ROTATIONAL CAPACITY TEST

FOR LONG BOLTS IN TENSION CALIBRATOR

 

SCOPE

This IM provides the test procedure for determining the rotational capacity of long bolts in the tension calibrator.  The Rotational Capacity (RC) Test for all high strength fasteners shall be performed in the shop and in the field as required by Standard Specification 2408.03, S.

 

EQUIPMENT REQUIRED

 

1.   Calibrated bolt tension measuring device of size required for bolts to be tested.

 

2.   Calibrated torque wrench.

 

3.   Shims shall have a minimum cross-sectional area of 5 times the cross-sectional area of the bolt being tested.  The hole in the shim adjacent to the washers shall not be larger than 1/16” than the bolt diameter being tested.

 

4.   Steel section to mount tension-measuring device (Flange of girder or cross frame accessible from the ground is satisfactory.)

 

PROCEDURE

 

1.   Install the bolt into the tension calibrator. Install the required number of shim plates and/or washers.  One washer under the nut must always be used to cover a minimum of three full threads.  A combined total of no more than five shims and washers may be used.  (Need a minimum of 2-3 threads behind nut, when properly installed.)

 

2.   Tighten the nut using a hand wrench to the initial tensions listed on the following page. Tolerance: - 0 kips / + 2 kips

 

                                                                                Table A1

 

Bolt Diameter (in.)

 

1/2

 

5/8

 

3/4

 

7/8

 

1

 

1 1/8

 

1 1/4

 

1 3/8

 

1 1/2

 

Initial Tension (kips)

 

1

 

2

 

3

 

4

 

5

 

6

 

7

 

9

 

10

 

                                                                               

3.   Match mark the bolt tip, nut, and the faceplate of the bolt calibrator in a straight line.

 

4.   Using the calibrated manual torque wrench, tighten the nut to at least the bolt tension listed below.  Record the values of the torque and tension.  Torque must be measured with the nut in motion.

 

                                                                                Table A2

 

Bolt Diameter (in.)

 

1/2

 

5/8

 

3/4

 

7/8

 

1

 

1 1/8

 

1 1/4

 

1 3/8

 

1 1/2

 

Tension (kips)

 

12

 

19

 

28

 

39

 

51

 

56

 

71

 

85

 

103

 

 

5.   Calculate and record the value: 0.25 x Bolt diameter (inches)/12 x Tension (kips) x 1000.  The torque measured and recorded in Step 4 must be equal to or less than this calculated value. Assemblies with torque values exceeding this calculated value fail the test.

 

6.   Further tighten the nut to the rotation listed below.  The rotation is measured from the initial marking in Step 3.  Record the bolt tension.  Assemblies fail the test if stripping or fracture occurs.

 

Table A3

 

Bolt Length

(Measured in Step 1)

 

4 x bolt diameter or less

 

Greater than 4, but no more than 8 x bolt diameter

 

Greater than 8 x bolt diameter

 

Required Rotation

 

2/3

 

1

 

1 1/3

 

7.   The bolt tension measured in Step 6 after the required rotation must equal or exceed the values in the table listed below. Assemblies, which do not meet this tension, have failed the test.

 

                                                                                Table A4

 

Bolt Diameter (in.)

 

1/2

 

5/8

 

3/4

 

7/8

 

1

 

1 1/8

 

1 1/4

 

1 3/8

 

1 1/2

 

Tension (kips)

 

14

 

22

 

32

 

45

 

59

 

64

 

82

 

98

 

118

 

 

8.   Loosen and remove the nut, and examine the threads on the nut and bolt.  No signs of thread shear failure, stripping, or torsional failure of the bolt should be evident.  Assemblies, which have evidence of stripping, fail the test.