國道高速公路橋梁採隔震與基礎置換之耐震補強規劃設計

Seismic Isolation Retrofit and Foundation Replacement of Freeway Bridge

陳吟亘(Yin-Xuan Chen) ； 蕭天任(Tien-Jen Hsiao) ； 吳明興(Ming-Shing Wu) ； 彭康瑜(Kang-Yu Peng) ； 陳國隆(Guo-Long Chen)

《結構工程》 36卷1期 (2021/03) Pp. 63-74

https://doi.org/10.6849/SE.202103_36(1).0004

摘要

國內橋梁設計規範自民國76年版起，經過歷年耐震設計規範的改版更新，地震力多有提昇，為使既有橋梁符合現行規範之耐震能力標準，國道高速公路局自民國88年921集集地震後，持續推動橋梁耐震能力詳細評估，針對耐震能力不足者，分期辦理耐震補強工程。橋梁基礎補強之工程經費較高，故優先採用「系統補強」的策略，研擬隔震或減震方案，當既有上部結構與橋墩之接合為故固接時，無法直接增設隔震支承，本文以國道3號高速公路「東山服務區跨越橋」為例，說明既有固接橋墩增設隔震支承之設計考量重點及方法。另外，部份橋梁有於河川行水區設置直接基礎的情形，因環境變遷與河床逐年下降，恐有基礎板底部承載層沖蝕疑慮，為一併辦理橋梁基礎耐震與耐洪能力的提昇，可考慮採用基礎置換工法（或稱換底工法），本文第二部份以國道3號高速公路「梅林溪排水橋」為例，說明直接基礎置換為樁基礎之施工步驟及方法。

關鍵字

系統補強 ； 隔震支承 ； 換底工法

並列摘要

Taiwan's bridge seismic design specifications have evolved several version from 1987. In order to meet the seismic requirements under newest version specification. Freeway Bureau, MOTC has started existing bridge seismic capability evaluation and retrofitted after Chi-Chi Earthquake in 1999. Because foundation retrofitting are expansive, we prefer to use ＂system retrofit method＂. Conduct the feasibility studies on seismic isolation and damping devices. While the superstructure and pier are rigid connected, isolation bearing can't install directly. An example of this is ＂Dong-Shan Bridge＂. In this study, we explain the design considerations and methods of adding seismic isolation bearing to existing rigid piers. Furthermore, there are some cases where the spread foundation base will be scouring. An example of this is ＂Mei-Lin Bridge＂. In order to increase earthquake and flood resistance at the same time. We use foundation replacement method to make spread foundation replace to pile foundation.

並列關鍵字

system of retrofit method ； seismic isolator ； foundation replacement method