Seismic Assessment of Asymmetric Building Systems
Date Issued
2007
Date
2007
Author(s)
Lin, Jui-Liang
DOI
en-US
Abstract
Plane-asymmetric structures that suffered from torsional and translational deformations are most vulnerable to seismic excitations. Instead of lengthy and complicated nonlinear response time history analysis, there is still void of a more systematic and simpler assessment method to deal with this type of structures. Thus, this research is conducted.
In this study, a more rational and informative multi-degree-of-freedom modal stick is derived for asymmetric structures from investigating the modal equation of motion representing the dynamic behavior of a single-degree-of-freedom (SDOF) modal stick.
At elastic state, the proposed modal sticks are equivalent eventually to the conventional SDOF modal stick. In addition, they can provide the information about the quantities of translational and rotational displacements at the center of mass observed in each mode. Meanwhile, at inelastic state, they can simulate the bifurcation of hysteretic loops due to the non-proportionality of the translational and rotational deformations. Hence, the interaction of translational and rotational motion is captured. Moreover, in utilizing the proposed modal sticks, the rotational displacement, velocity and acceleration at center of mass are available and are required to acquire the corner responses of asymmetric structures.
Several translational and rotational inelastic response spectra are constructed based from the proposed modal stick. It illustrated further that the SDOF modal stick is just a special case of the proposed modal stick. By investigating the constructed spectra, the trends on the responses resulted from varying the parameters in the proposed sticks are more understood as compared with the responses in SDOF modal stick. And, this will be helpful to the design of asymmetric structures and can be considered for the revision of code in the future.
It is believed that this study will provide a systematic, generalized and simpler assessment method to deal with asymmetric structures. Alongside, the contributions on the art of performance-based earthquake engineering are achieved. It is hoped also to extend these researches to probabilistic-based earthquake engineering.
Subjects
非線性動力分析
振態分析
振態桿狀模型
不對稱建築
偏心
nonlinear dynamic analysis
modal analysis
modal stick
asymmetric building
eccentricity
Type
thesis
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