## 1 Introduction  
The rapid growth in global construction and urbanization has led to a substantial increase in sand consumption in recent years [1]. Astonishingly, estimates reveal annual global consumption ranging from 32 to 50 billion tons of sand [2]. This soaring demand has triggered a depletion of sand resources, accompanied by severe environmental challenges like landslides, earthquakes, and island erosion. A recent study highlights the threefold increase in sand costs in India since 2007 [3]. Consequently, several nations are actively seeking alternative materials to alleviate natural sand dependence. In this context, the adoption of dune sand (DS) emerges as a viable strategy, offering suitable material for this endeavor. The use of DS as a partial replacement for traditional construction sand can yield concrete specific to engineering applications. This approach not only reduces engineering expenses but also safeguards the local environment, fostering the rational development and utilization of natural resources. Prudent utilization of desert resources can ease the pressures of river sand supply and demand while fully harnessing local desert resources. Furthermore, projecting ahead, the utilization of DS holds the potential to be more cost-effective and competitive than the reliance on river sand. In recent decades, a substantial amount of experimental research has focused on the mechanical properties of DS concrete [4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19]. These studies consistently demonstrate that DS concrete, compared to ordinary concrete, exhibits lower compressive strength, tensile strength, and elastic modulus. These are attributed to the smaller size, smoother texture, and suboptimal grading of DS particles, predominantly composed of ultrafine and uniform particles. Extensive exploration into the workability of DS concrete reveals that incorporating DS as a partial substitute for fine aggregate enhances workability [4; 6; 7; 8; 10; 11; 14; 20], with the majority of researchers reporting favorable conclusions. In contrast, the exploration of structural components made from DS concrete remains limited. The mechanical characteristics of concrete-filled steel tubular (CFST) stub columns using DS concrete were investigated by [PERSON] et al. [21] and [PERSON] et al. [22], which indicated no negative impacts on mechanical performance. [PERSON] et al. [23; 24] examined the shear and flexural behavior of reinforced concrete beams with DS concrete, finding minimal impact on failure modes. [PERSON] and [PERSON] [25] assessed the strength and cyclic behavior of DS-reinforced concrete (DS-RC) columns, demonstrating stable performance up to 60% replacement ratios. [PERSON] et al. [26] also investigated the seismic performance of DS concrete beam-column joints, concluding that DS replacement ratio did not significantly affect failure modes or stiffness degradation. [PERSON] et al. [27] studied the shear behavior of DS-RC deep beams, noting improvements in load capacity and ductility at a 30% replacement level, although a 50% replacement level resulted in reduced load capacity and ductility. Concrete-filled steel tubes (CFSTs) are known for their exceptional structural performance due to the effective interaction between the steel tube and the infilled concrete, fostering robust composite action. This makes them highly applicable to various engineering applications [28; 29]. Recent studies have focused on the axial load-bearing capacity and the effects of confinement on CFST columns, particularly CFST stub columns, to determine their ultimate load-bearing capacity. These studies often explore local buckling in the steel tube and concrete failure under compression [30; 31]. In axial compression, the concrete infill can delay or prevent steel tube buckling, and the steel tube's confinement significantly enhances concrete's mechanical properties.