| Co-Investigator(Kenkyū-buntansha) |
MINOWA Chikahiro National Research Institute of Earth Science and Disaster Prevention, Scientific Research Adviser, 総括主任研究員 (90425512)
HANAZATO Toshikazu Mie University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (60134285)
河合 直人 独立行政法人建築研究所, 構造研究グループ, 上席研究員 (70186047)
前川 秀幸 職業能力開発総合大学校, 建築工学科, 講師
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2006: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2005: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2004: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
To obtain the basic data of dynamic characteristics of five story pagodas, we executed micro tremor measurement and human power excitation tests on three pagodas, which were built in middle or pre-modern age. As the results, the values of natural period based on the micro tremor measurement were, 1.20 (sec.), 0.41 (sec.) and 0.23 (sec.) for primary, secondary and third degree mode respectively for main structure, and 0.19 (sec.) for center column of Nakayama-Hokekyo-ji Temple, 1.15 (sec.), 0.41 (sec.) and 0.23 (sec.) for main structure, and 0.73 (sec.) and 0.38 (sec.) for center column of Itsukushima Shrine, and 1.32 (sec.), 0.50 (sec.) and 0.25 (sec.) for main structure, and 0.85 (sec.) and 0.38 (sec.) for center column of Myojo-ji Temple. The values of damping factor derived from the natural vibration after the human power excitation were, 1.56% and 2.10% for NS and EW direction respectively of Nakayama-Hokekyo-ji Temple, 2.76% and 3.97% for Itsukushima Shrine, and 2.15% and 1.40% fo
… More
r Myojo-ji Temple.
Next, using the data from above mentioned measurements and preceding researches, we investigated the relationship between natural period and height, and the values of damping factor for 21 pagodas. By a least squares method, the relationship between the natural period y (sec.) and the height x (m) was y=0.0391x in case the total height was used, and y=0.0528x in case the height of the main structure was used. And the values of damping factor for these pagodas were from 1.4% to 5.3%.
Finally, modeling of vibration models considering both shear and flexural deformation was proposed for five story pagodas. The valuables in the model were fixed by system identification using primary to third degree natural periods and vibration modes of Myojo-ji Temple as the target. As the results, it revealed that this model can represent well the natural periods and vibration modes of the pagoda. And next, one earthquake response calculation was tried using this model with the modification that the hysteresis curves of shear springs were assumed to be combination of bi-linear and slip. The result was that this pagoda does not collapse even against the strong ground motion record, JMA Kobe-NS. Less
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