UPLIFT MODELING FOR FRACTURE-MECHANICS ANALYSIS OF CONCRETE DAMS

The modeling of uplift pressures within a dam, on the foundation on wh ich it was constructed, and on the interface between the dam and found ation is a critical aspect in the analysis of concrete gravity dams. T he procedures for modeling uplift pressures are well established for t he traditional hand-calculation methods, but this is not the case for finite element (FE) analysis. In this paper, the procedures for includ ing uplift pressures in the hand-calculation methods, as prescribed by various government agencies, are reviewed and compared. Three separat e models for including uplift pressures in a FE analysis are proposed. The use of these models is demonstrated in cracked-base analyses of t wo different dam geometries with identical material properties. A line ar elastic fracture mechanics criterion is used to determine the final crack length rather than the strength criterion used in the hand-calc ulation methods. The results of these analyses are compared with one a nother and with results published elsewhere for one of the two geometr ies but with different material properties.