| Summary: | 碩士 === 國立臺灣科技大學 === 營建工程系 === 101 === In the energy method for seismic design of structures, the total input
energy is equal to the sum of kinetic energy, damping energy, elastic
strain energy and hysteretic energy. To date, there have been two energy
methods in evaluating the damage potential of earthquake ground
motions to structures: (1) the total input energy method and (2) the
momentary input energy. The first method is based on the accumulated
energy input to the structure during the ground shaking. The second
method is conceptually similar to the “input power” to the structure.
However, the significance of momentary input energy is to evaluate the
input energy during certain time period rather than an infinitesimal time
period. In the previous researches, the finite time interval is often adopted
as one half cycle of structural vibration, i.e. the time duration from the
absolute maximum displacement to the next absolute maximum
displacement of the cyclic history response of a structure subjected to a
ground excitation. The momentary input energy is the focus of this thesis.
According to the report published by Uang and Bertero, the input
energy is identified as the absolute input energy and the relative input
energy. In this study, the absolute momentary input energy spectrum and
the relative momentary input energy spectrum are calculated based on the
elastic response history of a single degree of freedom system.
Base on the study it is found that the elastic momentary input energy
spectrum is better than the elastic spectrum to reflect the damage
potential of an earthquake. Furthermore, the relative momentary input
energy spectrum is better than the absolute momentary input energy
spectrum to indicate the inelastic displacement demand by an earthquake
ground motion.
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