Seismic Performance of Reinforced Concrete Building Retrofitted by Multi-story Steel Braced Frame Subjected to Tri-lateral Earthquake Excitations

为了更好地评估多层钢支撑框架加固的钢筋混凝土（R/C）建筑在三向地震作用下的抗震性能，对以下两个主要课题进行了研究。本研究主要探讨多层钢支撑框架-钢筋混凝土组合结构在弯矩作用下的柱受拉破坏问题，课题A：研究钢筋混凝土组合结构在面内剪力、面外弯矩及柱轴力作用下的抗震性能，课题B：研究钢筋混凝土组合结构在面内剪力、面外弯矩及柱轴力作用下的抗震性能。观察和掌握剪力墙下钢筋混凝土导柱在钢支撑框架与导柱相邻安装时的运动性能。针对这些问题，进行了平面框架和带柱框架的三维框架结构的三向静力试验研究，并对框架和带柱框架的三维框架结构进行了多层钢支撑加固 ...更多信息 框架的三向静力分析、多层钢支撑框架加固带导柱的三维钢筋混凝土结构的三向静力分析和多层钢支撑框架加固平面钢筋混凝土结构在平面外弯矩作用下的三维非线性有限元分析。这些研究得出的结论如下。(1)在双向水平荷载作用下，加固后的钢筋混凝土框架的抗侧力比无面外荷载作用时的抗侧力小约10%。这是由于在双向弯矩作用下，钢筋混凝土边柱底部的混凝土过早受压破坏造成的。(2)当侧阻力达到峰值时，不仅一个由钢支撑框架加固的R/C边柱（与导柱相同）底部的混凝土受压失效，而且另一个边柱由于第二层横向剪力墙对R/C子组合与钢支撑框架的约束作用而产生的力传递而受到额外的压力。钢支撑框架中的钢竖弦杆代替混凝土，起到了防止两个钢筋混凝土边柱轴压倒塌的作用。(3)在钢筋混凝土建筑抗震加固设计中，钢筋混凝土边柱底部混凝土受压破坏和多层钢支撑框架加固的导柱底部混凝土受压破坏是一个值得注意的问题。多层钢支撑框架的设计是为了在两端钢筋混凝土边柱和中部钢支撑框架组成的工字形截面的底部形成柱拉伸屈服。少

Two principal subjects mentioned below were studied for good estimation of earthquake resistant performance in a reinforced concrete (R/C) building retrofitted by a multi-story steel braced frame subjected to tri-lateral earthquake excitations. This study focuses on the column tension failure due to bending moment in a R/C sub-assemblage with a multi-story steel braced frame.Subject A; to investigate seismic behavior of a retrofitted R/C building subjected to in-plane shear, out-plane bending moment and column axial load, and Subject B; to observe and grasp kinematic behavior of a R/C pilotis-column under a shear wall when a steel-braced frame is installed adjacently to the pilotis-column for preventing the column from collapse due to severe axial compression.Following studies were carried out to resolve these subjects; tri-lateral static loading test using a plane R/C frame and a three-dimensional R/C building with a pilotis-column which were retrofitted by a multi-story steel braced … More frame, tri-lateral static loading analysis using a 3-D R/C building with a pilotis-column retrofitted by a multi-story steel braced frame and nonlinear three-dimensional finite element analysis of a plane R/C frame retrofitted by a multi-story steel braced frame under out-plane bending moment. Concluding remarks taken by these studies are as follows.(1) Lateral resistance of a retrofitted R/C frame subjected to bi-directional horizontal loading was by approximately 10 percent smaller than that without out-plane loading. This was caused by premature compression failure of concrete at the bottom of R/C edge columns subjected to bi-axial bending moments.(2) When lateral resistance reached the peak, concrete failed in compression at the bottom of not only one R/C edge column retrofitted by a steel-braced frame, which is identical to a pilotis-column, but also another edge column which suffers additional compression due to force transfer derived from restraining effect of a transverse shear wall in the second story on the R/C sub-assemblage with a steel-braced frame. Steel vertical chords in a steel-braced frame contributed to prevent two R/C edge columns from axial collapse due to resisting compression force instead of concrete.(3) In the design for seismic rehabilitation to a R/C building, note that concrete may fail in compression at the bottom of a R/C edge column as well as the pilotis-column retrofitted by a multi-story steel-braced frame which is designed to form column tensile yielding at the base of a I-shaped section consisting of two R/C edge columns at both ends and a steel-braced frame at the middle portion. Less