Model updating techniques for damage detection in concrete beam using optical fiber strain measurement device

The article aims at detecting and quantifying early structural damages using deterministic and probabilistic model updating techniques. To achieve this purpose, local information in a form of optical strain measurement is employed. The strategy consists in updating physical parameters associated to damages, such as Young’s modulus, in order to minimize the gap between the numerical strain obtained from finite element solves and the strain sensor outputs. Generally, the damage estimation is an ill-posed inverse problem, and hence requires regularization. Herein, three model updating techniques are considered involving different type of regularization: classical Tikhonov regularization, Constitutive Relation Error based updating method and Bayesian approach. An illustration of these three approaches is proposed for localizing and quantifying an early damage in a real 8 meter post-tensioned concrete beam. Numerical results show that all the methods properly localize the damaged area and give similar estimation of the damage level