**
**### E. DiPasquale, A.S. Cakmak

NCEER-88-0022 |** **6/15/1988 | 88 pages

## About the Report:

**TOC:** The table of contents is provided.

**Keywords:** Seismic Structural Damage, Damage Detection, Serviceability Limit State, and Reinforced Concrete Structures.

**Abstract:** Damage analysis models based on equivalent modal parameters are used to identify the serviceability limit state for structures subjected to earthquake loads. A model for the analysis of seismic structural damage consists of a finite number of numerical indicators (damage indices) and of a procedure for their computation. A structure exhibits a nonlinear behavior when it experiences an earthquake. Nonetheless, an equivalent linear structure can be defined. Damage indices can be defined from the vibrational parameters of the equivalent linear structure considered. In the first place, it is shown that the problem of identification of the serviceability limit state is equivalent to the problem of detection of seismic structural damage. A limit state can be defined as a surface in the space of the damage indices relative to the model considered. Experiments on small-scale models are analyzed to obtain an analytical definition of the serviceability limit state. Since many uncertainties are present in any damage analysis problem, a probabilistic definition is obtained, in terms of the probability that the structure considered is damaged after the seismic event. Finally, records from large-scale models and full-scale structures are analyzed. The model proposed performs very well in detecting seismic structural damage.