This study integrates Isogeometric Analysis (IGA) with upper-bound limit analysis to evaluate the load-bearing capacity of strip footings situated on a clay layer over sand. Employing B-spline basis functions facilitates the precise modeling of soil domain geometry. The upper-bound limit analysis is formulated as a second-order cone programming (SOCP) problem, which is subsequently solved using advanced numerical optimization techniques. To ensure robustness, the results are benchmarked against Finite Element Limit Analysis (FELA) conducted through Optum CE software. The research investigates several critical design factors, including layer depth, surcharge effects, cohesion ratio, unit weight of soil, internal friction angle, and footing roughness. Findings demonstrate the accuracy and computational efficiency of this approach, establishing its practicality for real-world engineering scenarios. Additionally, this study paves the way for further explorations into load-bearing capacities and potential applications in more complex soil-structure systems.