Subcritical crack propagation under cyclic load of concrete structures

The safety of cracked concrete dams is fundamentally affected by the mechanical behaviour of the material under cyclic loading conditions. In this case the crack can grow at a lower load level compared to the monotonic case. This phenomenon is called sub-critical crack propagation and depends on the mechanical behaviour of the fracture process zone. To assess this phenomenon, a number of experimental tests where the loading process is based on a first monotonic step (stopped before reaching the peak load) followed by a series of cyclic loading phases until collapse are examined. The results of numerical analyses appear in good agreement with the experimental data obtained in the case of wedge splitting tests.