TIME-DEPENDENT RELIABILITY OF REINFORCED CONCRETE CONSIDERING CHLORIDE PENETRATION VIA BOUNDARY ELEMENT METHOD

Abstract

STRENGTH DEGRADATION OF STRUCTURAL MATERIALS IS AN INEVITABLE PROCESS, DUE TO DELETERIOUS ACTIONS SUCH AS CORROSION AND FATIGUE. THESE PHENOMENA ARE ALSO TYPICALLY RANDOM, WITH DEGRADATION RATES AND STARTING TIME OF DEGRADATION PROCESS LARGELY UNCERTAIN. IN THE PARTICULAR CASE OF REINFORCED CONCRETE STRUCTURES, CORROSION OF REINFORCING BARS CAUSED BY CHLORIDE IONS IS ONE OF THE MAIN PATHOLOGICAL MANIFESTATIONS. PAST STUDIES ON THE TIME-VARIANT RELIABILITY OF REINFORCED CONCRETE STRUCTURES SUBJECT TO CORROSION HAVE RELIED ON SIMPLIFIED ANALYTICAL MODELS FOR ESTIMATING THE DEPASSIVATION TIME, I.E., THE TIME REQUIRED FOR CHLORIDE CONCENTRATION AT CONCRETE/STEEL INTERFACES TO BECOME CRITICAL. THIS STUDY CONTRIBUTES WITH AN ACCURATE MODELLING OF CHLORIDE DIFFUSION THROUGH CONCRETE USING THE BOUNDARY ELEMENT METHOD, WHICH IS EMPLOYED FOR THE FIRST TIME WITHIN A TIME-VARIANT RELIABILITY FRAMEWORK. CUMULATIVE FAILURE PROBABILITIES ARE EVALUATED IN TIME BY CONSIDERING RANDOM DEPASSIVATION TIMES, RANDOM CORROSION EVOLUTION, AND RANDOM LOAD PROCESSES. THE TIME-VARIANT RELIABILITY PROBLEM IS SOLVED USING MONTE CARLO SIMULATION. AN APPLICATION EXAMPLE IS PRESENTED, DEMONSTRATING THE CAPABILITIES OF THE PROPOSED FRAMEWORK.