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从20世纪70年代末开始,对偏心支撑框架(EBFs)已进行了许多试验和分析研究。但关于几何特征对于结构重量和整体非弹性性能影响的研究还非常有限。这类参数的研究需要对大量偏心支撑框架进行归纳,实际上,最优化设计对得到可靠结果也很重要。因此,编写了一个基于迭代优化设计的计算程序,用于设计偏心支撑框架。在本研究中,设计了420个考虑剪切屈服的连接,105个考虑弯剪屈服连接和105个考虑弯曲屈服的连接。采用DRAIN-2DX对20个SAC地面运动下的这类结构进行非弹性动力分析。通过改变DRAIN输入文件,使其自动计算,直到其中一个连接达到位移角限值,测量了每个结构所有的地震记录,并且采用合成比例因子用于比较结构的非弹性性能。由于AISC-2005给出的计算偏心支撑框架塑性转角连接的公式中,没有考虑柱末端的竖向位移,所以对其进行修正,以考虑这些位移并能用于非弹性分析当中。同时给出了几何特征对于结构抗震性能的影响。采用DRAIN-2DX对部分结构进行推覆分析,与其位移延性相对比。
Since the late 1970s, many experimental and analytical studies have been conducted on Eccentric Support Frames (EBFs). However, the research on the influence of geometric characteristics on the structural weight and overall inelasticity is still very limited. The research of such parameters needs to summarize a large number of eccentric support frames. In fact, the optimal design is also very important for obtaining reliable results. Therefore, a program based on an iterative optimization design has been written to design the eccentric support frame. In the present study, 420 connections considering shear yielding, 105 considering bending yielding connections and 105 considering yielding connections were designed. Inelastic dynamic analysis of such structures under ground motion of 20 SACs using DRAIN-2DX. The DRAIN input file is automatically calculated by changing it until one of the connections reaches the displacement angle limit, all the seismic records for each structure are measured, and a composite scale factor is used to compare the inelastic behavior of the structure. Since AISC-2005 does not consider the vertical displacement of the end of the column in the formula for calculating the plastic corner connection of an eccentric support frame, it is corrected to take these displacements into consideration and to be used in inelastic analyzes. At the same time, the influence of geometric characteristics on the seismic performance of the structure is given. Using DRAIN-2DX, part of the structure is subjected to pushover analysis, which is compared with the displacement ductility.