Data Assimilation for Fatigue Life Assessment of RC Bridge Decks Coupled with Path-Integral-Mechanistic Model and Non-Destructive Inspection

Remaining fatigue life of reinforced concrete (RC) slabs subjected to traveling wheel-type loads is estimated by data assimilation procedure, i.e., coupled life-span simulation with inspection data. Multi-scale analysis (MSA) with path-integral-mechanistic models is used for the platform of data assimilation on which the visual inspection of concrete cracking on the members’ surfaces and the acoustic emission tomography (AET) are numerically integrated. For investigating the applicability of the proposed data assimilation, the wheel running experiments of RC slabs was conducted. Both crack patterns (2D) and 3D-AET were measured over the fatigue life till failure. In the pseudo-cracking assimilation, observed cracks are converted to space-averaged surface strains and the internal strain fields are simply assumed by in-plane hypothesis. This pseudo-cracking assimilation brings about fair assessment of the transient maximum deflection, but the residual deformation was found to be overestimated. Another non-destructive inspection data applied in this assimilation is the 3D-AET associated with the acoustic wave velocity, which has much to do with stiffness of some control volume with and without cracking. The AET velocity is converted to the initial fracture parameter of un-cracked concrete based on the elasto-plastic and fracture model used. Although cracking is not explicitly taken into account unlike the pseudo-cracking method, the small number of load repetition automatically generates internal cracks over the volume of analysis domains, and the remaining life of the slabs inspected was successfully estimated.