The Use of Additive Construction in All Structural Components of a Building (2024-09)¶

The use of additive construction for buildings has primarily focused on wall construction, while the integration of the additive construction process for roofs, slabs, beams, and other building components has not kept pace. Industry currently relies on conventional, experimental (e.g. rapid set over-hangs), or tilt-in-place techniques to construct the portions of the structure that are non-vertical. Both rapid set overhangs and tilt-in-place preprinted components have sought to solve this challenge through directly incorporating the roof into the structure through continuous print of the building envelope and roof diaphragm. However, there are questions regarding the strength and orientation of interfaces required to bear a horizontal load, the methods of incorporating shear and tension reinforce-ment, and the proper design of connections between elements of the structure. Due to geometric constraints in the structure that interfere with integrating rein-forcement, unconventional methods are often used, but may not be deemed ap-propriate under current building codes. For example, a structure of this type typi-cally requires a foundation prior to emplacement, but there are no defined stand-ards for anchoring the structure to the foundation. Therefore, non-traditional con-nections are used. Despite the challenges, the utilization of additive construction for the majority or entirety of a structure is advantageous in scenarios when the reduction of logis-tics and accelerated project timelines are priorities. Conversely, when including preprinted components there are also challenges with the size and weight of com-ponents, limits on the lifting capacity of equipment, transport limitations, and ac-cess to sufficient equipment (e.g. cranes and telehandlers) under such scenarios. The implementation of additional components requires special considerations for placement of structural elements, proper strength, serviceability, reinforcement, and connections. By utilizing a printer system, local concrete mixing assets, and locally available materials, additive construction was utilized to complete an en-tire structure. This structure was constructed by uniform personnel and the US Army Engineer Research and Development Center (ERDC) in August 2023 uti-lizing a combination of pre-print and print-in-place techniques. Through iterative research including testing, design, and construction, ERDC has developed a struc-tural system that in-corporates wall, beams, and slabs. This paper will cover the design options and considerations (e.g. geometry, material properties, reinforce-ment, and connections), materials and structural data, and concepts that were 2 explored to achieve the first building to utilize additive construction for all struc-tural components (Camp Atterbury, IN, USA).