Analysis of a combined structural plus thermal retrofitting
SPEctRUM project funded by Marie Skłodowska-Curie Actions.
This project has been inspired by the always more demanding need to upgrade the existing masonry EU buildings due to their poor performance during earthquakes which has resulted in severe human and economic losses and their low energy performance which significantly increases their energy consumption. The issue of upgrading the unreinforced masonry (URM) buildings is of a great priority since they are unengineered vernacular structures and far from the levels of the current standards for seismic capacity and energy consumption. Moreover, the latter combined with deterioration due to ageing of materials, environmental degradation, the experience of several earthquakes and lack of maintenance, yield to an even higher vulnerability and energy deficiency. Every recent moderate to high seismic shaking has caused damage ranging from cracks to partial or total collapse with a high death toll and economic loss. Therefore, this project aimed to confront both deficiencies in one solution developing innovative techniques. This project was complementary with the work of the JRC exploratory project iResist+ which focused on the upgrading of RC old buildings, and in line with the relevant EU regulations for energy savings of buildings and protection of cultural heritage.
A simultaneous seismic and energy retrofitting of the masonry building stock can be realised by integrating advanced strengthing and insulating materials. In masonry buildings, however, there are some more requirements for the set targets of the retrofitting apart from the structural and energy performance related to their traditional nature; these can be summarised in the reversibility and compatibility of the strengthening materials. Moreover, cost-effectiveness remains an important aspect which should be added to them.SPEctRUM proposed a hybrid structural-plus-energy retrofitting solution which combines inorganic textile-based composites with thermal insulation systems for masonry building envelopes to meet all the aforementioned requirements. The use of natural materials, including lime mortars and natural fibers has been investigated and found that can increase the structural capacity significantly. Analytical models and design solutions were developed to facilitate the investigation and the application of the proposed system. Parametric analyses showed that the capacity can be increased substantially with the use of various strength textiles. The cost-efficiency of the combined retrofitting system has been explored in a large-scale investigation across Europe and short payoff times have been found especially in regions of moderate to high seismicity as those in the Mediterranean region.