Kong, Jung Sik

The assessment of the current state and the prediction of the future condition of deteriorating structures are crucial processes in the management of civil infrastructure systems. Not only time-varying loads and resistances but also a series of maintenance interventions that are applied to keep structural systems safe and serviceable make the prediction process very difficult. In order to perform a realistic life-cycle analysis of deteriorating structures under different maintenance scenarios th

Life-cycle cost analysis of deteriorating structures has to consider not only time-varying resistance and loading affecting the reliability of these structures but also maintenance interventions applied during their lifetime. Finding the optimum maintenance scenario for a deteriorating structure is a complex process involving the selection of maintenance interventions and their application times associated with minimum life-cycle cost. There is a close relationship between maintenance interventi

In a world where financial resources do not keep pace with the growing demand for maintenance of deteriorating structures, it is imperative that those responsible for maintenance decisions make the best possible use of limited financial resources. Decision makers have to evaluate the expected life-cycle maintenance cost of deteriorating structures and use benefit/cost techniques for finding the optimal resource allocation. This paper proposes a methodology for the evaluation of expected life-cyc

The prioritization of maintenance interventions on aging structures is one of the most important decision processes in the management of existing civil infrastructure. This process has to consider the uncertainties in loads, resistances, and maintenance interventions over a given time horizon. A computational program for probabilistic maintenance optimization in which the reliability index is the quantitative measure of performance in the presence of uncertainties and the present value of expect

Fatigue life in critical parts of structure components, which is subjected to variable amplitude loading, is a very complex subject. When a fatigue life is influenced by these load variations, accelerations and/or retardations in crack growth rate can occur. Thus, an accurate prediction of fatigue life requires an adequate evaluation of these stress interaction effects. There are many different indexes for calculating fatigue damage at critical locations. The crack severity index based on crack

The purpose of a bridge maintenance strategy is to make effective decisions by evaluating current performance and predicting future conditions of the bridge. The social cost because of the rapid increase in the number of decrepit bridges. The current bridge maintenance system relies on traditional man-power-based methods, which determine the bridge performance by employing a material deterioration model, and thus shows uncertainty in predicting the bridge performance. In this study, a new type o

Since the mid-twentieth century, prestressed concrete (PC) bridges have been significantly developed to become the most important type of bridge in the world. However, only a few studies have dealt with the reliability-based design optimisation (RBDO) of PC bridges despite the fact that RBDO demonstrates the real behaviour of structures. Moreover, the corrosion of post-tensioned tendon in PC bridges seriously caused sudden failures which have been recorded in the world. Since then, this study pr

The reliability of civil infrastructure is time variant. This is due to strength deterioration and time-variant mechanical and environmental loadings. Demands for keeping civil infrastructure in functional and reliable states require maintenance interventions. Limited financial resources require optimal maintenance strategies. These strategies have to consider the effects of uncertainties not only on the structural reliability deterioration but also on the maintenance interventions. In this pape

The time-varying performance of deteriorating materials and structures can be simulated using probabilistic methods. The propagation of performance uncertainties is affected by the characteristics of input random variables. In general, the number of samples and/or their quality do not satisfy the rigorous statistical constraints required to obtain reliable probability distributions. This deficiency encountered at the beginning of assessment process can be alleviated later by investigating the im

A deterioration model plays an important role to predict the valid total maintenance cost for sustainable maintenance of bridges. In the current state-of-the-art, the deterioration model has regression parameters as a probabilistic process by an initially determined mean and standard deviation, called an existing model. However, the existing model has difficulty to predict maintenance costs accurately, because it cannot reflect an information based on structural damage at an operational stage. I