Investigating the effect of vertical load on the behavior of adobe walls under cyclic lateral loading

Adobe constructions are considered vulnerable subjected to lateral loading so that their failure in the past earthquakes has caused severe casualties and structural damages. Nonetheless, numerous adobe buildings are still being used in seismic-prone regions worldwide, including Iran, many which are of historical background. Therefore, evaluation of their lateral behavior and retrofitting stands of high priority and can lead to preserving these national assets. In this study, the cyclic lateral behavior of adobe walls made of adobe units and mud mortar was investigated under different constant axial load. The experimental specimens were comprised of four adobe wall panels measuring 1000 mm in length, 900 mm in height, and 200 mm in thickness. The main experimental parameter was the magnitude of axial compression applied on the wall. The experimental results were compared in terms of load-displacement hysteretic curves, cracking pattern, failure mode, stiffness degradation, cumulative energy dissipation, and hysteretic damping. With increasing axial stress from 0.1 to 0.7 MPa, the failure mode was changed from shear to shear-compression. Also, due to increased axial stress, lateral resistance increased, but the corresponding displacement decreased.