Comprehensive review of robotic wire arc additive manufacturing for steel structures: Process, material behaviour, structural applications and pathways to automated construction

As civil engineering advances toward next-generation construction, the integration of robotics, automation, and sustainable manufacturing is becoming increasingly critical. Robotic Wire Arc Additive Manufacturing (WAAM) provides a promising pathway through flexible deposition control and efficient material utilisation in steel structures. This review focuses on WAAM-fabricated steels and synthesises current developments in process, material behaviour, structural applications and future research directions. Relationships between WAAM parameters and deposition strategies are examined to clarify their influence on the performance of WAAM-fabricated steels. Reported material behaviours, including tensile, fatigue, corrosion, and high temperature behaviour, are systematically assessed. Structural applications relevant to direct fabrication, hybrid construction, and repair-related interventions are evaluated to illustrate practical pathways for WAAM in civil engineering. By linking WAAM process with both material and structural performance, this review establishes knowledge and guidance for advancing WAAM toward reliable and efficient adoption in both academic research and industrial practice within civil engineering.