ON THE EFFECTS OF CIRCULAR BOLT PATTERNS ON THE ...

3.2.4 Test Setup
The 400K compression/tension testing machine was used to apply a monotonic load to the T-Stubs.
All bolts were pretensioned to 70% of the ultimate strength (proof load) [1]. It is a common practice to
relate the bolt-force due to pre-tensioning, Fi, to a quantity that is easier to measure such as the applied
torque, T. The required torque was calculated to be 100. for a ½ in. diameter bolt. The detail
calculations to find a required applied torque are provided in Appendix-A. To verify the pre-tensioning
force in the bolts, the applied bolt force by wrench was compared by the data collected from the strain
gauges. The results revealed that the agreement between these two data set was satisfactory.
The specimens were covered with whitewash to permit better observation of the yielding within the
specimen. Two LVDT with 0.25 . stroke were installed on both sides of the specimen aligned with the
stem of the T-Stubs to measure the separation of the flanges during the test.
Figure 3-11, Figure 3-12, and Figure 3-13 show the locations of the LVDTs and the T-Stubs test
setup used for specimens TS-L, TS-S and TS-C, respectively. The instruments were calibrated prior to
the testing and connected to Vishay data acquisition system. The data was recorded using a PC-based
data acquisition system with the rate of two data points per second (2 Hz).
Figure 3-11 T-Stubs Test Setup With Line Bolt Pattern
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