【正文】
ral type, the importance of the building, its role in postearthquake emergencies, the economic consequences of business interruption, its historical or cultural significance, the construction material and socioeconomic factors. They can be specified as limits on one or more response parameter such as stresses, strains, displacements, accelerations, etc. Clearly, different limit states have to be correlated to the level of the seismic action, . to the earthquake demand level. The selection of the rehabilitation scheme and the level of intervention is a rather plex procedure, because many factors of different nature e into play. A decision has to be taken on the level of intervention. Some mon strategies are the restriction or change of use of the building, partial demolition and/or mass addition, methods such as base isolation, provision of supplemental damping and incorporation of passive and active vibration control devices may apply. The alternatives of ‘no intervention’ or ‘demolition’ are more likely the outes of the evaluation if the seismic retrofit of buildings is quite expensive and disruptive. Socioeconomic issues have to be considered in the decision of the level and type of intervention. Surprisingly, there are documented cases where aesthetic and psychological issues dictate the rehabilitation strategies. For example, in the Mexico City earthqua ke of 19 September 1985, where external bracing was popular, because it instilled a feeling of confidence in the occupants that significant and visible changes have been made to the structure to make it safer. Cost vs importance of the structure is a significant factor, especially in the case that the building is of cultural and/or historical interest. The available workmanship and t