Ahmad Yamin Rasa
This study presents a robust Lagrangian infinite fluid element (LIFE) for seismic analysis of dams. The proposed LIFE effectively replaces the conventional [Formula: see text]-fixed, [Formula: see text]-roller boundary conditions (BC) at the far end of the reservoir in Lagrangian fluid modeling, allowing for realistic simulation of unbounded water domains by absorbing outgoing seismic waves and preventing artificial reflections. The developed finite element (FE) model was implemented in FORTRAN 90 programming language and validated against benchmark solutions from the literature. A parametric study is conducted on the Koyna dam, subjected to horizontal (H) and horizontal [Formula: see text] vertical [Formula: see text] Koyna earthquake ground motions, considering three different near-field reservoir lengths (RL) of 1D, 2D, and 3D, where D is the reservoir water depth. The results revealed that the LIFE maintains accuracy and stability even for short RL domains [Formula: see text], whereas the traditional model required a minimum of [Formula: see text] to radiate wave reflections, thus decreasing computational cost without much loss of accuracy. Results also indicate that the displacement-decay parameter (DDP) in the LIFE strongly influences performance, with [Formula: see text] producing physically consistent crest responses and hydrodynamic pressure distributions.