Earthquakes and Structures, Vol. 4, No. 1 (2013) 41-62 41 Experimental and numerical studies on the cyclic behavior of R/C hollow bridge piers with corroded rebars D. Cardone  , G. Perrone and S. Sofia Scuola di Ingegneria, Università degli Studi della Basilicata, Via dell’Ateneo Lucano 10, 85100, Potenza, Italy (Received November 8, 2011, Revised February 16, 2012, Accepted February 20, 2012) Abstract. A comprehensive experimental program of cyclic tests on 1:3-scale models of bridge piers is going to be carried out at the Laboratory of Structures and Materials of the University of Basilicata. The testing models include eight RC single shaft piers with hollow circular cross section. Four piers have been realised using corroded steel rebars. In this paper, the results of preliminary numerical simulation analyses of the cyclic behaviour of the piers, carried out with Opensees using fiber-based models, are presented. Pull-out and lap-splice effects of steel rebars have been taken into account in the numerical analyses. First, the experimental specimens and the test set up are presented. Next, the results of the numerical analyses are discussed. In the numerical analyses, different configurations and levels of corrosion have been considered. The effective stiffness and equivalent damping of the piers is reported as a function of pier ductility and pier drift. Keywords: RC piers; nonlinear cyclic behavior; numerical simulation analyses; corrosion of steel rebars. 1. Introduction The seismic assessment of existing bridges is a primary concern, especially in regions where most bridges have been designed and built without specific rules and details for earthquake resistant structures. Past seismic events have shown that sub-standard details results in extensive damage or collapse during strong earthquakes, with dramatic consequences in terms of economic and social costs. The Italian highway network consists of approximately 5000 Reinforced Concrete (RC) bridges, most of them designed in the ‘60 and ‘70 considering gravity loads only or according to old seismic codes, based on elastic design approaches. The seismic vulnerability of many existing Italian highway bridges is then expected to be very high. An extensive program of experimental tests is going to be carried out at the Laboratory of Structures and Materials of the University of Basilicata, in order to assess the seismic behaviour of typical pier-deck sub-systems. The experimental program consists of a series of cyclic tests on eight 1:3-scale pier-deck sub-systems characterized by single shaft RC piers with hollow circular  Corresponding author, Professor, E-mail: donatello.cardone@unibas.it