標竿結構體D之系統識別與損壞評估

System Identification and Damage Assessment of Benchmark Model D

林億賢(Yi-Sian Lin)

指導教授 ： 王淑娟

朝陽科技大學/理工學院/營建工程系/碩士(2011年)

摘要

在各種系統識別方式的發展過程中，地震紀錄的取得是必要的。目前台灣各地重要大樓、學校及橋樑等土木結構物上皆裝有強震儀，可隨時記錄地震發生時之相關資料，利用其地震紀錄來識別對應之結構物系統參數，據此進行結構物安全評估，並根據結構物的破壞情形，進行修補工作。近二十年來，很多學者從事結構健康診斷之研究。所謂結構健康診斷是利用比較結構目前之狀態與未受損狀態或基線狀態(Baseline state)之過程來決定結構物受地震或其他型式外力作用下是否有損壞產生，從而決定損壞之位置及程度。
由於強震發生後，建築物因受損，其彈性動力參數會產生變化，因此需找出使代表性結構受損之強震，再針對強震發生前及發生後之中小地震資料進行系統識別，瞭解其在強震發生前後之參數變化，俾利進行健康診斷。因現在做的損壞評估實際上實測建築都為輕微或嚴重之損壞，建立損壞指標上是不足的，所以可利用實驗方式去模擬不同損壞狀態，藉用各種不同程度損壞狀態之識別參數，看能否找出描述損壞程度之損壞參數，甚至是不同損壞程度之門檻值，因此本文利用系統識別之技巧分析標竿結構體D模型，該模型為長向(X向)為3公尺，短向(Y向)為2公尺無斜撐之立體鋼構架。結構體進行之系列實驗主要可以分為三部份，包括第一類線性試驗、第二類線性試驗及第三類非線性試驗，第一類線性試驗為線性振動台試驗；第二類線性試驗同樣為線性振動台試驗，但一樓柱底以切削斷面來模擬弱斷面；最後第三類線性試驗是與第二類線性試驗同樣的模型，但是進行震度較大的非線性試驗。本文之分析首先以第一類線性試驗識別結果為基準，由第二類性試驗識別結果判斷樓層之損壞樓層與程度。最後再與第三類非線性試驗識別結果比較，判斷樓層之損壞樓層與程度。

關鍵字

標竿結構體D

並列摘要

ABSTRACT
Field of system identification has become important discipline due to the increasing need to estimate the behavior of a system with partially known dynamics. In the past few decades, many optimization techniques have been developed for system identification problems. In recent years, many scholars use the results of system identification to do the structural health monitoring research. Structural health monitoring is comparative the structure parameters or baseline state before and after earthquake to determine the location and extent of damage due to earthquake.
After the attack of the strong earthquake, buildings will be damaged and their elastic dynamic parameters will also be changed accordingly. Therefore, the strong earthquake damaging the representative structure shall be identified, and then system identification will be implemented on the data of earthquakes of low intensity before and after the strong earthquake to understand the changes in the parameters before and after the strong earthquake, so as to facilitate health monitoring. At present, the buildings under damage assessment are actually with minor or serious damages, so the damage indices evaluated accordingly may not be adequate. To solve the problem, the experimental method is used to simulate different states of damage, followed by identifying the parameters of the associated damaged structure. Then, the damage indices describing the damage degree can be computed using the identified parameters, and the threshold value of different damage state can be reached. Therefore, in the thesis, the technique of system identification is used to analyze the Benchmark Model D. The model is three-dimensional steel structure without diagonal bracings which is 3m in the longitudinal (x axis) direction and 2m in the transverse (y axis) direction. A series of experiments have been conducted on the structure which can be divided into three stages, including the first-stage linear test, the second-stage linear test and the third-stage nonlinear test of linear test. The first-stage linear test is a series of linear shaking table tests; the second-stage linear test is also a series of linear shaking table tests, but the bottom of the two columns of the first floor were tappered to simulate the weak section; the model of the third-stage non-linear test is the same model as that of the second-stage linear test, and a series of non-linear shaking table tests with earthquake of high intensity were conducted. The analysis of this paper is first based on the identified results of first-stage linear test, and then the degree of damage and the location or floor of damage are determined by the indentified results of the second-stage linear test. Finally, a comparison is made between the second-stage linear test and the third-stage nonlinear test to determine the degree of damage and the location or floor of damage.

並列關鍵字

Benchmark Model D

參考文獻

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