透過您的圖書館登入
IP:3.230.1.23
  • 學位論文

橋梁含功能性支承與直接基礎之振動台試驗研究

Shaking table study on the bridge system with functional bearing and spread footing

指導教授 : 張國鎮

摘要


本研究採用單跨簡支橋梁進行振動台實驗研究,探討橡膠支承摩擦滑動與直接基礎搖擺機制所提供之隔震效益,對落橋、橋柱塑鉸與基礎旋轉之影響。橋梁模型跨度4m、上部結構由混凝土版及配重塊組成,使4個5*7.5*2.5cm橡膠支承分擔6tf載重。下部結構為單柱式橋墩,由2座直徑16.9cm、厚度0.67cm、高度60cm之鋼管柱,搭配60*60*10cm鋼基礎版組成,分別放置於100*100*10cm、硬度60之橡膠墊上,或直接鎖固於地面。支承型式分為鉸接–滑動式及雙側半固定式,各代表強支承及弱支承系統。基礎版埋入相對密度50%之矽砂質土壤,埋入深度分別為0倍、2倍版厚。輸入地震為El-Centro 及TCU076,最大地表加速度為隨試驗組別不同由50 gal到550 gal。 實驗結果顯示,當基礎版固接時鉸接端橋柱之彎矩需求容量比最大,若允許基礎搖擺可延長週期使橋柱保持彈性,但其基礎版旋轉角有偏大現象,而覆土深度的增加會降低基礎搖擺產生的效應。而當基礎版固接時將鉸接–滑動式支承改為雙側半固定式支承亦可降低大梁加速度並降低橋柱之彎矩需求容量比,惟支承摩擦滑動位移亦隨之增加,應確保足夠防落長度避免落橋。不過當橋梁同時考慮基礎搖擺機制與支承滑動行為時,支承摩擦滑動將會受到抑制,結構的受震反應將由基礎搖擺所控制。此外,本研究根據FEMA 356設計規範所建議之分析方式,檢討直接基礎土壤彈簧之適用性。研究成果可提供公路橋梁耐震規範修訂直接基礎之設計寬幅與容許旋轉角規定,並應用功能性支承於直接基礎之耐震補強工程之參考依據。

並列摘要


To investigate the seismic performance provided by the sliding behavior of rubber bearings and rocking mechanism of the spread footing, this study introduced a series of shaking table test about a single span bridge model with different types of bearing system and foundation. The 4 m span bridge model was comprised of a reinforced concrete girder and eighteen massive blocks representing the superstructure. Under the girder, four elastomeric rubber pads (5*7.5*2.5 cm) at left and right end for bridge bearings sustain 6 tf weight of the superstructure. The substructure was composed of two steel pipes which have 0.67 cm thickness, 16.9 cm diameter, 60cm length and two 60*60*10 cm steel footing plate which were put on the 100*100*10cm rubber pads or fixed on the shaking table. The two types of bearing system are simple support and rubber bearing at each end which is allowed for sliding. The footing was embedded by dry silica sand with 50% relatively density for 0 cm and 20 cm, which represents the 0 times and 2 times of the footing thickness. Acceleration records from EL Centro and TCU076 station in Chi-Chi earthquake were chosed as th input ground motions. The peak ground acceleration strarted from 50 gal and achieved 550 gal for various test cases. Based on the experimental results, the observation demonstrated that the rocking mechanism can reduced the bridge pier bending moment but increase the footing rotation; furthermore, the rocking behavior will become weaker as the soil depth increasing. Otherwise, for fixed base cases, the sliding behavior of rubbering bearings can decline the pier bending moment but increase the girder displacement. However, if the sliding behavior and the rocking bechanism are considered at the same time, the sliding behavior will be reatrain, which means that the seismic behavior will controlled by the footing rocking. In addition, Structural safety issue on the allowable criteria should be addressed and verified from analytical simulations based on relevant designing codes.

參考文獻


[5]葛伊仁,「地震作用下橋梁基礎搖擺機制之數值分析」,台灣大學土木工程學研究所碩士論文,民國99年7月。
[7]陳皇嘉,「裝設橡膠支承墊於橋梁縮尺模型之試驗與分析」,台灣大學土木工程學研究所碩士論文,民國94年6月。
[1]劉光晏,「橋梁功能性支承系統耐震性能設計與評估補強方法之研究」,台灣大學土木工程學研究所博士論文,民國95年6月。
[17]陳能鴻,「單跨樁基礎橋梁模型之振動台實驗研究」,台灣大學土木工程學研究所碩士論文,民國102年6月。
[10]張國鎮、盧智宏、劉光晏「含功能性支承橋梁位移設計法之研究」,國家地震工程研究中心研究報告(報告編號:NCREE-11-015),民國100年9月。

被引用紀錄


陳威宇(2015)。樁基礎橋梁含功能性支承之振動台試驗研究〔碩士論文,國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342%2fNTU.2015.01344
周宛萱(2014)。建構高精度數位影像相關法並應用於土木結構動態系統及 奈米材料微系統的變形量測〔碩士論文,國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342%2fNTU.2014.01974
黃文絹(2014)。向量式有限元應用於含功能性支承橋梁數值模擬分析〔碩士論文,國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342%2fNTU.2014.01631

延伸閱讀