Numerical Modelling of the Load Carrying Capacity Degradation in Concrete Beams due to Reinforcement Corrosion

PABLO SÁNCHEZ; ALFREDO HUESPE; JAVIER OLIVER; SEBASTIAN TORO

Venecia

Congreso; 8th. World Congress on Computational Mechanics (WCCM8) y 5th. European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008); 2008

International Association for Computational Mechanics (IACM) y European Community on Computational Methods in Applied Sciences (ECCOMAS)

In this contribution, we present a FE model suitable to simulate the evolution of the mechanical degradation mechanism in RC members due to reinforcement corrosion, such as: expansion of the corroded bars, crack pattern distribution, loss of steel-concrete bond adherence, net area reduction of the steel fiber cross section and the effects of the above mentioned mechanisms on the structural load carrying capacity. The proposed numerical model has been applied to beams, through two succesive and coupled mesoscopic mechanical analyzes, as follows:(i) Analysis of the structural member cross section:, we simulate the reinforced fiber expansion due to the volume increase of the steel bars as a consequence of corrosion. Damage distribution and cracking patterns in the concrete is evaluated, which defines the concrete net section loss in the structural member.(ii) Mesoscopic analysis of the structural member: considering the results of the previous analysis, it is evaluated the mechanical response of the structural member subjected to an external loading system. This evaluation determines the global response and the macroscopic mechanisms of failure.Each component of the RC structure ismodeled bymeans of a suitable FE formulation. For the concrete, a cohesive (damage) model based on the Continuum Strong Discontinuity Approach (CSDA [1]) is used. Steel reinforcement are simulated by means of a standard elasto-plastic model. The interface is simulated using contact-friction elements with the friction degradation as a function of the degree of corrosion attack.A consistent coupling between the two analyzes in points (i) and (ii) is also proposed. It is based on transfer, from one domain of analysis (cross section) to the other (structural member), the average value of the damage variable, ?d?, across horizontal slices of the cross section model.A set of numerical simulations are addressed in order to test the performance of the described finite element formulations. Some of the RC beams, experimentally investigated by Rodriguez et al. [2], have been analyzed. We follow very closely the guidelines and material characterization reported in [3].