日式編竹夾泥牆在水平返覆加載下之結構行為

Structural Behaviors of Japanese style Bamboo-Mud-Walls under Horizontal Cyclic Loading

台灣在1999 年九二一集集地震中，有很多具歷史價值之日式木造建築受到嚴重損壞，其原因多數與編竹夾泥牆之壁體強度無法抵抗水平地震力有關。為了瞭解編竹夾泥牆在水平作用力下之結構行為與破壞機制，並建立後續耐震評估及補強基礎，本實驗共製作了6 道純框架與5 道含框架之編竹夾泥牆，包括不同構造方式、添加物、高寬比等影響因素，藉由水平返覆加載，得到試體破壞模式、受力與變位角的遲滯迴圈，以及包絡線所包覆的面積…等。實驗結果顯示編竹夾泥牆的力學行為主要如下：（1） 木框架斜撐桿件之固定鐵釘拔出後，施加力量急遽下降，並有明 顯的最大加載點。（2） 框架加上雙斜撐構件比未加斜撐者，可以提高3 倍加載力量。（3） 含框架之編竹夾泥牆，首先在角隅產生擠壓；變位角加大後，土壁產生迴轉，並在中間部位出現剪力破壞的裂縫。（4） 編竹夾泥牆的最大加載與包絡線包覆面積，是純框架試體的3 至4 倍。（5） 土漿中添加麻絨纖維，並不能增加土壁強度，但可以減低裂縫數量及寬度等；土漿中添加水泥則可以提高35%的最大加載。

During the 1999 Chi-Chi, Taiwan earthquake, numerous Japanese wooden historic buildings suffered serious damage. Most of these buildings are important cultural property in Taiwan, and their damages are related to the bamboo-mud-wall. For investigating the structural behavior of the bamboo-mud-wall, and establishing the fundamentals for a seismic assessment and strengthening in this study, totally 11 specimens including different construction, different mud additive, and different height/width ratio are tested under horizontally cyclic loading. The obtained failure mechanism and load-drift angle relation curves under cyclic loading are deeply discussed. According to the tests followings are observed: (1) For the wooden frame equipped with bracing, the failure mode and horizontal load resistance will be changed visibly when the nails have been drawn-out. (2) The maximum load for frame with cross bracing is about 3 times of wooden frame without bracing. (3) For the bamboo-mud-wall, the first damage mode is compression failure at the corner, and then the wall panel rotating. With the increase of displacement angle, the main damage mode is the shear cracks on the middle wall area. (4) The maximum load and the area covered by the P-θ envelop curve for bamboo-mud-wall are more than 3 times of wooden frame. (5) The maximum load of specimen with cement added has 35% higher than that of specimen with mud only. The crack amount and length of specimen with hemp fiber added is less than that of specimen with mud only.