Modelado del comportamiento a pandeo de paneles y pilares esbeltos de hormigón armado

Modelling the buckling behaviour of slender reinforced-concrete panels and columns

This work reports a model that predicts the behaviour of lightly reinforced concrete panels and columns when subjected to buckling. The model simulates the loss of stiffness of these structures due to the initiation and development of cracks during loading. The fracturing process was represented by considering a single crack at the centre of the panel or column. The behaviour of the concrete under traction was described by means of a cohesive model. When subjected to compression an analogous model was used: before reaching the maximum load the behaviour of the concrete was described by a stress-strain relation- ship, whereas a stress-displacement relationship was employed after the maximum load. The proposed model contemplates large deformations so that in each iteration the change in geometry is taken into account. In this manner, failure due to buckling is explicitly simulated. The methodology of the proposed model is simple and practical, and can be integrated into commercial finite element programs. The model was validated comparing its predictions with experimentally obtained results. The sensitivity of the model to changes in the slenderness of the panel or column, the reinforcement ratio and the characteristics of the concrete was determined.