Creating an eccentrically braced frame model for application in seismic performance assessments.

摘要

This thesis was written to describe the process of creating a model of eccentrically braced frames (EBF) in order to determine the performance of EBFs in moderate seismic regions.;The author used the results of a shake table test in 1985 to calibrate the model. The model was able to predict the average roof displacement and the maximum link rotation on the second level of the test structure to within 13%. The author designed and created a different model for the same location and load conditions as the shake table test above, and found that the new model performed as well as the previous one, despite the design being weaker and the fact that it was designed according to modern standards. There was a 9.8% difference in the average roof displacement and a 3.5% difference in the maximum link rotation on the second level of the two models.;A preliminary performance assessment of a nine-story EBF designed for moderate seismic regions showed that there was a 75% probability that it would fail under design ground motions. Modal analysis showed that second mode behavior was responsible for that high probability of failure. Strengthening the links that were most vulnerable to that second mode behavior reduced the probability of failure under design ground motions to 2%.