Abstract

A research collaboration between the Department of Architecture of the Universidad de Chile and the Department of Architecture of University of Florence (Italy) was carried out on the Church of San Francisco in Santiago, Chile, the oldest building of the city. This research is included in the research project 'Rediscovering Vernacular Earthquake-resistant Knowledge: Identification and analysis of built best practice in Chilean masonry architectural heritage' (2013-2016), funded by the Chilean National Fund for Scientific and Technological Development, FONDECYT. The Church of San Francisco is located in the historic centre of Santiago, just on the main street, being an architectural and urban symbol of the city. The important historical and heritage values make the religious complex –the church together with its convent- a Historic Monument protected by the Chilean Law of Monuments since 1951. The Monument is also included in the ‘Tentative list’ to be presented to the UNESCO because of its Outstanding Universal Value. However there is a value that has not been recognized yet: the earthquake-resistant behavior of the building, considering that it is 400 years old and it faced tens earthquakes that have hit the city of Santiago. The church of San Francisco was built in stone masonry in1586 by a cross-shaped plan. The religious complex was the only survived building in Santiago during the 1647 earthquake, the most destructive of the Colonial period. After that, the building also withstood the earthquakes of 1730 and 1751, which produced significant damages in the city. At the end of the XVIII century, two side aisles in brick masonry were built and one hundred years after, a wooden tower was incorporated. These constructive addictions changed the morphology and the structural performances of the church; despite that, the building exhibited only local structural damages after the numerous following earthquakes. This paper presents an historical, constructive and structural analysis of the church of San Francisco, in order to assess dynamic behavior and seismic vulnerability, both in its original shape and in its current state. The aim of this analysis is to discover the characteristics that are the basis of good mechanical behavior of the church in such a seismic context as Chile