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

The analyses were conducted by applying the increasing cyclic variable amplitude displacement at
the tip of the beam. The cyclic displacement amplitude followed the loading protocol in the AISC Seismic
Provisions [73], which is identical to the SAC loading protocol, and FEMA [74]. The loading protocol
composed of the following steps was incorporated in ABAQUS:
Step 1: 6 cycles with peak drift angle of 0.00375 rad
Step 2: 6 cycles with peak drift angle of 0.005 rad
Step 3: 6 cycles with peak drift angle of 0.0075 rad
Step 4: 4 cycles with peak drift angle of 0.01 rad
Step 5: 2 cycles with peak drift angle of 0.015 rad
Step 6: 2 cycles with peak drift angle of 0.02 rad
Step 7: 2 cycles with peak drift angle of 0.03 rad
Step 8 and further steps will be repeated with the drift angle of 0.01 rad for each 2 cycles until the
beam or connection zone reaches inelastic mode.
The loading protocol is shown in
Figure 5-4. The tip displacement corresponding to a story drift ratio of 0.01 rad was 2.4 in. (60 mm).
A rigid part (un-deformable mesh region) was attached to the tip of the beam to simulate a rigid beam
end-cap which distribute the load caused by the cyclic displacement control evenly at the tip of the beam
(Figure 5-3). Similarly, two rigid parts was attached at both ends of the column to distribute the support
reaction forces evenly at the tip of the column (see Figure 5-3).
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