1991 Fiscal Year Final Research Report Summary
Vortex-induced oscillations of reinforced concrete chimneys and its wind tunnel studies using elastic models.
| Project/Area Number |
63550424
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Building structures/materials
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| Research Institution | Tokyo Polytechnic University |
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Principal Investigator |
TAMURA Yukio Tokyo Institute of Polytechnics. Architecture Professor, 工学部, 教授 (70163699)
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| Project Period (FY) |
1988 – 1990
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| Keywords | wind tunnel testing / elastic model / similarity law / reinforced concrete / vortex excitation / Reynolds number / Strouhal number / drag coefficient |
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| Research Abstract |
When the dynamic behavior of buildings or structures is simulated in the wind tunnel testings, the dynamic similarity requirements both of the wind characteristics and the structures should be satisfied. The model air density is usually equal to the full-scale air density. Therefore, in order to make the mass ratio identical, the material density of the model should be equal to that of the full-scale structure. When attention is paid on some particular reduced frequencies, e. g. the vortex resonance, the value of the elastic modulus of the material of the model restricts the windspeed of testings as well as the size of the model. The interested reduced frequency of the phenomena should be realized in the available windspeed range inherent to the wind tunnel and its facilities or instruments.
The new material for the wind tunnel simulations of reinforced concrete structures is investigated and composed. The Epoxy resin was selected as the stuff of the material of the model. The density of the reinforced concrete is about 2.4g/cm^3 while the density of the Epoxy resin is 1.2g/cm^3. As the density of the Epoxy resin is smaller than that of the reinforced concrete, in order to make the mass parameter identical, the iron powder is added into the solvent.
Then, the wind tunnel testings on the vortex-induced oscillations of a reinforced concrete chimney are carried out using a model made of this material. The dynamic behavior of the model is compared with the full-scale data, and it is confirmed that the material is available to the wind tunnel testings.
Finally, the method for wind resistant design of the reinforced concrete structures with a circular section are proposed.
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