A methodology to evaluate corroded RC structures using a probabilistic damage approach

TL;DR

This paper introduces a probabilistic methodology combining damage mechanics and stochastic analysis to evaluate the failure probability of corroded RC structures over time, accounting for environmental and structural variability.

Contribution

It proposes an improved damage-based probabilistic model for RC structures that considers concrete cracking, rebar yielding, and corrosion, enhancing reliability assessment accuracy.

Findings

The methodology accurately predicts failure probabilities over 50 years.

It identifies critical failure paths and collapse scenarios.

The approach is validated on RC beam and frame examples.

Abstract

Several aspects influence corrosive processes in RC structures, such as environmental conditions, structural geometry, and mechanical properties. Since these aspects present large randomnesses, probabilistic models allow a more accurate description of the corrosive phenomena. On the other hand, the definition of limit states, applied in the reliability assessment, requires a proper mechanical model. In this context, this study proposes an accurate methodology for the mechanical-probabilistic modelling of RC structures subjected to reinforcements' corrosion. To this purpose, an improved damage approach is proposed to define the limit states for the probabilistic modelling, considering three main degradation phenomena: concrete cracking, rebar yielding, and rebar corrosion caused either by chlorides or carbonation process. The stochastic analysis is evaluated by the Monte Carlo simulation method due to the computational efficiency of the LDMC. The proposed mechanical-probabilistic methodology is implemented in a computational framework and applied to the analysis of a simply supported RC beam, and a 2D RC frame. Curves illustrate the probability of failure over a service life of 50 years. Moreover, the proposed model allows drawing the probability of failure map and then identify the critical failure path for progressive collapse analysis. Collapse path changes caused by the corrosion phenomena are observed.