Reinforcement lattices for 3DCP: A fabrication method based on ruled surfaces

Abstract

3D Concrete Printing (3DCP) is one of the most used digital fabrication processes with concrete. As a technology, 3DCP promises an economy of resources by creating optimized geometries that require no formwork. But, before material reduction can be achieved, the 3DCP should be comparable in mechanical performance with conventionally reinforced concrete. Existing literature already acknowledges the difficulty of adding reinforcement compatible with 3DCP. Even if several reinforcement strategies for 3DCP are reported, the direct implementation of conventional rebar in 3DCP remains limited. The presented work shows how the geometric freedom for 3DCP enables the efficient placement of continuous and straight rebar in a lattice that activates both loading orientations. The presented prototypes reduce the overall concrete use. The material reduction is achieved by creating a hollow structural element in which the printed concrete acts as formwork for the infill and as a simple guide for reinforcement. This design strategy simultaneously simplifies the assembly of an elaborate reinforcement cage and utilizes linear, readily available, and cheap rebar.