本研究於台灣某橋設計並建置橋梁健康監測系統，記錄橋梁使用外置預力補強過程的短期與完工後的長期行為，監測項目包含溫度計、應變計與傾斜計，監測項目包含大氣溫度、箱梁溫度、橋體溫度、箱梁應變與縱向、橫向轉角，其中傾斜計的縱向轉角進一步以二次撓曲線近似法計算出橋體位移。兩年半的監測資料中，包含了外置預力補強過程的橋體應變及完工後的長期位移與應變。因大跨度箱型梁橋的變形受到溫度的影響相當顯著，容易影響資料的判讀，本研究中以全相經驗模態分解法（ensemble empirical mode decomposition, EEMD）作為資料分析的主要方法，將監測資料拆解成為數個本質函數，並進一步應用其中的日週期與年週期的分量進行分析。在本案例中，橋梁長期位移主要受到環境溫度與外置預力損失的影響，研究中以年週期的溫度與位移關係進行回歸，得到兩者間的關係後，用於消除位移資料中的長期溫度影響，使資料更容易研判預力損失的影響；日週期應變資料則應用於計算橋梁斷面中性軸位置，中性軸位置為斷面勁度的重要參數，因此可以作為橋梁的狀況指標。

A 889 days performance evaluation of a prestressed concrete box girder viaduct retrofitted by external postensioning tendons is presented in this thesis. A PC viaduct exhibits substantial vertical deflection ever since construction completion. External postensioning tendons were designed and installed to increase the load carrying capacity and to lessen the deflection of the bridge. Deflection curves are calculated based on an approximation model using the tilting angles measured at five points along the girder. In this case, the deflection of bridge varies due to two chief parameters, prestress loss and temperature changes, in the long-term monitoring data. To extract the prestress-loss part in overall deflection data, the Ensemble Empirical Mode Decomposition (EEMD) method is used. Finite intrinsic mode functions (IMFs) without mode mixing were then obtained by EEMD method. Daily and annual components were identified from IMFs and applied in calculating the variation of neutral axis position of cross-section with time and eliminating thermal effects from deflection data. The data analysis process and monitoring program is introduced in this thesis.

1. Bazan, Z.P., Qiang, Y., Li, G.H., Klein, G.J., and Kristek, V., “Excessive Deflections of Record-Span Prestressed Box Girder,” ACI Concrete International, Vol. 32, No. 6, pp. 44-52 (2010).
2. Collins, M.P., and Mitchell, D., Prestressed Concrete Structures, Prentice Hall, New Jersey, Englewood Cliffs, pp. 168-240 (1991).
3. Newson, N.R., Prestressed Concrete Bridges: Design and Construction, Thomas Telford Ltd, London (2003).
4. 林樹柱，預力混凝土設計及施工，第十版，弘揚圖書有限公司，台北，第120-154頁(2009)。
5. Nilson, R.H., “Design of Prestressed Concrete,” 2nd edition, John Willey & Sons, New York, pp. 165-123 (1987).
6. Branson, D.E., and Trost H., “Application of the I-Effective Method in Calculating Deflections of Partially Prestressed Members,” PCI Journal, Vol. 27, No. 5, pp. 62-77 (1982).
7. Vítek, J.L., “Long-Term Deflections of Large Prestressed Concrete Bridges,” CEB Bulletin d’Information No. 235–Serviceability Models–Behaviour and Modelling in Serviceability Limit States Including Repeated and Sustained Load, CEB, Lousanne, pp. 215-227 and 245-265 (1997).
8. Bazant, Z.P., Yu, Q., and Li, G.-H., “Excessive Long-Time Deflection of Prestressed Box Girders,” Technique Report, Northwestern University, Illinois, (2010).
9. Oh, B.H, and Yang, I.-H., “Sensitivity Analysis of Time-Dependent Behavior in PSC Box Girder Bridges,” Journal of Structural Engineering, Vol. 126, No. 2, pp. 171-179 (2002).
10. Bazant, Z.P., and Baweja, S., “Justification and Reinement of Model B3 for Concrete Creep and Shrinkage ¬1. Statistics And Sensitivity,” Material and Structures, Vol. 28, No. 181, pp. 415-430 (1995).
