Seismic Performance of 3D-Printed Concrete Structures: A Comprehensive Review of Material Behaviour, Geometry, and Optimization

The convergence of additive manufacturing and earthquake engineering is rapidly redefining the design and construction of resilient infrastructure. This review presents a comprehensive synthesis of the current state of knowledge on the seismic performance of 3D-Printed Concrete (3DPC) structures, with a particular emphasis on the role of shape optimization. 3DPC introduces unique opportunities for geometric freedom, material efficiency, and construction automation, but also poses critical challenges related to anisotropy, interlayer bonding, and reinforcement integration under dynamic loading conditions. The review classifies 3DPC structure behaviour in terms of key performance indicators, such as ductility, damping, stiffness, and energy dissipation, to examine experimental results and modelling strategies that can describe the anisotropic and interface-driven behaviour of 3DPC structures. Shape optimization is also investigated as a designing transformational technology development on the basis of computational optimization, using computational techniques, topology optimization, gradient-based approaches, and AI-based structures to operate seismic resilience and reduce material consumption. Optimized walls, shells, and lattice columns case studies illustrate high returns on the resistance against lateral loads, energy dissipation, and tuning to a frequency. Multiscale modelling and hybrid simulation, as well as machine learning-based optimization, are emerging fields of research recognized to be unique in closing the gap between material behaviour and structural performance. More so, the integration of intelligent materials with embedded sensors makes this technology more likely to be on the path of creating intelligent, adaptive 3DPC systems, which can supervise the status of the system in real time, as seismic events happen to it. Despite its encouraging nature, there are severe issues on the front of the field in the form of the lack of standards in terms of testing procedures, the limited full-scale validation, and the lack of characterization of the reinforcement functionality. This review identifies these deficiencies and offers research directions for future work, aiming to develop a single, scenario-free, performance-based design for 3DPC seismic applications. The final product of this work will assist the basic knowledge base required to advance 3DPC out of the laboratory-based innovation to working seismic infrastructure.