木造三重塔の構造特性に関する実験的考察: 第3報　軒の衝撃的な振動性状に関する縮小模型実験

摘要

本研究では大地震における木造層塔の小屋組や建物下部の浮き上りに伴う軒の衝撃的な振動に着目した。層塔は地震時の水平力によって大きな変形を生じた場合、小屋組のロッキングに伴い大斗に浮rnき上りを生じて軸部と小屋組が瞬間的に離間したり、初層軸部のロッキングによって初層柱脚に浮き上りを生じて建物下部と基礎が剛体的に瞬間的に離間する。%In this study, we refer to earthquake related damages of Japanese traditional wooden pagoda. According to records, few pagodas have been completely destroyed by earthquakes, but often pagoda's eaves are damaged by earthquakes. We performed the eave-beat tests and free vibration tests with a 1/10 model of a three-story pagoda by changing the weight of the model. We obtained the following results from these tests. 1. By an increase in amplitude of high degree mode, the vibration of eaves is activated. 2. If the shoe supporting the roof system jumps up from the column, the shock of the shoe hitting the parts below induces the excitation of the vibration of eaves. 3. The size of the pagoda effects the characteristics of earthquake-damage of these eaves.