure 1 for location of sample. See Figure 2 for the cross section of the sample. 2.2. The manufacturer will saw a triangular sample from the seam at one end of a length of pipe to show the cross section normal to the seam.
4、The base of the triangular sample shall be of sufficient width to show complete lock seam profile (see Figure 1). Figure 1Location of Sample 2.3. The edges of the sheets within the cross section of the lock seam shall lap at least 4.0 mm for pipe 250 mm or less in diameter and at least 7.9 mm for pi
5、pe greater than 250 mm in diameter, with an occasional tolerance of 10 percent of lap width allowable. The lapped surfaces shall be in tight contact. There shall be no visible cracks in the metal, loss of metal-to-metal contact, or excessive angularity on the interior of the 180-degree fold of metal
6、 at the completion of forming the lock seam. Measure the seam lap and retaining offset distances (Figure 2) for conformance with specified maximum or minimum dimensions. See Figure 3 for examples of unacceptable seam cross sections. WidthApprox 25 mm forPipes 250 mm orless in DiameterApprox 30 mm fo
7、rPipes greater than250 mm in Diameter 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4b T 249-2 AASHTO Figure 2AType I Lock Seam Cross Section Figure 2BType IR Lock Seam Cross Section Figure 2CType
8、IA Lock Seam Cross Section Detail Att = Sheet ThicknessRetainingOffsetNeutralAxisPitchSeeDetail ARetainingOffsetRetainingOffsetPoint ofContact1/2PitchLapt = Sheet ThicknessRetaining OffsetPoint ofContact1/2Distance between RibsLapOutside ofPipett = Sheet ThicknessRetaining OffsetPoint ofContactLapOu
9、tside of Pipet 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.TS-4b T 249-3 AASHTO Figure 3Examples of Unacceptable Seams TENSION TEST METHOD 3. APPARATUS 3.1. A standard calibrated tensile testing mac
10、hine. 4. TEST SPECIMEN 4.1. Cut a sample from the end of a fabricated pipe by sawing or burning, with dimensions at least 100 mm parallel to the lock seam and 150 mm perpendicular to the lock seam. If the ends of the pipe have been rerolled to form annular corrugations, take the sample from an area
11、that has not been rerolled unless it is specifically intended to test for the seam strength after rerolling. 4.2. Trim the edges of the sample by sawing to provide a test specimen 25 mm wide (measured parallel to the lock seam), with the edges parallel (see Figure 4). Figure 4Type of Lock Seam Coupo
12、n Tension Specimen 4.3. Flatten the ends of the specimen for gripping in the testing machine, using a vise or similar tool. Insert one end at a time into the vise to 13 mm from the lock seam. As the vise flattens the corrugations, the unrestrained end will rotate. Realign the lock seam with the flat
13、tened ends by use ExcessiveInterior AngularityExcessiveInterior Angularityand Roller IndentationInsufficientRetaining OffsetPiece Cut from Pipefor Lock Seam Specimen100 mm150 mm25 mm25-mm-Wide LockSeam Specimen Saw Cut 2016 by the American Association of State Highway and Transportation Officials. A
14、ll rights reserved. Duplication is a violation of applicable law.TS-4b T 249-4 AASHTO of a crescent wrench (or similar) tightened over the lock seam to prevent distortion of the seam itself while bending the strip back into line. 5. PROCEDURE 5.1. Measure the width of the specimen at the lock seam t
15、o the nearest 0.2 mm. Measure the thickness of the sheet to the nearest 0.02 mm to determine the nominal sheet thickness. 5.2. Insert the specimen in the testing machine and apply a tensile load until the specimen separates at the lock seam. Record the maximum load. 6. CALCULATION AND REPORT 6.1. De
16、termine the lock seam tensile strength by dividing the maximum load by the width of the specimen. Report the results as kilonewtons per meter (kN/m), and indicate whether the specimen is from an area where the corrugations have been rerolled. 2016 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.
