详情

原文传递 Full-Scale Cyclic Testing of Low-Ductility Concentrically Braced Frames

题名：	Full-Scale Cyclic Testing of Low-Ductility Concentrically Braced Frames
正文语种：	英文
作者：	Cameron R. Bradley, S.M.ASCE; Larry A. Fahnestock, Ph.D., P.E., M.ASCE; Eric M. Hines, Ph.D., P.E., M.ASCE; Joshua G. Sizemore, S.M.ASCE
作者单位：	Tufts Univ;Univ, of Illinois at Urbana-Champaign
关键词：	Buildings; Earthquake-resistant design; Concentrically braced frames; Moderate seismic regions; Low-ductility systems; Reserve capacity; Full-scale testing; Metal and composite structures.
摘要：	Two full-scale, two-story, low-ductility steel concentrically braced frame (CBF) systems were tested to evaluate failure mechanisms, postelastic frame behavior, reserve capacity, and overall collapse performanee. These frames were designed for a moderate seismic region, where reserve capacity is emerging as a parameter that can be employed instead of primary system ductility to economically prevent seismic collapse. One test unit used a split-x bracing configuration and satisfied seismic detailing and proportioning requirements in the AISC Seismic Provisions for an ordinary concentrically braced frame (OCBF) with R — 3.25. The other test unit used a chevron CBF con figuration with R = 3 and included no seismic detailing. Each test unit was subjected to a quasistatic cyclic loading protocol and was cycled to total frame drifts in excess of 3.0%. rhe split-x OCBF exhibited ductile brace buckling behavior up to 1.5% total frame drift, but possessed little reserve capacity after two weld fractures. The R = 3 chevron CBF exhibited brittle brace buckling and subsequently developed several distinct reserve capacity mechanisms. These tests demonstrate overall hysteretic behaviors that are highly dependent on two underlying design parameters: system type and system configuration. OCBF brace local slenderness and connection capacity design requirements are effective for providing ductile brace-buckling behavior.The split-x configuration appears more vulnerable to developing multistory mechanisms that possess limited reserve capacity, but this can be improved with strategically placed, enhanced beam-column conn ections. The chevron configuration is more prone to single-story mechanisms that possess significant reserve capacity developed through beam and column flexure. DOI: 10.106l/(ASCE)ST.1943-541X.0001760. © 2017 American Society of Civil Engineers.
出版日期：	2017.06
出版年：	2017
期刊名称：	Journal of Structural Engineering
卷：	Vol.143
期：	NO.06
页码：	04017029