Small-Scale Physical Modeling of Reinforced Concrete Joints Using Additively Manufactured Reinforcement

Abstract

This paper discusses quasi-static cyclic tests conducted on 1:30-scale physical models of RC exterior and knee beam-column joints, with additively manufactured [three-dimensional (3D)-printed] reinforcement cages. These models can be used for centrifuge modeling of RC structures both to study soil–structure interaction problems and to validate system-level assumptions of numerical models used in earthquake engineering. A gypsum-based model concrete is used because at such small scales, it better replicates the tensile strength of prototype concrete and the bond between prototype concrete and reinforcement. Exterior and knee beam-column joint specimens were tested under different levels of axial loads. Comparisons are made between the results of these small-scale tests and full-scale tests that experienced the same failure mode (beam flexural failure). Additionally, numerical models are developed using the OpenSees platform, and their predictions are compared with experimental data. The findings indicate that the tested specimens behave very similarly to their full-scale counterparts. Moreover, the comparison between numerical models and experimental outcomes suggests that commonly employed numerical modeling methods for RC structures effectively predict the component-level behavior of the tested beam-column joints.