Seismic reinforcement of adobe houses using external polymer mesh

The tragic Bam 2003 earthquake was a cruel reminder that earthen houses are highly vulnerable and that millions of people who live in adobe houses in the most seismic areas of the world are at great risk. It is urgent therefore to find simple and economic ways to reinforce adobe houses. This paper summarizes a research project developed to explore the use of plastic meshes as reinforcement for adobe structures. Three full-scale adobe house modules were tested on the shaking table of the Catholic University of Peru. The first module was unreinforced and represented a typical adobe dwelling. Its behavior under strong shaking was quite poor, with brittle failure of the walls. The second module was overreinforced by completely wrapping all walls with a polymer mesh. During the dynamic tests the module moved practically as a rigid body, with little damage on the adobe walls and a sliding failure of the walls on their concrete foundation. The third module had a more sparse reinforcement consisting of bands of polymer mesh placed at selected locations. Its seismic behavior was quite good, because although the walls were damaged, the reinforcement bands were able to hold the pieces together and collapse was therefore averted. These results show that it is possible to use plastic mesh as a convenient seismic reinforcement of adobe houses. The next steps will be to optimize the reinforcement design and to develop guidelines for the retrofit of existing houses and the design and construction of new seismic resistant adobe houses.