Engineering structures are often subjected to the influences of performance deterioration and multiple hazards during their service lives, and consequently may suffer from damage/failure as a result of external loads. Structural reliability and resilience assessment is a powerful tool for quantifying the structural ability to withstand these environmental or operational attacks. This paper proposes new formulas for structural time-dependent reliability and resilience analyses in the presence of multiple hazards, which are functions of the duration of the reference period of interest. The joint impacts of nonstationarities in multiple hazards due to a changing environment, as well as the deterioration of structural performance, are explicitly incorporated. The correlation between the structural resistances/capacities associated with different hazard types is modeled by employing a copula function. It is observed that, under the context of multiple hazards and aging effects, the time-dep
This paper proposes a semi-analytical method for the time-dependent reliability assessment of steel pipelines exposed to localized corrosion. The failure modes considered in this paper include corrosion perforation and local burst due to the growth of defect depth and length. For a short pipeline, a spatial-temporal Poisson model is used to describe the occurrence of corrosion defects. The method is further generalized for the reliability assessment of a long pipeline, which is treated as a series system consisting of different segments. The spatial correlation of the behaviour of adjacent segments is taken into account, and is modeled by the Nataf transformation method. An example is presented to demonstrate the applicability of the proposed method. Analytical results show that the reliability of a short pipeline can be significantly underestimated if the assessment method for a single corrosion defect is used instead. For a long pipeline, the failure probability is smaller in the pre
The capacity deterioration of structures over time may impair their seismic structural reliability significantly, and, thus, they should be taken into account when assessing their seismic performance. In this study, a closed-form solution was proposed for time-dependent seismic reliability analysis of deteriorating structures. The capacity deterioration on the temporal scale was captured by the generalized capacity and deterioration function, and the Fréchet distribution was used to describe the probabilistic behavior of the peak ground acceleration. The deterioration of structural seismic capacity was modeled by a power function of time, and, thus, it was a nonlinear process if the exponent was other than 1. For a representative case, with some minor assumptions about the probability models of the deterioration process and of the seismic hazard, the proposed reliability analysis method was further simplified without the computation of integrals, which is beneficial for use in practic
Reliability assessment of engineered structures is a powerful and useful concept to estimate the structural capacity of withstanding hazardous events during their service lives. Taking into account the time variation of both structural resistance and the external load processes, the structural safety level is dependent on the duration of service period of interest, due to the accumulation of hazards by exposure in time. This paper presents an overview on the nonempirical assessment methods for time-dependent reliability of deteriorating structures. Generally, these methods can be classified into two types, namely simulation-based and analytical methods. The former is usually brute, and is especially suitable for solving high-dimensional reliability problems. Conversely, analytical solutions may improve the calculation efficiency significantly, and offer insights into the reliability problem that otherwise could be difficult to achieve through Monte Carlo simulation. Both the simulation
This paper proposes explicit approaches for time-dependent reliability assessment of aging structures, taking into account the correlation associated with the load process and that arising from the resistance deterioration process. For the load process, temporal correlation may arise due to the impacts of underlying common causes. With this regard, a closed-form solution is developed for structural reliability, which models the sequence of load effects as a Markov process. Furthermore, the resistance deterioration is by nature a non-increasing stochastic process with autocorrelation on the temporal scale. The Gamma process is used to describe the stochastic behaviour of resistance deterioration, based on which an explicit reliability method is derived. The proposed reliability methods are straightforward to implement and thus are promising to be adopted in practical engineering regarding the safety evaluation of aging structures. Illustrative examples are presented to demonstrate the a