Collapse Behavior of Building Frames under Severe Earthquakes and Performance-based Seismic Design Method

本项目旨在揭示建筑框架在强震作用下的倒塌行为，并开发一种新的基于性能的抗震设计方法。在本项目中获得了以下结果：据了解，当建筑物框架受到强烈地震时，变形集中在建筑物框架的下部几块石头上。推导了抑制这种低楼层变形集中和抑制漂移的条件。数值响应分析验证了这些条件的有效性。对三层一跨钢框架模型进行了恒定垂直荷载和重复水平荷载作用下的静动力试验。建立了一种新的弓形变形起始和振动中心漂移起始的预测方法。经证实，这些预测与实验结果吻合得很好。提出了一种新的响应分析方法，可以模拟梁端破坏和滞回阻尼器破坏。通过新开发的数值分析程序揭示了这些破坏对建筑框架地震反应的影响。提出了一种寻找弹性脆性构件发生断裂时荷载-位移关系中不稳定平衡路径的新方法。提出了一种分析建筑物框架断裂发展的方法，并推导了其稳定性判据。提出了一种新的基于性能的抗震设计方法。设计了剪力建筑模型的层间刚度，使剪力建筑模型在设计中地震作用下具有一定的层间位移分布。然后通过简化模型-框架逆变换确定相应框架模型的成员大小。设计强震下的另一种设计方法是利用新开发的等效线性化方法。少

The purpose of this project is to disclose collapse behaviors of building frames under severe earthquakes and to develop a new performance-based seismic-resistant design method. The following results have been obtained in this project.1. It has been revealed that, when a building frame is subjected to severe earthquakes, deformation concentration could happen on lower few stones of a building frame. The conditions have been derived for suppression of such deformation concentration on lower few stories and for suppression of drifts. The validity of these conditions has been demonstrated through numerical response analysis.2. Static and dynamic experiments on three-story one-span steel frame models have been conducted under constant vertical loads and repeated horizontal loads. A new prediction method of initiation of bow-shaped deformation and initiation of drift of the vibration center has been constructed. It has been confirmed that these predictions coincide well with the experimenta … More l results.3. A new response analysis method has been developed which can simulate failure at beam ends and failure of hysteretic dampers. The effects of these failures on the seismic response of building frames have been disclosed via the newly developed numerical analysis program.4. A new method has been developed for finding an unstable equilibrium path in the load-displacement relation in the case where a fracture develops in a structure consisting of elastic brittle members. An analysis method of fracture development in a building frame has been presented and its stability criterion has been derived.5. A new performance-based seismic-resistant design method has been developed. The story stiffnesses of a shear building model have been designed so that the shear building model would exhibit a specified distribution of interstory drifts under design moderate earthquakes. The member size of the corresponding frame model has then been determined via reduced model-frame inverse transformation. Another design method under design major earthquakes has been proposed utilizing a newly developed equivalent linearization method. Less