Numerical Simulation of the Tatara Bridge and its Aerodynamic Stability Optimization

The importance of bridge aerodynamic investigations was immediately realized after the Tacoma Narrows Bridge collapsed in 1940. Since then the aerodynamic control system that using moveable flaps to increase the aerodynamic stability of bridge has been an important aspect in bridge aerodynamic designs. In last two decades, the record of longest bridge in the world is refreshed frequently, which means the size of current bridges is much bigger than previous bridge. Basically, aerodynamic control system is an indispensable part of a super long bridge, and the active control system seems the only solution to improve the aerodynamic stability when the main span exceeds 3000 m. The purpose of this thesis is to study the effect of active aerodynamic control system with two sharp shape control devices installed on the edges of deck by FEM simulation. Here, the Tatara Bridge is analyzed via FEM software ABAQUS and SOLIDWORKS. This study consists of FEM modal analysis of the bridge, wind tunnel test simulation and wind effect test modeling for the entire bridge under the wind from different directions. In the bridge modal analysis, first 400 vibration mode shapes and their corresponding frequencies are calculated through Lanczos method solver in ABAQUS and the first order mode shape is found to be lateral bending of the deck. Therefore, the target is to optimize the deck shape to reduce the lateral aerodynamic force. To achieve this goal, 9 deck shapes are designed and tested under wind load from 15 different directions in the wind tunnel test simulation through SOLIDWORKS. The result of this test shows the optimized deck shapes can significantly reduce the lateral aerodynamic force. Then the wind effect tests of the entire bridge before and after optimization are performed in ABAQUS. As shown in the results, the displacement of midspan is decreased, especially in lateral direction. The results of this study indicate that this actively transformable sharp control surface can significantly reduce the response of the bridge under lateral aerodynamic force