Using two-stage method in reinforced concrete bridge piers for damage quantification

In inverse methods of damage detection, it is generally assumed that the damage values and imperfect vibrational information are predefined scenarios. In fact, imperfect vibrational information is obtained based on acquired data from installed sensors on real structures. Then the location and intensity value of damage is calculated using inverse optimisation methods. In this paper, a two-stage method is proposed to eliminate the assumed imperfection of the first stage and accurately calculate its required damage information using a numerical-experimental method. Then, with the information on the damaged pier, the mode shapes are obtained and the total degrees of freedom is compacted as needed to specific degrees of freedom (having installed sensors on the real structure). Finally, introducing the objective function in Matlab for the bridge pier, the variable (stiffness reduction percentage) is inversely calculated using the linear optimisation simplex method. Agreement between the experimental and numerical results shows that the proposed method can be precisely applied for damage detection and quantification of reinforced concrete bridge piers. The validation of the proposed method indicates 0.4% error considering three expected vibrational modes.