Essential though for their correct application is an organized and thorough study.

Earthquakes prove even in Greece that the majority of the existing buildings are not safe. On the other hand, science has already reached a point where the seismic evaluation of an existing building regarding the stages of damages and collapse is possible. New materials, new analysis methods, the use of computers and knowledge of application of modern construction techniques significantly contribute in the solution of the problem of earthquake resistance of buildings.

Earthquake resistant design or strengthening is not just following the regulations. It is a complex process demanding deeper knowledge, experience and imagination. Basic criteria are already placed on a new basis. We are mainly talking today about objectives such as ductile behaviour and avoidance of brittle failure that result to the non-linear response of the building under static and dynamic loads.

Earlier, the earthquake was simulated through a horizontal loading on an extremely simplified elastic model of a ‘storey’ and the design was based on permissible elastic stresses. The nature of the earthquake and the actual behaviour of the structure in a higher stress state were not considered at all.

The preparation of this book is the result of a creative procedure of the last decade where many colleagues contributed either directly or indirectly. First of all P. Dimitrakopoulos writing the code of the modern earthquake-resistant design software and N. Tsikos, F. Heraklides, M. Skamantzoura and M. Koutsokosta who did the electronic processing of the book. The chapters on ductility and fracture of concrete are based on the research of the author between 1980-1985 in ETH Zuerich under Prof. B. Thuerlimann. For the planning and materialization of the projects based on the pushover method collaboration with V. Abakoumkin, D. Ziakas, N. Ktenas, Chr. Kostikas, E. Makrykostas, E. Mystakides, E. Papageorgiou and the late P. Papakyriakopoulos as well as the swiss colleagues J. Theiler, H. Elmer, C. Graber, H. Maag and P. Stephen of cubus proved valuable. I would also thank the select cubus Hellas collaborators that since 1990 contributed to this effort J. Georgiades, N. Glynatsis, M. Doumeni, K. Zisimou, A. Natsias, N. Metsis, A. Syrrakou, M. Niaka and Th. Kourkouvela.

My warmest thanks to E. Papageorgiou and D. Pentzas for their effort and time to review the draft and their remarks and clarifications that were included in the final text.

The tanslation of this book in English has been performed by D. Pentzas with a lot of care and hard work. Its very difficult to render such a specialized technical script in a foreign language, unless one is very well versed in the particular subject.

Finally I have to thank the hundreds of colleagues that are using cubus software for their everyday planning practice and flood us with remarks and suggestions. I hope this book will prove to be useful for the elaboration of their earthquake-resistant designs and generally to give them ideas for new approaches.

E-mail: info@cubushellas.gr