11. Kristek, V., Vrablik, L., Bazant, Z.P., Li, G.-H., and Yu, Q., “Misprediction of Long-Time Deflections of Prestressed Box Girders: Causes, Remedies and Tendon Layout effect,” Creep Shrinkage and Durability Mechanics of Concrete and Concrete Structures: CONCREEP 8, T. Tanabe et al., eds., CRC Press/Balkema, London, UK, pp. 1291-1295 (2008).
12. Massicotte, B., Picard, A., Gaumond, Y., and Ouellet, C., “Strengthening of A Long Span Prestressed Segmental Box Girder Bridge,” PCI Journal, Vol. 39, No.3, pp. 52-65 (1994).
13. Park, Y. H., Park, C., and Park, Y. C., “The behavior of an in-service plate girder bridge strengthened with external prestressing tendons.” Engineering Structures, vol. 27, No. 3, pp. 379-386 (2005).
14. Daly, A. F., and Witarnawan, W., “Strengthening of bridges using external post-tensioning.” Conference of EASTS, Korea (1997).
15. Tandler, J., Collapse Analysis of Externally Prestressed Structures, Diplomica Verlag GmbH, Hamburg, pp. 7-22 (2009).
16. Nordin, H., “Strengthening Structures with External Prestressed Tendons,” Technical Report, Lulea University of Technology (2005).
17. Picard, A., Massicotte, B., and Bastien, J., “Relative Efficiency of External Prestressing,” Journal of Structural Engineering, Vol. 121, No. 12, pp. 1832-1841, (1995).
18. Tan, K.H., and Ng, C.K., “Effects of Deviators and Tendon Configuration on Behaviour of Externally Prestressed Beams,” ACI Structural Journal, Vol. 94, No. 1, pp.13-22 (1997).
19. Ng, C.K., and Tan, K.H., “Flexural Behaviour of Externally Prestressed Beams. Part I: Analytical model,” Engineering Structures, Vol. 28, No. 4, pp. 609-621 (2006).
20. 邱惠生，「長跨懸臂節塊式預力混凝土橋梁長期變位控制研究」，博士論文，國立台灣大學土木工程學研究所，台北 (1995)。
21. Kulprapha, N., and Warnitchai, P., “Structural Health Monitoring of Continuous Prestressed Concrete Bridges Using Ambient Thermal Response,” Engineering Structures, Vol. 40, pp. 20-38 (2012).
22. Peeters, B., Maeck, J., and Roeck, G.D., “Vibration-based damage detection in civil engineering: excitation sources and temperature effects,” Smart materials and Structures Vol. 10 pp. 518–527 (2001).
23. Deraemaeker, A., Reynders, E., Roeck, G. De, and Kullaa, J., “Vibration-based structural health monitoring using output-only measurements under changing environment,” Mechanical System and Signal Processing, Vol. 22, pp. 34-56 (2008).
24. Yan, A.-M., Kerschen, G., Boe, P. De, Golinval, J.-C., “Structural damage diagnosis under varying environmental conditions—Part I: A linear analysis,” Mechanical Systems and Signal Processing, Vol. 19, pp. 847-864 (2005).
25. Wang, Y.-U., Huang, C.-K., and Chen, C.-S., “Damage Assessment of Beam by A Quasi-Static Moving Vehicular Load,” Advances in Adaptive Data Analysis, Vol. 3, No. 4, pp. 417-445 (2011).
26. 蔡欣局，「軌道不整檢測及識別方法」，博士論文，國立中央大學土木工程研究所，桃園 (2012)。
27. Huang, N.E., and Shen, S.S.P, Hilbert-Huang Transform and Its Applications, Word Scientific, Singapore, pp. 263-282 (2005).
28. Burdet, O., and Badoux, M., “Deflection Monitoring of Prestressed Concrete Bridges Retrofitted by External Post-Tensioning.” IABSE Symposium, Brazil, (1999).
29. Bazant, Z.P., Yu, Q., and Li, G.-H., Klein, G.J., and Kristek, V., “Excessive Deflections of Record-Span Prestressed Box Girder,” ACI Concrete International, Vol. 32, No. 6, pp. 44-52 (2010).
