A two-level strategy to assess the bearing capacity of corroded structures via long-gauge fiber-optic sensors

Abstract

Corrosion of steel in concrete is the most common deterioration mechanism for structures located in aggressive environments. This research proposes a two-level strategy to assess the residual bearing capacity of corroded structures by detecting and quantifying corrosion via a new kind of long-gauge fiber Bragg grating (FBG) sensors. Compared with the traditional point strain gauges, this new sensor has been developed for both local and global structural monitoring by measuring the averaged strain within a long gauge length. According to the mechanical relationship between the moving load and the long-gauge strain influence line (IL), an IL aera-based difference index is established to identify the presence of the damage and the corrosion is quantified in terms of reduction of sectional area of reinforcement (Level 1); and then an elaborate finite element (FE) model is built to perform failure analysis to assess the residual bearing capacity by modifying the material constitutive model according to the corrosion condition (Level 2). A laboratory experiment is conducted to verify the effectiveness and accuracy of the proposed method.