容量位移雙反應譜－基於損傷之鋼筋混凝土橋梁耐震設計與評估法

Capacity-Based Inelastic Displacement Spectra for Seismic Design and Evaluation of Reinforced Concrete Bridges

王柄雄(Ping-Hsiung Wang) ； 張國鎮(Kuo-Chun Chang) ； 歐昱辰(Yu-Chen Ou)

《結構工程》 33卷4期 (2018/12) Pp. 91-112

https://doi.org/10.6849/SE.201812_33(4).0004

摘要

本研究提出一套容量位移反應譜(Capacity-based inelastic displacement spectra)，其係由一個非彈性位移比C_R反應譜與一個相應之損傷指標DI反應譜所構成之雙反應譜(Dual spectra)，可用於鋼筋混凝土橋梁之耐震性能設計與評估。反應譜之建置係藉由一個功能強大的平滑型遲滯模型，可考慮不同橋柱設計參數之影響，並分別就遠域及近斷層地震進行單自由度系統之非線性動力歷時分析而得。本研究證實在任何的位移加載歷程下，Park and Ang所提出之損傷指標不但可用來準確地預測橋柱的強度衰減時機，更可作為評估橋柱真實可視破壞狀態的良好指標，進而得到較佳的橋梁耐震性能評估結果。採用遠域地震所計算之C_R反應譜顯示，當結構週期約略大於0.8秒時，非彈性位移比C_R可近似滿足等位移原理；但就近斷層地震而言，在全部反應譜週期範圍內則皆不滿足此原理。此外，分析結果顯示近斷層地震會較遠域地震產生明顯較大的C_R及DI值，且當相對強度比R = 5.0時，大部分本研究所考量之設計方案皆無法承受所考慮之近斷層地震的侵襲。最後，根據所計算之反應譜分析結果，本研究分別就遠域及近斷層地震各提出一套非彈性位移比C_R及相應之損傷指標DI之反應譜公式，並依據所建置之容量位移反應譜，提出一套基於損傷之鋼筋混凝土橋梁耐震性能設計與評估方法。

關鍵字

反應譜 ； 非彈性位移比 ； 損傷指標 ； 平滑型遲滯模型 ； 遠域地震 ； 近斷層地震 ； 耐震設計與評估 ； 鋼筋混凝土橋梁

並列摘要

Capacity-based inelastic displacement spectra that comprised an inelastic displacement (C_R) spectrum and a corresponding damage state (DI) spectrum was proposed in this study to aid seismic evaluation and design of reinforced concrete (RC) bridges. Nonlinear time history analyses of SDOF systems were conducted using a versatile smooth hysteretic model that accounted for the influences of various column design parameters when subjected to far-field and near-fault ground motions. It was proved that the Park and Ang's damage index not only can be used to accurately predict the onset of strength deterioration, but also can be a good indicator for assessing the actual visible damage condition of column regardless of its loading history, providing a better insight into the seismic performance of bridges. The computed spectra show that the C_R for far-field ground motions approximately conforms to the equal displacement rule for structural period (T_n) larger than around 0.8 seconds, but that for near-fault ground motions departs from the rule in the whole spectral regions. Moreover, the near-fault ground motions would lead to significantly greater C_R and DI than far-field ground motions and most of the design scenarios investigated in this research cannot survive the near-fault ground motions when relative strength ratio R = 5.0. Based on the computed spectra, C_R and DI formulae are presented as a function of T_n, R, and various design parameters for far-field and near-fault ground motions. Finally, application of the proposed spectra to the performance-based seismic design and evaluation of RC bridge was presented using DI as the performance objective.

並列關鍵字

spectrum ； inelastic displacement ratio ； damage index ； smooth hysteretic model ； far-field earthquake ； near-fault earthquake ； seismic design and evaluation ； RC bridges