Experimental and Numerical Studies on the Stiffening of Tubular T-joint of Offshore Jacket Structures

Present study investigates the stiffening effect on the behavior of tubular T-joints in offshore platform jacket structures subjected to axial compression. Stiffening is crucial to enhance the structures' strength and lifetime. Tubular cross section structures are preferred due to their mechanical properties and cost-efficiency. The study introduces an innovative technique by adding stiffeners at the interface between braces and chords to effectively distribute loads from multiple directions. The T-joint specimen used has specific dimensions: Chord length 400 mm, brace length 200 mm, chord diameter 100 mm, brace diameter 50 mm, chord thickness 4 mm, and brace thickness 3 mm. Experimental tests and Numerical simulations were conducted to measure failure loads for both stiffened and unstiffened T-joints. Stiffened configurations (4, 6, and 8 strips) has a notable impact on the ultimate capacity of the T-joint, showcasing an increase in strength compared to the unstiffened joint. Stiffened joints showed a significant increase in ultimate strength compared to unstiffened joints, with improvements ranging from 67.18 to 73.33% for different stiffener configurations. Joint local stiffness also improved substantially, with percentage increases ranging from 67.03 to 140.80% for various stiffener configurations. Present research work demonstrates the positive impact of stiffeners on tubular T-joints, improving their strength and stiffness while showing strong agreement between numerical simulations and experimental results and the study also concludes that the addition of stiffeners effectively enhances the ultimate capacity and local stiffness of tubular T-joints. These findings emphasize the effectiveness of the proposed reinforcement strategies for optimizing tubular T-joints in offshore structures.