Development of a two-stage inspection process for the assessment of deteriorating infrastructure

Abstract

Inspection-based maintenance strategies can provide an efficient tool for the management of ageing infrastructure subjected to deterioration. Many of these methods rely on quantitative data from inspections, rather than qualitative and subjective data. The focus of this paper is on the development of an inspection-based decision scheme, incorporating analysis on the effect of the cost and quality of NDT tools to assess the condition of infrastructure elements/networks during their lifetime. For the first time the two aspects of an inspection are considered, i.e. detection and sizing. Since each stage of an inspection is carried out for a distinct purpose, different parameters are used to represent each procedure and both have been incorporated into a maintenance management model. The separation of these procedures allows the interaction between the two inspection techniques to be studied. The inspection for detection process acts as a screening exercise to determine which defects require further inspection for sizing. A decision tool is developed that allows the owner/manager of the infrastructural element/network to choose the most cost-efficient maintenance management plan based on his/her specific requirements.

Stochastic improvement of inspection and maintenance of corroding reinforced concrete structures placed in unsaturated environments

“…The probabilities of good and wrong assessment are estimated taking into account the probability density functions (PDF) of the noise and the signal [34,33]. Therefore, the PDFs of noise and signal (chloride concentration) and the repair concentration should be determined for a particular problem.…”

“…The transition probabilities a i,j in the complete Markov matrix for a year between inspections P bet are computed in terms of those of the Markov growth matrix P gr (estimated according to the methodology described in section 3) and the probability of corrosion initiation for the corresponding state as [34]:…”

Markov chain modeling of evolution of strains in reinforced concrete flexural beams

“…6. Determine the mean and standard deviation of unconditioned strain state at any load step using [11] and [12].…”

“…Thus, there is a need to develop suitable stochastic models for the prediction of response state of the structure/structural element at different stages of loading. Markov chain (MC) models are the simplest stochastic models that are extensively applied in engineering (7)(8)(9)(10)(11). MC models have been successfully used for modeling crackwidths in RC flexural members under monotonic and fatigue loading (12,13), for modeling load-deflection behavior of ferrocement elements (14), for condition assessment of RC bridge girders based on limited inspection data (15) and for condition assessment and remaining life assessment of RC flexural members subjected to corrosion of reinforcement (16).…”

Probabilistic Optimization of the Management of Corroding RC Structures

“…An optimal inspection interval minimizes the costs of inspection, preventive or corrective repair and failure. The method of optimization takes as starting point the work of Sheils et al (2010) and is presented in the following section. Afterwards, the discussion focuses on the estimation of the transition matrices from a comprehensive model of chloride penetration and the cost modeling.…”