角形鋼管を用いた接合部パネルの２方向せん断力と曲げモーメントを考慮した解析モデル

In Japan, steel moment frames, which consist of H-shaped beams and square tube columns with through diaphragms, are often used for low and medium rise steel building structures. Joint panel usually has the same cross section as the column just below it. In case of these steel frames, it is very probable that joint panels will yeild earlier than columns or beams under strong ground motion.A lot of numerical studies have been conducted to examine the influence of in-plane elasto-plastic behavior of joint panels on seismic response of plane frames under uni-directional ground motion. However there are few researches to focus on seismic response of 3D frame under bi-directional ground motion.On the other hand, axial force, bi-direction shear force and bi-axial bending moment will act on the joint panel under bi-directional ground motion. Although shear force has a dominant influence on the elasto-plastic behavior of joint panel, the influence of bending moment is not negligible for the joint panel with large aspect ratio or under bi-direction loading. However, an analytical model, which is considering the elasto-plastic behavior of joint panel under bi-direction shear force and bi-axial bending moment, has not been proposed yet.This paper proposes a new analytical model for squqre steel tube joint panel with through diaphragm. Chapter 2 describes the basic concept of the analytical model for joint panel, which consists of 3 multi-spring components are placed in series as shown in fig. 1. Those multi-spring components, which are built by introducing the degree of freedom of shear force to each spring, can consider the the elasto-plastic behavior under correlation between axial force, bi-direction shear force and bi-axial bending moment. As the bending moments at the end of joint panel is larger than the one in the middle, the multi-spring components at the ends consider axial deformation, shear deformation and flexural deformation, while the multi-spring component in the middle consider axial deformation and shear deformation. And the total length of 3 multi-spring components must equal to the panel length.Chapter 3 describes the numerical method to build the analytical model for joint panel by multi-spring components and the stiffness equation of the model. Chapter 4 describes the restoring force characteristics of springs under axial and shear force. Chapter 5 proposes the method to calculate the length of multi-spring components at the ends, in order to ensu