This paper describes the implementation of a dynamic testing technique based upon experimental modal analysis (EMA) methodology that has been used to ascertain the inservice behaviour of two reinforced concrete bridges. Basic descriptive parameters (e.g., end support conditions, Young's modulus of concrete) in FEM models of these bridges were `tuned' to provide matching of the predicted modal properties with those observed from EMA testing. These `tuned' FEM models were observed to provide reasonably accurate predictions of the static response to prescribed loading which was subsequently verified from the results of static testing. It is therefore suggested that these FEM models can be used with some degree of confidence by bridge engineers to ascertain a load rating for the bridges concerned. In the case of Fuge's bridge, static load test levels were taken to `proof loading' proportions and stiffness monitored to verify that the behaviour remained elastic and to provide an alternative method for load rating the bridge concerned. (A)
Abstract