Simplified approach on modeling of embedded reinforcementsin flexural concrete members

Several factors need to be considered in modeling of reinforced concrete beams. Bond-slip is one of the most important factors that play a key role in the behavior of reinforced concrete structures, under static and dynamic loads. A comparison between the results of experimental tests and numerical models show that considering a complete bond (perfect with no slip) instead of real bond-slip phenomenon, in numerical finite element models leads to higher estimations for the stiffness. In this study, the effects of the bond-slip phenomenon on the behavior of the reinforced concrete beams are considered. It is shown that the influence of bond-slip behavior between steel and concrete depends on the compressive strength of concrete, the concrete cover, stirrups and rebar diameter. Subsequently, a method is proposed to consider the effects of the interfacial behavior between concrete and rebar while a complete bond assumption remains and the rebar is introduced as embedded element in concrete. The bond-slip effect is considered by adding an equivalent strain of bond to the strain of steel rebar and then modifying the terms of the modulus of elasticity of steel. Validation model and parametric analyses are conducted to consider the effects of bond-slip properties and other parameters affecting the behavior of reinforced concrete beams.