ABSTRACT
For the majority of buildings in seismic regions, the ground motion due to a nearby strong earthquake causes the most severe load among all loading conditions to which a building can possibly be subjected. On the other hand, the probability that such a ground motion will occur within the service life of the building is low. For example, we have already seen in Section 1.3 that, according to Eurocode 8, a building of ordinary importance is designed and constructed to withstand, without life-threatening local or global collapse, a ‘design seismic action’ associated with a recommended probability of exceedance of 10% in 50 years, which corresponds to a mean return period of 475 years. Since the probability is small, it is a common belief that for economic reasons it is not rational to build structures which would survive a strong earthquake without damage, that is, in the elastic range of behaviour.
