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標題: | 建築物隔震補強及其位移限制機制設計 Design of Building Retrofit by Isolation System and its Displacement Restraint Mechanism |
作者: | Peng-Yu Lin 林芃妤 |
指導教授: | 鍾立來 |
共同指導教授: | 楊卓諺 |
關鍵字: | 隔震補強,摩擦單擺支承,鉛心橡膠支承,磚造建物,隔震建物,位移限制機制, Seismic isolation,retrofit design,Friction Pendulum Bearing system,Lead Rubber Bearing system,brick structure,displacement restraint mechanism, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 1999年的9月21號,台灣發生歷史上第二嚴重的地震,921集集地震。此地震造成數以萬計人員的傷亡以及無數建物倒塌。而在921地震發生之後,內政部營建署再度修正發布建築物耐震設計規範及解說,提升耐震設計標準。然而許多建物隨著時間逐漸老化,其耐震能力逐漸下降,或因規範對於地震力需求的提升,未能滿足新規範的規定強度。在此情況下,補強的議題因應而生。傳統常見的補強工法包含擴柱、翼牆、斜撐等,得以提升建物基本耐震能力,使之高於耐震需求,然而傳統的補強方法會改變建物外觀,不適用於外觀需要被保存的歷史建物,因此,另一種補強策略,則為隔震之手段。在上、下部結構之間,置入隔震器,或阻絕、或減緩上傳的地震力,降低耐震需求,使之低於耐震容量,達到補強的目標。採用隔震補強之建物,於設計時可採用性能設計法,亦即預先選定耐震性能目標,再設計隔震系統以滿足該預設之性能目標。對於補強結構而言,一般可選原結構系統之耐震容量作為隔震設計之性能目標。本研究首先以側推分析取得一範例構架之耐震能力,接著採用摩擦單擺支承 (Friction Pendulum Bearing) 以及鉛心橡膠支承 (Lead Rubber Bearing) 作隔震器,擬訂其設計程序,再以側推分析驗證其補強結果,最後以實際歷史磚造建物闡述其流程,供工程界參考。
而對於隔震系統之效應已有許多相關研究驗證,然而許多研究亦指出由於隔震系統長週期的特性,使的近斷層地震可能導致系統過大的位移反應且有傾倒的可能性。因此,本研究提出一由阻尼及彈簧組成的位移限制系統,加裝於隔震建物及擋土牆之間,用以限制隔震建物的位移,接著將建物視為一單自由度線性系統模擬,並觀察加裝位移限制系統之表現。此位移限制系統擁有三個重要設計參數包含其本身之勁度、阻尼係數以及與建物之間的撞擊距離,且這些參數的特性將透過參數分析來探討。由模擬結果可知,當建物撞擊到位移限制系統,雖然位移反應成功降低,但其加速度反應將會放大,因此如何訂定滿足位移及加速度設計目標的設計參數範圍相當重要,而其設計流程亦闡述於本文中。此外,對於不同阻尼比、不同週期的隔震建物,其在一近斷層地震下設計結果呈現於表格中,工程師可根據此表設計出對應於該結構適當的位移限制系統,進而成為隔震建物的最後一道安全防線。 On September 21st, 1999, the second-deadliest earthquake in the history of Taiwan, Chi-Chi earthquake had struck Nantou that several thousands of people were killed and countless buildings were damaged. Seismic Design Code were revised and became more restrict in the aftermath of the disaster. However, many buildings that were built earlier are lack of seismic capacity and are not safe based on the revised Seismic Design Code. Therefore, seismic retrofit is a measure to improve these old structures’ safety. Conventional retrofitting methods such as concrete jacking, wing wall, diagonal bracing, etc will destroy the structure’s original appearance that another method, seismic isolation is introduced. By using hydraulic jack, the base of the structure is risen slowly and safely. Next, the seismic isolation system is inserted between the ground and the structure’s base. After the seismic isolation system is installed, the structural period and the damping ratio both increase, and the incoming earthquake force is reduced subsequently. Finally, since the seismic demand is reduced, the seismic capacity will exceed the demand and the goal of retrofit can be reached. For the structure using the seismic retrofit method, the performance design method is adopted for its design procedure. The original structure’s seismic capacity is usually set to be the performance point, then the seismic isolation system is designed to satisfy the performance point. In the study, first, the seismic capacity of an example structure is obtained by the pushover analysis. Next, the retrofit design procedure of the Friction Pendulum Bearing (FPB) and the Lead Rubber Bearing (LRB) systems are drawn up. Then, the design result is checked by the pushover analysis again. At last, the design procedures are verified by an actual brick structure in order to give engineers an example to refer to. The effectiveness of the isolation system has been proved by many researches, however, some other researches also indicated that excessive displacement response due to near-fault ground motion may cause such a system with long period to fail. Thus, a displacement restraint mechanism is suggested to be installed between the isolated structure and the retaining wall to prevent the structures from collapsing. In the thesis, a linear system possessing the displacement restraint system is studied. The displacement restraint system consists of a spring and a damper and is installed between the isolated structure and the retaining wall. It has three important design parameters which are the stiffness, the damping coefficient and the stroke, and these parameters are discussed through parametric study. It is clear from the simulation results that as the isolated structure strikes the displacement restraint sysem, the maximum absolute acceleration of the total system is increased due to the impact. Therefore, the displacement restraint system should be properly designed to remain the design targets. In the thesis, the design procedure is established and presented. Also, the design results of the different structure with different damping ratio and period are presented in the tables, and the engineers are able to design the displacement restraint system of a certain structure under the seismic excitation based on the tables. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/7773 |
DOI: | 10.6342/NTU201903434 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 土木工程學系 |
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