Seismic performance of stabilised/unstabilised rammed earth walls

Abstract

This experimental study investigates the in-plane seismic performance of unstabilised/stabilised rammed earth (RE) walls. The experimental program consists of five specimens including three unstabilised and two stabilised walls. All walls are 1000mm long, 900mm tall and 200mm thick. To simulate earthquake forces at the presence of gravity loads, the walls are subjected to an in-plane cyclic loading reversal combined with a constant vertical pre-compression stress. The experimental parameters comprise pre-compression stress (0.1, 0.3 and 0.5 MPa) and stabiliser type (lime and cement). The outcomes are compared in terms of failure mode, hysteretic response, ductility, energy dissipation, stiffness degradation, residual deformation and damage index. Further discussion is also provided by evaluating the envelope curves of the hysteretic load–displacement responses implementing a capacity spectrum approach. It is indicated that the level of vertical stress affects the hysteretic response of the walls with higher levels producing more favourable responses. However, increased vertical stress is caused by the greater gravity loads which in turn intensify the seismic induced forces that may dominate the seismic response of the walls. In addition, the effect of stabilisation process is highly dependent on the stabiliser type.