Vehicle-bridge Coupling Vibration Of Simply Supported Bridge Based On Coupled Method

Simply Supported Bridges are mostly commonly used in highway systems ofdifferent counties. The bridge of this type is characterized by relatively low mass andhigh modal frequencies and therefore may exhibit significant bridge-vehicleinteractions when subject to heavy and fast-travelling vehicles. This significantinteraction would not only harm bridges load carrying capacity, but also negativelyimpact the comfort of drivers and passengers of passing vehicles. The dynamicinteraction between vehicles and simply supported highway bridges are treated in thisstudy, and the research approaches and some influencing parameters on vehicle bridgedynamic interaction are analyzed and discussed. The impact coefficients of simplysupported highway bridges are evaluated through the study of a real example. Themain work and result are described as follow.(1) The research background and objectives are presented in the first chapter. Twotypes of methods, namely coupled method and iterative method, for analyzingvehicle-bridge interaction is reviewed.(2) By considering several kinds of vehicle model, the differential equation of vehicleand bridge interaction system is formulated following coupled method. The modelsuperposition technique is utilized to reduce degrees of freedom of the mentioneddifferential equation, and the unevenness of road surface is also included for abetter simulation of vehicle-bridge interaction. The differential equation of vehicleand bridge interaction system is solved via using time domain numerical method.Additionally, the FORTRAN language is selected to compile the whole modelingand solution system.(3) A simple bridge with span of40m is selected as examples to investigate dynamicresponses of bridge subject to a passing vehicle, and the result is compared withthe published results for method validation. The effects of different vehicle models,travelling velocity and road roughness on dynamic responses are explored. It isshown that a) the half vehicle model and quarter vehicle model yields very closeresults of bridge dynamic response;(b) while vehicle s speed could affect bridge sresponse, a critical vehicle speed exist that would lead to t he maximum responseof bridge;(c) the unevenness of road surface could influence can impact theresponse of vehicle-bridge system, and response becomes higher while theunevenness of road gets worse (4) The influence of different vehicle sequences on bridge s response is studied. Theresults indicate that (a) the response of bridge initially grows as the ratio ofvehicle interval to bridge span increased, and then become stable as the ratioresearches a certain value;(b) The dynamic response of bridge becomes larger asthe number of vehicle series grows at first, which then becomes stable as thenumber of vehicle series reaches a certain number.