Characterization of earthquake forces for probability-based design of nuclear structures

Research is underway to develop probability-based loading criteria for the design of safety-related steel and reinforced concrete nuclear plant structures. The random nature of earthquake loads and related structural response must be established before load criteria for design that include earthquake effects can be developed. This report provides a general statistical description of earthquake actions. Sources of uncertainty that might affect structural response are considered, including uncertainties in the peak ground motion at the site and in the structural response to prescribed ground motions. Power spectral density representations of earthquake ground motion needed for predicting response using random vibration analysis are examined and related to site conditions. The emphasis is on probabilistic models that are consistent with available data on seismicity and structural response