Material and geometric nonlinear analysis of reinforced concrete frame structures considering the influence of shear strength complementary mechanisms

Abstract

A mechanical model for the analysis of reinforced concrete frame structures based on the Finite Element Method (FEM) is proposed in this paper. The nonlinear behavior of the steel and concrete is modeled by plasticity and damage models, respectively. In addition, geometric nonlinearity is considered by an updated lagrangian description, which allows writing the structure equilibrium in the last balanced configuration. To improve the modeling of the shear influence, concrete strength complementary mechanisms, such as aggregate interlock and dowel action are taken into account. A simplified model to compute the shear reinforcement contribution is also proposed. The main advantage of such a model is that it incorporates all these effects in a one-dimensional finite element formulation. Two tests were performed to compare the provided numerical solutions with experimental results and other one-and bi-dimensional numerical approaches. The tests have shown a good agreement between the proposed model and experimental results, especially when the shear complementary mechanisms are considered. All the numerical applications were performed considering monotonic loading.

Ductility Analysis of RC Beams Considering the Concrete Confinement Effect Produced by the Shear Reinforcement: a Numerical Approach

“…The basis and all the details concerning to the finite element formulation and the nonlinear solution strategies of the problem, as described above, were developed and published in Nogueira et al (2013), as some numerical examples to validate the model. To improve the capability of the model in simulate confinement effect, it was incorporate a module to calibrate the internal damage parameters set of the concrete, based on a specific constitutive law for concrete in compression able to consider such effect.…”

“…Each element has 2 nodes and the nodal movement description is given by 3 degrees of freedom (dof): 2 translational displacements (u and v in x' and y' respectively) and 1 rotation ( in z), which implies in the total of 6 dof per element (3 per each node). Nogueira et al (2013) presented the original formulation of the 1D finite element adopted here, which is based on the traditional displacement approach. …”

“…After the evaluation of the damage parameter for each integration point along the cross section height, the influence of the degradation state is taking into account to evaluate the contribution of such integration point at the assessment of the local stiffness matrix for the next iteration. More details about the FEM mechanical model can be found in Nogueira et al (2013). Figure 7 shows a schematic flowchart of the mechanical model with the introduction of the parameters calibration procedure.…”

An efficient mechanical-probabilistic approach for the collapse modelling of RC structures

“…The improved version of the lumped damage model was implemented into a finite element platform, which considers the 2D frame finite element. Initially, the numerical model was utilized in the simulation of one RC beam and one 2D RC frame, which were previously analysed numerically and experimentally in other researches available in the literature (Alvarez [25]; Nogueira et al [26]; Vecchio and Collins [27]). Afterwards, these structures were analysed accounting for the randomness.…”

Stability of concrete beam-columns under follower forces

“…Exceptionally, Aristizabal-Ochoa has emphasized the significance of investigating the behaviour of beam-column connections undergoing finite rotations under the action of tangential follower forces (Aristizabal-Ochoa, 2004. Need has been felt for carrying out more accurate analysis of concrete structures including the effects of material and geometric nonlinearity (Nogueira et al, 2013). Stiffness degradation caused by fire (Caldas et al, 2014) can render such concrete structures vulnerable to static and dynamic instabilities.…”