Millions of people across the world live in earth constructions. Adobe buildings which are made of un-burned sun-dried bricks realized with a mix of clay, sand, water and (occasionally) organic fibres are a common type of earth construction. The wide spread use of adobe buildings is due to both their low cost and facility of construction and also due to their excellent thermal and acoustic properties. However, this category of buildings has proven to be particularly vulnerable to the seismic action. The high vulnerability of this class of buildings to earthquakes can be attributed to their heavy weight, insufficient continuity in the walls, insufficient roof-to-wall anchorage, and degrading material properties due to extreme environmental conditions. This results normally in a brittle loss of load-bearing capacity in the form of out-of-plane wall failure, roof loss of support, and in plane wall failure.

Typically, these structures are one-storey with a rectangular plan. The roof is made up of wood beams using corrugated iron, tiles or dry vegetation as the secondary cover material. From the structural point of view, vertical panels -characterized as masonry walls- and horizontal panels -characterized as spandrel beams- can be identified as vertical and lateral load-resistant elements.

This paper has the objective of evaluating various easy-to-implement upgrading solutions based on both performance-based criteria and also based on life cycle cost considerations. As a preliminary effort, analytic (linear and non-linear) structural modelling tools are employed in order to investigate the suitability of various simple upgrading strategies. In particular, a generic one-storey adobe building is modelled based on the equivalent frame concept. This study takes into account the effects of degrading material properties due to extreme environmental conditions (e.g., high humidity, heavy rain) in increasing the seismic vulnerability. On the other hand, it is shown that decreasing the percentage of wall openings and optimal division of internal spaces using internal walls can reduce the seismic vulnerability of the adopted model. Moreover, the seismic vulnerability of the generic adobe structure is assessed by modelling upgrading strategies such as addition of a ring beam, bamboo vertical and horizontal braces, and wire meshes.