Numerical Simulation of the Behavior of Cracked Reinforced Concrete Members

Abstract

Refined non-linear static or dynamic analyses of reinforced concrete structures require the knowledge 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 between concrete and reinforcing steel. For this reason the definition of improved local models taking 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 particular 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

Experimental Assessment and Numerical Modeling of the Bond–Slip Correlation for Steel Rebars in r.c. Members

“…Although both specimens, the 100 cm- and 23 cm-long ones, can be classified as “long” specimens characterized by a long member behavior [ 25 ], the formation of multiple cracks is possible, allowing us to study the evolution of progressive cracking phenomena until their complete stabilization. The shorter specimens, whose length was calibrated to avoid intermediate cracks, were used to verify the evolution of the bond slip law in the absence of transversal cracking.…”

“…A numerical procedure to solve the non-linear differential equation that governs the bond–slip problem was proposed in [ 25 ]. The algorithm is summarized in Figure 2 and is based on an iterative shooting solution of the system of ODEs which can be suitably derived from Equation (7).…”

“…The test results, in terms of steel strains and the derived slips and bond stresses, are compared with the corresponding theoretical data, which were obtained by implementing a numerical procedure for the solution of the differential equations governing the interaction between steel bars and concrete [ 25 ]. The numerical procedure, described in Section 2 , allows us to predict the relative displacement between the steel reinforcement and the surrounding concrete in a reinforced concrete tie, once we have assigned the stress in the naked steel bar and the bond–slip law.…”

Applied element method simulation of experimental failure modes in RC shear walls

“…The associated numerical simulations may yield important data for a performance-based design, including the complete time history of the structural behavior, from the first moment the load is applied, until the total collapse of the structure. However, the evolution of the cracking pattern in geometrical discontinuous zones of RC elements and the associated failure modes are relatively complex and, despite the great effort that has been made to develop performing numerical models, e.g., Ngo and Scordelis (1967), Vecchio (1989), Vecchio and Collins (1993), Yang and Chen (2005), Azevedo et al (2010), Dujc et al (2010), Dominguez et al (2010), Mamede et al (2013), Croce and Formichi (2014), Balomenos et al (2015), their simulation is still considerably challenging, ACI (1997), Maekawa and Okamura (2003), Borosnyói and Balázs (2005).…”