本研究主要探討基礎結構受複合式災害，即基礎受沖刷裸露後又受地震荷載之結構行為，在研究中分別採用不同土壤彈簧，由前人提出的等值線性土壤彈簧、美國石油協會（API）與日本道路橋示方書（JRA）三種不同土壤彈簧對基樁沖刷裸露後振動台實驗做受震行為分析，藉由與基樁振動台實驗比較能對現有常用規範與等值線性彈簧對沖刷裸露後結構的適用性探討與比較，結果顯示在採用等值線性彈簧模型分析相對於其他兩種規範能更有效地模擬實驗的受震反應，且在受近斷層地震下，等值線性彈簧能完整地模擬結構受震後的行為。
但由於現地橋梁公路基礎結構多為群樁基礎，在群樁基礎中對於群樁折減因子需進行探討，因此根據之前單樁分析的經驗，進而對群樁基礎沖刷裸露實驗進行探討，分別以等值線性彈簧、API與日本鐵道構造物（JRA）規範三種土壤彈簧經由群樁折減因子，嘗試模擬群樁基礎受沖刷裸露後受到大位移的靜態荷載下的結構反應，在研究中也比較了等值線性彈簧在實驗中適用之群樁折減因子，最後以3組不同土壤彈簧模型對群樁在不同裸露深度下受靜態荷載之結構反應進行分析，試圖比較出對於群樁沖刷裸露結構能最有效地模擬之土壤彈簧。
結果顯示：比較不同土壤彈簧側推曲線與群樁實驗比較時候，等值線性彈簧與API土壤彈簧在不同裸露深度下皆能模擬實驗之結果，而比較樁身彎矩分析中顯示，在群樁基礎之基樁未產生降伏時，3種土壤彈簧模型分析結果皆對實驗結果誤差不大；但當基樁受力至降伏時，等值線性彈簧模型分析結果對群樁之後排樁能有效地模擬；而API土壤彈簧模型分析結果與群樁之前排樁的結構行為接近。最後，希望本研究之比較探討能讓工程師在分析橋梁結構受複合式災害之結構行為能以更有效之土壤彈簧去模擬其結構行為。

In Taiwan, there are many bridges that were destroyed by the nature disasters every year. Although the civil engineers did the best on designing the bridges, the nature disasters would decrease the seismic capacity of the bridges. The survey of the collapsed bridge pointed out that the scoured depths increased by the hydraulic and the seismic capacity decreased.
In this study mainly discusses the structural behavior of the composite structure, ie, the structural behavior of the foundation exposed to erosion and exposed to seismic loads. In the study, the equivalent linear soil springs proposed by previous researchers ,the American Petroleum Institute（API） and Japanese Road Association（JRA） soil spring were used respectively. This study used different soil springs to analyze the vibration behavior of shaking table experiments after bare pile erosion, and compare with the existing single and group pile foundation experiments.
The discussion and comparison of the applicability of the soil springs on exposed structure shows that the response of the experiment can be more effectively simulated by using the equivalent linear spring model. The most important is that the model using equivalent linear spring under near-fault earthquakes completely simulate the behavior of the structure after the shock.

[1]Seed HB, Idriss IM. Soil Moduli and Damping Factors for Dynamic Response Analysis. Report No. EERC 75-29, Earthquake Engineering Research Center, University of California, Berkeley, California 1970.
[2]Jason T. DeJong, Site Characterization – Guidelines for Estimating Vs Based on In-Situ Tests, Stage 1 – Interim Report, University of California, Davis, 2007.
[3]邱煌傑，「花蓮大比例尺模型地震試驗之地盤振動反應分析」，台灣大學土木工程學研究所碩士論文，民國85年。
[4]商宇，「冲刷条件下的桩基桥梁振动台试验」，中國公路學報，2017。
[5]Ju,S.H ,Determination of scoured bridge natural frequencies with soil–structure interaction. Soil Dynamics and Earthquake Engineering, 55, 247-254. doi：10.1016/j.soildyn.2013.09.015.
[6]Bhowmik, S. K., Three-dimensional nonlinear finite element analysis of laterally loaded piles in clay, Ph.D. Thesis, University of Illinois at Urbana-Champaign, 1992.
[7]Wang,X.,Eexperimental investigation on Resonance Behavior of RC Pile Foundation considering bridge scour effects. The 5th Asia Conference on Earthquake Engineering, 2014.
[8]Wang, S.-C., Liu, K.-Y., Chen, C.-H., & Chang, K.-C.,Experimental investigation on seismic behavior of scoured bridge pier with pile foundation. Earthquake Engineering & Structural Dynamics, 44（6）, 849-864. doi：10.1002/eqe.2489, 2015.
[9]賴姿妤，「樁基礎沖刷橋梁模型之振動台試驗研究」，台灣大學土木工程學研究所碩士論文，民國100年6月。
[10]陳正鴻，「樁基礎沖刷橋梁模型之振動台試驗分析研究」，台灣大學土木工程學研究所碩士論文，民國105年6月。
[11]王修駿，「橋梁受沖刷後之耐震行為研究」，台灣大學土木工程學研究所博士論文，民國103年12月。
[12]鄧爵明，「單柱式橋墩與群樁基礎裸露之靜態側推研究」，台灣大學土木工程學研究所碩士論文，民國106年6月。
[13]Poulos, H. G.,Behavior of Laterally Loaded Piles：Ⅰ-Single Piles,Journal of the Soil Mechanics and Foundations Division,ASCE, Vol.97, SM5, May, pp.711-731, 1971.
[14]Poulos, H. G.,Behavior of Laterally Loaded Piles：Ⅱ-Single Piles,Journal of the Soil Mechanics and Foundations Division,ASCE, Vol.97, SM5, May, pp.733-751, 1971.
[15]周南山，譯張有齡「張氏簡易側樁分析法」，地工技術，第25期。
[16]RP2A-WSD, API, Recommended practice for planning, designing and constructing fixed offshore platforms–working stress design–. In Twenty, 2000.
[17]薛朝光，「場鑄單/群樁側向荷載非線性行為研究」， 國立海洋大學論文，2004。
[18]道路橋示方書.同解說（四.下部結構編）平成14年3月，編輯發行所：財團法人日本道路協會。
[19]蔡益超、張荻薇、黃震興、周功台、張國鎮、宋裕祺，「公路橋梁耐震設計規範之補充研究」，交通部台灣區國道新建工程局發行，民國86年4月。
[20]日本鐵道構造物等設計標準及解說（2003）。
[21]California Amendments to AASHTO LRFD Bridge Design Specifications－fourth edition, Page 10.84A.
[22]柯永彥、邱俊翔、蔡煜青、陳正興，「受沖刷橋梁耐洪能力評估方法」，民國101年。
[23]Matlock, H., and Reese, L.C. 1960. Generalized solutions for laterally loaded piles. Journal of the Soil Mechanics and Foundation Engineering Division, ASCE, 86（5）: 63–91.
[24]K.-C. Chang, H.-H. Yang, and C.-H. Chen, "Use of Plastic Hinge Model in Nonlinear Pushover Analysis of a Pile," Geotech. Geoenviron.Eng, 2009.