Effect of strain hardening material on seismic performance of 3D printed concrete wall: a numerical study

3D concrete printing (3DCP) is an innovative additive manufacturing technique. To enable this emerging technology for large-scale structural applications under complex loading conditions such as cyclic loading, reinforcement is necessary but the incorporation of reinforcement into 3DCP is challenging, since provided reinforcement should be compatible with layer-by-layer construction. In this context fibers are the first choice of researchers to provide as reinforcement but their applications are limited to nonstructural component with an ulti-mate strain of 2-3%. Strain-hardening concrete which enhances the material's ability to deform gradually under stress, ensuring safety, and adaptability in diverse loading scenarios for large scale applications, offer one possible solution to this challenge. This study explores the utilization of strain-hardening concrete to improve the strength and seismic performance of 3DCP lattice walls. Material characterization and finite element analysis (FEA) are conducted, considering detailed input parameters derived from experimentation, such as stiffness coeffi-cient and interlayer parameters, to accurately replicate 3DCP behavior. Compo-site micro-modelling, employing the cohesive zone model and concrete damage plasticity model, is adopted to analyze load-bearing 3DCP walls under quasi-static cyclic in-plane loading. The resistance of 3DCP lattice walls is examined using shear and flexure specimens with specific aspect ratios of one and two, respectively. Effects of different material properties such as mortar, concrete and fiber reinforced strain hardening concrete are studied using the developed model based on the failure pattern of specimens. A validation study to evaluate the per-formance of the proposed model is also carried out, and found out that the pro-posed model is well capturing the pinching effect in hysteretic curve. It is con-cluded that the effectiveness of strain hardening material even with a minimal 0.5% steel fiber dosage and 15% coarse aggregate, the ultimate strain exceeds 3% and increases the cyclic lateral strength of 3DCP lattice wall including de-formation capacity, promising resilient structural applications in 3DCP.