人行吊橋的現有內力評估及動力分析;A Method of Internal Force Estimation and Dynamic Analysis for Suspension Footbridges

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Title:	人行吊橋的現有內力評估及動力分析;A Method of Internal Force Estimation and Dynamic Analysis for Suspension Footbridges
Authors:	盤森;Pan, Sen
Contributors:	土木工程學系
Keywords:	吊橋內力;向量式有限元;非線性;大變形;行人荷載;人工地震;footbridges;VFIFE;non-linear;large displacement;pedestrian load;spectrum matching
Date:	2018-07-17
Issue Date:	2018-08-31 11:23:14 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究使用向量式有限元(VFIFE)建立一套適用於吊橋動力行為分析的數值方法，研究的第一階段依據橋梁設計資料、現地量測資料、光達掃描點雲建立吊橋之數值模型。再使用VFIFE理論，透過一套幾何構形迭代程序，反算出模型在承受自身材料重量下，維持其現有構形的內力分布狀態。並與現地實驗比對最大索力值、振態頻率識別，驗證成橋內力與實際情形的符合程度。後續動力分析則對已校正之模型施加不同形式之外力，本研究使用人流概念模擬行人移動荷載的分布情形，行人個體在橋面上模擬為移動質點，經由不同運動狀態的定義，整體人流對橋面行為將造成不同的外力影響。另外採用振動台概念對模型地表支承處施加位移控制，真實模擬吊橋受到地震歷時的作用。本文以新北市碧潭吊橋為例，綜合兩項外力條件，考慮在日常使用狀況、高承載情況下，外力條件造成橋面的振動情形變化，並根據規範對此時的行人舒適度給予分級，同時對模擬過程中各項破壞模式進行檢核。;This thesis proposes a systematic dynamic analysis procedure to predict the behavior of suspension footbridges with different load patterns, including pedestrian load and seismic load. The parameters of model, properties of materials and sections has been confirmed by the field measured data and point clouds of 3D LiDar. In the first stage of analysis, the internal force of members will be calculated through geometric shape iteration by the VFIFE (Vector Form Intrinsic Finite Element) method. The accuracy of results has been confirmed through comparison the internal forces with the tension force in cables determined by experiments and modal analysis. This calibrated numerical analysis model is used for dynamic behavior prediction of suspension footbridges. Pedestrian load has been simulated by the concept of pipe-flow, applied on the bridge models in the form of moving masses. The source of seismic load is spectrum compatible time series, and it controls the displacement of joints which has restrained with boundary conditions from the ground. A comprehensive application about estimating the serviceability of Bi-Tan footbridges with normal and extreme load conditions has been conducted in this research, and the safety performance in different failure modes has been checked in addition.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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