Empirical flexural behaviour approach of adobe masonry

Abstract

Adobe masonry is one of the most widespread low cost material used for housing in the world. Unfortunately, it shows very low mechanical strength and it is mainly used in seismic. Therefore, there is a requirement for sustainable and efficient reinforcement techniques, as well as design guidelines based on scientific research to apply them. It is necessary to build healthy and safe earthen houses, as well as to preserve earthen constructions heritage sites, which most of them are in danger of collapse. Polymeric geogrids have proven to be an efficient reinforcement technique. The dynamic response of geogrid reinforced adobe constructions has been analyzed in dynamic seismic simulation tests. When comparing with non reinforced constructions, they significantly increase the strength of the construction and reduce the danger of collapse under a seismic load. This paper presents an empirical approach for the assessment of the flexural behavior and flexural strength of adobe masonry, considering the effect of geogrid reinforcement. The approach is based on the analysis of experimental results of bending tests of adobe walls reinforced and non reinforced with geogrids. Analytical models for the flexural behavior were initially based on the constitutive laws of the individual materials. Then, they have been simplified and updated so they agree with experimental moment-curvature relationships. The analytical approach show that it is necessary to consider the tensile behavior of adobe in order to obtain a realistic moment-curvature relationship. However, in the ultimate state of the wall, tensile strength of adobe can be neglected, and the ultimate flexural strength of the wall is defined by the cracking of adobe under compression or the breakage of the geogrid under tension. The paper includes a simplified method for the assessment of the ultimate strength of adobe walls, based on similar methods used for reinforced concrete.