Fracture of mass concreete under simulated seismic action

The numerical simulation of concrete dams subject to earthquake loading requires realistic material laws which take into account material properties as effected by seismic action. Experiments under simulated seismic action were performed to examine the effect of rapid compressive loading on the fracture properties of mass concrete at high tensile deformation rates. Loading histories, representing typical seismic action, were applied to the specimens. Fracture properties have been investigated by two types of tests : - Uniaxial tensile tests were performed to study the ascending stress against strain curve (up to tensile strength) to describe continuous material under tensile stresses; and, - wedge splitting tests were conducted to investigate tensile softening properties and cracking of mass concrete. The test results showed that the effect of high deformation rates and loading histories must be considered in the seismic analysis of dams. The tensile strength and the specific fracture energy showed a high rate sensitivity. Compressive pre-loading led to some damage of the concrete and a significant decrease in the values of fracture properties. A procedure for the development of material laws, based on these results, is proposed.