Increased roof displacement occurs in masonry-free flats on the ground floor (Pilotis) or large openings in the masonry. The maximum possible elastoplastic earthquake displacement is almost proportional to the eigenperiod.
Increased resistance to horizontal loading (eg, earthquake) present apartment buildings with reinforced concrete shear walls, masonry (reinforced or un reinforced) and to a certain extent the structures that have been reinforced by application of jackets to pilotis columns.
A great demand for ductility appears in case of pilotis without masonry, with pilotis having eccentric masonry or large openings in the masonry. In a design earthquake there is a risk of collapse, because the required ductility is generally not available.
In the future, pre-seismic strengthening will be required in several building cases, which can be analyzed by applying the Push Over method, in accordance with EC8 Eurocode and the new Greek Intervention Regulation (KAN EPE).