Collapse Behavior Evaluation of Reinforced Concrete Buildings considering Axial Load Redistribution and Successive Huge Earthquakes

2021 Fiscal Year Final Research Report

• Project/Area Number: 17K06636
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Building structures/Materials
• Research Institution: Niigata University
• Principal Investigator: Nakamura Takaya 新潟大学, 自然科学系, 教授 (50305421)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Keywords: 鉄筋コンクリート建物 / 軸力再配分 / 崩壊時間 / 旧耐震基準 / 地震応答解析

Outline of Final Research Achievements

Many RC buildings with brittle columns are in danger of story collapse owing to gravity load collapse of columns following shear failure in the future earthquakes. When it comes to the structural frames, once the brittle columns are severely damaged, some of the axial load sustained by them transfers to the neighboring columns through girders. Dynamic analysis is performed for columns with decreased / increased axial load, and responses of the model buildings, including collapse, are studied.
Once buildings are damaged by the large earthquake, it is important to evaluate the effect of subsequent ground motions. In addition, to plan for building evacuation, the time required for such buildings to collapse must be known. This study aims to examine the collapse time of RC buildings considering successive huge earthquakes by conducting dynamic analysis. The effects of a predominant period of ground motion (short-period or long-period) and the collapse time were assessed.

Free Research Field

建築材料・構造

Academic Significance and Societal Importance of the Research Achievements

RC造建物の耐震性評価および構造設計において，柱の破壊に付随する軸力再配分を考慮することができればより精密な評価が可能となる。そこで，本研究により，軸力再配分を考慮したRC造建物の地震応答解析を実施して検討した結果，倒壊を免れるために必要なベースシア係数等を明らかにした。また，近年問題となっている巨大地震が連続して発生する場合を想定して，地震応答解析により避難時に重要な指標となる崩壊時間について検討し，建物周期の変化と地震動周期の関係等を明らかにした。以上の成果は，RC造建物の耐震性評価および構造設計法の拡張に資するところが大きいと考えている。