長跨徑橋梁之受風影響甚劇，而風洞實驗為目前認為可靠的研究方法，但最終仍然需要以實場量測來驗證其準確性。本文以目前國內最長之斜張橋-高屏溪橋為標的，於其主跨二分之一處裝置三維風速計與速度計，主跨三分之一處裝設速度計，以風速計量測颱風經過時週遭之風場特性。同時以速度計量測橋梁速度反應，藉此研究橋梁受風之效應。
    本文利用凱米與寶發颱風經過時所紀錄到的資料進行研究，風場特性分析包括分析其平均風向、平均風速、紊流強度、紊流長度尺度及風速頻譜。結構反應則分別使用FDD法與多自由度RD法分析其結構動力特性，包括自然頻率、阻尼比與模態。結果顯示紊流強度隨著風速提高而減小，而順風向紊流長度尺度有隨風速增加有變大的趨勢，風速頻譜則和Karman的經驗公式吻合。由於監測到的平均風速不大，所識別的橋梁振動頻率對於風速變化並不敏感，而橋梁阻尼識別的結果較為散亂。最後將分析得之風場特性與結構動力特性代入數值模式中模擬橋梁抖振抖振反應，並與實場量測及風洞實驗的結果作比較。利用識別的結構參數代入數值模式的結果與實場監測的結果在托曳向的差異較大，約有52%的差異，而垂直與扭轉向則分別有44%與12% 的差異。

The effect of wind excitation on long-span bridges is extremely significant. Such effect is usually studied and analyzed through wind tunnel test which is one of the most reliable methods. However, the predicted results should be verified by field measurements. This study chose the longest cable-stayed bridge in Taiwan - Kao-Ping-Hsi Bridge as the target for field measurements. Two 3D anemometers were installed at the middle point of the longer span to measure the wind characteristics. Two sets of speedometers were respectively installed at the middle point and the one third point of the longer span to measure the dynamic responses of the bridge. Each set of speedometers contain two in vertical direction and one in drag direction. All the speedometers were positioned inside of the box girder.

  The measured data including velocity, wind speed and wind direction were continuously recorded during Typhoon Bopha and Typhoon Kaemi attacking Taiwan in 2006. Detailed analysis of these data was conducted in this study. The analysis of wind characteristics includes mean wind direction, mean wind speed, turbulence intensity, turbulence length scale and spectra of wind fluctuations. The dynamic parameters of the targeted bridge, including modal frequencies, damping ratios and mode shapes, were identified by the methods of FDD and RD, respectively. The analyzed results show that the turbulence intensity decreases as the mean wind speed increases. The turbulence length scale in along wind direction increases with the mean wind speed. The measured wind spectrum agrees well with Von Karman spectrum. Since the wind speed is not large enough, the vibration frequencies are not sensitive to the mean wind speed and nearly remain constant. However, the damping rations are varied dispersedly. The identified structural frequencies and damping ratios and the fitted wind spectrum were substituted into the numerical model to evaluate the buffeting responses. The results from the re-analysis, the field measurements and the wind tunnel tests are compared. The comparative study indicates that the differences between the numerical results obtained from the re-analysis and the results analyzed from the field measurements are 12-52%. The discrepancy is larger in drag direction.

誌謝...................................................I
摘要..................................................II
Abstract.............................................III
目錄..................................................IV
表目錄................................................VI
圖目錄...............................................VII
第一章 緒論............................................1
1.1前言................................................1
1.2文獻回顧............................................2
1.3研究內容............................................4
1.4論文架構............................................4
第二章 理論背景........................................6
2.1 前言...............................................6
2.2 風場分析...........................................6
2.2.1 平均風速.........................................6
2.2.2 平均風向.........................................6
2.2.3 紊流強度（Turbulence Intensity）.................6
2.2.4 紊流長度尺度（Turbulence Length Scale）..........7
2.2.5 風速擾動頻譜（Spectra of Velocity Fluctuations）.7
2.2.6 風速擾動交頻譜（Cross-Spectra of Velocity 
      Fluctuations）...................................9
2.3 FDD識別理論.......................................11
2.3.1 FDD識別之理論背景...............................11
2.3.2 FDD識別流程.....................................13
2.4 隨機遞減法識別理論................................14
2.4.1 隨機遞減法......................................14
2.4.2 單自由度系統....................................15
2.4.3多自由度系統.....................................17
第三章 長跨徑橋梁受風反應之頻率域分析.................19
3.1前言...............................................19
3.2橋梁受風之氣動力效應...............................19
3.2.1 顫振效應（Flutter）.............................19
3.2.2 抖振效應（Buffeting）...........................20
3.2.3 扭轉不穩定（Torsion Instability）...............20
3.2.4 渦流振動（Vortex Shedding）.....................20
3.2.5 風馳效應（Galloping）...........................21
3.3橋梁受風反應的分析模式.............................22
3.3.1 自身擾動力(Self-Excited Force)	.................22
3.3.2 抖振力(Buffeting Force).........................23
3.4橋體運動方程式之建立...............................24
3.5橋梁受風載重之位移反應.............................26
第四章 實場量測之分析與結果...........................29
4.1 前言..............................................29
4.2 高屏溪橋地理位置與幾何形狀........................29
3.3 現地儀器配置......................................29
4.4 風速計率定........................................30
4.5 風場分析..........................................30
4.6 結構特性分析......................................33
4.6.1 以FDD法識別結構參數.............................33
4.5.2 以多自由度隨機遞減法識別結構參數................34
4.6分析結果與比較.....................................35
4.6.1風場分析.........................................35
4.6.2結構動力參數分析.................................35
4.6.3氣動力阻尼的評估.................................36
第五章 風洞實驗、實場量測與數值計算...................38
5.1前言...............................................38
5.2建立數值模型.......................................38
5.2.1 斷面性質........................................38
5.2.2結構特性模擬.....................................38
5.3氣動力阻尼的評估...................................39
5.4抖振反應分析.......................................39
5.5結果討論與比較.....................................41
第六章 結論與建議.....................................43
6.1 結論..............................................43
6.2 建議..............................................44
參考文獻..............................................45

