The invention discloses a method for rapidly evaluating the
flexural rigidity of a bridge under vehicle-induced excitation, and belongs to the technical field of
flexural rigidity evaluation of variable cross-section beams. The method comprises the following steps of: firstly, acquiring a bridge time-history response by adopting vehicle movement loading, separating a
power component by utilizing a VMD method, then identifying a main frequency of an IMF component through FFT, removing the
power component higher than a bridge
fundamental frequency, and reconstructing a bridge actual measurement quasi-static time-history response; then, an axle effect in bridge actual measurement quasi-static
time history response is eliminated, an
influence line recognition model is established, and
Tikhonov regularization is introduced to further solve a deflection
influence line; then deriving an analytic solution of a deflection
influence line of the variable cross-section
continuous beam based on a
virtual work principle, establishing a
mathematical relationship between the
flexural rigidity and the deflection influence line, and identifying the flexural rigidity of the bridge through the deflection influence line based on the
mathematical relationship to obtain flexural rigidity distribution of the
full bridge; finally, multiple evaluation indexes are defined and calculated, the bending rigidity distribution of the
full bridge is comprehensively evaluated, and the method has the advantages of being good in
engineering applicability and high in safety evaluation innovativeness.