Study On Refined Modeling Methods For Vibration Analysis Of Box Girder Bridges

Architectural work is started on a large scale in our country at the present stage,thin-walled box cross section is widely used in all kinds of bridge as the bridgeconstruction is booming. With the rapid development of software and hardwaretechnology of computer, more factors need to consider in calculation and analysis ofbridge structure, in order to minimize the influence of the above factor on bridgevibration, the influence of some ignored factors on vibration of box girder bridge isresearched by using finite element method and based on theory of thin-walled boxgirder.Some new element forms are discussed in this paper to consider the influences ofshear effect and warp on vibration of box girder bridge, MATLAB programconsidering shear coefficient and warp has been developed to calculate dynamicproperties of bridge structure, program module conclude static analysis and dynamicanalysis, The accuracy and practicability of program is verified through examples.The error of beam element model and solid model which calculate low-orderfrequencies of thin-walled beam with box cross section is very small, when theaccuracy of frequency doesn’t has strict requirements, the beam element model ispreferred. Natural frequency calculated using consistent mass matrix is more accuratethan which calculated using lumped mass matrix in beam element model, the result ismore ideal when considering shear coefficient and warp into dynamic propertiesanalysis of bridge structure. Due to shear effect, the natural frequency of each orderreduces, but considering warp makes low-order frequencies of structure increase andincreasing trend of high-order frequencies change slowly.