30. Kristek, V., Bazant, Z.P., Zich, M., and Kohoutkova, A., “Box Girder Bridge Deflections,” Concrete International, Vol. 28, No. 1, pp. 55-63 (2006).
31. Huang, N. E., Shen, Z., Long, S. R., Wu, M. C., Shih, H. H., Zheng, Q., Yen, N. C., Tung, C. C., and Liu, H. H., “The Empirical Mode Decomposition and the Hilbert Spectrum for Nonlinear and Non- stationary Time Series Analysis,” Proc. R. Soc. Lond. A, vol. 454, pp. 903- 995 (1998).
32. Wu, Z. and Huang, N. E., “A study of the characteristics of white noise using the Empirical Mode Decomposition method,” Proc. Roy. Soc. A460, 1597-1611 (2004).
33. Inaudi, D., and Vurpillot, S., “Monitoring of Concrete Bridges with Long-Gage Fiber Optic Sensors,” Journal of Intelligent Material System and Structures, Vol. 10, pp. 280-292 (1999).
34. Mast, R.F., “Analysis of Cracked Prestressed Concrete Section: A Practical Approcah,” PCI Journal, Vol. 42, No. 4, pp.80-91 (1998).
35. Wu., Z., and Huang. N. E., “Ensemble Empirical Mode Decomposition: A Noise-Assisted Data Analysis Method,” Advances in Adaptive Data Analysis, Vol. 1, No. 1, pp. 1-41 (2009).
36. Huang, N. E., and Wu, Z., “A Review on Hilbert-Huang Transform: Method and Its Application Geophysical Studies,” Reviews of Geophysics, Vol. 46 (2008).
37. Moorty, S., and Roeder, C.W., “Temperature Dependent Bridge Movements,” Journal of Structural Engineering, Vol. 118, No. 4, pp. 1090-1105 (1992).
38. AASHTO, “Guide Specifications for Design And Construction of Segmental Concrete Bridges,” Second Edition, American Association of State Highway and Transportation Officials, Washington, D.C. (1999).
39. Imbsen, R.A., Vandershaf, D.E., Schamber, R.A., and Nutt, R.V., “Thermal Effects in Concrete bridge superatures,” NCHRP Repor 12-22, TRB, Washington, D.C. (1985).
40. 陳振雄，「應用希爾伯特¬黃轉換訊號濾波之研究」，科學與工程技術期刊，第六卷，第一期，第75-84頁 (2010)。
41. Yang, I.-H., “Prediction of Time-Dependent Effects in Concrete Structures Using Early Measurement Data,” Engineering Structure, Vol. 29, pp. 2701-2710 (2007).
42. Massicotte, B., and Picard, A., “Monitoring of a Prestressed Segmental Box Girder Bridge During Strengthening,” PCI Journal, V. 39, No. 3, pp. 66-80 (1994).
43. Barr, P.J., Stanton, J.F., and Eberhard, M.O., “Effects of Temperature Variations on Precast, Prestressed Concrete Bridge Girders,” Journal of Bridge Engineering, Vol. 10, No. 2, pp. 186-194 (2005).
44. Jain, R., and Lee, L., Fiber Reinforced Polymer (FRP) Composites for Infrastructure Applications, Springer, New York (2012).
45. Hou, X., Yang, X., and Huang, Q., “Using Inclinometers to Measure Bridge Deflection,” Journal of Bridge Engineering, Vol. 10, No. 5, pp. 564-569 (2005).
46. 陸景文，「台灣地區混凝土橋梁溫度、彈性應變、潛變及乾縮特性之整合研究」，博士論文，國立台灣大學土木工程學研究所，台北 (2001)。
47. Roberts-Wollman, C. L., Breen, J. E., and Cawrse, J., “Measurements of thermal gradients and their effects on segmental concrete bridge,” Journal of Bridge Engineering, Vol.7, No.3, pp. 166–74 (2002).
48. Shushkewich, K.W., “Design of Segmental Bridge Thermal Gradient,” PCI Journal, Vol. 43, No. 4, pp. 120-137 (1998).
49. AASHTO, “AASHTO LRFD Bridge Design Specification,” 4th edition, American Association of State Highway and Transportation Officials, Washington, D.C. (2007).