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Title: | 隔震建築耐震風險簡易評估方法研究 Developing a Simplified Seismic Risk Assessment Approach for Base-Isolated Buildings |
Authors: | Yun-Ting Li 李筠婷 |
Advisor: | 黃尹男(Yin-Nan Huang) |
Keyword: | 隔震,耐震風險評估,地震危害度,易損性曲線,鉛心橡膠隔震支承, seismic isolation,seismic risk assessment,seismic hazard,fragility curve,lead rubber bearing, |
Publication Year : | 2022 |
Degree: | 碩士 |
Abstract: | 由美國聯邦緊急事務管理局補助的ATC-58計畫,於2018年發表第二版建物耐震性能評估規範(FEMA P-58),其針對建築物的耐震風險提出一套評估方法。雖然該規範對於耐震風險的主要評估方式與精神幾乎可以用於所有類型的建築結構,然而對於耐震能力較高的隔震結構,則因原定義之地震危害度曲線的地震動強度分析範圍不足,忽略較大地震對隔震建築所造成的風險,而使失效風險被大幅低估。 為了改善因地震動強度範圍不合適而導致失效風險推估產生誤差的問題,本研究首先探討不同地震動強度上界、下界與區間分段數量對失效風險的影響,並透過失效風險在區間分段數量大量下,有隨上界增加而收斂的特性,發展一套隔震建築的簡易風險評估方法,快速求取不同強度範圍的失效風險,以輔助決定隔震結構進行耐震風險評估時,於不同區間分段數量下合適的地震動強度分析範圍。 簡易風險評估法之推估程序大致包含四步驟:(1) 結構反應分佈推估,包含隔震層最大位移與上部結構最大層間變位角;(2)計算元件個別失效機率,將結構反應分布與元件易損性曲線透過一階二次矩可靠度分析法計算而得;(3)計算系統失效機率,運用聯合失效機率方法求取;(4)求取失效風險,將失效機率搭配地震危害度曲線求取。上述各流程步驟與使用該法對隔震結構風險推估範圍建議之適用性,皆透過所設計之5樓與12樓鉛心橡膠隔震支承結構予以驗證。 結果顯示,雖然簡易風險評估法所計算之失效風險有低估的現象,然而透過該法輔助決定之地震動強度選取範圍,在實際進行非線性歷時分析之風險評估時,不但能得到合理的風險值,還能有效減少分析數量與時間。透過簡易風險評估法所建議之地震強度分析範圍對於隔震建物之風險計算的適用性,已透過本研究之12樓與5樓案例隔震建物獲得驗證,此方法預料對於不同樓層數或不同種類之隔震結構亦可適用,但須針對不同隔震系統或上述樓層數範圍外之上部結構進行參數調整,進行更多研究予以釐清。 The ATC-58 program, funded by the Federal Emergency Management Agency of the United States, published the second edition of Seismic Performance Assessment of Buildings (FEMA P-58) in 2018. FEMA P-58 proposed a set of assessment methods for the seismic risk of buildings. The scope of analysis of the ground motion intensity of the seismic hazard curve, which is defined in the code, is not enough for isolated structures with a high seismic capacity, although the main idea and assessment method for seismic risk of the code can be applied to nearly all types of buildings. The seismic risk of an isolated building is greatly underestimated due to the insufficient scope of analysis in the defined seismic hazard curve, which ignores the risk caused by large earthquakes. This study initially investigates the influence of various upper and lower bounds of ground motion intensity and the number of intervals on the risk assessment to address the errors in estimating the seismic risk caused by inappropriate ground motion intensity range. Then, a simplified seismic risk assessment approach for base-isolated buildings is developed based on the characteristic of the failure risk, which is converging alongside the increase of the upper bound of ground motion intensity. The simplified approach can quickly determine the failure risk of various strength ranges to determine the appropriate seismic intensity analysis range for seismically isolated structures under the number of subsections in different intervals. The estimation procedure of the simplified seismic risk assessment approach, in general, includes four steps: (1) Estimate the distribution of the structural responses, including the maximum displacement of the seismic isolation layer and the maximum story drift of the superstructure; (2) Determine the individual failure probability of each component by combining the distribution of the structural responses and the fragility curve of the element obtained using the first-order-second-moment reliability approach; (3) Determine the failure probability of the system using the joint failure probability method; (4) Obtain the failure risk by combining the failure probability with the seismic hazard curve. The applicability of the proposed method for the risk estimation of the isolated structure is verified using the 5-story and 12-story lead-rubber-isolated structures. The results show that despite the failure risk obtained in the simplified seismic risk assessment approach is still underestimated, the range of ground motion intensity selected by this method can effectively reduce the number and duration of analyses and ensure a failure risk of less than 1% error when performing non-linear time history analysis. The applicability of the seismic intensity analysis range suggested by the simplified seismic risk assessment approach to the risk calculation of seismically isolated buildings has also been verified by the case of 12-story and 5-story isolated buildings in this study. This method is expected to be applicated for various numbers of floors or various kinds of seismic isolation structures, but parameter adjustment for different systems and additional study is needed. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/84275 |
DOI: | 10.6342/NTU202203992 |
Fulltext Rights: | 同意授權(限校園內公開) |
metadata.dc.date.embargo-lift: | 2022-09-29 |
Appears in Collections: | 土木工程學系 |
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U0001-2509202210501800.pdf Access limited in NTU ip range | 7.45 MB | Adobe PDF | View/Open |
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