The production of a topology-optimized 3D-printed concrete bridge

In the last few years, the development of 3D concrete printing (3DCP) technology has flourished exponentially both in academics and the construction industry. Many problems inherent to 3DCP are already being tackled on a material level. However, in the practical realization of large-scale components there are still a lot of questions to be answered. In this study, we discuss the production process of a topology-optimized 3D-printed concrete bridge structure. As the entire process is largely different compared to the manufacturing of traditional concrete structures, the problems, workarounds, and insights gathered from this project are valuable for future constructions using 3DCP. The geometry of the bridge was based on topology optimization results and further developed through the use of parametric modelling. After careful considerations, the bridge geometry was discretized into four segments and printed as integrated formwork. Several measures were taken during the printing process in order to produce the separate sections. The assembly process entailed the handling of the printed components, the placement of reinforcement and prestressing tendons, the production of the end blocks, and the handling and joining of the printed sections. For the latter, also the process of pouring self-compacting concrete in the printed formwork is discussed and more details about the post-tensioning procedure are provided