Résumé: Column jacketing is an effective technique to strengthen reinforced concrete structures,enhancing load capacity and ductility. For example in Algeria, the RPA 99 V 2003 and RPA2024 seismic codes requires larger column sections, whereas older buildings have smaller ones, making jacketing essential for compliance. Using fiber-reinforced polymer (FRP) bars instead of steel improves corrosion resistance, reduces weight, and enhances durability. This numerical investigation of this paper highlights the technical and economic benefits of FRP jacketing as a cost-effective solution for structural upgrading. The previously conducted experimental test served to validate the developed numerical model, implemented using the finite element software ABAQUS, which accurately captures significant physical phenomena of RC columns under compressive loading. The validated simulation was then utilized to conduct a parametric study, analyzing RC columns subjected to eccentric loading at various positions while incorporating different types of FRP rebars with diameters of 10 mm, 14 mm, and 20 mm and comparing their performance to that of steel rebars. Although the load capacity of the RC column under concentric loading was not fully restored, the performance of FRP rebars was comparable to that of steel rebars, with some cases showing a load improvement ranging from 27% to 33%

Résumé: This study is concerned with the study of the plastic behaviour of overlapped K-joint of lattice girders, made up of elements of rectangular hollow section with very thin walls. An experimental study was carried out on three full-scale truss girders with the same sections and different geometry. According to studies, the main parameters which have defined the strength of overlapped K-joints are the ratio between the width of the diagonals and that of the chord, the ratio between the width of the chord and that of its thickness and the angle of the diagonal with the chord. The latter was the parameter taken in this work. A numerical investigation was combined in order to draw up a comparative assessment of the behaviour. This study will certainly make it possible to better apprehend one of the main parameters governing the behavior of the joints of beams of hollow rectangular sections and to define the analytical model appropriate to this type of beam. It appears that in this study the very thin-walled sections exhibit a different behaviour compared to the trusses with more or less thick or thin sections. Pl