具遲滯回復力折減之鋼筋混凝土構架的系統識別

System Identification of Degrading Hysteretic Restoring Forces of Reinforced Concrete Frames

黃致仁(Jhih - Ren Huang)

指導教授 ： 羅俊雄

國立臺灣大學/工學院/土木工程學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.00105

摘要

建築結構物通常會因為受到嚴重的外力作用下，例如地震力、風力等等，而使得結構物因而產生非線性行為和塑性行為。當結構系統受到循環載重作用下，結構的塑性行為通常以遲滯迴圈的形式來做表示。結構系統之遲滯現象是指塑性系統的遺傳性和記憶本質，其中系統之恢復力不僅取決於瞬時的變形，也決定過去變形的紀錄。所以希望藉由了解筋混凝土結構的非線性遲滯現象，以便可以有效掌握結構系統在受到強烈地震力作用下的行為與安全性。
本文主要針對同時具有強度衰減現象、勁度衰減現象與擠壓效應的鋼筋混凝土構架，當在輸入不同強度之地震力於結構系統時，希望可以有效透過Bouc-Wen非線性系統模式來了解鋼筋混凝土構架在受地震力作用時，系統所表現出來的衰減情形，也就是透過系統模式中之具有隨時間變化之系統參數來解釋其真實鋼筋混凝土構架所發生之強度衰減情況、勁度衰減情況和擠壓效應。其中系統參數之決定，主要利用實驗量測之輸入與輸出值並透過系統識別之方式來決定之。
利用差分進化法(Differential Evolution)之全域最佳化理論來進行識別非線性系統模式中的系統參數，藉由系統參數具有隨時間改變的性質，以便可以更有效的掌握鋼筋混凝土構架隨時間之衰減情形。也會藉由Park and Ang破壞指數去描述當結構系統受到地震力作用下的破壞行為，希望可以和識別出來之結果互相呼應，以便可以有效建立其相關性。研究分析結果顯示，可以有效的利用系統模式中的系統參數來反應真實結構系統在受到地震力作用下的衰減情形。

關鍵字

系統識別 ； 差分進化理論 ； 勁度衰減 ； 強度衰減 ； 擠壓效應

並列摘要

Building structures usually exhibit nonlinear and inelastic behavior under severe dynamic loading such as earthquakes, severe winds, and waves. Inelastic behavior often manifests itself in the form of a hysteresis loop, when the structure is subjected to a cyclic load. Hysteresis refers to the hereditary and the memory nature of an inelastic system, in which the restoring force depends not only on the instantaneous deformation but also on the past history of deformation. The most important, the performance and safety of reinforced concrete structures under severe earthquake loading depend on nonlinear hysteretic behavior.
A total of six reinforced concrete frames, designed with the same dimensions and the same seismic design code, subject to different level of ground excitation individually from shaking table test. Cyclic loading curve of each frame after the ground excitation from shaking table test was also generated to examine the remaining capacity of each frame. The modified Bouc-Wen hysteretic model was used and the system identification process was applied on the shaking table test data to identify the physical parameters such as stiffness degradation, strength deterioration and pinching hysteresis behavior of the reinforced concrete frame. The stiffness and strength degradation of RC frame in relating to the level of ground shaking and damage situation are discussed.
In this study, the differential evolution (DE) method was used as the system identification method to identify the optimal time-varying parameters of the nonlinear hysteretic model. The characteristics of the structure nonlinear behavior under different intensity level of earthquake loading were evaluated and the Park and Ang damage indices were also generated. The relationship between the damage index and the system hysteretic behavior was studied. As a result, it may efficiently grasp at the degradation of the reinforced concrete frame through the hysteretic parameters of the Bouc-Wen model.

並列關鍵字

System identification ； differential evolution algorithm ； stiffness degradation ； strength degradation ； pinching effect

參考文獻

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