ABSTRACT
In EC8 Part 1, the fundamental requirements for seismic performance are set out in Section 2. There are two main requirements. The first is to meet a ‘no collapse’ performance level, which requires that the structure retains its full vertical load-bearing capacity after an earthquake with a recommended return period of 475 years; longer return periods are given for special structures, for example casualty hospitals or high-risk petrochemical installations. After this earthquake, there should also be sufficient residual lateral strength and stiffness to protect life even during strong aftershocks. The second main requirement is to meet a ‘damage limitation’ performance level, which requires that the cost of damage and associated limitations of use should not be disproportionately high, in comparison with the total cost of the structure, after an earthquake with a recommended return period (for normal structures) of 95 years. Note that Section 2 of EC8 (and hence these basic requirements) applies to all types of structures, not just buildings.
