FP-96 English Version - Eastern Federal Lands Highway Division

Section 555Bolt Sizeinches0.500.630.750.881.001.131.251.381.50Table 555-6Minimum Fastener Tension (1)AASHTO M 164pounds12,00019,00028,00039,00051,00056,00071,00085,000103,000AASHTO M 253pounds15,00024,00035,00049,00064,00080,000102,000121,000148,000(1) Equal to 70 percent of the specified minimum tensile strength of bolts (asspecified for tests of full size ASTM A 325 and ASTM A 490 bolts with UNCthreads loaded in axial tension) rounded to the nearest 1,000 pounds.For short grip bolts, direct tension indicators (DTI) with solid plates may beused to perform this test. First check the DTI with a longer grip bolt in theSkidmore-Wilhelm calibrator. The frequency of confirmation testing, numberof tests to be performed, and test procedure shall conform to (3) through(5) as applicable. Confirm the accuracy of the tension measuring device byan approved testing agency at least annually.Install fasteners together with washers of size and quality specified, locatedas required below, in properly aligned holes and tightened by any of themethods described in (3) to (6) inclusive to at least the minimum tensionspecified in Table 555-6 after all the fasteners are tight.If approved, tightening may be performed by turning the bolt while the nutis prevented from rotating when it is impractical to turn the nut. If impactwrenches are used, provide adequate capacity and sufficient air to tighteneach bolt in approximately 10 seconds.Do not reuse AASHTO M 253 fasteners and galvanized AASHTO M 164fasteners. If approved, other AASHTO M 164 bolts may be re-used once.Touching up or retightening previously tightened bolts that may have beenloosened by the tightening of adjacent bolts will not be considered as reuse,provided the snugging up continues from the initial position and does notrequire greater rotation, including the tolerance, than that required by Table555-7.442