High Pier Span Continuous Rigid Frame Time Domain Buffeting Analysis

Along with the quick development of our country's highway transportation business, Continuous rigid frame bridges with high pier and long-span girde have been widly generalized and applied in engineering field, at the same time, anti-wind problem becomes more and more essential as this variety of bridge enhancing. Wind-induced buffet is inevitable during building bridge and using stage, which effects construction's safety, construct members' fatigue and driving comfortableness.Classical method to solve wind-induced buffet problem is response in spectrum analysis, but this is only used in linear system. high pier and long-span bridge has geometric nonlinear behavior when force works, so analysis in time-history which can takes geometric nonlinear behavior into account should be adopted to this kind of bridge. In this paper, firstly model random wind speed and build buffeting force model based on Davenport theory, self-excitation force is inputed by aerodynamic damping and aerodynamic stiffness matrix, the pier of bridge considers the function of resistance only; Considered the average wind load, buffeting and self-excitation force respectively which contribute to structure's response; Lastly, discuss the influence of geometric non-linearity on buffeting. Newmark- β and Newton-Raphson methods are used to solve the nonlinear equation of motion.Based on above theory, model the continuous rigid frame bridge with high pier and long-span girde using the finite element analysis program ANSYS, then taking the Luohe bridge in Shanxi province as a example, analyze the buffeting in Time-history, and compare with test of wind tunnel. The result show: The calculating and test are consentaneous under equality wind load and buffeting force, especially in front side which is sensitive to wind; Take the buffeting force into account, the structure response more intensely than when only consider equality wind load; The self-excitation force haves some influence on bridge buffeting; In designed fiducially wind speed continuous rigid frame bridge with high pier and long-span girder have obvious non-linear characteristics.