ANALISI NUMERICA NON LINEARE DEL COMPORTAMENTO POST FESSURATIVO DI CALCESTRUZZI RINFORZATI CON FIBRE DI ACCIAIO

The present paper deals with numerical analysis of post cracking behaviour of Steel Fiber Reinforced Concrete (SFRC) beams in bending. Starting from experimental results of four point bending tests (4BPT), made on notched beams, the scope of the work was the determination of material tensile constitutive relationship by means of numerical modelling ("inverse analysis"). The numerical analyses were carried out by using the software TNO Diana 9.4.2.Two different models were developed to analyse the post cracking behaviour of SFRC notched beam: the first was based on the discrete crack approach and the second on the smeared crack approach. The results of the two analysis were than compared. The constitutive material relationship proposed by CNR DT 204-2006 was also analysed using both the models afore mentioned. Results of the numerical analysis are presented and discussed