水平二方向入力を受ける層崩壊型鋼構造多層骨組の倒壊挙動と終局耐震性能

摘要

現行の耐震設計では、強震下において骨組が梁崩壊型あるいはパネル崩壊型といった全体崩壊型のメカニズムを形成することを原則とする.一般的な多層骨組に多い冷間成形角形鋼管を柱に用いる場合では、全体崩壊型のメカニズムを実現するために必要な柱梁耐力比・柱パネル耐力比は設計マニュアルl)に示されているが、想定したとおりに全体崩壊型のメカニズムを形成したとしても、歪硬化に伴う梁やパネルの耐力上昇などによって柱が塑性化することは十分起こり得る.%In seismic design, moment resisting frame is designed to form the overall sway mechanism under severe earthquake. However, it is possible to form the weak column mechanism with the rise of strength of beams and panel zone due to strain hardening. The causes to collapse the weak column type frame are strong bi-axial seismic force, P- A effect and deterioration of restoring force. In this study, a series of response analyses of weak column type multi story steel frames under bi-axial ground motion are carried out. At first, using the elasto-perfectly-plastic hysteresis model, influence of the bi-axial ground motion and P- A effect on collapse behavior of frames are evaluated. Moreover, using the realistic hysteresis model including deteriorating range, collapse behavior and ultimate earthquake resistance of frames governed by deterioration of columns are evaluated.