In the News

US Army Corps of Engineers’ Megan Kreiger on the State of Construction 3D Printing

April 22, 2024   3D

View Source

Despite last year’s gloomy reports about the financial state of the additive manufacturing (AM) industry, there’s no doubt that we’re actually witnessing the birth of a sector rather than its death. One segment of 3D printing, in particular, demonstrates that we’re just getting warmed up: additive construction (AC).


In just a few years, a seemingly endless string of AC firms have emerged to constitute a fully-fledged industry. However, a look at the construction 3D printing landscape shows us that it’s still the Wild West out there. To get a better lay of the land, we spoke to Megan Kreiger, Portfolio Manager of AC and the Department of Defense’s subject matter expert of AC at the U.S. Army Corps of Engineers, Engineer Research and Development Center (ERDC).


Scaling up AC

Now that the AC sector is beginning to gain traction, the next key step is to develop the standards and quality control necessary to advance construction 3D printing from a novelty to a robust technological solution. According to Kreiger, this transition requires solid data to substantiate claims of cost savings and efficiency, moving beyond prototypes to widespread adoption. Kreiger highlights the importance of real-world performance data, materials science, and the development of codes and standards to ensure the structural integrity and long-term viability of 3D printed structures.


“This isn’t about creating regulation just for the sake of it, but about providing the community with robust tests and practices that will standardize the industry. These standards will give us the assurance that the structures we build are structurally sound. There is, at this moment, a worldwide lack of such initiatives, which we need to address to effectively meet the broader community’s needs,” Kreiger said.


So far, strides have been made with the release of the Unified Facilities Criteria (UFC) on Additively Constructed Concrete developed with ERDC-CERL’s expertise to establish a framework to allow innovation, through validation testing.  This was followed by the ASTM/ISO standard (ISO ASTM 52939:2022), laying the groundwork for more formalized codes, standards, and guidelines in additive construction. ERDC-CERL also conducted a workshop with NIST (Additive Construction: Path to Standardization) to map out a strategy for the development of these codes, standards, and guidelines.  The workshop encouraged openness in communications and put the research community into alignment on key themes, priorities for standards, and the next steps to make sure data can be compared instead of stand-alone.


A fully printed structure with printed roof panel formwork, roof beam formwork, lintel formwork, walls, and footer formwork. Printed by Airmen, Marines, and Soldiers at Camp Atterbury as part of the ACES JCTD. Image courtesy of ERDC-CERL.


Additionally, this brought to the forefront that “There’s not enough data”, which was highlighted in the 123 Forum: Should 3D printing be codified and sessions on Structural performance of additively constructed concrete at ACI.  This workshop resulted in cross-organization collaboration between entities such as ASTM, ACI, & ICC. This in turn reemphasized ASTM’s work on new guidelines, ACI ITG-12 Code Requirements Construction of Additively Constructed Walls, ICC 1150 Standard for 3D Automated Construction Technology for 3D Concrete Walls, as well as jumpstarted the Additive Construction by Extrusion (ACE) Consortium under NIST.


This workshop was followed by the Additive Construction: DoD Path to Adoption workshop hosted by ERDC, ERCWERX, and Army Materiel Command, where stakeholders across the Joint force contributed to promoting a fundamental understanding of additive construction, discussed opportunities and limitations, and initiated the development of a roadmap for integration of additive construction technology for the DoD.


ERDC in collaboration with the U.S. Army Materiel Command recently hosted the Additive Construction: DoD Path to Adoption workshop at U.S. Army Fort Bliss. During this event, Department of Defense (DoD) and Military Construction (MilCon) stakeholders across the Joint force contributed to promoting a fundamental understanding of additive construction, discussed opportunities and limitations, and initiated the development of a roadmap for integration of additive construction technology into the MilCon and DoD construction process. Industry representatives, downselected by ERDC in an ERDCWERX tech challenge (Additive Construction: Solutions in DoD Path to Adoption) addressed real world data driven metrics and capabilities for recent projects in additive construction. Image courtesy of ERDC.


Yet, the main obstacle faced has been the reliance on unsubstantiated assumptions about the performance and behavior of these structures and technologies. For instance, the durability of printed structures is largely unknown since the oldest known printed structure, a castle in Minnesota made by Andrey Rudenko in 2014, serves as the sole long-term data point.


A test structure similar to an Entry Control Point was printed on Guam and then subjected to blast experimentation, with work performed by ERDC-CERL, ERDC Geotechnical & Structures Laboratory, and the 554 Red Horse Squadron. Image courtesy of ERDC-CERL.


To bridge the gap in testing and data validation, Kreiger suggests a collaborative involving academic institutions, the private sector, and government. While academia can provide rigorous testing and data, but has limited access to full-sized machines; private sector can perform the actual printing processes and benefit from the test data, while government can maintain the 3rd party neutral to ensure developments are unbiased and benefit the public.


The Beginning of the AC Industry

Right now, public entities are engaged in funding advanced manufacturing at unprecedented levels. Ideally, this should drive all of 3D printing forward, but AC has particular potential when it comes to infrastructure, affordable housing, defense applications, and humanitarian aid/disaster relief. At the same time, commercial entities are participating in ways that benefit the industry as a whole.


“In recent years, there has been enough funding to work with various different partners and move forward in ways we hadn’t been able to do previously. Funding has enabled us to get more engaged and bring the field into what it’s capable of today, including getting engaged in codes and standards to move things forward,” Kreiger said. “The amount of interest is a different flavor, changing in recent years. Mostly because private sector has opened up a lot more than they used to. At the workshop with NIST, we actually got people from multiple competitive companies in the same room talking to each other about what the limitations and opportunities of the field are. That was the first time we’d actually gotten more communications across the field where people aren’t necessarily just trying to, you know, do it for their own gain, but understand that a rising tide lifts all boats.”


Kreiger discusses the Additive Construction program with Rep. Nikki Budzinski (IL-13). Image courtesy of ERDC-CERL.


It is perhaps because AC has proven itself to be a viable and useful technology that public funding opportunities and commercial openness are more than lip service, compared to past waves of hype. Kreiger outlined the growing viability of alternative construction methods due to challenges in traditional construction, such as material scarcity, a shortage of skilled labor, and rising costs. From her perspective, the key advantages of AC include manpower and injury reduction, less physical strain on workers, logistical and cost efficiency through local materials, improved energy efficiency, innovative design potential, and the capacity to modernize construction while assessing performance in extreme conditions.


“These benefits align with modernization priorities in the military and have broader implications, as research continues on the structural resilience of these buildings against weapons effects and natural disasters. This holistic approach to construction not only saves lives but also paves the way for inventive applications and efficiencies across the field,” Kreiger concluded.


It should be no surprise then that ERDC is playing a clear role in advancing not only the state of the art for AC, but also the standards and quality control framework that will hold the industry together. In this way, the U.S. military is applying the dual use principal at work in so much of its research and development to construction 3D printing, where the peacetime applications could potentially be even more profound than during wartime.