5-79
8.Test bolts that are too short to fit in the tension-measurin g device in a solid joint such as a bearing stiffener or connection plate. The hole in t he joint may not be more than 1/16 inch greater in diameter tha n the bolt being tested. Rand omly select two fastener assemblies from each R-C lot. Mark the nut relative to the ste el joint in such a manner that rotation can be measured. Snug tighten the bolt with a spud wr ench using approximately the same effort used to snug-tighten longer bolts in a tension meas uring device. Restrain the bolt with a wrench to prevent rotation. Rotate the nut from sn ug tight to 1/3 turn with a torque wrench. Record the torque required to reach that rotati on while the turned element is in motion. If the measured torque exceeds the maximum torque l isted in Table 3 the fasteners have failed the test. If the fasteners fail the firs t test, re-lubricate all fasteners from that R-C lot, randomly select t wo samples and re-test. If ther e is no stripping or fracture the fasteners pass. If the either fastener fails the second test, the R-C lot is rejected. Table 3 Maximum Allowable Torque Bolt Diameter (inches) 3/4 7/8 1 1 1/8 1 1/4 1 3/8 1 1/2 Torque (ft-lbs) 500 820 1230 1500 2140 2810 3690
9.Discard bolts used for the Rotational Capacity Test.
504.49 DTI Verification Test Perfo rm the DTI Verification Test for each production lot
of DTIs in combination with eac h R-C lot of fasteners. If any of the three test assemblies fails, three additional samples from the same production lot sh all be tested as the first. If any of the three samples fails the second test, the lot shall b e rejected. Perform the test in TWO STEPS:
1.Step 1 is a test to determine that the DTI’s are acceptabl e when the fastener is brought to the minimum allowable tension. a) Randomly select three fastener assemblies from each R-C lot.
b.Install each bolt in the tension-measuring device with the b olt head bearing against the faceplate (the front of the tension-measuring device). Pla ce the DTI under the bolt head with the protrusions bearing aga inst the washer face of the bol t. This is done so that the DTI is accessible for inspection with a feeler gauge. Install the nut and hardened washer using a filler sleeve between the bolt bushing (the back of the tension -measuring device) and the hardened washer under the nut. Two or more hardened washers ma y be used under the nut instead of a filler sleeve if the washers do not interfere with the proper operation of the tension-measuring device. When the bolt is brought to snug-tig ht condition, there should be 3 to 5 threads visible.
c.Using two wrenches, one to restrain the unturned element of the bolt assembly, tighten the nut to the Bolt Tension listed in Table 4. If an i mpact wrench is used, tighten the bolt to approximately 50% of the required tension and use a tor que wrench to bring the fastener to the required tension. 5-80 TABLE 4- Minimum Installation Tension
U.S. Customary Bolt Diameter (inches) 5/8 3/4 7/8 1 1-1/8 1-1/4 1-1/2 Bolt Tension (kips) 20 29 41 54 59 75 108
d.Using a thickness gauge pr ovided by the DTI manufacturer, r ecord the number of spaces between the protrusions on the DTI that a 0.005 inch thi ckness gage is refused.
e.If the number of refusals exceeds the number in Table 5, the DTI has failed the DTI Verification Test for minimum tension. Reject the DTI lot. TABLE 5 *If the test is a coated DTI, the maximum number of spaces the gage is refused is the number of spaces on the DTI minus one
2.Step 2 is to determine the maximum bolt tension allowable u sing a DTI.
a.After completing step 1, the bolt shall be further tighten ed to the smallest gap to be used during installation. Normally, this is defined as a condi tion where all gaps refuse a 0.005 inch gage but at least one visible gap remains.
b.Remove the bolt from the tension measuring device and turn the nut on the threads of the bolt by hand. If the nut ca n be run the length of the th reads, excluding the thread run out, the DTI lot is acceptable. I f the nut is unable to run th e thread length at the smallest gap condition (defined in a) above), the test shall be performed ag ain using a larger acceptance gap.
504.50 Installation and Tensioning High Strength Bolts Select one of the methods listed
below for installing and tensioning high strength bolts. Do no t use standard torque determined by the use of tables or formulas that attempt to rel ate torque to tension.
504.51 Installation Install a hardened washer under the turned element and a hardened
washer on oversize holes. Install fasteners in all holes in a contiguous group, except for holes containing drift pins and br ing them to a snug tight cond ition, progressing systematically from the most severely restrained location in a connection to the free edges. Do not remove the drift pins until a minimum of 50% of the fast eners have been tensioned. Do not force the bolts. If the bolts cannot be installed easil y by hand, correct the hole alignment by installing more drift pins. Bolt Diameter (inches) ¾, 7/8 1, 1-1/8 1-1/4, 1-3/8 Number of Spaces in DTI 5 6 7 Maximum Number of gaps in which gage is refused * 2 2 3
Source: Maine Standard Specifications for Road and Bridge Construction, 2020 Edition. Pages 371–372 of 817.