Model identification of bridges using measurement data

Measurements are increasingly used to augment traditional assessments of structural state. Measurements of deflections, rotations, and strain provide indications of damages as well as changes in the values of parameters such as Young's modulus. Finite-element model-updating methods have been developed in the 1990s for identifying structural state from measurements. Currently most methods aim to determine the values of stiffness coefficients that result in measured responses. In the present work, a model calibration method identifies causes of structural behavior such as support conditions and material properties. Static measurement data are employed for model calibration. A case study of the Lutrive Bridge in Switzerland illustrates the methodology. Candidate models whose responses reasonably match measured data are identified. These models are then examined to determine whether the calibrated values are physically possible. Such examinations lead to either model rejection or further measurements.