Experimental analysis of the cyclic behavior of rammed earth walls reinforced with arundo donax natural fiber

This experimental study analyzes the seismic behavior of rammed earth walls with Arundo donax natural fiber inclusions, also called "caña brava” (REWC), and without inclusions (REW). The experimental program consists of two stages: physical and mechanical characterization of materials, where properties such as particle size, density, Atterberg limits, and compressive and flexural strength were determined; and dynamic tests, which included compressive and cyclic load tests on REW and REWC walls. The walls were subjected to cyclic loading with derivatives between 0.2 % and 1.4 % in-plane combined with a constant vertical compressive stress of 13 kPa to simulate seismic forces in the presence of gravity loads. The results regarding loading, hysteretic response, energy dissipation, stiffness degradation, and failure mode are compared. In addition, the envelope curves of the load-displacement hysteretic responses are analyzed using a capacity spectrum approach. It is observed that the inclusion of Arundo donax natural fiber negatively affects the mechanical properties of the walls and their hysteretic response. It is also observed that the energy dissipation is affected by the inclusion of Arundo donax natural fiber. However, the stiffness behavior is similar in all the walls. Rigid body failure modes are identified in all the walls, but the walls, including Arundo donax natural fiber, form failure planes that divide the wall into two bodies.