The attached document describes the newly implemented Westergaard's added-mass feature to deal with the hydrodynamic effects induced by the impounded water on the response of a dam subjected to earthquake excitation. This feature is implemented as fully dynamic behaviour, not as a pseudo-static calculation enhancement.
A simple example is presented to illustrate the Westergaard's added mass implementation in PLAXIS to model the effect of hydrodynamic pressure on a dam (with fixed displacements in the vertical direction). For this example, the horizontal displacement at the top of the dam at the upstream face was monitored. The results show an agreement between the simulations of PLAXIS 2D and PLAXIS 3D.
Hydrostatic and hydrodynamic forces during earthquake excitation.
Note: this feature has been made available as a Technology Preview with the release of PLAXIS 2D/3D CONNECT Edition V20 Update 1 (January 2020) and requires the Dynamics module in order to run a Dynamic analysis.
How does Plaxis deal with water pressures during dynamic calculations? [Tips and Tricks]
Pseudo Static acceleration [Tips and Tricks]