Static and dynamic testing for validating the polymer grid as external reinforcement in earthen buildings

In 2004, the first static test using polymer grid as structural reinforcement for earthen walls was performed at the Structures Laboratory of the Pontifical Catholic University of Peru. In 2005 the first dynamic test using the same reinforcement showed excellent results in substantially reducing the seismic vulnerability of earthen buildings. Since then, more than 20 static tests and at least 12 earthquake simulation tests have been performed with different types of grid reinforcement, amount of reinforcement and architectural configurations to validate and perfecting the solution. In 2007 after a magnitude 8.0 earthquake caused extensive damage in adobe houses in the coast of Peru, this type of reinforcement was included in the national building code for earthen buildings. The extensive testing comprises out of plane flexural tests and in plane cyclic shear tests on adobe walls and shaking table tests on traditional adobe modules scaled at ¾ of its full size with four orthogonal walls and square layout plans with light timber roof. Masonry with normal sun dry adobe units bonded with soil mortar and masonry with compressed earth blocks dry stack have also been used for the walls in static and dynamic tests. In all cases, the polymer grid placed on both sides of the wall and connected through the wall provided enough strength and deformation capacity to overcome the natural weakness and fragility of this type of constructions. This paper shows a survey of the more relevant testing that support the use of the polymer grid as seismic reinforcement for earthen buildings in general.