Multi-Hazard Risk Assessment of Civil Infrastructure Systems with a Focus on Long Linear Structures Such As Levees

Multi-hazard risk assessment enables one to estimate the benefit of expenditures for risk mitigation - a reduction in potential future losses. This leads to improved decision-making in design, inspection and repair of all types of structures, new and existing. It is especially relevant and useful for complex, spatially distributed systems - such as levees, pipelines and railroads - when seeking to allocate limited resources to different `segments' comprising a long linear `lifeline' (or a network of such lifelines). To demonstrate an approach based on random field concepts (to characterize how loads and resistances vary in space and time), we assess the risk of sliding (limit-equilibrium failure) of long earth slopes, dams or levees. In this instance, the stochastic model indicates fitting observations: (1) that slope failure events involving very long or very short distances along the slope axis are highly improbable; and (2) predicts the "most likely width of the failure zone" for long earth slopes and embankments. It can also evaluate the mean rate of increase in the `system failure' risk-per-unit length, a key controllable parameter in risk management of a system of long linear structures such as levees.