Issue 30

O. Sucharda et alii, Frattura ed Integrità Strutturale, 30 (2014) 375-382; DOI: 10.3221/IGF-ESIS.30.45 380 histogram parameters and COV for the input variables of concrete and steel. The initial value was the compressive strength of the concrete. Tab. 8 shows the correlation matrix used for the concrete in the stochastic modelling. Input E c f c f t G f Distribution Lognormal Lognormal Weibull Weibull COV 0.15 0.10 0.18 0.2 Table 6: Material properties in the stochastic modelling - concrete. Input Fy Fu Histogram Lognormal Lognormal COV 0.05 0.05 Table 7: Material properties in the stochastic modelling - steel. Input E c f c f t G f E c 1 0.7 0.9 0.5 f c 0.7032 1 0.8 0.9 f t 0.8972 0.7987 1 0.6 G f 0.5021 0.8991 0.6014 1 Table 8: Correlation matrix of concrete. Figure 7: Final histogram, estimate - ultimate load . D ISCUSSION he University of Toronto tested the beams without shear reinforcement. Three basic phases of load can be identified in working diagrams and photos published in [19]. It follows from the comparison of the working diagrams, photos and numerical calculations that these are the three basic phases of the loading process. At the beginning of the loading process, cracks appear at the lower edge in the middle of the span. Then, shear cracks appear. They become dominant, until the beam collapses. The collapse occurs fast. In case of beams with a big span (OA2 and OA3), the crack is located towards the loading point and is almost horizontal. The crack propagates in places where the reinforcement is located. In each numerical calculation the final way of collapse in a beam was same as in the experiment. These were diagonal- tension failures. The comparison of the total bearing capacity obtained in calculations and that obtained in experiments shows very good correlation for both the first and second alternatives. The medium values of P u, Test /P u, Calc are 0.97 and T