RISK ASSESSMENT OF BRIDGES AND HIGHWAY SYSTEMS FROM THE NORTHRIDGE EARTHQUAKE

A risk assessment methodology for highway transportation systems based on vulnerability and importance criteria is developed. As part of the vulnerability assessment new bridge classes and new damage states for components of concrete bridges are developed. Bridge damage observed in the Northridge earthquake is analyzed to identify structural characteristics that correlate well with the observed damage. Empirical fragility curves are developed for bridges grouped by these structural characteristics. The observed damage data are also compared to the available ground motion-damage relationships. The importance criterion is discussed for emergency response planning and management applications. Performance of highway systems before and after the Northridge earthquake is studied. The methodology is implemented within a geographic information system (GIS).