Metamaterials Break the Constraints of Traditional Civil Infrastructure

Advanced materials are essential for enhancing the resilience, efficiency, and adaptability of civil infrastructure. Yet, the core materials used in civil infrastructure systems today have remained largely unchanged for nearly a century, with fixed properties that limit their ability to realize these capabilities. Mechanical metamaterials offer a path to overcome the inherent constraints of conventional civil infrastructure materials. This perspective explores how mechanical metamaterials can redefine the backbone of civil infrastructure systems at the material level by encoding function in geometry, thereby enabling programmable mechanics and advanced multifunctional responses. Their scope of influence spans buildings, transportation networks, underground structures, offshore platforms, and architectural or interior systems, where thousands of components currently designed with conventional materials can be reimagined using optimized metamaterial counterparts. A mechanical metamaterial approach to civil infrastructure design can enhance structural performance by improving strength-to-density ratios, expanding the design space beyond conventional Ashby plot limits, and supporting applications such as seismic isolation, vibration damping, and lightweight construction. The discussion underscores the potential of mechanical metamaterials to introduce advanced functionalities such as energy harvesting, sensing, and wireless communication within civil infrastructure systems. These capabilities, traditionally associated with electronic devices, can be incorporated directly into structural components to create infrastructure with higher autonomy and adaptability. Multimodal integration with electromagnetic and photonic metamaterials further extends these possibilities by allowing materials to exhibit intrinsic communication, stealth behavior, or visual responsiveness. The perspective concludes with a roadmap outlining key developments and challenges toward a more integrated and responsive metamaterial-driven infrastructure. Within this framework, structurally tuned construction metamaterials can sense their environment, process information, and communicate with surrounding systems, functioning as the brain, eyes, and skin of future civil infrastructure.