Reinforced concrete bridge serviceability displacement estimation for DInSAR data interpretation

Structural health monitoring of existing bridges is gaining attention of the technical community for an informed management of the structural safety under service conditions. In this context - complementary to the to traditional installation of sensors - the satellite interferometry is exhibiting a large potential in monitoring the displacements of the existing bridges network. To date, the scientific literature high- lights that this technique is still critical in evaluating the deformations of the structures induced by thermal variations, being it difficult to establish when the displacement field is due to physiological temperature gradients or to structural defects. The present paper deals with an estimation of the displacements induced by thermal effects (in combination with traffic loads) in existing reinforced concrete bridges by means of simplified approaches in order to support satellite (or instrumental) data interpretation and expand capabilities of existing remote sensing-based monitoring techniques. Analytical formulations and numerical procedures to estimate the displacements of the structural members associated with uniform and linear thermal load distributions are proposed. As outcomes, diagrams and schedules including displacements associated with the considered variables have been generated: they allow to quantify the displacements due to thermal effects for all the considered cases, also representing a baseline to help the processing of the displacement detected through monitoring systems (instrumental- or satellite-based).