Explicitly Assessing the Durability of RC Structures Considering Spatial Variability and Correlation

Cao Wang

doi:10.3390/infrastructures6110156

Abstract

The durability design of reinforced concrete (RC) structures that are exposed to aggressive environmental attacks (e.g., corrosion due to chloride ingress in marine environment) plays a vital role in ensuring the structural serviceability within a reference period of interest. Existing approaches for the durability design and assessment of RC structures have, for the most part, not considered the spatial distribution of corrosion-related structural properties. In this paper, a closed-form approach is developed for durability assessment of RC structures, where the structural dimension, spatial variability, and correlation of structural properties such as the concrete cover thickness and the chloride diffusion coefficient are taken into account. The corrosion and crack initiations of an emerged tube tunnel segment that was used in the Hong Kong-Zhuhai-Macau bridge project were assessed to demonstrate the applicability of the proposed approach. The accuracy of the method was verified through a comparison with Monte Carlo simulation results based on two-dimensional random field modeling. The proposed method can be used to efficiently assess the durability performance of RC structures in the marine environment and has the potential to become an efficient tool to guide the durability design of RC structures subjected to corrosion.

Highlights

In-service reinforced concrete (RC) structures often suffer from corrosion-induced performance deterioration and, as a result, the reduction of structural serviceability and reliability below an acceptable level
Reliabilitybased durability design approaches can be used to help achieve the goal of a long service life for corrosion-prone structures, taking into account the uncertainties arising from the structural properties and the environmental factors [7,8,9,10]
This paper develops a closed-form approach for the durability performance assessment of RC structures subjected to corrosion-induced deterioration, which provides an explicit link between the durability performance of a structural component and that at the material level

Summary

Introduction

In-service reinforced concrete (RC) structures often suffer from corrosion-induced performance deterioration and, as a result, the reduction of structural serviceability and reliability below an acceptable level. In an attempt to ensure the expected service lives of these structures, one key step is to conduct a durability design, where the requirements for the structural properties (e.g., concrete cover layer) are specified and the mechanism of deterioration is taken into account. Akiyama et al [22] conducted a reliability-based durability design and service life assessment of RC jetty structures They used a Markov process to model the structural deterioration process and considered a limit state that the chloride concentration does not exceed the critical threshold for a single location. The existing durability design approaches have, for the most part, considered a limit state with respect to the initiation of steel corrosion at a single point, which does not account for the role of spatially distributed parameters such as the steel diameter, concrete cover thickness, diffusivity, and other factors, meaning that the durability design is at the material level. Kong-Zhuhai-Macau (HZM) bridge project was performed to demonstrate the applicability and accuracy of the proposed method

Corrosion-Induced Deterioration of RC Structures

Material-Level Durability Assessment

Example

Findings

Conclusions