Rammed earth construction for sustainable and seismic-resilient buildings: structural advances and constraints methods

Rammed earth construction, known for its sustainability and aesthetic appeal, has traditionally faced limitations in terms of seismic performance owing to the inherent properties of the material. This study addresses these limitations by investigating the seismic behavior of rammed earth walls enhanced with different structural constraints and material compositions. Nine test models, all of the same size but produced using distinct construction techniques and material mixes (Mixes 1 and 2), were categorized into three series: unconstrained rammed earth walls (W1-1 to W1-3), reinforced concrete frame-constrained walls (W2-1 to W2-3), and steel frame-constrained walls (W3-1 to W3-3). Low-cycle repeated loading tests were conducted to evaluate the structural responses. The results showed that the reinforced concrete and steel frame constraints significantly improved the load-bearing capacity and deformation resistance of the walls. The unconstrained walls exhibited a minimum cracking load and ultimate load of 245 and 382 kN, respectively. In contrast, the reinforced concrete frame-constrained walls achieved superior performance, with a minimum cracking load and ultimate load of 400 and 597 kN, respectively. The steel frame-constrained walls displayed intermediate results, with a minimum cracking load of 338 kN and an ultimate load of 554 kN. Additionally, the specimens using Mix 2 (W1-3, W2-3, and W3-3) demonstrated the highest energy dissipation. These findings provide valuable insights for designing earthquake-resistant rammed-earth wall systems, highlighting the crucial role of structural constraints and material composition in enhancing seismic resilience.