CASE-INFORMED FINITE ELEMENT ANALYSIS OF ALTERNATIVE STEEL STOPLOG GATE CONFIGURATIONS

Introduction: Steel stoplog gates are used to temporarily isolate water-conveyance channels in hydraulic and wastewater treatment facilities. Field inspections of damaged gate systems show that geometrically similar panels may exhibit fundamentally different deformation and failure patterns. This study evaluates how the load-bearing configuration affects the structural response of steel stoplog gates and uses field-observed damage to guide interpretation of numerical results. Methods: Two three-dimensional finite element models representing alternative reinforcement configurations of a steel stoplog panel were compared. The first configuration incorporated a spatial frame formed by structural profiles, whereas the second used a cellular arrangement of plate ribs. Identical boundary conditions and a normalized triangular hydrostatic pressure distribution of 1 kPa were applied to both models. Maximum displacement and equivalent stress fields were evaluated, and zones of local stress concentration were compared with damage locations identified during field inspection. Results: The frame-reinforced configuration exhibited a maximum displacement of 5.03 mm, whereas the plate-rib configuration reached 237.71 mm. The displacement ratio between the two structural systems was approximately 47.3. The less rigid configuration also demonstrated pronounced numerical stress peaks at load-transfer zones and weld termination regions. These locations corresponded qualitatively to areas of panel deformation and connection damage observed in the inspected structures. Conclusions: The reinforcement layout has a decisive influence on stoplog gate stiffness and load-transfer mechanisms. Field-informed finite element modelling is an effective comparative tool for identifying structurally vulnerable configurations and supporting the redesign of hydraulic gate equipment.

Keywords: steel stoplog gate; finite element modelling; field inspection; structural stiffness; load transfer; welded connection; stress concentration; hydraulic equipment