Story Stiffness and Damping Identification of Buildings Based on Real Measurements

本文為建築結構健康監測與損壞評估之實務應用研究，依結構實測動態反應紀錄經由積分器處理，推導力平衡方程式，識別出層間勁度。接著，由識別之層間勁度的變化作為結構損壞之指標，進而識別出層間阻尼，並以識別阻尼做為設定阻尼值效益之驗證。另外，考量量測之不足，設立一擬勁度值並探討擬勁度之便利性與局限。 首先依NCREE標竿結構建立一簡單三層樓鋼結構進行層間勁度、阻尼之識別，確定識別方法之適用性。接著介紹與三聯科技合作研究目標結構，位於台北之八層樓建築結構及其感應器裝設位置，並依多筆實測地震量測反應，輸出各樓層量測訊號經由積分器處理，應用運動方程式，識別出層間勁度。由於真實結構並無損壞，因此利用ETABS結構分析軟體依據結構圖與實測前三模態頻率，建立相應之有限元素分析模型，並依照建築物可能發生之破壞模式進行損壞評估。 研究方法為在ETABS進行動力歷時分析，輸出各層加速度反應，應用本方法識別結構參數，利用破壞前後之參數計算層間損壞指標，以評估結構損壞位置以及損壞程度，並驗證本法於實際應用時之準確性及實用性。In this study, according to floor acceleration response measurements, the story drifts are obtained by the integrator. Force balance equation above the identified story is then introduced to identify the story stiffness. The change of the story stiffness is regarded as the index of structural damage. After this, the story damping coefficient is also identified from story force balance. The identified damping coefficient is used as the verification of the designated damping value and the performance of the damper equipped. In addition, with the consideration of limited number of measurements, the psudo stiffness is established and explored its workability. To verify the applicability of the proposed method, the NCREE three-story benchmark steel building structure is employed for the identification of story stiffness and damping coefficients. Then, an eight-story RC building structure located in Taipei city is investigated. This building was built and fully instrumented with accelerometers by the Sanlien technology cooperation. According to several earthquake-induced acceleration response measurements, the inter-story drifts are calculated through the integrator processing and used in the force balance equations to identify the story stiffness. Because of the real structure is not damaged, the finite element model is generated and updated by the ETABS computer program based on structural configuration and measured modal frequencies.. The damage assessment is carried out based on the damage pattern that the building may occur. First, the dynamic responses of floor accelerations calculated from the ETABS program are analyzed. The proposed method is then used to identify the story stiffness and damping coefficients. The damage indices are calculated by using the story stiffness before and after the failure to evaluate the damage location and the degree of damage. The accurate identified results show the applicability of the proposed method.誌謝 i 摘要 ii Abstract iii 目錄 iv 表目錄 vi 圖目錄 viii 第一章 緒論 1 1.1 研究動機與目的 1 1.2 文獻回顧 3 1.2.1 系統識別理論 3 1.2.2 損壞指標 6 1.3 本文內容 9 第二章 層間勁度與阻尼識別之理論 10 2.1 狀態空間模型 10 2.1.1 連續時間狀態空間方程式 11 2.1.2 離散時間狀態空間方程式 13 2.1.3 馬可夫參數之唯一性 14 2.1.4 隨機狀態空間方程式 15 2.2 依量測數據識別層間勁度 17 2.2.1 積分器處理介紹 17 2.2.2 運動方程式推導識別層間勁度之方法 18 2.2.3 變異數介紹 19 2.3 依量測數據識別層間阻尼 20 第三章 以平面剪力模型驗證 21 3.1 NCREE三層標竿鋼結構之基本資料 21 3.2 層間勁度之識別 22 3.3 層間阻尼之識別 22 第四章 以ETABS三維模型驗證 23 4.1 量測資料座標轉換技巧 23 4.2 模擬NCREE模型之結果與比較 25 4.3 不同破壞模式之識別層間勁度與阻尼 26 第五章 以八層樓實際模型驗證 28 5.1 八層結構之基本資料 28 5.1.1 結構之基本架構與材料特性 28 5.1.2 量測技術及配置 28 5.2 依實際量測資料識別層間勁度 29 5.3 數值模擬破壞識別層間勁度 30 第六章 結論與建議 32 參考文獻 3