Fluid-Structure Interaction Analysis for Dam-Reservoir systems
Fluid-Structure Interaction (FSI) problem occurs in many engineering structures such as dams, offshore structures, large storage tanks, long-span bridges etc., those are in contact with fluid and analyses of such interaction problems are important for safe and economic design of the structures. Past record of dam failures and location of many dams in seismic prone areas have created a worldwide concern for dam safety against seismic hazards.
Considering the effects of fluid–structure dynamic interactions is important for the design and safety evaluation of earthquake-excited gravity dams. Significant research has been devoted to this subject since the pioneering work of Westergaard (1933) who modeled hydrodynamic loads as an added mass attached to the dam upstream face. Although Westergaard’s analytical formulation was developed assuming rigid dam impounding incompressible water, it has been widely used for many decades to design earthquake-resistant concrete dams because of its simplicity.
During the last four decades, several researchers developed advanced analytical and numerical approaches to account for dam deformability and water compressibility in the seismic response of concrete dams (Chopra, 1970; Chakrabarti and Chopra, 1973; Chopra, 1978; Zienkiewicz et al., 1978; Hall and Chopra, 1982; Fenves and Chopra, 1984; Liu and Cheng, 1984; Chopra et al., 1986; Tsai and Lee, 1987; Humar and Jablonski, 1988; Maeso et al., 2004). Most of these methods are based on a coupled field solution through sub-structuring of the dam–reservoir system, making use of analytical formulations, finite elements, boundary elements or a mix of these techniques. In the approach proposed by Chopra and collaborators the reservoir is modeled analytically as a continuum fluid region extending towards infinity in the upstream direction.
For practical engineering applications, simplified procedures are still needed to globally evaluate the seismic response of gravity dams, namely for preliminary design or safety evaluation purposes (Fenves and Chopra, 1985; Fenves and Chopra, 1987; Bouaanani et al., 2003; Bouaanani and Lu, 2009).