傳統寺廟木棟架附壁柱震損變形探討

A Study on the Deformation of Wood Pilasters of Traditional Temples

台灣傳統寺廟建築絕大部分為木棟架與砌體混合構造，其中木棟架之配置，在左右山牆之內側常有附壁棟架，背牆則有附壁柱。附壁棟架或附壁柱與壁體在地震作用下會有互制行為發生。為探討附壁柱與壁體間之互制行為，本文針對柱腳未滑移及滑移時摩擦力之作用，根據材料彈性線性行為，以能量法推導附壁柱同時受軸力及側向力之不同載重條件下之變形、內力及其破壞模式。根據此項推導，本文實際探討台南孔子廟兩處震害附壁柱，分析顯示附壁棟架之中柱外彎變形並非完全來自受力產生之彎矩，主要是中脊楹端在地震過程下移後未能回復所造成。而另一處背牆之附壁柱在地震作用下，來自壁體之互制力導致此附壁柱產生無可恢復之彎曲變形，並脫離壁面及柱珠。兩處附壁柱在地震下之損壞經驗值得修復設計者參考並做防範。

In Taiwan most of the traditional temples are constructed with wood frames and masonry. Wood pilasters usually appear at the side or back walls. In order to understand the structural functions and failure modes of pilasters, this paper derives the linear elastic formula of deformation and internal forces under axial load combined with lateral load by energy method. Based on this, two earthquake damaged pilasters of the Confucian Temple in Tainan are investigated. The analysis shows that interactive actions may cause large deformation of the pilaster on the side wall due to irreversible downward displacement of the top end. In the case of back wall pilasters, the interactive action may result in permanent detachment of the pilaster from the back wall. For the safety and preservation of traditional historic buildings this phenomenon is necessary to be well studied. The result of this study will provide very useful information and reference to the repair and strengthening of earthquake damaged historic temple wood pilaster columns.