ABSTRACT
The intensity of ground shaking and seismic demand on structures are generally characterized using parameters such as peak ground acceleration or strength-based response spectrum ordinates (e.g., spectral acceleration) that describe the maximum amplitude of shaking for specified natural period and damping values. To assess seismic demands on structures, one might instead employ an energy-based approach, especially when interest is in assessing damage potential. An energy spectrum, requiring the same level of effort as a conventional response spectrum, offers a convenient description of both the amplitude and duration of ground motion and is a useful means of describing the seismic performance of structures.
Ground motion prediction equations for Northwestern Turkey are developed for energy-related parameters; 195 recordings from 17 seismic events are considered in the selected database. These prediction relationships are for two energy parameters (input energy-equivalent acceleration, A i , and absorbed energy-equivalent velocity, A a ). Proposed predictions of these parameters are compared with spectral acceleration predictions. They are also compared with Western U.S. predictions for the same energy-based parameters. Finally, energy-based amplification factors are proposed as a function of site class in an analogous manner to amplification factors for spectral acceleration; these amplification effects for strength- and energy-based parameters are compared.
