Earthquake Response Analysis of Steel Frames with Composite Beams by Computer-Actuator On-Line System

本文利用“微机-执行器联机系统”对钢框架-混凝土金属楼板组合框架体系进行了地震反应分析。“该系统即使是因混凝土破碎等而使恢复力降低的框架，也能够进行精确的响应分析，分析的框架为单跨单层刚性框架，结构尺寸约为足尺结构的一半。组合梁是由钢梁和混凝土板组成的完全组合梁。在“在线试验”前，根据静力试验得到的组合框架的弹性层刚度和框架的预定质量计算框架的自振周期。“分析中采用的地面加速度是埃尔森特罗NS分量（1940）。加速度的最大值约与每一框架屈服加速度的0.95倍成正比。（1）最大反应层位移与框架变形能力的关系，（2）最大反应梁转角与组合梁转角承载力的关系;（3）混凝土板的存在对结构地震反应的影响;（4）结构自振周期对结构响应的影响;（5）混凝土板刚度对结构响应的影响;（6）“在线系统”变形控制方法的可靠性。"

Earthquake response analyses of composite frames, which are defined as steel frames plus a metal decking concrete floor system, were carried out by the "Computer-Actuator On-Line System." This system enables a precise response analysis of even a frame whose restoring force is deteriorated by concrete crushing, etc., without assuming any analytical model of complicated hystersis loops of the frame.Analyzed frames are one bay-one story poetal rigid frames and about half the size of the full scale structure. Composite beams which consist of a steel beam and a concrete slab are disigned so as to be fully composite beams. Natural periods of the frames are calculated based on the predetermined mass of the frames and the elastic story stiffness of the composite frames obtained from static tests prior to the "On-Line Test." A ground acceleration abopted in the analysis is EL centro NS component (1940). The maximum values of the acceletaton are proportioned to approximately 0.95 time of the yield acceleration of each frame.As concluding remarks, the results of the response analysis sre fiscussed from the following six aspects; (1) Relationships between the maximum response story displacements and the deformation capacities of the grames, (2) Relationships between the maximum response beam rotations and the rotation capacities of the composite beams, (3) Effects of the presence of concrete slabs on the earthquake response of structures, (4) Influence of the natural periods of the structures on the response od structures, (5) Effects of the stiffness of concrete sdlabs on the response of structures, and (6) Reliability of the deformation control method of the "On-Line System."