Final outcomes on the multi-disciplinary long-term monitoring and preservation state investigation on the medieval external Façades of Palazzo Ducale in Venice, Italy

The paper presents the results of the survey, research and monitoring activities carried out at Palazzo Ducale in Venice, Italy, between 2009 and 2013. A team of academic and technical personnel of the IUAV University designed and carried on the programme. The aim was to acquire knowledge and data to establish a clear picture of the preservation state of the two XIV-XV Century external façades (South and West). The size of the façades, their complex and uncertain consistency, as well as their long and complicated history dictated the choice of multi-disciplinary, integrated and nondestructive methodologies. In detail, the diagnostics consisted of static monitoring of cracks and rotation, dynamic monitoring along a critical vertical section, sonic wave velocity measurements, endoscopic probing and ground penetrating radar, infrared thermographic imaging and finally chemical analyses of stone samples. The results of the diagnostic procedures were supported by other information from visual and geometric surveys, bibliographic research and conventional calculations. The outcomes of the programme enlightened specific conclusions for each activity as well as crossing multi-disciplinary points of view; the latter are about the quality and consistency of the load-bearing masonry, the stress state in the façade walls and the potentially critical issues. Optimization of the then-available knowledge and programme results was definitely an objective and could finally be reached. The outcomes could update the scientific knowledge basis and support maintenance design for this unique and world-famous monument.