| 摘要 |
PROBLEM TO BE SOLVED: To inhibit the weight of a sheet-metal girder, and to improve the wind resistance of a bridge by forming a corner cut preventing separation at the lower end of the girder of a wind having a speed component in the bridge-axial orthogonal direction at the lower end of the girder. SOLUTION: A sheet-metal girder is formed in a corner cut shape by a flange under one girder and a corner cut 10, the shape of a sectional corner angle is changed slightly and a fluid pattern in the periphery of a cross section is altered largely, and aerodynamic characteristics are stabilized. Since a flow separated from the first separation point of a bridge girder collides with the next separation point and a separating flow is generated anew even from the next separation point at that time, both flows interfere. The separating flows are brought near to sectional side faces by an interference, and the generation of large separation is prevented and a harmful vibrations are damped. According to the bridge girder, the installation of the corner cuts 10 such as the installation of a fairing and the installation of a plate is made unnecessary, and the weight of the girder is lightened. Consequently, the corner cuts 10 are formed at the lower flange of the sheet-plate girder and vibrations are damped, and the weight of the girder is lightened and an economical design can be conducted.
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