Non‐linear Finite Element Analysis

Abstract

Reinforced Concrete (RC) has become one of the most commonly used materials up to now. Despite their efficiency, RC structures have posed some disadvantages, primarily related to durability and corrosion of steel reinforcement. Just over a decade ago, however, a new concept has been developed with the idea of replacing the steel reinforcement with alkali-resistant textile fibres resulting in a new composite material called Textile Reinforced Concrete (TRC). This new construction material offers important advantages such as resistance to corrosion and thinner and lighter structures. An application which has become of great interest as of late is the use of TRC in rehabilitation, such that it can strengthen different structural elements like slabs, beams or columns.The main purpose of this report is to model and analyse the effects of strengthening RC structures using TRC layers, particularly focusing on a TRC strengthened RC slab. The main method used in this project was numerical modelling based on the Finite Element Method (FEM). The finite element software DIANA FX+ was utilized to develop a 2-D non-linear model of a TRC strengthened RC slab. The verification of the developed model was accomplished by means of experimental and numerical results from a previous study.The results showed that the RC slabs strengthened with TRC present significant increase in the load-bearing capacity compared to the unstrengthened RC slabs. Furthermore, for a similar load level, the final deflection was reduced in the case of strengthened slabs. The hand calculations of the ultimate load were consistent with the numerical results. This project has shown the efficiency of strengthening RC slabs with TRC layers. The modelling of the bond-slip relation between concrete and reinforcement using interface elements lead to a parametric study of this behaviour. This showed the importance of implementing interface elements instead of embedded reinforcement with full interaction in order to achieve realistic results. Further analysis of bidirectional slabs using 3D modelling is recommended for a better representation of the bonding behaviour between the textile reinforcement and the concrete.