本研究探討半主動控制於單跨含樁基礎簡支橋梁之耐震行為，利用磁流變阻尼器、雙砂箱剪力盒與振動台實驗，研究結構控制之控制效果。本研究目標橋梁分為兩種，基礎裸露實驗與固定基礎實驗，基礎裸露實驗符號分別以H與R 說明鉸接端樁基礎、輥接端樁基礎，D 說明樁徑之倍數代表沖刷深度，共H0D-R0D、H0D-R3D、H3D-R3D、H3D-R6D、H6D-R6D 等5組，固定基礎實驗不含樁基礎並固接於振動台檯面上，以HFix-RFix表示。控制方法有未控制、被動控制與半主動控制共三種。輸入地表加速度歷時有El Centro 地震、集集大地震附近測站TCU076及與符合規範之人造地震TCU076，其最大地表加速度分別為350 gal、200 gal與200 gal。 根據實驗與分析結果，結構週期隨著基礎裸露的深度增加而增加，橋面板加速度隨著基礎裸露的深度增加而減少。運用滑模變控制下，半主動控制的控制效果十分顯著，且5組基礎裸露實驗於震波集集大地震TCU076 測站與人造地震下，與未控制相比，橋面板位移皆下降約30 %，顯示半主動控制於受沖刷之橋梁可行性。 ;This study investigated the seismic performance of a scoured bridge with exposed pile foundation and the feasibility of the semi-active control system with MR(Magneto-rheological) damper by dual biaxial laminar shear boxes and shaking table tests. In this study, the experimental testing was divided into a scoured bridge with exposed pile foundation and a bridge without pile foundation. The pile is designated to be scoured as a ratio pile diameter (D) at either hinge-end (H) or roller-end (R). The bridge without pile foundation was bolted on the shaking table (Fix). Category: H0D-R0D, H0D-R3D, H3D-R3D,H3D-R6D, H6D-R6D and HFix-RFix. There were three structure control methods in this study, they were uncontrolled, passive control and semi-active control. The input ground motions included acceleration records from El Centro (PGA 350 gal), Chi-Chi earthquake TCU076 station (PGA 200 gal), and artificial TCU076 (PGA 200 gal). According to experimental and analytical results, the structural period changed longer gradually when the scoured depth increased, but acceleration of the deck decreased as the scoured depth increased. The semi-active control system with the sliding mode control could effectively reduce the displacement of the deck from the experimental testing of the scoured bridge. Compared with uncontrolled bridge, the semi-active control could decrease about 30% displacement of the deck under the Chi-Chi earthquake TCU076 station (PGA 200 gal).