| Project/Area Number |
06452261
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
構造工学・地震工学
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| Research Institution | Saitama University |
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Principal Investigator |
YAMAGUCHI Hiroki Saitama Univ., Dept.of Civil Eng.Professor, 工学部, 教授 (50134474)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAI Masatsugu Nagaoka Univ.of Technology, Dept.of Civil Eng.Assoc.Professor, 建設系, 助教授 (20207971)
SHEN Chi Saitama Univ., Dept.of Civil Eng.Research Assoc., 工学部, 助手 (10251141)
OKUI Yoshiaki Saitama Univ., Dept.of Civil Eng.Assoc.Professor, 工学部, 助教授 (40214051)
ITO Manabu Saitama Univ., Dept.of Civil Eng.Professor, 工学部, 教授 (00010661)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥5,600,000 (Direct Cost: ¥5,600,000)
Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1994: ¥4,100,000 (Direct Cost: ¥4,100,000)
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| Keywords | Suspension Bridge / Cable-Stayd Bridge / Modal Damping / Database / Damping Analysis |
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| Research Abstract |
The modal structural damping is indispensable but is usually assumed empirically for the wind resistant design of cable-supported bridges. Although many data of damping ratio have been collected through field vibration tests, there haven't been many theoretical research works for analyzing the experimental data. The main objectives of this study are to propose an analytical method for the estimation of the modal damping in cable-stayd bridges and to show its potential by conducting the damping analyzes.
The main research results are summarized as follows.
1.The modal damping characteristics of cable-supported bridges were discussed by using the database of modal damping which was completed by the literature survey. It was found that the mode-dependent damping characteristics is peculiar to cable-stayd bridges but is not identified in suspension bridges.
2.The damping analysis of Tsurumi Tsubasa Bridges was conducted in detail with the data of field vibration test. Not only the internal damping in the girder, the towers and the cables, but also the aerodynamic damping, the support friction and the damping due to cable dampers, were estimated semi-analytically. As a result, the contribution of each damping source to the modal damping was clearly shown.
3.The analytical method for the damping evaluation based on the energy representation of modal damping was proposed and applied to three different types of long-spanned cable-stayd bridges ; Ikuchi Bridge with composite box-girders, Yokohama Bay Bridge with truss girder and Tsurumi Tsubasa Bridge with the stay-cable system in single plane. The modal damping ratios for different modes of each bridge were evaluated and compared with the field-measured values. The high potential of the analytical evaluation of the damping characteristics was also shown through these damping analyses.
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