Evaluation of dynamic properties of traditional wooden shrines in Yurihonjo, Japan

摘要

Japanese traditional wooden shrines located in Yurihonjo city are investigated to evaluate their dynamic characteristics and seismic performance. Some of the selected constructions for this research are declared as buildings of cultural interest by the local government and therefore efforts are made to preserve these kinds of buildings. The structure corresponds in general to framed wooden constructions with traditional connections between columns and beams. In general, nails are not used in these joints, and instead, the beams are narrowed at the extreme to be inserted into a hole cut in the columns. These buildings are supported by columns that rest directly on stone bases forming a kind of pinned joints. Ambient vibration measurements of the buildings were planned and undertaken by the authors. A comparative study of the predominant periods of the structures is done by plotting the periods versus building heights. Preliminary results show that wooden temples in this region have long periods in comparison to temples of other regions of Japan. The damping ratio was estimated from a free vibration portion of the response curve after the impulse force given by a person. The damping ratios are compared by considering the influence of the number of bays and the dimension of the frame structure in each direction. Ambient vibration measurements provided a valuable basis for evaluation of the dynamic characteristics of wooden heritage structures.