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Preservation of historic reinforced concrete housing buildings across Europe

Final Activity Report Summary - CA REDIVIVUS (Preservation of historic reinforced concrete housing buildings across Europe)

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 in comparison to 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 occurring from the necessity to bring these buildings to a corresponding safety standard as well. Pre-code reinforced concrete frame buildings are highly vulnerable to earthquake damage 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 such as those from the first half of the 20th century, is rare. From this point of view it contributes substantially to the advancement in the state of the art in conservation of the avant-garde buildings that are exposed to seismic risk.

Employing methods dedicated to interventions on existing buildings goes across the point of view of several disciplines, from which the retrofit is regarded. Based on the building value from a historical and architectural point of view the amount of allowed interventions can be specified. The necessary intervention extent is determined, on the other hand, by structural parameters. The optimal method to identify it is based on structural assessment techniques. This concerns both the concepts, e.g. performance based retrofit, and tools, such as software for building assessment, that are used. Both the view on historical pre-code reinforced concrete buildings and the view on historical condominium housing are novel. To solve problems concerning the first aspect technical solutions are required, while management solutions come in question to solve problems regarding the second aspect. Technical issues refer to retrofit measures optimisation. Furthermore, social issues concern the comprehensibility of the justification for the applied measures, in order to get user support for the retrofit strategy implementation, which is of vital importance in the case of condominium buildings.

The CA REDIVIVUS project was an interdisciplinary endeavour encompassing concrete technology, building design and urban sociology. The project results referred on how to reduce earthquake vulnerability of multiple housing constructions with reinforced concrete structure of the modern movement, with their physical, social and cultural characteristics. The modularisation of a collaborative decision model was of importance, with modules customised for each actor involved in the retrofit measure, namely the engineer, architect, investor and inhabitant. The modularisation was achieved through taking into account a suitable method for non-measurable criteria, such as cultural value and architecture social issues. Perception was also taken into consideration. Documentation regarding the distribution and regional characteristics of buildings that constituted the study objective in Europe was also produced as part of the project. This information was not available prior to this project initiation.

The emphasis laid on Romania, Greece, Italy and Portugal. The reasons for the targeted buildings being that vulnerable were analysed, 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 was developed, taking into consideration the actors' criteria. The best suitable retrofit method proved to be fibre reinforced polymer wrapping. In summary, the project reached its ambitious objectives via the analysis and concrete measures for buildings' conservation.