Research concerning the seismic damage decrease of the traditional wooden building and the cultural asset enshrined there.

2004 Fiscal Year Final Research Report Summary

• Project/Area Number: 15500671
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Cultural property science
• Research Institution: NAGANO NATIONAL COLLEGE OF TECHNOLOGY
• Principal Investigator: HATTORI Hideto NAGANO NATIONAL COLLEGE OF TECHNOLOGY, DEPT. OF CIVIL ENGINEERING, PROFESSOR, 環境都市工学科, 教授 (20043044)
• Co-Investigator(Kenkyū-buntansha): ENOMOTO Norimasa NAGANO NATIONAL COLLEGE OF TECHNOLOGY, DEPT. OF CIVIL ENGINEERING, PROFESSOR, 環境都市工学科, 教授 (40332019) ; ABE Hirohumi NAGANO NATIONAL COLLEGE OF TECHNOLOGY, DEPT. OF CIVIL ENGINEERING, PROFESSOR, 環境都市工学科, 教授 (00021014)
• Project Period (FY): 2003 – 2004
• Keywords: Characteristics of vibration / Traditional wooden building / Microtremor / Natural frequency / Damping constant

Research Abstract

We researched concerning the seismic damage decrease of the traditional wooden building and the cultural asset enshrined there. Experimented buildings are the three-storied wooden pagoda in Miyota town in Nagano Prefecture and the main temple of Shogenji in Nagano City. About the seismic damage decrease of the cultural asset, study results concerning the seismic isolator in the past were examined. The vibration characteristic before it repaired and after it had repaired was examined along with the repair of the three-storied pagoda. The microtremor was observed for about 30 minutes. Moreover, the resonance experiment by the human strength excitation was done according to the first natural frequency that had been obtained from the microtremor. As a result, natural frequency was 1.5Hz, 2.3Hz, 3.7Hz before it repaired and after it had repaired respectively. The damping constant was about 0.03. The mode of vibrations were obtained up to third modes. The first mode showed bending deformation, and the second mode showed shearing deformation. The vibration measurement was done while repairing before it repaired along with the repair of the main temple of Shogenji that existed in Nagano City. As for the measurement after it repairs, it is scheduled to do after the repair is completed. The microtremor was observed for 30 minutes as well as the case of true easy temple Three-Storied Pagoda. And, the resonance experiment by the human strength excitation matched to the first natural frequency was conducted. As a result, the first natural frequency was 1.35Hz before it repaired and was 1.45Hz under the repair. The damping constant were 0.026 and 0.027 respectively. About the seismic damage decrease of the cultural asset, study results concerning the seismic isolator in the past were examined. It has been understood that response acceleration decrease about 1/12 against the revised earthquake wave of JMA Kobe NS, adjusting to 50 kine as the maximum velocity value.