Design and fabrication of Hong Kong's first constructional 3D-printed metal pavilion 'Weaving Love'

'Weaving Love' is Hong Kong's first outdoor pavilion constructed using the constructional 3D metal printing through Wire Arc Additive Manufacturing (WAAM) technology, making a transformative milestone in the application of this emerging technology for large-scale construction in the region. This paper documents the entire process-from the concept and design to fabrication and construction-of the "Weaving Love" pavilion, a constructional 3D-printed metal structure situated at the New Immigration Headquarters of Hong Kong. The project demonstrates the seamless integration of advanced WAAM technology, innovative parametric design, and collaborative efforts among government, industry, and academia. By leveraging these advanced technologies, the project team has created a structure that is not only visually stunning but also environmentally friendly and cost-effective-achievements that would have been unattainable using conventional construction methods. The project achieved significant reductions in construction time, cost, and material waste while pushing the boundaries of architectural design and structural engineering. The structure is one of the largest 3D-printed steel structures in the Hong Kong region, designed in accordance with established codes of practice, just like conventional steel structures. This pioneering project successfully utilized WAAM technology to bring the innovative design of an artistic expression to fruition, incorporating advanced structural analysis methods, optimization techniques, and supplementary physical tests. This paper presents summarized project data and methodological frameworks for implementing WAAM technology in construction applications, thereby contributing to the advancement of WAAM technology in construction industry.