Adobe in Sardinia. Static and dynamic behaviour of the earthen material and of adobe constructions

In the last years, in Western countries there has been an increasing interest in adobe constructions, especially for sustainability and comfort reasons. Also, some billion people live in earth houses all over the world, also in seismic areas. Since in some plain areas of South Sardinia (Italy) earth constructions are widespread, the Sardinian Government has funded a scientific research on their static and dynamic behav-iour, which is described in this article. The behaviour of the earthen material reinforced with straw and other natural fibres was initially studied. For this aim, the fracture behaviour of notched earth specimens reinforced with natural fibres was investigated through static and dynamic three-point bending tests. The mechanical properties of earth bricks were then experimentally investigated by carrying out numerous compressive and flexural tests. Mean and characteristic values of compressive and flexural strength were evaluated. Since in structural design the behaviour in tension of the earth masonry is to be assumed as elastic-perfectly brittle, a constitutive stress-strain relationship for compression only was defined by processing the experimental data. Moreover, the behaviour of adobe panels (actually numerically studied by finite elements) will be experimentally investigated later for comparison by carrying on the research. Besides earthen material, bricks and panels, also earth constructions were studied by first comparing the behaviour of simple adobe buildings and traditional masonry buildings with same geometry. The Equivalent Frame method was used. The problem of how to model an adobe building using the Equivalent Frame method was also studied by retrieving from the literature the results of the tests on the shaking table of a simple adobe construction, and by then comparing them with those obtained from modelling the seismic behaviour of the adobe construction through the Equivalent Frame method.