Materials Sciences and Applications, 2014, 5, 883-894 Published Online October 2014 in SciRes. http://www.scirp.org/journal/msa http://dx.doi.org/10.4236/msa.2014.512090 How to cite this paper: Croce, P. and Formichi, P. (2014) Numerical Simulation of the Behavior of Cracked Reinforced Con- crete Members. Materials Sciences and Applications, 5, 883-894. http://dx.doi.org/10.4236/msa.2014.512090 Numerical Simulation of the Behavior of Cracked Reinforced Concrete Members Pietro Croce, Paolo Formichi Department of Civil and Industrial Engineering—Structural Division, University of Pisa, Pisa, Italy Email: p.croce@ing.unipi.it Received 26 July 2014; revised 6 September 2014; accepted 27 September 2014 Copyright © 2014 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract Refined non-linear static or dynamic analyses of reinforced concrete structures require the know- ledge of the actual force-displacement or bending moment-rotation curves of each structural member, which depend on the crack widths and on the crack pattern, and after all on the slip be- tween concrete and reinforcing steel. For this reason the definition of improved local models tak- ing into account all these local aspects is a fundamental prerequisite for advanced assessment of r.c. structures. A numerical procedure which allows to predict the relative displacement between steel reinforcement and the surrounding concrete in a reinforced concrete element, once assigned the stress in the naked steel bar and the bond-slip law is discussed. The method provides as final outcomes the sequence of crack openings and the individual crack widths, regardless of the par- ticular bond-slip correlation adopted. The proposed procedure is implemented referring to two relevant experimental case studies, demonstrating that it is able to predict satisfactorily actual strain fields and slips along the investigated reinforced concrete elements. Keywords Bond-Slip, Reinforced Concrete, Non-Linear Behavior, Numerical Analysis, Crack Pattern, Crack Opening, Bond Stress 1. Introduction Non-linear static or dynamic analyses are increasingly used to study the behavior of reinforced concrete struc- tures, especially for seismic design [1], but they call for the knowledge of the actual force-displacement or bending moment-rotation curves of each structural member. These curves represent also the starting information for the evaluation of the available ductility of structural elements and for an appropriate estimation of their relevant parameters, required to perform equivalent elastic