Author(s)

Salima Djehaichia & Rachid Lassoued

Abstract

The vulnerability of reinforced concrete structures, which were built in the 1970s, under the effects of an earthquake is one of the major concerns of researchers, because the designs of these structures have been based on regulations, which are no longer valid. The parameters taken into account in this study to idealize the regulatory shortcomings are: low ratio of reinforcement, type of reinforcement and moderate resistance of concrete. The analysis to test these altered structures with one or both of the above parameters is carried out in the non-linear domain from the perspective of analysing their behaviour in an earthquake. In this paper, the modelling strategy is based on finite elements combined with a discretization of the shear wall most stressed by successive thin layers. The estimation of level of performance is achieved using capacity curves under increasing incremental loads; a non-linear characteristic force-displacement relationship can be determined. The results of the numerical model are compared with those of the Algerian seismic code (RPA). Through this comparison, it was found that there is an improvement in terms of displacement, shearing action and ductility. The introduction of confining as a local model makes it possible to refine the numerical model and improve the total behaviour of the structure. A parametric analysis is carried out to highlight the obvious weakness of structures designed and built in the 1970s.

Keywords

finite-element method, former structures, modelling, pushover analysis, RPA