Periodic BEM and FEM-BEM coupling - Application to seismic behaviour of very long structures

The main motivation of this work is the dynamic behavior of very long struc tures such as diaphragm and quay walls. Indeed despite a seemingly bi-dimen sional or periodic geometry, a true three dimensional analysis has to be ca rried out since the seismic loading is fully three-dimensional. Unfortunate ly usual 3D models are not able to account for such large structures either from the theoretical or the numerical point of view. The development of a periodic approach accounting for general 3D loadings and using a Boundary E lement Method is addressed in this paper. After introducing geometrical and functional frameworks, a generalised theory for periodicity fields and ope rators is given. It accounts for periodic domains and fields decompositions in view of a subdomain approach. Periodic boundary elements and special Gr een functions are then worked out. The third part points out some numerical validations and results issued from this theory applied to a real quay wal l.