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Earthquakes and Structures Volume 18, Number 1, January 2020 , pages 45-56 DOI: https://doi.org/10.12989/eas.2020.18.1.045 |
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Generation of synthetic accelerograms using a probabilistic critical excitation method based on energy constraint |
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Arsalan Bazrafshan and Naser Khaji
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| Abstract | ||
| The application of critical excitation method with displacement-based objective function for multi degree of freedom (MDOF) systems is investigated. To this end, a new critical excitation method is developed to find the critical input motion of a MDOF system as a synthetic accelerogram. The upper bound of earthquake input energy per unit mass is considered as a new constraint for the problem, and its advantages are discussed. Considering this constraint, the critical excitation method is then used to generate synthetic accelerograms for MDOF models corresponding to three shear buildings of 10, 16, and 22 stories. In order to demonstrate the reliability of generated accelerograms to estimate dynamic response of the structures, three target ground motions with considerable level of energy contents are selected to represent \"real critical excitation\" of each model, and the method is used to re-generate these ground motions. Afterwards, linear dynamic analyses are conducted using these accelerograms along with the generated critical excitations, to investigate the key parameters of response including maximum displacement, maximum interstory drift, and maximum absolute acceleration of stories. The results show that the generated critical excitations can make an acceptable estimate of the structural behavior compared to the target ground motions. Therefore, the method can be reliably implemented to generate critical excitation of the structure when real one is not available. | ||
| Key Words | ||
| critical excitation; non-stationary random process; total input energy per unit mass; synthetic accelerograms; energy constraint | ||
| Address | ||
| Arsalan Bazrafshan: Faculty of Civil and Environmental Engineering, Tarbiat Modares University, P.O. Box 14115–397, Tehran, Iran Naser Khaji: Department of Civil and Environmental Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan | ||