Analysis Of Factors Affecting The Vibration Frequency For Special-shaped Continuous Girder Bridge

The codes requires that line of the highway network needs more fluid in standard and no longer controlled by the bridges, tunnels and other controlling buildings, which leads to the arrangement of the bridge structure more complicated.The skew bridge,curved bridge,slope bridge or more complex special-shaped bridge has got applied frequently. In recent decades,it is possible to calculate the special-shaped bridge structure with the development of the theory for finite element method and electronic computing technology.Designers can have discretization analysis for a special-shaped bridge structure,and accurately calculate the shaped-bridge structural response under loads through the finite element method,which makes the calculation of the special-shaped bridge becomes more simple.On the research of special-shaped bridge, most scholars at domestic and foreign focus more on the static characteristics, but less on the study of the dynamic characteristics.Dynamic properties of the bridge related to its structural characteristics. Different bridge structures have different vibrational frequencies, thus to reflect the different bearing capacity of the bridge.structure.There is no explicit formula given to calculate the vibration frequency of special-shaped continuous beam bridge in specifications.Therefore, it is quite necessary to research the vibration frequency calculation of the special shaped continuous beam bridge, which is directly related to the safety of the bridge operation.In this paper, the finite element model under the undamped state is established based on the engineering general situation of the test bridge,and the vibration frequency of the three span continuous beam is acquired by solving the eigenvalue of the finite element model.At the same time, according to the original bending vibration theory of Euler-Bernoulli beam, the analytical solution of the vibration frequency of the three span continuous beam is obtained based on the structural characteristics of the test bridge, and the values of the two are compared to verify the correctness of the model.,Considering the influence factors of the vibration frequency of the special-shaped continuous girder bridge on the basis of the undamped model, and establishing the finite element model with skew angle, span ratio for the variable. By finite element analysis,to get the vibration frequency of special-shaped continuous girder bridge with different oblique angle and span ratio, and analyze the influence trend of the two factors on the vibration frequency of the structure. Based on the analysis results of the two influential factors and combined with the calculation formula of continuous bridge vibration frequency in the current specification to fit out the vibration frequency calculation formula of the special-shaped continuous girder bridge with the parameters of oblique angle and span ratio.Finally, having got the measured vibration frequency of the special-shaped continuous girder bridge according to the dynamic characteristics experiment of the test bridge, which to verify the correction formula is correct.