Load Capacity, Stiffness and Dissipation Energy of L-Shape Joints with Material Variation

Structural Behaviors, Bridle/Knee Joints, Cyclic Load, Hysteretic Loops.

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March 30, 2026
April 6, 2026

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Joints structure are the weak points of all structural system. The limited length of structural elements in frame, truss and other structural systems requires a joint system during construction. Furthermore, the joint system must be strong, rigid, and have sufficient energy dissipation resist to reverse loads. Wood, steel, and concrete are common construction materials used for building, bridges, and other civil engineering applications. Joint of structural systems need to be tested and analysis to determine their load capacities, especially cyclic loads such as earthquake and wind loads. This research aims to compare several load capacities, stiffness, and energy dissipation from the testing of bridle or knee joints made of wood, steel and concrete. The wooden bridle joint test specimens were made from the type of wooden which is a type of softwood (Gmalina arborea). The test specimens were formed from a pair of beams with dimensions of 70x140x800 mm that were connected using bolts, nails, screws, and wooden pins as initial specimens. The retrofitting specimen used was a strip plate with dimensions of 60.4 and a length of 300 mm on each of its side edges. Meanwhile, the test object knee joint made of steel from previous research consists of tubular steel 300.300.6.9 with a length of 850 mm each. The concrete knee joints are in the form of beams with dimensions of 200x400 and a length of 1550 mm, with reinforcement of 4Ø25 (As) and 2Ø25 (As’) as well as shear reinforcement Ø10-100, and column elements with a cross-section of 300x700 and a length of 2700 mm, with longitudinal reinforcement of 6Ø20 (Ast) and 4Ø12 (intermediate) and shear reinforcement Ø12-80. Testing was conducted in two directions of loading (opened and to closed) until maximum loads and deflections values were obtained. The results obtained from the tests were then compared for strength, stiffness, and energy dissipation. The experimental test results show that the maximum load of the concrete joint has the highest value followed by the steel and wooden joints. This means it is proportional to its strength and stiffness. Stiffness in to opened and to closed load directions shows that the concrete joint has the highest value, about 8 times greater than the steel joint, while the steel joint has a stiffness 4 times greater than the wooden joint. The energy dissipation value of the steel joint about 2 and 4 times greater than the wooden joint the concrete joint. The maximum deflection value after testing shows that the wooden joint has the highest value followed by the steel and concrete joints.