Practices

Combined seismic and energy upgrading of existing buildings using advanced materials

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Case studies on Reinforced Concrete Buildings in South Europe.

Of the current EU building stock, 80% was built before the 90's, while 40% are pre-60's and a considerable amount being even older and classified as cultural patrimony, thus requiring preservation techniques if we want to maintain this cultural heritage for our future generations. Upgrading the existing EU buildings and the cultural heritage ones is becoming increasingly important due to:

 

(1) their poor seismic performance during recent earthquakes (i.e. Italy, Greece) that have resulted in significant economic losses, severe injuries and loss of human lives;

(2) their low energy performance which increases significantly their energy consumption.

 

However replacing a big part of the existing buildings is prohibitively expensive or not allowed for historical heritage buildings and would have a significant societal and environmental impact, their lifetime extension requires considering both seismic and energy retrofitting.

 

The Exploratory research project iRESIST+ explores a novel concept, by applying a hybrid structural-plus-energy retrofitting solution which combines inorganic textile-based composites with thermal insulation systems for building envelopes. In this report, the iRESIST+ concept is examined through a number of case studies conducted on model buildings designed according to outdated regulations. Specifically, seismic and thermal analyses were conducted prior to and after the application of selected retrofitting schemes in order to quantify the positive effect that retrofitting could provide to RC buildings both in terms of their structural and energy performance.

 

Advanced materials, namely the so-called Textile Reinforced Mortar (TRM) was used for providing seismic retrofitting by means of TRM jacketing of the masonry infills around the RC frames. Moreover, following the application of the TRM jackets, thermal insulation materials were simultaneously provided to the RC building envelope, exploiting the fresh mortar used to bind the TRM jackets. In addition to the externally applied insulation material, all the fenestration elements (window and doors) were replaced with new high energy efficiency ones.

 

Afterwards, an economic measure, namely the Expected Annual Loss (EAL) was used to evaluate the efficiency of each retrofitting method, but also to assess whether the combined seismic and energy retrofitting is economically feasible. From the results of this preliminary study, it was concluded that the selected seismic retrofitting technique can indeed enhance significantly the structural behaviour of an existing RC building and lower its EAL related to earthquake risks. Finally, it was found that the combined seismic and energy upgrading is economically more efficient than a sole energy or seismic retrofitting scenarios for seismic areas of south Europe.