Hydraulic and Structural Numerical Assessment of a Smart Rubber and Steel Movable Weir for Selective Gate Operation

Conventional full-span movable weirs may require complete lowering for sediment or debris release, reducing upstream water-level control and limiting operational efficiency. This study evaluates a smart rubber and steel (SRS) movable weir that enables selective gate operation through a one-way coupled hydraulic–structural framework using the Environmental Fluid Dynamics Code (EFDC) and MIDAS Civil. Four gate-operation scenarios and gate heights of 0.5, 1.0, 1.5, and 2.0 m were analyzed to characterize flow redistribution, hydraulic loading, gate response, longitudinal-rib performance, and the safety of anchor bolts, clamping plates, and the airbag system. Selective lowering substantially altered flow distribution, with side-gate lowering producing the most critical condition and increasing maximum velocity by approximately 267% relative to the fully raised condition at a 2.0 m gate height. Hydraulic demand became strongly localized near the lowered and adjacent raised spans, although the governing static load remained dominated by hydrostatic loading. Rib comparisons showed that redistributing stiffness through additional longitudinal stiffeners reduced stress and deformation without relying solely on gate thickening, while all component-level static checks satisfied the adopted safety criteria. The results demonstrate that integrating span-specific hydraulic redistribution with structural response provides a practical basis for structurally safe and material-efficient river-infrastructure design.