Time Domain Buffeting Reponse Analysis Of Long Span Bridge Under Non-Stationary Wind Filed

With the development of bridge to long and super long-span in recent decades, the flexibility of bridge becomes larger and larger, and the research on vibration caused by wind has become more and more important.The wind resistance design of bridge has become the essential part of the design of bridge. Based on the mature of stationary buffeting response analysis,A statistical analysis of the observation and measured wind speed data indicates that the fluctuating wind speed has the remarkable characteristics of non-sationary in under strong wind and complex terrain of mountain wind environment. That is to say,it cannot be regarded as a stationary random process to analyze the buffeting response.In this research,the Pu Li Te Bridge in Yunnan is taken as the research object, and, the spatial 3-D finite element model of it is established with program ANSYS. This paper sets up a calculation formula for the structural and optimal time step,making the related computer program in accordance with the structural dynamics and modal analysis theory. Based on wind characteristics of bridge spot simulat three-dimensional fluctuating of stationary wind.Then, the time-history of buffeting force is calculated according to this way, analyze the mainly study-factors such as self-excited force considering or not and different time step At on the influence of time domain analysis of buffeting responses of large span-susension bridge. The calculation results mainly impact the effect -damping of part position direction under self-excited forces, vertical response is more significant than horizontal and torsional response. It will distortion for buffeting response of bridge under no consider self-excited forces, and in order to analyze in accuracy and efficiency guarantee well, The factors cannot be ignored. The time domain analysis of buffeting response is calculated under optimal time step At =0.05s and set time step At=0.25s exhibites significant differences between the two kinds of results, it proves that it is very necessary of adopting the optimal time step for structure analysis and calculation.The results are of reference values for wind- induced buffeting response analysis of long-span suspension bridges,In this research, based on the method of harmonic synthesis’ improvement and time-varying parameter in which statistical analysis of the observation and measured wind speed get to successfully simulate the non-stationary wind.The time-varying mean wind force, non-stationary self-excited force, and non-stationary buffeting force have been given a detail description, the time-history of buffeting force is calculated under this way. The time-varying mean wind response and non-stationary buffeting response of bridge under different case studies has been computed. Key research is that influences of time-varying mean wind, EPSD to the non-stationary buffeting response of Pu Li Te Bridge have been examined and compared. The results indicate that it is essential to consider the non-stationary buffeting response of long-span Bridge under strong wind loading with time-varying mean and plus EPSD.