Taking a new simply supported girder skew bridge in an actual project as an example,the appli-cation of modal test and modal rigidity identification in the acceptance and assessment of new bridges was ex-plored.A virtual load test was designed,and the minimum modals was determined for calculation.Modal test under environmental excitation was conducted to identify the first three measured modal parameters and the structural flexibility matrix of the bridge.Based on the measured modal parameters,the measured modal deflec-tion under the virtual load test was predicted.Compared with the theoretical deflection under the design model,combined with relevant codes,the construction quality of bridge was evaluated.The results showed that the mo-dal deflection of the simply supported girder bridge can be predicted by using only the first three order modal pa-rameters under the virtual load test,with the error less than 5％under the medium load case and partial load case.The first three order modal parameters of the skew simply supported girder were accurately identified by the modal test under the environmental excitation.The mid span deflection calibration coefficients calculated ac-cording to the specifications were between 0.55 and 0.70,indicating that the simply supported girder bridge was in good construction condition.The construction quality of the simply supported girder bridge can be evalua-ted accurately,conveniently,and quickly by modal test,which has broad application prospects in practical en-gineering.
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