An integrated computational framework for structural optimization of prestressed concrete structures with 3D-printed formwork

In this paper, we present an integrated computational framework for the optimal design of post-tensioned concrete structures, assembled from segments that are composed of printed formwork and complementary casting. The framework hinges upon shape optimization of B-spline surfaces that parameterize castable concrete members, and accounts for both the load-balancing stage and the service stage, commonly referred to in prestressed concrete design. Buildability of the formwork is guaranteed by separating the geometry of the printed toolpath and imposing a set of stress constraints according to the material properties of the fresh concrete. Numerical results show how the capacity of the fresh concrete and fabrication parameters affect the outcome of shape optimization, and how the optimizer successfully finds geometrical forms that are buildable. This paves the way towards a holistic, seamless design-for-manufacturing approach in 3D concrete printing.