Cohesive - frictional crack model applied to bi-material interfaces

The necessity of ensuring conditions of reliability and safety for constructions in both civil and infrastructural fields, have led more and more to the development of numerical methods that are able to simulate the behavior of cracked materials, wherever a comparison with laboratory tests is not possible because of the size of the works. Given the importance of cracking phenomena in quasi-brittle materials, such as concrete, rocks and bricks, and considering the importance of fully understanding brittle type collapses, it would seem useful to develop numerical procedures that are able to supply correct predictions of the behaviour of a structure. In the first part of the thesis, starting from considerations made on homogeneous material , a method has been developed on the basis of the asymptotic development of a crack that propagates at the interface of two generic materials. Then, referring to the foundations of a dam , this method has been applied to an interface between Rock and Concrete, and a comparison has been made between the acquired results and those obtained using a Finite Element Method. In the second part of the thesis, the mechanical behaviour of the interface between Mortar and Brick and Mortar and Stone has been analyzed through the use of a cohesive model, as part of the REFRESCOS project. Numerical simulation of laboratory tests has described the detachment phenomenon between the two materials in a satisfactory manner. This simulation can be used to predict such a phenomenon, that is frequently encountered in plasterwork in historical brickwork constructions.