STUDY ON AERODYNAMIC DEVICES OF THE STEEL DECK BOX GIRDER BRIDGE CROSSING CLASS A RIVER

Abstract

This paper describes examination on aerodynamic stability of 4-span continuous steel deck box girder bridge with 144m main span length crossing class A river with a width of 145m and a national route. This bridge is in an open area where typhoons pass through well, and flexible. Moreover, this bridge has the ratio of width B to height d is B/d=2.67, the possibility of galloping and vortex-induced vibration is predicted. So, wind tunnel tests are conducted to investigate the aerodynamic devices. From the spring supported model wind tunnel tests, galloping and vortex-induced vibration occurred in case of without aerodynamic devices, and it is concluded horizontal plates and double flaps are necessary to suppress galloping and vortex induced vibration. However, structural safety is ensured by horizontal plates. Therefore, take account of the cost, it was decided to attach double flaps if any usability issues occur after the bridge is constructed.