結構物的阻尼比為評估其耐震性能與能量耗散能力之重要參數，能夠反映結構在地震或外力作用下的衰減能力與損傷程度。傳統常見的估算方法如對數衰減法與半功率法雖具理論基礎，並廣泛應用於線性動力系統中，惟其推導多基於理想假設條件，包含系統為單自由度（SDOF）、行為為線性彈性，且外力為穩定的單頻正弦波等，致使在實務應用上，特別是面對非線性與非穩態特性明顯的地震紀錄時，其適用性與準確性不足，導致無法有效反映結構實際之動態反應。
為解決上述限制，本研究提出結合有限元素分析與希爾伯特-黃轉換之阻尼比估算方法。將實際建物加速度資料經過HHT轉換後繪製邊際譜，再以 ETABS 建立不同預設阻尼比之多個單自由度模型，以相同基底加速度作用後將得到資料同樣進行HHT並繪製邊際譜，再配合半功率法推估阻尼比，最後比對實際資料與模型響應結果並進行內插，推估出結構真實阻尼比之可能範圍。
研究分為兩階段，第一階段採用中央氣象局之同一測站的不同地震資料，觀察其在不同地震作用下所得結果是否具有一致性與穩定性，作為方法可行性的初步驗證依據。若三筆地震資料阻尼比推估值差異甚小，則認為此估算方式可行。第二階段則以具實際損壞案例之建築物—台東縣消防局作為分析對象，分別選取損害前、造成損害之地震，以及損害後所遭遇之地震資料，進行同樣分析流程，探討此方法對於建物在不同健康狀態下之阻尼比評估能力，進一步驗證其對震後結構診斷與健康監測之應用可行性。

Traditional methods for estimating structural damping ratios, such as the logarithmic decrement and half-power bandwidth methods, are based on simplified assumptions: linear behavior, single-degree-of-freedom systems, and steady sinusoidal excitation. These conditions limit their accuracy when applied to real seismic records, which are typically nonlinear and non-stationary.
To address these limitations, this study employs the Hilbert-Huang Transform (HHT) in combination with ETABS finite element models to simulate the marginal spectrum response under different damping ratios. The goal is to estimate the damping ratio of actual structures based on the observed HHT spectral features.
The study is conducted in two phases. In the first phase, earthquake records from the same station but different events are analyzed to assess the consistency and reliability of the proposed method. In the second phase, a damaged reinforced concrete building is analyzed to evaluate damping ratio variations before, during, and after damage.
Results from the first phase show that the estimated damping ratios are consistent with code-recommended values and are similar across different seismic events, supporting the method’s feasibility. In the second phase, the estimated damping ratio increases significantly after structural damage. While the estimated values do not fully reach the code-recommended values, they still provide valuable insight for structural assessment and post-earthquake evaluation.

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