Large Scale 3D Printing of Complex Geometric Shapes in Construction Jochen Teizer, Alexander Blickle, Tobias King, Olaf Leitzbach and Daniel Guenther Pages 948-956 (2016 Proceedings of the 33rd ISARC, Auburn, USA, ISBN 978-1-5108-2992-3, ISSN 2413-5844) Abstract: 3D printing, also known as additive manufacturing, has become an established technology in many industry sectors for the fabrication of three-dimensional (3D) objects. The layered production of scaled prototypes and smaller series typically use automated computer controlled systems that rely on a-priori designed digital 3D models. General principles for 3D modeling, printing, and finishing exist utilizing the cutting, melting, or softening of paper, polymer, or metal materials. While advantages and limitations of the 3D printing processes require careful review for its final application, the construction industry itself has adopted industrial applications successfully in many examples where, for example, consecutive layers of concrete are combined into a desired structure or form. One of construction?s key challenges though is its need for large scale 3D printing of complex geometric shapes on projects where construction time, cost, and quality are the predominant and determining success criteria. While complexity and scale of the planned structure become available at finer detail during the architectural design process, final fabrication of large scale geometric shapes often fails because of constructability issues. This article introduces conventional construction methods for building large scale and complex geometric structures using on purpose built, automated and robotic 3D printing machines. It therefore contributes the missing link between demanding architectural design that otherwise could only be built at large cost. Commonly known advantages and limitations of existing 3D printing processes, including modeling, printing, and finishing principles are reviewed. Significance of resolution, speed, and quality of materials in 3D printing are explained. Results to an implementation of complex formwork in a major capital construction project are shown. Preliminary benefits and limitations from the perspective of a construction company explain what it takes to advance 3D printing to a field-ready construction method. Keywords: 3D printing, additive manufacturing, concrete formwork, contour crafting, machine automation and robotics, modularization. DOI: https://doi.org/10.22260/ISARC2016/0114 Download fulltext Download BibTex Download Endnote (RIS) TeX Import to Mendeley

This article presents an overview of the SmartSite research project that adopts machine learning, decision theory and distributed artificial intelligence to design and test a multi-agent system (MAS) for asphalt road construction. SmartSite puts major emphasis on sensing and communication technologies that integrate real-time automated information exchange in the supply chain of road construction. As part of the larger SmartSite project, this article introduces a novel real-time path planning system for compactors and presents the results of several simulation and field realistic experiments conducted to evaluate the system in a sophisticated simulation and harsh construction environment, respectively. The system operates based on Belief-Desire-Intention (BDI) software agents and real-time sensory inputs. The newly developed integrated and information rich process benefits asphalt compactor operators, as they are now capable to control their machinery and react to changing environmental, material-related and process-related disturbances or changes. This improves the quality of the delivery and laying of asphalt material, prevents compactors from over-compacting certain road segments, increases the road's pavement longevity during the operational life cycle phase; refocuses the work tasks of the site managers, and reduces the construction budget and schedule. The system's ability to maneuver an asphalt roller during real-word operation also makes it an important step towards a fully automated asphalt compactor.