Local seismic cultures: The use of Timber Frame Structures in the South of Portugal

Abstract

The well-known timber frame Pombalino construction system was devised after the 1755 Lisbon earthquake by the Portuguese government and its use was mandatory for the complex reconstruction process carried out in the city. It can be considered as the first technical regulation regarding seismic resistance. However, its use was not limited to Lisbon and the system was also embraced by local communities, which adopted it as a model of earthquake resistant construction. Its use thus spread around the country and eventually took root in the vernacular way of building of the country, becoming part of the Portuguese Local Seismic Culture. Nowadays, frontal walls can be identified in many vernacular constructions scattered across the country. This paper studies the use of frontal walls in vernacular buildings in the South of Portugal, which is the area with highest seismic activity within the country, focusing on the city of Vila Real de Santo António, which was chosen as the main case study. The paper also discusses the possible negative effects of the abandonment of this distinctive technique resulting from the Portuguese Seismic Culture on the overall vulnerability of vernacular constructions.