CONDITION ASSESSMENT, TIME-DEPENDENT RELIABILITY AND REMAINING SERVICE LIFE PREDICTION FOR DETERIORATING STRUCTURES

Reinforced concrete (RC) structures often deteriorate due to chloride and/or carbonation induced corrosion. A new model for corrosion-induced crack propagation is described. A spatial time-dependent structural reliability model is developed that calculates (i) strength degradation with time, (ii) probability and extent of corrosion damage (cover cracking) and (iii) probability of collapse for RC structures subject to pitting corrosion. This enables accurate service life predictions to be made. These models include the spatial and temporal variability of cover, concrete strength, chloride exposure, corrosion rate, corrosion initiation, cover cracking, pit depth, etc., as well as the time-dependent variability of loadings. The effect of maintenance strategies, such as periodic inspections, on updated reliability and service life predictions are also estimated. Illustrative examples are given for RC beams whose performance and reliability are updated using visual inspection findings of corrosion damage. Information about service life prediction, and updating based on (new) condition assessment findings, is essential for asset management of deteriorating structures.