Incremental dynamic analysis
Incremental Dynamic Analysis (IDA) is a computational analysis method of Earthquake Engineering for performing a comprehensive assessment of the behavior of structures under seismic loads[1]. It has been developed to build upon the results of probabilistic seismic hazard analysis in order to estimate the seismic risk faced by a given structure. It can be considered to be the dynamic equivalent of the static pushover analysis.
IDA involves performing multiple nonlinear dynamic analyses of a structural model under a suite of ground motion records, each scaled to several levels of seismic intensity. The scaling levels are appropriately selected to force the structure through the entire range of behavior, from elastic to inelastic and finally to global dynamic instability, where the structure essentially experiences collapse. Appropriate postprocessing can present the results in terms of IDA curves, one for each ground motion record, of the seismic intensity, typically represented by a scalar Intensity Measure (IM), versus the structural response, as measured by an Engineering Demand Parameter (EDP).
Possible choices for the IM are scalar (or rarely vector) quantities that relate to the severity of the recorded ground motion and scale linearly or nonlinearly with its amplitude. They are chosen well so that appropriate hazard maps (hazard curves) can be produced for them by probabilistic seismic hazard analysis. Possible choices are the peak ground acceleration, peak ground velocity or Arias intensity, but the most widely used is the 5%-damped spectral acceleration at the first-mode period of the structure.
The EDP can be any structural response quantity that relates to structural, non-structural or contents' damage. Typical choices are the maximum (over all stories and time) interstory drift, the individual peak story drifts and the peak floor accelerations.
References
- ^ Vamvatsikos D., Cornell C.A. (2002). Incremental Dynamic Analysis. Earthquake Engineering and Structural Dynamics, 31(3): 491–514.
See also
External links
- [1] IDA-related publications from the personal page of D. Vamvatsikos at the National Technical University of Athens