Changes of dynamic properties in an ancient masonry building due to environmental conditions

The Emiliano Giñazú Museum of Argentina, which has a heritage of frescous and painting of Fernando Fader, presents a level of damage that has forced its temporary closure until rehabilitation works planned by 2016 are made. Among the work to be done, is to assess the level of damage that presents the structure of the museum and also the study of the efficiency of their rehabilitation when this is realized. These actions will be made with computer simulations, updated based on dynamic properties measured in the building. Estimates must then be made of the dynamic parameters at different times, so it is necessary to evaluate the influence of changing environmental conditions in determining these modal parameters. In the literature, there are few studies that indicate a clear trend on the influence of such factors; neither has it quantified its importance. Therefore, given the actions to be carried out at the museum, these study variations in frequencies in a sector of the museum, due to variations in temperature and humidity recorded in the same study for 120 days. The dynamic parameters were obtained from measurements of ambient vibrations, applying operational modal analysis technique. The results show a slight increase of the frequencies with temperature, and approximately zero influence of humidity. In the conclusions, the importance of the results obtained are highlighted.