에지거더단면의 풍응답에 미치는 하부거더형상의 영향에 관한실험적 연구

Abstract

In this study, the aerodynamic characteristics of two edge girder sections with aspect ratio of 5 are investigated throughwind tunnel tests. In tests, six types of girder section are employed such as I-section (I), two kinds of trapezoid (S1, S2), pentagon(P1, P2) sections and circular section (R) to clarify the effects of sectional shape of lower girder on wind-induced response. From thestatic wind force tests, drag coefficients at attack angle α =0°, pentagon and circle sections have lower value than the other sections. The vertical static displacement tends to linearly increase with the increment of attack angle. The torsional displacement of P2 has thelowest value among employed sections in the study. In the dynamic tests, the torsional flutter has occurred in all employed sectionswhere the onset velocity decreased with increment of attack angle. As the effects of sectional shape, the section P2 has the highestonset velocity and the order of critical velocity is such as trapezoid < I < pentagon and circle. In the case of vertical vortex inducedoscillation, the maximum amplitude tends to increase as the attack angle increases. As the effects of sectional shape, orders ofmaximum amplitude is trapezoid > I and pentagon > circle. From the results of consideration, the circular section and P2 of pentagonsection have good performance among employed sections in this study.