Preservation of historic reinforced concrete housing buildings across Europe

Publishable summary report

The planner of today cannot go out from a "tabula rasa" situation any more. Environmental and sustainability issues have already formed the public idea that a "green belt" of our cities is necessary, a kind of fortification leading to intensive development of towns inside a clearly delimitated area within the surrounding nature. Since building on the periphery is limited, and the existing built substance has a certain cultural, architectural or at least environmental value, upgrading of existing buildings gains more and more ground from the design of new buildings. While in the majority of cases this upgrading means bringing the buildings to the comfort required by changed living standards, earthquake prone countries face a particular challenge given by the necessity to bring them also to a corresponding safety standard. Pre-code reinforced concrete frame buildings are highly vulnerable to earthquake damage. high vulnerability is due to their high degree of occupation and low capacity. Structural research on concrete reinforced with steel in buildings of historical importance, like historic pre-code reinforced concrete buildings, namely those from the first half of the XXth century, is rare. From this point of view it contributes substantially to the advance in the state-of-the-art in the field of conservation of the Avant-Garde buildings exposed to seismic risk.

Employing methods dedicated for interventions on existing buildings goes across the points of view of several disciplines, from which the retrofit is regarded. Based on the building value from a historical-architectural point of view the amount of allowed interventions can be specified. The intervention amount needed is determined, on the other hand, by structural parameters. The dedicated method to determine it is based on structural assessment techniques. This concerns both the concepts (performance based retrofit) and tools (software for building assessment) used. New are the view on historical pre-code reinforced concrete buildings and also the view on historical condominium housing. To solve problems concerning the first aspect technical solutions are required, to solve problems concerning the second one management solutions come in question. Technical issues regard retrofit measures optimisation. Societal issues concern the comprehensibility of the reason for the measures, in order to get user support for the retrofit strategy implementation, of central importance in case of condominium buildings.

The CA'REDIVIVUS project is an interdisciplinary endeavour encompassing concrete technology, building design and urban sociology. The project results regard how to reduce earthquake vulnerability of multiple housing constructions with reinforced concrete structure of the Modern Movement, with their physical, social and cultural characteristics. Of importance is the modularisation of a collaborative decision model, with modules customised for each actor involved in the retrofit measure (engineer, architect, investor, inhabitant). The modularisation was achieved taking into account a method suitable for non-measurable criteria, as cultural value and architecture societal issues are. The perception was taken into consideration. The documentation on the distribution and regional characteristics of buildings constituting the object of the study in Europe, information lacking before, has been also done within the project. The emphasis laid on Romania, Greece, Italy and Portugal. This way it was analysed why the buildings subject of the study are that vulnerable, given the architectural and urban development conditions in which they were built. A concrete building was designed, according to these rules and a retrofit method for it developed, considering the actors' criteria. The best suitable retrofit method proved to be fibre reinforced polymer wrapping.

The project reached its ambitious objectives through the analysis and concrete measures for conservation of buildings.