Seismic Retrofit of Adobe Constructions: Fid-Bau Portal

Seismic Retrofit of Adobe Constructions

Vargas-Neumann, Julio / Oliveira, Cristina / Silveira, Dora / Varum, Humberto

Abstract Earthen construction has been widely used since ancient times. Currently, this type of construction is used by approximately one third of the world population. In comparison to other, more modern building materials, such as brick masonry, reinforced concrete, and steel, earth is costless and primarily accessible. For these reasons, it is massively used by no-income or low-income families, in developing countries and in communities where the mentioned industrial materials were never incorporated, frequently without adequate attention being paid to structural safety and reinforcement issues. Moreover, buildings are generally constructed and rehabilitated by non-specialized staff, with empirical knowledge passed through generations, lacking information and understanding of their structural behaviour. The seismic behaviour of earthen structures is typically characterized by fragile and sudden failure, because earth is a brittle material with very low tensile strength. Thus, earthen constructions and, in particular, adobe constructions, if not adequately designed and strengthened may perform very poorly when subjected to seismic loads. There are, in fact, various examples of recent earthquakes that caused severe damage to earthen buildings. The study of the structural behaviour of earthen constructions and the development of effective strengthening solutions are fundamental. In the present chapter, an introduction to earthen construction, including a brief description of its use throughout the world and main vulnerabilities, is presented. The structural behaviour of adobe construction is explained, in particular when subjected to seismic demands. Different repair and strengthening solutions are presented, together with various experimental studies conducted by different authors. A short review of the existing standards and codes that address the seismic design of earthen buildings is also presented. Finally, a brief reference is made to the numerical modelling of adobe construction.