考慮近斷層脈衝影響之隔震設計-以臺北盆地為例

Design of Base-Isolation Systems at Sites Facing the Threat of Pulse-Like Ground Motions

楊甯凱(Ning-Kai Yang)

指導教授 ： 黃尹男

國立臺灣大學/工學院/土木工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202100220

摘要

近斷層脈衝型震波因為含有中長週期速度脈衝，已為隔震結構之有效性帶來挑戰，特別是隔震結構物，長週期速度脈衝有可能造成隔震器位移過大而破壞。然而台灣建築結構耐震設計規範在設計隔震系統時並未提供具體考慮脈衝效應影響的做法，若因為脈衝型地震有可能造成隔震器過大位移而無法在近斷層區域採用，影響將十分重大。
本研究提出一套流程將脈衝型地震的影響合理地納入隔震系統之設計，此設計流程不更動現行法規要求，建議以現行耐震設計規範公告之設計反應譜進行隔震系統設計，再輔以定值法建立之脈衝地震檢核反應譜以及適當選取之脈衝型地震紀錄，透過非線性動力歷時分析進行隔震系統及上部結構之性能檢核。除了非線性分析之外，本流程另外提供一考慮脈衝型地震之等效線性方法，以快速評估隔震系統初始設計在所選取之脈衝型地震紀錄作用之下是否能符合所設定之性能要求，目的在於降低非線性動力歷時分析之次數。
本文以一棟位於臺北盆地的15層韌性抗彎鋼構建築為例，考慮山腳斷層發生規模7.3並產生長週期脈衝之地震，說明如何以本文提出之流程進行隔震系統之設計，包括檢核反應譜之建立、地震紀錄之選取與縮放、脈衝型地震之等效線性評估、以及隔震系統和上部結構之性能檢核。

關鍵字

近斷層地震 ； 隔震 ； 鉛心橡膠支承墊 ； 非線性動力歷時分析 ； 強地動模型

並列摘要

Pulse-like ground motions lead to severe damages and large structural demands for base-isolation systems. However, Taiwanese Building Code doesn’t provide clear guidelines for the design of base-isolation systems subjected to pulse-like ground motions, which may produce excessive displacement of isolators and endanger the systems. A procedure is proposed in this paper to reasonably incorporate the impact of pulse-like ground motions into the design of isolation systems. The procedure involves: (1) the development of an “evaluation spectrum” using newly developed Taiwan ground motion prediction equations and a model for pulse-like ground motions, (2) selection and scaling of pulse-like records for nonlinear response-history analysis of the isolated building of interest, and (3) the evaluation of the peak isolation displacement response form nonlinear dynamic analysis by equivalent linear method under pulse-like ground motions.
This paper presents an example using a 15-story steel special moment resisting frame isolated with lead-rubber bearings to demonstrate the proposed procedure.

並列關鍵字

Near-Fault Ground Motions ； Base Isolation ； Lead-Rubber Bearings ； Non-Linear Response-History Analysis ； GMPE

參考文獻

Abrahamson, N. A. (1992). Non-stationary spectral matching. Seismological research letters, 63(1), 30.

Ancheta, T. D., Darragh, R. B., Stewart, J. P., Seyhan, E., Silva, W. J., Chiou, B. S. J., ... Donahue, J. L. (2014). NGA-West2 database. Earthquake Spectra, 30(3), 989-1005.

Anderson, J. C., Bertero, V. V. (1987). Uncertainties in establishing design earthquakes. Journal of Structural Engineering, 113(8), 1709-1724.

American Society of Civil Engineers. (2017). Minimum design loads and associated criteria for buildings and other structures: ASCE/SEI 7-16.

Baker, J. W. (2007). Quantitative classification of near-fault ground motions using wavelet analysis. Bulletin of the Seismological Society of America, 97(5), 1486-1501.