不同橋梁耐震評估方法之比較

Comparison of different bridge seismic assessment methods

10.6849/SE.201609_31(3).0005

黃仲偉(Chang-Wei Huang)；洪曉慧(Hsiao-Hui Hung)；陳常麒(Chang-Chi Chen)

性能設計 ； 側推分析 ； 多跨橋梁 ； 動力歷時 ； 耐震評估 ； performance design ； pushover analysis ； multiple span bridge ； dynamic time history ； seismic assessment

結構工程

31卷3期（2016 / 09 / 01）

104 - 132

繁體中文

結構的「耐震設計」與「耐震評估」長久以來一直是國內推廣永續發展之重大課題，歐、美、日本在內的許多國家皆已採用性能設計理念的精神與內涵於新世紀技術規範。國內亦於民國98 年起推動本土化公路橋梁耐震性能設計規範，目標為控制橋梁結構於各等級地震作用下之使用性、可修復性與安全性。確保新建橋梁在不同等級地震作用下達到預期耐震設計目標之可靠度，降低橋梁地震中的受損風險。本文旨在介紹公路橋梁耐震能力設計規範草案中的耐震評估方法，並以四座多跨連續數值橋梁為探討對象。利用非線性側推分析建立橋梁整體容量曲線，分別以不同的耐震評估方法計算橋梁性能點，由性能點反推橋梁上部結構整體之側向位移。最後以非線性動力歷時分析所得之橋梁上部結構整體之側向位移作為基準，比較不同耐震評估方式所得結果的差異。希冀透過此研究可讓國內實務單位對於不同橋梁耐震評估方法能有初步的認識。

Structural seismic design and seismic assessment are important issues in the sustainable development. Today, the concepts of performance-based design have been adopted in the building codes of European Union, Untied of States, Japan and other advanced countries. As a result, the performance-based seismic design provisions and commentary for highway bridges has also been introduced in Taiwan from 2009. The aims of the new seismic design provisions are to ensure the serviceability, retrofit, and safety of highway bridges under seismic hazards. In addition, the new seismic design provisions focus on the real responses of structures suffer from different levels of earthquakes, which can guarantee the new bridges, according to the performance-based design, achieving the reliability of anticipated targets and decreasing the damage ricks. In this paper, the draft of the new seismic design provisions for highway bridges is introduced and compared with other two existed method (ATC-40 and refined seismic assessment method). Pushover analyses with uniform lateral load pattern for four numerical multiple-span bridges are carried out. Then the pushover curves are transformed to the corresponding capacity spectrum curve with multiple monitoring points. Then the performance points are obtained by three seismic assessment methods and can be used to estimate the maximum lateral displacements. Compared with the results from nonlinear dynamic analyses, one can know the differences between three seismic assessment methods.