Experimental and Numerical Quantification of the Structural Capacity of Hybrid 3D Printed and Cast Concrete Beams After Topology Optimization (2025-07)¶

In order for 3D printed concrete (3DPC) to be a valid alternative to traditionally cast concrete, the technology should fully exploit its advantages towards production process automation and the realization of complex geometries for efficient material use. A hybrid 3DPC-cast beam concept is presented, where the lower part of the beam consists of traditionally reinforced cast concrete. The upper part consists of an unreinforced 3DPC segment, for which there is an option to reduce the volume by for example structural topology optimization. Two hybrid beam configurations, a ‘full’ beam and an optimized beam, are investigated based on structural testing in a bending set-up. A numerical model is developed, informed by material tests, in order to portray the hybrid beam’s structural behavior. The modelling of the interface between the printed and cast concrete plays an important role in the prediction of the structural hybrid beam behavior. The peak shear stress shows to be a critical factor for the prediction of the beam capacity.