| Summary: | 碩士 === 淡江大學 === 土木工程學系碩士班 === 99 === Since long-span bridges have greater flexibilities, they are more susceptible to wind excitation. In general, the aerodynamic instability problems for the bridges in constructed stage need more attention than in completed stage. For this reason, the main objective of this thesis is to investigate the aerodynamic behavior of a bridge under construction through section model tests. The wind tunnel tests include the measurements of the static wind force coefficients and the flutter derivatives in smooth flow and buffeting responses in turbulent flow.
The critical flutter wind speed and the buffeting responses measured from the tests are compared with those measured from the full bridge model test which was conducted earlier. Also, a numerical model in conjunction with flutter derivatives and wind force coefficients, measured in the tests, is performed. The numerical results are also compared with the experimental results. The comparison show that the flutter wind speeds respectively obtained from section model test and calculated based on the flutter derivatives are in good agreement. For the buffeting responses at the design wind speed, the results obtained from section model tests, full bridge model tests and numerical analysis agree well to some extent. The discrepancies are in the range of 5-30%.
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