The safety of cracked concrete dams is fundamentally affected by their mechanical behaviour under cyclic loading conditions. It is well known that concrete presents a diffused damage zone within which micro-cracking increases and stresses decrease as the overall deformation increases. This results in the softening of the material in the so-called fracture process zone (FPZ), whose size is comparable to that of a characteristic dimension of the structure. This dimension is not constant and may vary during the evolutionary process. In this context, a numerical method has to be used together with the cohesive or fictitious crack model, also known as Barenblatt, Dugdale and Hillerborg model. The proposed approach combines a micromechanical model for the static softening behaviour of cracked concrete in the fracture process zone (Huang & Li (1989)) with a local model along the FPZ for the hysteresis loop under unloading-reloading conditions (see Hordijk (1991)). The loading process analysed in this paper is based on a first monotonic step stopped before reaching the peak load. Afterwards, a series of cyclic loading phases is applied, at increasing load levels, until collapse occurs. The results of numerical analyses appear in good agreement with the experimental data obtained in the case of wedge splitting tests.

Subcritical crack propagation in concrete structure / Barpi, Fabrizio; Valente, Silvio. - (2005). (Intervento presentato al convegno XVII Conf of Italian Assoc for Theor and Applied Mech tenutosi a Firenze nel 11-15 Sep 2005).

Subcritical crack propagation in concrete structure

BARPI, Fabrizio;VALENTE, Silvio
2005

Abstract

The safety of cracked concrete dams is fundamentally affected by their mechanical behaviour under cyclic loading conditions. It is well known that concrete presents a diffused damage zone within which micro-cracking increases and stresses decrease as the overall deformation increases. This results in the softening of the material in the so-called fracture process zone (FPZ), whose size is comparable to that of a characteristic dimension of the structure. This dimension is not constant and may vary during the evolutionary process. In this context, a numerical method has to be used together with the cohesive or fictitious crack model, also known as Barenblatt, Dugdale and Hillerborg model. The proposed approach combines a micromechanical model for the static softening behaviour of cracked concrete in the fracture process zone (Huang & Li (1989)) with a local model along the FPZ for the hysteresis loop under unloading-reloading conditions (see Hordijk (1991)). The loading process analysed in this paper is based on a first monotonic step stopped before reaching the peak load. Afterwards, a series of cyclic loading phases is applied, at increasing load levels, until collapse occurs. The results of numerical analyses appear in good agreement with the experimental data obtained in the case of wedge splitting tests.
2005
8884532485
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/1408232
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