Structural Assessment and Seismic Retrofitting of Existing Adobe Constructions

Earth is one of the oldest building materials, having been used throughout the world since ancient times until the present day (Houben and Guillaud 1994). Nowadays, a significant percentage of the world population still lives in earthen buildings (Minke 2012). There is also a vast earthen built heritage, with many examples inscribed in UNESCO's World Heritage List (Gandreau and Delboy 2012). In Portugal, adobe, which is one of the most common earthen building techniques, was very used until the mid-twentieth century. At present, there are still many adobe buildings in use, some of which with great cultural and architectural value (Silveira et al. 2013, Oliveira et al. 2013). Earthen constructions have many advantages, such as low cost and reduced environmental impact (Morton et al. 2005, Shukla et al. 2009). However, these constructions, if not effectively designed and strengthened, may perform very poorly when subjected to seismic loads, as has been observed in recent earthquakes (Blondet 2008, Elnashai et al. 2010, Gautam et al. 2016). Knowledge on the mechanical properties and structural behaviour of these constructions is thus fundamental to support their adequate rehabilitation and strengthening. In order to contribute to this knowledge, research on the existing adobe constructions in Aveiro district, Portugal, has been developed in the last decade. A brief overview of some of the studies carried out is presented in the following sections