according to performance-based seismic design method by using energy concept, in this paper it is tried to investigate the duration and damping effects on elastic input energy due to strong ground motions. based on reliable iranian earthquake records in four types of soils, structures were analyzed and equivalent velocity spectra were computed by using input energy. these spectra were normalize...

Most instruments used in seismological practice to record ground motion are pendulum seismographs, velocigraphs, or accelerographs. In most cases it is assumed that seismic instruments are only sensitive to the translational motion of the instrument’s base. In this study the full equation of pendulum motion, including the inputs of rotations and tilts, is considered. It is shown that tilting th...