從近年來震害調查中發現,在地震作用時,當橋梁上下部結構間產生的相對位移量超過其防止落橋長度或防止落橋裝置之極限時,即發生落橋;因此,防止落橋乃橋梁耐震因應對策中非常重要的課題。本論文旨在討論橋梁功能性防落裝置對於橋梁耐震性能的影響,希望對於工程師在日後設計或維修補強方面提供有效且經濟性的方法和分析流程。由於目前耐震設計以橋柱為主要消能構材,所以提供橋柱塑性鉸不同的模擬方法,以提供側推分析(Pushover)和非線性動力分析。為了了解防落裝置系統對於橋梁耐震性能之影響,本研究模擬分析一座位於台灣地區的實尺寸橋梁,並依據之前各防落設施裝置實驗研究結果,利用結構分析軟體(SAP2000)建立各防落設施之數值分析模型。探討在地震作用下,此橋梁在裝設不同防落設施後所發揮之效能。將結構分析軟體(SAP2000)之非線性動力分析結果經由希爾伯特-黃轉換(Hilbert-Huang Transform, HHT)後之2D希爾伯特頻譜(Hilbert spectrum)比較,以了解防落設施在頻率域之變化,找出防落設施裝置之作用時間與頻率之改變量。
In this thesis, the mechanical behaviors of bridge with functional unseating prevention devices were investigated. The functions of the devices are to prevent bridge from unseating and to prevent most of the seismic force transfer to the bridge column. The static pushover analysis with SAP 2000 was used to simulate the real bridge. The Hilbert-Huang Transform (HHT) was also used to transfer the time history response into the time-frequency domain and also to obtain the Hilbert spectrums of the superstructure. The Hilbert spectrums can determine when the functional unseating prevention devices were operated and their operation sequences.