Using Additive Manufacturing to Develop Shape Topology Optimization of Internal Structures for Reinforced Concrete Designs

Technical advancements of reinforcement in structural concrete has been halted for generations due to manufacturing practices of rebar and construction processes. Typically, reinforcements are rolled into a straight rebar and only bent when necessary. This study uses the advent of 3-D printing fiber reinforced polymers to reimagine the possible patterns of reinforcement in structural concrete. Some plastics that can be 3-D printed were found to have tensile strengths that can be used as concrete reinforcement. Formation of cracks in concrete members was analyzed and possible mitigation techniques were assessed for structural beams. Topology optimization and generative design were utilized in order to yield the most efficient continuum model of reinforcement, which varies from typical strut and tie models by having contiguous reinforcement rather than interlocking elements. The continuum models were compared to rebar layouts using 3-D printed PLA and CF-PETG by four point bending tests. The filament with the higher ductility and lower tensile strength (PLA) was ultimately more effective at mitigating catastrophic failure. CF-PETG is much more brittle therefore failed with less elongation compared to PLA. Rebar models were found to be efficient at counteracting loads and failed after greater elongation essentially because of their concrete to reinforcement bonding.