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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.

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Apart from mechanical actions, structural components in the construction industry may be subjected to a thermal gradient, causing (internally) restrained thermal expansion. These thermal loads can alter the mechanical response of components in a structural topology optimization procedure. Therefore, the influence of thermal loading should be considered in the sensitivity analysis to efficiently update the structural layout of material. In this paper, a density-based topology optimization procedure is developed for compliance minimization of structural components subjected to thermo-mechanical loads considering steady-state heat conduction and weak thermomechanical coupling. The adjoint method is employed to obtain the analytical sensitivities, taking into account the influence of the design-dependent temperature field and thermal properties. The proposed topology optimization procedure is demonstrated on the MBB problem, extended with thermal loading, to investigate the influence of the proposed sensitivities on the optimized results. Furthermore, the thermo-mechanical load ratio is quantitatively defined and its effect on the resulting topologies is studied. The results show that the thermo-mechanical load ratio significantly changes the topology of the optimized results. Finally, the topology optimization procedure is presented in an efficient 138-line MATLAB code and provided as supplementary material, serving as a basis for further research.