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水平地震作用下梁填充钢框架结构抗震性能研究
Study on Seismic Behavior of Deep Beam Infilled Steel Frame under Horizontal Earthquake Action
【作者】 胡立黎;
【导师】 郑宏;
【作者基本信息】 长安大学 , 结构工程, 2010, 博士
【摘要】 剪力墙和钢框架是两种常用的建筑结构体系。钢筋混凝土剪力墙大多呈脆性破坏且震后不易修复;钢框架结构侧向刚度小易引起非结构构件的破坏,因此在高地震烈度区的使用受到限制。为了满足建筑结构刚度能够在一定范围内变化,可把深梁作为一种新型抗侧力结构形式或加固构件。它能够在工厂预制、拆卸方便、可回收利用,符合建筑节能发展方向,因此可广泛应用于新建结构,已有建筑物改造和加固。本文根据模型试验、计算分析和静力弹塑性分析,研究该种结构的抗震性能,以推动深梁构件的应用。本文主要研究内容有:1.通过对纯钢框架、钢板深梁填充钢框架、钢筋混凝土深梁填充钢框架以及组合深梁填充钢框架在水平低周反复荷载作用下的模型试验研究,分析结构的变形性能,滞回曲线和耗能等抗震性能。试验证明:试件滞回曲线饱满,深梁可作为结构抗震设防的第一道防线,钢框架作为第二道防线;通过改变深梁跨高比可使框架初始刚度在一定范围内调幅,将钢板深梁或组合深梁作为抗侧构件或耗能构件(阻尼器)。相同尺寸下,钢筋混凝土深梁提高结构初始刚度最显著(比钢板深梁提高了41.2%),组合深梁次之;组合深梁的耗能性能最佳(比钢筋混凝土深梁的提高了27%);组合深梁比钢板深梁节省约33.3%,降低了钢材使用量。最后,对深梁的受力机理进行了分析。建议钢板深梁和组合深梁填充钢框架取弹性层间位移角限制为层高的1/300,弹塑性位移角限值为1/40;钢筋混凝土填充钢框架弹性层间位移角限值为层高的1/550,弹塑性层间位移角限值为1/50。建议采用跨高比属于(1,2)之间的钢筋混凝土深梁、钢板深梁和组合深梁。2.在外荷载作用下,深梁和钢框架组成的混合结构体系共同受力。将混合结构简化为简单的协同工作计算模型,分析深梁和钢框架之间的水平荷载分配。钢板深梁简化为:两个承载对边为固定约束,两个未承载的对边为自由边,利用能量法分析其在非均匀受压状态下的临界应力。允许钢材发生屈曲,以屈曲后强度作为极限状态,分析钢板深梁受弯屈曲后的有效高度。3.采用试验拟合的方法,分别建立能考虑刚度退化等特征的钢筋混凝土深梁、组合深梁和钢板深梁填充钢框架的恢复力模型,并给出恢复力模型中骨架曲线、滞回曲线各阶段刚度的退化规律。4.利用SAP2000有限元分析软件,对钢筋混凝土深梁填充钢框架的模型进行push-over分析并验证其可行性。同时建立一层和两层的足尺钢框架模型,分析填充钢筋混凝土深梁后的受力性能。
【Abstract】 Shear walls and steel frame are two commonly used system for building structure. Most of reinforced concrete shear wall is brittle failure and difficult to repair after the earthquake; Lateral stiffness of steel frame is small,so it easily lead to the destruction of nonstructural members. Therefore, it is limited in high earthquake fortification zone. In order to realize the modulation of structural stiffness in a certain range, Deep Beam can be as a new anti-lateral force member or the strenghening member. It can be widely used in the new building, and strenghening or renovation building. Based on the model test, calculation analysis and push-over analysis, seismic behavior of the structure was studied.The main content is described as follows:1. According to model test of pure steel frame, steel plate deep beam infilled steel frame (SDBF), reinforced concrete deep beam infilled steel frame (RDBF) and composite steel and concrete deep beam infilled steel frame (CDBF) under horizontal load, deformation, hysteresis curves and so on of these structure were analyzed.These results showed that: The hysteresis loops of the tests are replete;deep beam can be used as the first defence line of earthquake-resistance and the steel frame can be used as the second;by changing span-height ratio, the initial stiffness of the structure can be ajusted within a certain range; reinforced concrete deep beam is the most prominent in raising the initial stiffness; energy dissipation of composite steel and concrete is best.Finally, the failure mechanism of the deep beams were investigated.The thesis suggested that elastic angular displacement limited value is 1/300 and plastic angular displacement limited value is 1/40 of SDBF and CDBF; elastic angular displacement limited value is 1/550 and plastic angular displacement limited value is 1/50 of RDBF.2. The deep beam and steel frame composed of hybrid structural system to stressing under the external load. In order to analyse load distribution of the deep beam and the steel frame,the hybrid structural system can be simplified as a caulation model.The steel deep beam is simplified as:two opposite edges with load clamped and the other two without load free.Analyzing the critical stress of the beam under non-uniform pressed status with the energy method.Making the post-buckling strength as ultimate limit state to analyze the effective height after the bending of the steel deep beam.3. According to hysteresis loops of the tests, the thesis suggested restoring force mode of RDBF,SDBF and CDBF under horizontal load. The thesis also gave the stiffness calculative formulas of exponential and hysteresis curves.4. Finite element model of RDBF was established by the SAP2000 software to make push-over analysis and verify the feasibility.At the same time, one layer or two layers model of full-scale steel frames were established to analyze the structure performance with reinforced concrete deep beam.