| After the first simply supported continuous T girder bridge is a commonlyused structure form on the medium span bridge of highway in our country. Aftersimply supported continuous system has the advantages of simple construction,mature technology,good driving conditions and reasonable economiy,synthesizethe advantages of simply supported beam and continuous beam bridge. In thepresent car induced vibration response analysis of after simply supportedcontinuous girder bridge, does’t consider effects of across’s number,which leadto certain differences with the actual test results.With the continuousimprovement of vehicle load and traffic flow increasing, The existing multi-spanconcrete girder bridge diseases emerge gradually,The number of multi-span mayhave great influence on bridge using performance,which is founded in thedetection of bridge technique condition.Take Hou bao bridge as engineering background, this paper take after thefirst simply supported continuous T girder bridge as the rearch object,based onthe vehicle bridge interaction vibration theory and the finite element method,using the finite element software ANSYS and the mathematical software MATLAB, Compiled the vehicle bridge interaction analysis program, do thenumerical calculation of vehicle bridge interaction dynamical response, studythe effect on multi-span concrete girder bridge dynamical performance of themulti-span number、path、span、Vehicle driving arrangement、driving speed androad roughness etc. the main contents are as follows:1）Summarize the characteristics and the dynamic characteristics of after thefirst simply-supported continuous concrete girder bridge and the currentresearch of vehicle bridge coupling vibration, illustrates the research of vehiclebridge interaction vibration theory and unsolved problems.2) Deduce vehicle vibration equation according to d ’alembert’s principle,and establish a quarter and half vehicle model.3) Deduced the bridge vibration equation and use the finite element softwareANSYS to make a one-dimensional storage form of mass and stiffness matrixinto full rank bridge. Take hou bao bridge as research object, establish grillagesystem model and entity model, and use the entity model to modify the grillagesystem model.4) According to the national standard GB7031-7031《vehicle vibrationinput road plate representation method》 and based on the power spectrumdensity function in the standard, use MATLAB software to simulate samplecurve of the A, B, C, D four grade pavement irregularity degree.5) This paper expounds the calculation method、calculation steps andprogram flow chart of vehicle bridge interaction vibration. Based on finite element software ANSYS, combined with MATLAB software to to realize thesecondary development, compile the vehicle bridge interaction vibrationanalysis program and verify the correctness of the program.6) Select25m and30m span,35m and40m and common across a couponfor3~7multi-span beam bridge as the research object. Analysis the influenceof different span for multi-span bridge dynamic response; Discuss themulti-span number’s influence on dynamic deflection、mid-span moment、thepier top pivot section negative bending moment and shear near the pier top pivotsection under different driving conditions.; Research different axle frequencyratio’s influence on the multi-span bridge dynamic response.7)Analysis the effect of car speed、Vehicle driving arrangement and roadroughness etc on multi-span beam bridge,discuss the difference betweencalculated impact coefficient value based on vehicle bridge interaction andimpact coefficient value given by "highway bridge design general specification"(JTG D60-2004).Research conclusion of this paper can provide technical reference for furtherstudy after the first simply-supported concrete continuous girder bridge dynamicperformance, to improve the multi-span girder bridge impact factor calculationmethod and optimize muliti-span girder bridge structure designparameters,which has engineering practical value. |
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