Interface engineering in infilled RC joint: Structural impact of rubber and bitumen with varying thickness

Reinforced concrete (RC) frames infilled with brick masonry are widely used in construction due to their improved lateral resistance. However, their behavior under lateral loading is complex due to the interaction between the frame and the infill. Modifying the interface materials has shown potential in improving the overall performance under lateral loads. However, the influence of interface material type and thickness on structural response needs further exploration. Limited research exists on the effect of interface materials and their thicknesses on the non-linear behavior of infilled frames, particularly when using flexible materials. This study evaluates the static lateral performance of Y-joint with brick masonry infill using three interface materials—cement mortar, bitumen, and rubber—across varying thicknesses. The interaction is analyzed for displacement, stress concentration, and failure load in ABAQUS. Rubber interfaces increase displacement by 80–90% compared to cement mortar and bitumen interface, while bitumen interfaces show negligible variation in stiffness across different thicknesses. Rubber interface with 20 mm thickness reduces stress concentration by 34.3% compared to 5, 10, and 15 mm. Cement mortar presents bonding issues at increased thicknesses for 20 mm thick model, with maximum debonding of 58.9% was found. These findings demonstrate that selecting appropriate interface materials and thicknesses can significantly enhance structural resilience. ANN-based approaches can efficiently identify optimal configurations, reducing dependence on computational simulations. The regression (R) value among the training, testing and validation for all cases reaches above 0.9 for stress distribution, stiffness, and contact area.