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http://dx.doi.org/10.5000/EESK.2006.10.3.057

Overstrength and Response Modification Factor in Low Seismicity Regions  

Lee, Dong-Guen (성균관대학교 건축공학과)
Cho, So-Hoon (탄탄스틸(주))
Ko, Hyun (성균관대학교 건축공학과)
Kim, Tae-Jin (성균관대학교 건축공학과)
Publication Information
Journal of the Earthquake Engineering Society of Korea / v.10, no.3, 2006 , pp. 57-64 More about this Journal
Abstract
Seismic design codes are mainly based on the research results for the inelastic response of structures in high seismicity regions. Since wind loads and gravity loads may govern the design in low seismicity regions in many cases, structures subjected to design seismic loads will have larger overstrength compared to those of high seismicity regions. Therefore, it is necessary to verify if the response modification factor based on high seismicity would be adequate for the design of structures in low seismicity regions. In this study, the adequacy of the response modification factor was verified based on the ductility and overstrength of building structures estimated from the result of nonlinear static analysis. Framed structures are designed for the seismic zones 1, 2A, 4 in UBC-97 representing the low, moderated and high seismicity regions and the overstrength factors and ductility demands of the example structures are investigated. When the same response modification factor was used in the design, inelastic response of structures in low seismicity regions turned out to be much smaller than that in high seismicity regions because of the larger overstrength of structures in low seismicity regions. Demands of plastic rotation in connections and ductility in members were much lower in the low seismicity regions compared to those of the high seismicity regions when the structures are designed with the same response modification factor.
Keywords
low seismicity regions; overstrength; ductility demand; plastic rotation angle; response modification factor;
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