Acceptance evaluation of continuous beam bridge with variable section based on modal testing
In order to assess whether the actual working condition of the completed bridge meets the conditions for delivery and acceptance,a rapid non-destructive testing approach based on modal testing is proposed.A three-span variable-section continuous girder bridge with a span arrangement of(67.5+115+67.5)m is taken as the engineering background,and its basic power characteristics are analyzed by simulation.Under environmental excitation,acceleration sensors are used to collect the time course data of vertical acceleration at the quarter-point cross section of the bridge structure,and the stochastic subspace method is used to identify the dynamic characteristic parameters of the bridge;the displacement flexibility matrix of the structure is identified,and the modal deflection of the bridge is predicted under different loading conditions,and the structural calibration coefficients are calculated comparing with the theoretical design values of finite element theory,so as to evaluate the actual operation state of the bridge in combination with the relevant specifications.The test shows that the modal test is able to recognize the dynamic parameters of the bridge accurately under environmental excitation;according to the specification of bridge inspection,the operational status of this consecutive girder bridge meets the design demands,and it has a certain degree of safety reserve.The method can assess the actual operation state of the bridge without damage and conveniently,and has a broad prospect for practical application in engineering.
finite element modelenvironmental incentivesmodal deflectionstructure check coefficient
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