Experimental study on the structural performance of full-scale tyre wall for residential housing applications

Abstract

End-of-life (EOL) tyres infilled with compacted soil can form segmental tyre-encased-soil elements (TESEs) with considerable load-bearing capacity. The TESEs can be laid course by course in a staggered manner similar to masonry walls to build a load-bearing structure, namely tyre walls. Tyre walls, commonly used in Earthship housing constructions, proved to offer numerous environmental and economic benefits as EOL tyres are effectively upcycled and soil is a widely available and environmentally friendly construction material. However, these walls have been designed based on experience, and there are no certified design guidelines or code provisions available for such systems. Insufficient understanding of the structural performance of tyre walls restrict further applications. This study investigated the structural performance of a tyre wall by conducting experimental tests on a large-scale model. Both axial and horizontal loads were applied. The wall was loaded axially to simulate the roof load before it was subjected to incrementally increasing cyclic out-of-plane load applied at the wall’s mid-height. The wall’s hysteresis load–displacement response and other key behavioural parameters were studied. The influence of vertical compressive load on the wall’s out-of-plane capacity was also investigated. Results revealed that the tyre wall has a linear elastic vertical compressive load–displacement response, and an inelastic out-of-plane load–displacement performance. The out-of-plane failure of the tyre wall was characterized by a joint rotation opening mechanism at the wall’s mid-height. “Fat” force–displacement hysteresis curve indicated the tyre wall could perform well in the case of seismic events. The increment of the vertical compressive load had small impact on the tyre wall’s out-of-plane performance. Analytical approaches based on the stability of the wall were proposed for calculating the out-of-plane resistance and the results agreed reasonably well with the observed experimental results. This research concluded that tyre walls can be used as structural members for residential housing constructions.