Issue 35

S. Valente et alii, Frattura ed Integrità Strutturale, 35 (2016) 306-312; DOI: 10.3221/IGF-ESIS.35.35 311 Figure 9 : Results for the 5-th step of the global stage. COD and CSD are divided by 3.0 mm. The water level is 0.5 m above the dam crest. Figure 10 : Results for the 6-th step of the global stage. COD and CSD are divided by 3.7 mm. The water level is 0.8 m above the dam crest. C ONCLUSIONS 1) The cohesive crack model can be used in the context of a large-scale engineering problem. 2) The uplift pressure induced by the water penetrating the open part of the crack can be taken into account. 3) The corrosion induced by the water penetrating the closed part of the crack can be taken into account through an appropriate reduction of the joint strength properties (sub-critical crack propagation). 4) In this case the phenomenon cannot be modeled through a continuous sequence of load increment in the context of the Newton-Raphson method. On the contrary, it is necessary to divide the whole process in a sequence of LArge Time INcrement (shortened LATIN). Therefore each large time increment can be simulated independently from the previous one. 5) This two-stage approach is able to model three different mechanical regimes occurring during the crack propagation process. R EFERENCES [1] International Commission Of Large Dams (ICOLD), Imminent failure flood for a concrete gravity dam, 5th International Benchmark Workshop on Numerical Analysis of Dams,(1999), Denver, CO. [2] Karihaloo, B.L., Xiao, Q.Z., Asymptotic fields at the tip of a cohesive crack, Int. Journal of Fracture, 150 (2008) 55- 74. [3] Barpi, F., Valente, S., The cohesive frictional crack model applied to the analysis of the dam-foundation joint, Engineering Fracture Mechanics, 77 (2010) 2182-2191. DOI:10.1016/j.engfracmech.2010.02.030. [4] Alberto, A., Valente, S., Asymptotic fields at the tip of a cohesive frictional crack growing at the bi-material interface between a dam and the foundation rock, Engineering Fracture Mechanics, 108 (2013) 135-144. DOI:10.1016/j.engfracmech.2013.05.005. [5] Bolzon, G., Cocchetti, G., Direct assessment of structural resistance against pressurized fracture, Int. Journal for Numerical and Analytical Methods in Geomechanics, 27 (2003) 353-378. [6] Barpi, F., Valente, S., Size-effects induced bifurcation phenomena during multiple cohesive crack propagation, Int. Journal of Solids and Structures, 35(16) (1998) 1851-1861. [7] Barpi, F., Valente, S., Fuzzy parameters analysis of time-dependent fracture of concrete dam models, Int. Journal for Numerical and Analytical Methods in Geomechanics, 26 (2002) 1005-1027. [8] Barpi, F., Valente, S., A fractional order rate approach for modeling concrete structures subjected to creep and fracture, Int. Journal of Solids and Structures, 41(9-10) (2004) 2607-2621.