Eccentric compression behavior of desert sand concrete columns: Experimental and numerical investigation

Desert sand concrete (DSC) has emerged as a sustainable alternative to river-sand concrete. However, the performance of DSC column under eccentric compression has not been fully explored. Therefore, experimental and numerical investigations of 17 reinforced DSC columns were conducted under eccentric loading. The desert sand replacement ratio (DSRR) (0%, 20%, 40%, 60%, 80%), longitudinal reinforcement ratio(ρₛ) (0.98%, 1.29%, 1.63%), and eccentricity ratio(e0/h) (0.2, 0.4, 0.6) were analyzed. Meanwhile, load-displacement behavior, strain response, lateral deflection, and ultimate load capacity were evaluated. Test results show that, the failure modes of DSC columns were similar to RC columns, classified as small- and large-eccentricity failures. The specimens with DSRR of 40% and 60% had the optimal performance, with peak loads increased by 16.11% and 6.99% compared with the specimen with DSRR of 0%. When the ρₛ increased from 0.98% to 1.29% and 1.63%, the peak load increased by approximately 2.4% and 12.7% respectively. When the e0/h increased from 0.2 to 0.4 and 0.6, the peak load decreased by approximately 64.8% and 72.2% respectively. A validated FEM was used to assess the effects of stirrup spacing, height-to-width ratio, and slenderness ratio on DSC columns under eccentric compression. Ultimate loads according to GB 50010 and ACI 318 were compared with experimental load. Based on the GB 50010, an improved predictive formula was proposed and validated, providing a practical basis for designing DSC columns under eccentric loading.