Fundamental Study on Seismic Response of Steel Moment Frames Sustaining Beam-Hinging Mechanism

本研究旨在开发一个数值分析程序，精确地模拟钢框架的动力行为，并检查由分析结果得出的地震反应。框架为弱梁式框架，其梁相对于柱的全塑性弯矩弱。作者已经开发的框架分析程序不仅处理节点板，还处理柱基础，以保证纯钢框架的轨迹行为的准确性。为了进一步完善程序，在程序中实现了一个新的功能，这使得程序能够处理梁和钢筋混凝土板的复合作用。解析型主钢框架由一维有限元组成。此外，钢筋混凝土板在梁上沉降时，变形和应力-应变关系的一致性覆盖了整个恶化区域。利用新开发的程序进行了数值计算，比较了纯钢框架和裸钢框架与含R/C板框架的结果，研究了R/C板对整体框架性能的复合效应。因此，从数值研究中撤回了以下内容：(1)裸框架作为本征值的基本周期比加R/C板框架长5% ~ 10%。2)裸框架的最大层漂移角与含R/C楼板框架相同，为1.0 ~ 1.5倍。3)对于框架的最大层位移角，在适当增大梁的转动惯量的情况下，传统的塑性铰法得到了较准确的结果。

This research aims at developing a numerical analysis program, which precisely simulates dynamic behaviors of steel moment frames and at examining of seismic response derived from analytical results. The frames are weak-beam type frames, whose beams are weaker than their columns with respect to full plastic bending moment.The frame analysis program, which the author already has been developed, deals with not only joint panels but also column-bases for accuracy of trace behaviors of pure steel frames. For a further refinement of the program, a new function was implemented into the program, which makes the program be able to deal with composite action of beams and reinforced concrete slabs. The analytical main steel frame consists of one-dimensional finite elements. Moreover, the reinforced concrete slabs settled en the beams were modeled with the consistency of deformation and stress-strain relationship covering over deteriorating region.A numerical work was conducted using the new developed program to examine the composite effect of R/C slabs on the behaviors of over-all frames comparing results of pure or naked steel frames with those of frames with R/C slabs. As a result, followings were withdrawn from the numerical study; 1) The basic period as eigen-value of naked frames is longer than that of frames with R/C slabs from 5 to 10 percent. 2) The maximum story drift angle of naked frames is as large as that of frames with R/C slabs from 1.0 to 1.5 times. 3) As for the maximum story drift angle of frame, the legacy method, which is called as the plastic-hinge method gives rather accurate results in case where moment of inertia of beams are suitably increased.