表目錄
表3-1 氣動力參數代表的意義	50
表4-1風速計量測範圍	50
表4-2風速計率定公式	51
表4-3寶發颱風風向22.5°~67.5°各分量上紊流長度及紊流長度尺度	51
表4-4寶發颱風風向22.5°~67.5°之紊流頻譜參數	51
表4-5 FDD、MRD與微動試驗識別之自然頻率(1Hz以下)比較	52
表4-6 FDD與MRD識別無風狀態下之阻尼比(1Hz以下)比較(%)	52
表5-1 高屏溪橋橋面斷面性質	53
表5-2高屏溪橋橋塔斷面性質	53
表5-3高屏溪橋鋼纜材料性質	54
表5-4 高屏溪橋數值模型前十個振態	54
表5-5 數值計算實場與風洞實驗之條件說明	55
表5-6 風速9 m/s數值計算與實場反應比較	55

圖目錄
圖1-1 Tacoma Narrow Bridge 發生顫振（flutter）的情形	56
圖3-1扭轉不穩定之幾何示意圖	57
圖3-2橋面版節點與單位長度受風力之示意圖	57
圖4-1高屏溪橋之幾何形狀與鋼纜編號	58
圖4-2高屏溪橋長期監測系統架設位置圖	59
圖4-3高屏溪橋長期監測系統架設剖面圖	59
圖4-4高屏溪橋長期風力監測系統架構圖	60
圖4-5高屏溪橋長期振動監測系統架構圖	60
圖4-7振動量測的自由度設定圖	61
圖4-8率定公式圖	62
圖4-9 風場分析流程圖	63
圖4-10寶發颱風侵颱期間10分鐘平均風速歷時	63
圖4-11寶發颱風侵颱期間10分鐘平均風向歷時	64
圖4-12寶發颱風侵颱期間10分鐘平均風向分佈圖	64
圖4-13寶發颱風8月9日03：50 ~ 04：00風速歷時	65
圖4-14寶發颱風8月9日03：50 ~ 04：00三分量風速歷時	65
圖4-15寶發颱風8月9日03：50 ~ 04：00 順風向風速分佈概率	66
圖4-16寶發颱風8月9日03：50 ~ 04：00 橫風向風速分佈概率	66
圖4-17寶發颱風8月9日03：50 ~ 04：00 垂直向風速分佈概率	66
圖4-18寶發颱風8月9日03：50 ~04：50順風向紊流頻譜	67
圖4-19寶發颱風8月9日03：50 ~04：50垂直向紊流頻譜	67
圖4-20 FDD法分析流程圖	68
圖4-21 多自由度RD法分析流程圖	68
圖4-22寶發颱風8月9日03：50 ~04：50振動資料奇異值圖	69
圖4-23接近無風狀態(>1m/s)下之奇異值圖	69
圖4-24寶發颱風8月9日03：50 ~04：50 1/2跨垂直向RD訊號	70
圖4-25寶發颱風8月9日03：50 ~04：50 1/2跨扭轉向RD訊號	70
圖4-26寶發颱風8月9日03：50 ~04：50 1/2跨水平向RD訊號	71
圖4-27寶發颱風8月9日03：50 ~04：50 1/3跨垂直向RD訊號	71
圖4-28寶發颱風8月9日03：50 ~04：50 1/3跨扭轉向RD訊號	72
圖4-29寶發颱風8月9日03：50 ~04：50 1/3跨水平向RD訊號	72
圖4-30寶發颱風風向22.5°~67.5° 紊流強度與風速的關係	73
圖4-31寶發颱風風向22.5°~67.5° 紊流長度尺度與風速的關係	73
圖4-32 各方向第一振態所識別之風速與振動頻率之關係	74
圖4-33 各方向第一振態所識別之風速與識別阻尼比之關係	75
圖5-1高屏溪橋塔立面圖	76
圖5-2 樑元素之自由度編號	76
圖5-3桁架元素之自由度編號	77
圖5-4 高屏溪橋有限元素數值模型	77
圖5-5 有限元素分析之mode Shape	78
圖5-6 各方向第一振態所識別之風速與識別氣動力阻尼之關係	79
圖5-7 風速1 ~ 20 m/s橋面板1/2跨位置垂直反應RMS值	80
圖5-8 風速1 ~ 20 m/s橋面板1/3跨位置垂直反應RMS值	80
圖5-9 風速1 ~ 20 m/s橋面板1/2跨位置水平反應RMS值	81
圖5-10 風速1 ~ 20 m/s橋面板1/3跨位置水平反應RMS值	81
圖5-11 風速1 ~ 20 m/s橋面板1/2跨位置扭轉反應RMS值	82
圖5-12 風速1 ~ 20 m/s橋面板1/3跨位置扭轉反應RMS值	82
圖5-13 風速1 ~ 120 m/s橋面板1/2跨位置垂直反應RMS值	83
圖5-14 風速1 ~ 120 m/s橋面板1/3跨位置垂直反應RMS值	83
圖5-15 風速1 ~ 120 m/s橋面板1/2跨位置水平反應RMS值	84
圖5-16 風速1 ~ 120 m/s橋面板1/3跨位置水平反應RMS值	84
圖5-17 風速1 ~ 120 m/s橋面板1/2跨位置扭轉反應RMS值	85
圖5-18 風速1 ~ 120 m/s橋面板1/3跨位置扭轉反應RMS值	85

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