METHODS FOR COMPLEX INFRASTRUCTURE SYSTEMS BY

The failure event of a structure or lifeline network is often described by a complex logical function of multiple component failure events. Despite significant advances in theories on reliability analysis of individual components and their adoption in practice, the critical knowledge and quantitative methods for reliability assessments of complex system events remain elusive, leading to unknown accuracies in the risk assessment. Such a system reliability analysis is computationally challenging, especially when the definition of the system event is complex, the system has a large number of components, or the component events have significant statistical dependence due to common source effects. To overcome these challenges, this study develops two system reliability analysis methods, termed the Matrix-based System Reliability (MSR) Method and the Sequential Compounding Method (SCM), and applies the methods to risk assessment of complex structural systems and lifeline networks. Unlike existing system reliability analysis methods, the MSR method is applicable to any general system events, and can estimate not only system reliability but also component importance measures and parameter sensitivities of system reliability, which are essential metrics for risk-informed decision-makin