Selection of efficient earthquake intensity measures for evaluating seismic fragility of concrete face rockfill dam

This study explores the crucial role of intensity measure (IM) selection for probabilistic seismic demand model development of concrete face rockfill dam (CFRD) subjected to earthquake ground motions. Nonlinear dynamic analyses are performed for CFRD with an advanced hysteretic soil model using a finite element analysis program to develop a database of earthquake-induced dam crest settlements. The numerical model is validated through centrifuge model test measurements. A selection process was carried out to evaluate the IMs based on the goodness of fit, as well as their efficiency, practicality, and proficiency. Eventually, a range of optimal IMs are selected. Conditional probability function is employed to develop fragility curves for CFRD employing both scalar and vector IMs. Five settlement ratio-based limit states are defined herein. The results show that vector fragility surfaces produce enhanced predictions of the dam damage compared with the scalar fragility curves that are most often employed.