Correlation Between Structural Performance Levels and Damage Indexes in Steel Frames Subjected to Earthquakes


Department of Civil Engineering,Sharif University of Technology


Abstract. Various damage indexes have been introduced in recent years incorporating di erent
parameters for estimating structural damage. Amongst these indexes, Plastic Ductility and Drift have been
the center of attention of standards and building codes, like FEMA-356, because of their straightforward
physical interpretation and ease of calculation. In this paper, several steel moment frames have been
considered and their responses have been evaluated under a set of scaled earthquakes. A group of various
damage indexes, which included cumulative and non cumulative, cyclic fatigue based, deformation based
and modal parameter based, has been considered and the damage to structures has been evaluated on their
basis. On the other hand, the performance levels of the frames have been estimated on the basis of the
FEMA-356 standard. Based on these results, the correlation between FEMA performance levels and the
values of damage indexes has been studied and some polynomial equations have been proposed. These
simple equations can be used to estimate the value of the damage indexes from FEMA performance levels.
Also, the range of each damage index for each FEMA performance level has been determined. At last,
based on the concepts underlying each damage index, the indications of some important aspects of the
structure response correlated to each FEMA performance level are investigated.