SUMMARY
      
     Nowadays, the steel fibre reinforced concrete (SFRC) has been performing an 
important role in construction industry. SFRC results of mixing short and discontinuous 
steel fibres randomly distributed with traditional concrete.  This material offers 
structural advantages mainly in post-crack state, because it provides higher flexural-
tensile strength and ductile fracture.
     
     Some authors have researched the SFRC behaviour; defining mechanical 
properties and different behaviour models. However, few researchers consider the 
simulation of SFRC behaviour as their principal goal using finite element software.
     
     The main aim of this doctoral thesis is to propose a simple numerical model for 
simulating SFRC elements behaviour in pre and post cracking state using a commercial 
program. To achieve this goal, scientific literature review, related to SFRC behaviour 
models and its simulations, has been carried out.  Besides, three stages have been 
established: experimental study, numerical study and analysis of the results obtained 
considering SFRC with different characteristics.
     
     On the experimental study different elements behaviour are analyzed (prismatic 
elements, round panel, and thin slabs).  Prismatic elements and round panel tests 
correspond to American and European standards, while thin slab tests are proposed in 
this study.  A finite element commercial software ANSYSŪ V11 has been employed in 
the numerical study to simulate the tested elements behaviour in the experimental 
study.  The simulation of SFRC elements uses a specific finite element for fragile 
materials and modifies the failure surface parameters to consider fibres effect.  The 
numerical study has three phases: Preliminary studies, Determination of influential 
parameters on the SFRC behaviour and Analysis of the main parameters.  Materials 
properties of the initial concrete (HI) were considered in these phases.  Finally, it is 
carried out an extrapolation to different SFRC, using the results obtained in the 
numerical study.
     
     Hence, it is possible to propose a simplified numerical model for simulating SFRC 
elements with different geometry, load conditions and mechanical properties, using 
only three parameters obtained from experimental tests: compressive strength (fc), 
tensile strength (ft) and residual tensile-strength of SFRC (fr), to define the failure 
surface material.