| Abstract: | 近年來國內外地震災害事故頻傳，地震工程與耐震設計的重要性，再度成為眾所 矚目的焦點，而傳統耐震設計方法的妥適性也受到考驗。因此，一個切合本土地震特 性並匹配本土地質條件的耐震設計規範極為重要。我國建築物耐震設計規範之訂定始 於民國63 年，並分別於71 年、78 年、86 年、88 年及94 年修改部分條文；由於台灣 早期在地震工程方面之基礎研究不足，且各地震測站之地盤特性並不明確，因此十數 年來，尤其是九二一集集地震之後，雖然已有大量本土化研究成果，但現行及研議中 之相關耐震設計規範，包括建築物、鐵路橋梁、及公路橋梁規範等，仍相當程度參考 美國及日本等國之規範。但各國國情、地震環境、地盤特性，及規範之發展過程與背 景畢竟不同，以致國內規範時有斷章取義或顧此失彼之憾；不同規範間，對於相同定 義或係數亦偶有不一致之處。譬如各規範之地盤分類標準並不一致，而對應之反應譜 工址放大係數的數值卻相同，常令從事耐震設計者無所適從。 鑑於地盤分類及對應之反應譜值乃耐震設計之最基本要項，所有設計皆根據該分 類及對應之譜值而來，若最基本要項存有太多不確定因素，後續之設計成果將缺乏信 服力。為了要突破此窘境，本研究將利用台灣本身之地震及測站地質資料，從事場址 效應(site effect)之研究，以圖根本解決之道。目前交通部中央氣象局在全國各地設置了 686 座自由場強震測站，收集完整的強震紀錄；國家地震工程研究中心也接受中央氣象 局之委託，逐年建立全國自由場強震測站的地質資料庫，目前已完成超過377 個測站 的調查，這些資料篩選後正可提供本研究從事地盤分類、強震測站場址效應、以及場 址條件與反應譜特性關係之研究。本子計畫屬於整個整合型計畫之最基礎部分（子計 畫一），所扮演角色極為重要。屆時，此本土性資料的研究成果將有助於現行設計規範 的修正建議，也可提供本整合型計畫之其他子計畫主持人作為結構物受震分析時輸入 地震力的參考，而援引他國規範所致之窘境將可逐一化解。 There are many seismic-induced damages in these years. It is undoubtedly that the earthquake engineering and seismic design is increasingly important, and it is a challenge for the appropriateness of the traditional methods of seismic design. Therefore, a code meets the requirements of design according to characteristics of earthquake and site condition in Taiwan is an urgent demand. The developments of seismic code in Taiwan started in 1974. Many modifications have been made after that year, such as in 1982, 1989, 1997, 1999, and 2005. Though there are a large amount of research results for earthquake engineering and related topics in the past decade, especially after 921 Chi-Chi earthquake in 1999, the current or oncoming codes of buildings and bridges of road and railway in Taiwan are still mostly based on other country codes, such as America and Japan, owing to lack of definite site condition. There are a lot of inconsistencies in different seismic code, such as site classification criteria and corresponding spectral site amplification. Thus, much confusion need to be settled is existed in seismic design practices. In view of site classification criteria and corresponding response spectra are the essential parts of seismic design, the uncertainty and indefinite factors influencing these results must be reduced to minimum if possible. The most effective method to resolve all the doubts is to perform site response analyses based on earthquake records and site conditions in Taiwan directly. Currently, there are 686 free field seismograph stations set up by Central Weather Bureau (CWB) and more than 377 boreholes data of CWB strong motion stations investigated by National Center for Earthquake Engineering (NCREE) are ready at hand. Strong ground motions are recorded for each earthquake, and site conditions are explored for every CWB strong motion stations year by year. These records and site information can provide an abundant database for setting up a site classification criterion suitable for Taiwan, and for performing site response analyses to establish the relationship between site conditions and response spectra. These are the main research items of this plan. It is meaningful to evaluate the site effects for Taiwan from that database, which form the basis of this research. This research is the most fundamental part of the entire integrated research project entitled by “Analysis and Simulation of Geotechnical and Structural Monitored Data and its Application to Design Code”. The results of this research will play a very important role which can not only provides a recommendation for revising current seismic design code, but also can supply the other plan of this integrated project a reasonable input ground motion for structural seismic analysis. Finally, the inconsistencies in different seismic code and confusion in seismic design practices will be eliminated at the same time. |
