Experimental Shear Behaviour of Rammed Earth Strengthened with a TRM-Based Compatible Technique

Abstract

Earthen constructions are spread worldwide, not only as architectural heritage but also as new buildings, in which a total of around one fourth of the global population is estimated to live in. Among the different raw earth techniques, rammed earth was widely used to build vernacular dwellings in different regions. Despite the raising awareness for the high seismic hazard, recognized seismic vulnerability and high seismic exposure associated with earthen structures, the reduction of their seismic risk has been a topic insufficiently addressed. In general, the seismic vulnerability of rammed earth structures is due to poor connections between structural elements (walls and floors), high self-weight and low strength of the material. Hence, a TRM-based strengthening technique is proposed to improve their seismic capacity. To estimate the enhancement of the in-plane performance achieved with the TRM, an experimental program was conducted. Rammed earth wallets were tested under diagonal compression considering their unstrengthened and strengthened condition. The TRM strengthening was performed by embedding a glass fibre mesh (GRE) or a nylon mesh (NRE) in a compatible earth-based mortar. In general, the proposed TRM-based strengthening seems to improve the shear behaviour of rammed earth by enhancing the shear strength and promoting stress distribution after cracking, while no significant influence on the shear modulus of rammed earth seems to occur.