Optimised and 3D printed steel garden bridge: from design to experimental verification

Wire-arc directed energy deposition (DED-Arc), or wire arc additive manufacturing (WAAM), enables large-scale, intricate metallic components to be created in an automated manner, with great promise in construction. This paper presents the design, manufacture and experimental verification of a 4 m-span, East Asian garden bridge-inspired and structurally optimised DED-Arc steel pedestrian bridge. The bridge consists of optimised DED-Arc steel tubular components as the main load-carrying structure, and wooden boards on top as the decking. The structural performance of the bridge was examined through non-destructive testing of the fully assembled bridge up to the design load and destructive testing to failure of a duplicate of the main arch, which confirmed the load-carrying capacity of the bridge and showed generally good correlation with the prior numerical simulations. This study successfully demonstrates the feasibility of integrating DED-Arc with structural optimisation at scale, and its significant role in construction automation and decarbonisation. • 4 m-span structurally optimised steel bridge designed and fabricated using DED-Arc. • Main structure topology optimised, rationalised and refined through sizing optimisation. • 3D laser scanning verified geometric accuracy of printed bridge components. • Physical testing confirmed load-carrying capacity and high structural efficiency. • Experimental results showed good overall agreement with prior numerical simulations.