- 學位論文
利用簡易速度脈衝模型模擬近斷層地震之可行性研究
Feasibility Study of Using Simple Velocity Pulse-Like Model to Simulate Near-Fault Earthquake Record
摘要
921集集地震對於台灣地區造成嚴重災情，主要是由於中部地區車籠埔斷層錯動所引起。這類型的地震動有著極強的地表速度脈衝與大量的地表永久位移，結構物主要的破壞原因就是由極大的速度脈衝所造成。同時台灣各地均存在不少活動斷層，不少還位在人口稠密的都會區，所以了解近斷層地震動特性是相當重要的。 本文主要就921集集大地震具有速度脈衝的速度歷時資料，藉由簡單之三角形函數去模擬速度歷時之速度脈衝波形。同時，對於單自由度系統受到實際地震歷時作用，使用杜氏積分法積分，得到不同週期之位移反應，繪製實際位移反應譜。另一方面，利用結構動力學的基本理論並利用程式計算出單自由度系統在此速度脈衝作用下的最大位移反應，求得各種不同的速度脈衝作用時間與結構物振動週期的比值之動態放大係數，繪製各種不同的速度脈衝反應譜，並將真實地震位移反應譜與之比較，若兩者之最大反應發生位置及最大位移值在相近，表示這個理論反應譜性可以作為日後斷層區域工程設計之參考。
並列摘要
The 921 Chi-Chi earthquake has caused grisly damage to central Taiwan area due to the rupture of the Chelungpu fault. The type of earthquake usually has a conspicuous velocity-impulse and a large permanent surface displacement. The cause of structural damage mainly originated from the enormous velocity-impulse. Some faults can be found in Taiwan and many of which are located in densely populated areas. Therefore, it is important for us to understand the characteristics of the near-fault earthquake. This study focuses on the ground velocity time-history with velocity-impulse during the 921 Chi-Chi earthquake, simple Triangle Function is used to stimulate pulse-like velocity wave. Meanwhile, for SDOF influenced by actual earthquake time-history, using Duhamel’s Integral will obtain the displacement response from different periods and allow the drawing of displacement response spectrum.On the other hand, the basic theory of dynamics of structure and the fortran code can be used to obtain displacement response of SDOF under velocity-impulse and dynamic amplification factor of different vibration periods, and draw velocity-impulse response spectrum of different wave. It was known that from the comparison between theoretical response spectrum and actual earthquake displacement, the largest response should happen when the time of velocity-impulse and structural vibration period are the same, and the largest displacement obtained from theoretical response spectrum calculation is similar to that of actual earthquake. As a result, the characteristics of this theoretical response spectrum can serve as the reference to future engineering design in fault.