Title: External Reinforcing System for 3-D Printed Concrete Elements: Technology and Design Approach

Author(s): Costantino Menna, Ferdinando Auricchio, Domenico Asprone

Publication: Web Session

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Date: 6/1/2020

Abstract:
Steel reinforcement integration into3-D printed concrete structures represents a challenging task for the deployment of digitally fabricated structures. Indeed, an effective approach to replace traditional steel reinforced concrete elements (i.e. made of concrete and steel rebar) by implementing one of available digital fabrication technologies has not been developed so far. One of the main reasons is the scarce adaptability of traditional steel reinforcing systems (in the form of stiff, straight and thick rebar or rods) to a specific/complex shape (large energies are required to bend the reinforcing steel) during additive manufacturing processes. This paper aims to contribute to this challenge by proposing an external reinforcement system for3-D printed reinforced concrete (RC) beam elements. In particular, the steel reinforcing system is designed to guarantee proper tensile reinforcement (at the bottom side of the beam) and, at the same time, to make the separately printed concrete segments as a single monolithic element. The rebar scheme adopted in this study is installed on both sides of the beam and consists in a combined in-plane and an out-of-plane reinforcement configuration made of stainless-steel threaded rods. The stainless-steel threaded rods of the in-plane system are linked to the out-of-plane system through male thread connectors and hex nut rod pipes. The main structural design features of such a reinforcing system are discussed in this paper along with the results of the corresponding mechanical characterization campaign.