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原文传递 Effect of Base-Connection Strength and Ductility on the Seismic Performance of Steel Moment-Resisting Frames

题名：	Effect of Base-Connection Strength and Ductility on the Seismic Performance of Steel Moment-Resisting Frames
正文语种：	英文
作者：	Tomasz Falborski; Pablo Torres-Rodas; Farzin Zareian, M.ASCE; Amit Kanvinde, M.ASCE
作者单位：	Gdansk Univ;Universidad San Francisco de Quito;Univ, of California
关键词：	Column-base connections; Steel moment-resisting frames (SMFs); Seismic response
摘要：	Column-base corm ections in steel moment-resisting frames (SMFs) in seismic regions are commonly designed to develop the capacity of adjoining column with an intent to develop a plastic hinge in the column member, rather than in the connection (i.e., a strong-base design). Recent research has shown base connections to possess high ductility, indicating that this practice may be not only expensive but also unnecessary. This suggests that concentrating inelastic rotations in the base connection may result in acceptable performance. Motivated by this finding, the performance of steel moment resisting frames with a weak-base design is investigated to examine the relationships between base-connection strength, deformation capacity, and structural performance. The main scientific basis of this study is nonlinear static pushover and nonlinear time history simulations on SMFs designed for high seismicity. These simulations interrogate parameters including frame height (4-, 8-, 12-, and 20-story), base-connection strength, base flexibility, and base rotation capacity, resulting in a total of 160 parametric combinations. The performance of each of these is assessed to estimate the probabilities of failure or collapse corresponding to a 2/50 (2% probability of exceedance in 50 years) intensity of shaking. The key finding is that for all frames, acceptable performance (i.e., comparable to current practice with capacity-designed bases) may be obtained by desig ning the base corm ections for overstrength seismic loads (i.e., based on the Q factor) rather than based on column capacity; this has the potential to offer significant cost savings. For a low-rise (i.e., four-story) frame, acceptable performa nee is achieved even without significant rotational demands in the base corm ection. For the other frames, a baseconnection rotation capacity of approximately 0.05 rad is necessary to achieve acceptable performance. Implications of these findings for prospective design practices, as well as future research, are outlined, and limitations are discussed.
出版日期：	2020
出版年：	2020
期刊名称：	Journal of Structural Engineering
卷：	Vol.146
期：	No.05
页码：	04020054