1996 Fiscal Year Final Research Report Summary
Effects of Hardening and Deteriorating Properties of Members on Collapse Behavior of Building Structures
| Project/Area Number |
07455220
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Building structures/materials
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
UETANI Koji Kyoto University, Graduate School of Engineering, Professor, 工学研究科, 教授 (40026349)
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| Co-Investigator(Kenkyū-buntansha) |
MASUI Takeshi Kyoto University, Graduate School of Engineering, Research Associate, 工学研究科, 助手 (60263109)
OHSAKI Makoto Kyoto University, Graduate School of Engineering, Associate Professor, 工学研究科, 助教授 (40176855)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Collapse Behavior / Symmetry Limit / Steady-State limit / Brittle Fracture / Weak-beam Frame / Local Buckling / Stability problem / Seismic Response Analysis |
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| Research Abstract |
The purpose of this project is to clarify the collapse behavior of building frames and to develop the design criteria for preventing the frames from falling into collapse under strong earthquake. The following results have been obtained in this project.
(1) Accurate dynamic response analyzes have been carried out for more realistic frame models which have a mass at every floor. It has been revealed that there exists deformation concentration phenomena in the process of dynamic collapse, which is characterized by the growth of bow-shaped deflection mode and the concentration of this mode in the restricted lower region. And the method have been proposed for predicting the height of the deformation concentration region.
(2) An unknown type of collapse behavior have been revealed for multistory weak-beam planar frames which consists of deteriorating members and subjected to a severe earthquake. It has been shown that the height of the deformation concentration region can be predicted by an e
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xtended version of the method developed in previous studies (1). The validity of the method is verfied through numerical response analyzes. The effects of the deteriorating properties of members on the dynamic collapse behavior are then clarified by investigating the collapse behaviors of several frames wiht different negative stiffnesses after reaching the maximum strengths.
(3) New criteria for preventing multistroy frames from severe collapse with an accelerative growth of the particular mode deflection during strong earthquake ground motion has been proposed. Criteria for suppressing the sway drift has also been proposed to meet higher-level safety requirements.
(4) Existence of growth phenomena of the bow-shaped mode and its characteristics have been revealed by experimental study using shaking table for weak-beam-type frame models. The drift of the sway-mode vibration center has also been clarified.
(5) Seismic response analyzes, considering the effects of brittle fractures at beam-ends during an earthquake excitation, have been carried out for steel frames. The response properties have been compared to those of ductile frames and the effects of fractures on the seismic response of steel frames are discussed. Less
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