Date of Graduation

12-2020

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering (MSCE)

Degree Level

Graduate

Department

Civil Engineering

Advisor/Mentor

Michelle Lee Barry

Committee Member

Richard A. Coffman

Second Committee Member

Gary Prinz

Keywords

cellular patterns, material efficiency, soil-based materials, 3D printing, compressive strength, load-to-weight ratio

Abstract

With the emergence of Additive Manufacturing (i.e., 3D printing) in construction, new strategically designed shapes can be created to improve load transfer through structural members and foundations. Cross-sections can be optimized to carry load using less material, or even using weaker constituent materials, like soils, which are cheap and abundant. The goal of this research is to investigate the benefits of using cellular patterns which leverage biomimicry in civil engineering applications, since nature has perfectly engineered materials and patterns which carry loads with the least amount of material possible. Most of the periodic cellular work to date has focused on metallic materials, which exhibit ductile performance. Therefore, this study is specifically related to brittle materials as there is a need to understand the load transfer mechanisms in this type of material. An initial investigation of biomimicry was carried out, and organisms thatpresented improved mechanical behavior due to geometry were identified. Analogue prototypes inspired by these biological findings were designed and specimens were 3D printed using a binderjetting device which offers a resulting part with a brittle behavior, mimicking a cemented soil. Solid samples using the same gross area were also printed to compare performance with the cellular shapes. Uniaxial compression tests were performed in the specimens and in cylinders used to track the properties of the material. The variability of the 3D printer utilized in this study and the material’s susceptibility to experimental differences were found to be important factors and some printer settings made it difficult to compare the cellular and solid specimens directly. Overall, the results show that the cellular structures exhibited a significant improvement in the load-toweight ratio compared to the solid configuration. Applying this improvement in material efficiency to building products can lead to more sustainable and cost-effective construction practices.

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