Experimental and numerical assessments of new concrete dry connections concerning potentials of robotic CNC manufacturing technique

Abstract

Coinciding with new manufacturing methods such as robotic additive manufacturing techniques and the gradual transition in construction approaches, new structural elements should be developed that, against the classic approaches, can easily be manufactured by new additive manufacturing techniques. Concrete Dry connections are one of these discussed elements. Appropriate geometries of dry concrete joints, manufactured by robotic CNC technique, accelerate the construction process by eliminating the necessity of formwork, scaffolding and concrete injection. Furthermore, desirable connections with higher interlocking and resistance in different degrees of freedom can be developed by facing the difficulties of traditional construction methods. Through some examples, this paper initially discussed the possibility of constructing dry concrete joints by robotic 3D-printing and robotic milling/sawing methods, and their geometrical accuracy was measured. In addition, 9 geometries of dry concrete joints were proposed and produced by formwork. Then, the performances of the proposed post-tensioned dry joints were discussed and compared to similar monolithic elements. On this basis, certain dry joints, entirely and easily manufactured by additive manufacturing technology (robotic concrete printing and CNC), could achieve up to 64% of the flexural capacity of a dimensional similar monolithic beam.