NEHRP Clearinghouse
- Title
- System Performance Under Multi-Hazard Environments.
- File
- PB2008112235.pdf
- Author(s)
- Kafali, C.; Grigoriu, M.
- Source
- Multidisciplinary Center for Earthquake Engineering Research, Buffalo, NY.; National Science Foundation, Washington, DC., March 4, 2008, 250 p.
- Identifying Number(s)
- MCEER-08-0006
- Abstract
- This study presents a new methodology to assess the performance of structural/nonstructural systems subjected to multiple hazards during their lifetime, and to identify an optimal strategy from a collection of design alternatives. The methodology is probabilistic in nature since the intensity and arrival time of different hazards such as earthquakes and hurricanes, the loads acting on the system due to a hazard event such as ground accelerations and wind velocities, and some system characteristics, are generally uncertain. Consequently, probabilistic models are developed to characterize the natural hazards that could occur at a given site at single/multiple points. These models specify the random arrival times of individual events at a site during a reference time, the random properties of the hazards under considerations at these times, and the random loads acting on the system due to each event. The models are implemented in computer programs and the life-cycle risk analysis methodology is illustrated through numerical examples. In the first example, the MCEER West Coast Demonstration Hospital is analyzed to identify an optimal rehabilitation strategy using the concepts of seismic activity matrix and fragility surfaces. It is shown that proposed retrofitting alternatives do not change the mean value of the life-cycle costs significantly, however, the probability of exceeding large costs is lower for the retrofitted systems. This example demonstrates how different hazards can be dominant at different reliability levels. The last example presents a method for selecting an optimal maintenance policy for a deteriorating system by minimizing the total life-cycle cost so that system reliability at any given time is greater than a specified level.
- Keywords
- System performance; Probabilistic models; Natural disasters; Hurricanes; Ground accelerations; Structural systems; Performance assessments; Design alternatives; Wind velocities; Multi-hazard environments; Nonstructural systems; Earthquakes