Study On The Flutter-Buffeting Performance And Flutter Mechanism Of Long Span Suspension Bridge Under Different Construction Stage

The flutter and buffeting analysis methodsfor long span bridge has been relatively mature and it could provide a lot of convenience and reference for long span bridge’s wind resistance study.As a results of lacking constraints in construction stage,it will have a lower natural frequency and the structure is more flexible,and the response of the structure is more obvious under the action of natural wind.This paper studied the flutter-buffeting performance and flutter mechanism of long span suspension bridge under different construction stages systematically and carefully.The otherness and sensitivities of wind induced response under different construction stage has been pointed out and highlighted.The dynamic characteristics of the project under different stages have been fully studied by using finite element software ANSYS and the key modes of the structure under different stages have been extracted and also the equivalent mass and the equivalent mass moment of inertia in these key modes.The basic theoretical framework of harmonic synthesis method has been introduced and a three dimensional single degree of freedom program by using Matlab has been developed.The fluctuating wind speed is simulated,and the simulation results are verified.The buffeting response of the project under different construction stages has been systematically studied by using the simulated results of fluctuating wind speed.The otherness of buffeting response under different construction stages have been highlighted.And the reasons led to these otherness are analyzed.The 2D-3DOF flutter analysis framework has been introduced and the flutter analysis program of 2D-3DOF method has been developed.By using flutter derivatives of ideal flat plate,the flutter performances of the structure under different construction stages have been fully studied.And the flutter mechanism under different construction stages has been briefly analyzed.Through analysis,it is concluded that attention should be paid to the flutter-buffeting performance and flutter mechanism of long span suspension bridge under different construction stages,and measures should be taken to ensure the safety and stability of the structure when necessary.