日式木造歷史建築耐震性能評估－以學校辦公室為例

Seismic Evaluation of Historic Japanese Wooden Buildings–Examples of School Offices

由於台灣地處地震帶，在歷史建築的保存與活用上，確保其耐震性能是重要的課題。國內對於日式木造歷史建築之耐震評估，多採用日本建築防災協會出版之木造住宅耐震精密診斷方法，藉由結構體保有強度與法規所規定需求強度相除所得數值，來判斷安全與否；惟從其結果並無法得知結構體的反應量，如層間變位角。近年地震工程裡主要趨勢之一的「性能評估與設計」，強調藉由結構體反應值的定量資訊，以便能更清楚對定義耐震性能的重要性。有鑑於此，本研究以3棟日式木造學校辦公室為對象，採用性能評估法進行耐震診斷，以更明確掌握其耐震能力；過程中針對結構耐震元素的性能曲線，如編竹夾泥牆已有本土資料者，即按其實驗數據設定之，而尚缺本土資料者，如板條灰泥牆，則參考日文文獻進行設定。從評估結果與2010年甲仙地震震損情形之比較，確認該方法之合理性，因而可提供實務上日式木造建築耐震評估一個簡便合理之方法。惟本評估法尚未考量耐久性對木構造耐震元素強度變化可能造成之影響，係應用時須注意之限制。

When conserving or reusing historic buildings in Taiwan, an earthquake zone, it is critical to ensure their seismic capacity. The methods published by the Japanese Building Disaster Prevention Association have often been used in Taiwan to assess a building’s performance during an earthquake, found by dividing the required strength by the constructed strength. In recent years earthquake engineering has emphasized the importance of quantitative data in determining earthquake performance. In this study, performance evaluation and design is used to conduct seismic evaluation of historic Japanese wooden houses. Three school office buildings damaged in the 2010 Jiashian earthquake were selected. First, the lateral resistance capacity of building structures was determined according to experimental data such as for wooden joints and bamboo-plaster walls. Then using the response spectrum method, the response drift angle of structures was obtained, which corresponds directly to a certain damage level based on experimental results. Comparison of the evaluation results and the damage observed following the Jiashan earthquake shows a high degree of correlation. Thus this method provides a practical and reliable technique for the seismic evaluation of historic Japanese wooden buildings. Note that variations in strength of wooden members due to durability has not yet been taken into consideration.