Despite being still in its infancy, modern 3D printing technology has proven to be a largely reliable building construction technique that’s ripe for widespread adoption.
Notwithstanding, some concerns have been raised over the years as to the safety and endurance of 3D-printed buildings, particularly when they’re under the inclement actions of nature.
In that sense, can 3D printed houses withstand earthquakes? 3D-printed houses could withstand earthquakes and other natural disasters in many instances, for most modern printers are capable of extruding and mixing strong and dense concrete composites – at times merged with insulation materials – as well as integrating different reinforcements and seismic isolation systems.
Here is a video of a company with a 3D printed structure tested on a 5.7 earthquake magnitude,
Even though 3D printing is not yet approved in current building codes, permits for building projects employing these methods have been granted already in various locations worldwide, owing to the demonstrable seismic load resistance they provide.
We also suggest reading our article on 3D printed houses durability to get the full picture and understand how 3D printed houses are safely constructed.
3D Printed Houses Rigidity/Elasticity Problem
Builders were historically placed in a conundrum when it came to assembling structures solid enough to remain in place indefinitely and that could hold their own during tremors.
For one, hard materials and rigid designs would become brittle in the event of a shock due to lost ground, making the shaft that is left suspended in the air susceptible to breaking (source).
On the other hand, overly elastic structures are not devoid of difficulties, as deformation resulting from ground motions can still ensue. While they won’t crack, you would expect them to lose consistency or shape during a strong shake (source).
Traditionally, rebars (reinforcement bars) were embedded into concrete slabs in order to enhance the material’s tensile strength while preserving solidity, but this procedure had to be performed in a formwork beforehand to ensure proper bonding through mechanical compacting.
However, whereas prior compacting is not required in additive manufacturing – mostly attained through gravity – other hurdles still ought to be addressed, such as material porosity and the potential appearance of “cold joints” during printing. To evade these, the Shotcrete 3D Printing Process (or SC3DP in short)was developed in a joint effort financed by the Ministry of Science and Culture of Lower Saxony, as a means to deal with these issues efficiently.
The technology consisted of an automated mechanism by which layers of concrete components would be tightly stacked through the addition of compressed air, ensuring strong bonding with the reinforcement material. The rebars would be incorporated into the mix, both by applying the concrete to pre-braided rebar meshes and by installing the reinforcement using the layered material as support (source).
What About The Foundation of 3D Printed Houses?
Foundation laying is another subject that’s often the focus of discussions within the 3D printing sector.
In this regard, the latest 3D printing systems appear to excel mostly at placing shallow foundations or mats. This would not pose a code compliance obstacle for most small-scale building projects.
At the time of writing, though, these printers don’t seem well-equipped to deliver soil reinforcement by making piles (which fare better in seismic-prone areas), albeit a recent study has shown the feasibility of replacing shallow foundations with piles conjoined with a printed wall (source).
Nevertheless, as was admitted by the authors of the study cited above, current printers still have height-related limitations to accomplish this task with optimal results, and prospective printers with a pile-driving head must be likewise capable of overcoming the loads from ground drilling.
As a side note, other isolation mechanisms could be implemented during an additive manufacturing process to elude earthquake impacts on the building, such as the placement of flexible pendulum-type isolation bearings between the structure and its foundation (source).
For more on this, check out our post Do 3D Printed Houses Have a Foundation? Materials and Methods
Creative Earthquake-Resistant 3D Printed Designs
Let’s segway into other initiatives that were undertaken to create structures with added damage control perks and resilience. For the purposes of this article, we’ll highlight only two of them:
The “Quake Column”
This attempt at creating a shock-resistant structure was made circa 2014 by Emerging Objects, a highly innovative California-based architecture firm concentrated mostly on breaking new grounds in the field of building materials for 3D printing (source).
The hollow bricks were designed with CAD tools and printed utilizing unorthodox ingredients like bone dust, ground-up tires, sawdust, and salt. These bricks were also endowed with molded handles that allowed for easy on-site assembly.
Firm members posited that this method could be translated into a code for load-bearing walls, consequently leading to the erection of livable homes that could serve as literal strongholds against nature’s wrath.
Using cement paste, mortar, and concrete, we would be capable of crafting an array of structures that emulate the toughening mechanisms of arthropod shells, as was shown in recent years by Purdue University engineers.
Structures designed with this setup can become more resistant to cracks by controlling the way the damage spreads between the layers of the 3D-printed material, similar to what happens when the exoskeleton of arthropods is put under pressure.
In addition, cement paste has been revealed to be instrumental in the creation of elements that behave in a spring-like fashion and that could be potentially employed for 3D-printed buildings. In the words of material engineer and Purdie professor Jeffrey Youngblood (cited by the Purdue University news portal):
“3D printing has removed the need for creating a mold for each type of design, so that we can achieve these unique properties of cement-based materials that were not possible before”
A good way to gain more perspective on this subject is to also read more about 3D print houses design guidelines in Design Guidelines For 3D Printed Structures – Your Full Guide.