Abstract: An aseismatic system for constructions such as buildings, bridges, tanks and like comprising abutment/decoupling means for the deck structure from the piers or for the building from its foundation as well as return means for resisting any relative displacements between the deck structure and the piers or between the building and its foundation, which is based upon the principle to prevent the bridge or the building to be subjected to the seismic effects caused by the deck structure mass by decoupling the construction on the horizontal plane by means of said multi-directional movable abutment means, with nearly null resistance to sliding movements and by means of a connection between the deck structure and its abutment members based upon a swinging device adapt to exert a predetermined action of constant value.