Issue 49

M. L. Puppio et alii, Frattura ed Integrità Strutturale, 49 (2019) 725-738; DOI: 10.3221/IGF-ESIS.49.65 735 (a) (b) (c) Figure 10: Principal stress distribution without (a) and with tie-rod (b); crack pattern with tie-rod (c). S IMPLIFIED ANALYSES IN THE 3- DIM MODEL inally, the three-dimensional model was assessed, in order to verify the occurred “spoon shaped” section breakage. A stretch of wall with length 46 meters was considered since the collapsed portion of the wall is about 30 m. By exploiting the symmetry of the problem, only half of it is modelled (Fig. 11). A careful modelling of the interface in contact with the adjacent portion of wall is necessary. It is chosen to model the constitutive law of the interface with a shear type non-linear behaviour by assuming a shear strength of 1.5 times the tensile strength (assumed equal to 10 kN/m 2 ) and a tangential modulus 0.4 times the elastic modulus. The other parameters and boundary conditions are analogous to those assumed for the 2-dim model. The displacements and the cracking pattern matched with the actual one. Anyway the macro- element approach as simplified way to detect of the correctness of the results is commonly adopted in masonry constructions [36]. Figure 11 : 3D model of the collapsed wall. By increasing the water level and pushing the 3d wall to collapse, it is possible to estimate the amount of out-of-plane displacement (Fig. 12 - a) and the cracking configuration (Fig. 12 - b), that is pretty similar to that actually occurred. The cracking pattern of the collapsed section of the 3 dim model is very similar to the one obtained by the 2-dim model of the F