A framework for performance-based earthquake engineering

develop a performance-based earthquake engineering methodology for buildings and bridges. The performance assessment process is described through four generalized vari-ables that characterize information from the relevant scientific and engineering disciplines in a logical and consistent manner. The process begins with defining a ground motion In-tensity Measure, which is often described by a seismic hazard curve for spectral accelera-tion or other quantity. Next, nonlinear computer simulations are used to determine response of a facility to earthquake ground motions. Output from these simulations is defined in terms of Engineering Demand Parameters, which may consist of interstory drifts, floor ac-celerations, local ductility demands, or other engineering response quantities. Engineering Demand Parameters are then related to Damage Measures, which describe the physical damage to the structure and its components. Damage states are delineated by their conse-quences or impact on Decision Variables, consisting of dollar losses (repair and restoration costs), downtime, and casualty rates. A key aspect of the methodology is consistent repre-sentation and tracking of uncertainties in predicting performance metrics that are relevant to decision making for seismic risk mitigation.