英文摘要 |
The characterization of earthquake demands for seismic analysis or design requires the specification of a level of intensity of the ground motion. Response history analyses require scaling of the ground motion records to a specified level of intensity. This study investigates the correlation between several ground motion intensity indices and four response variables: elastic and inelastic spectral ordinates, input energy and hysteretic energy, based on responses calculated for a specific set of earthquake records. An essential point of this study is that ground motion indices are relevant as long as they are a sign of the level of structural response. As expected, it is found that no index is satisfactory over the entire frequency range. Indeed, indices based on the ground acceleration history rank better in the acceleration-sensitive region of the spectrum, indices based on ground velocity are better in the velocity sensitive region, and correspondingly occurs in the displacement-controlled region. A rank of indices is presented, according to their correlation with response quantities. On the other hand, the structure’s ability to survive an earthquake may be measured in terms of the expected state of damage of the structure after the earthquake. Damage may be quantified by using any of several damage indices defined as functions whose values can be related to particular structural damage states. A number of available response-based damage indices are discussed and critically evaluated for their applicability in seismic damage evaluation. This study try to construct a new rational approach for damage assessment which provides a measure of the physical response characteristics of the structure and is better suited for non-linear structural analysis. |