This is going to be my last post about 3D printing of composites for a while. So, I thought that I would wrap up with something about 3D printing of reinforced concrete for housing, infrastructure, etc. Actually, I was inspired by an article in Composites World I saw about this subject. The images above are from an excerpt from “3D Printing Industry” which is an on-line trade publication about the 3D printing industry.
What is unique about this story is that a new record was set by GUTech, the German Technology University of Oman. They printed 3 buildings in 8 days in Oman. And, what I want to draw your attention to is the image to the right. This is a close up of the wall construction that they came up with. This is pretty clever. They use an undulating outer wall for geometric reinforcement and a straight inner wall that is tied to it with those little light colored ties that you see in this pic. This makes for a very robust structure that can be printed in record time – obviously because they set a record doing it.
You can see one of the 3D printers in the center pic at the top of this post printing a wall. This pic gives you a sense of scale and thickness of the composite concrete that is used to print the structure. The actual 3D print is relatively thin, and they have cleverly use geometry to stiffen their structure. That’s how they were able to get three buildings printed in 8 days. The gantry that is shown to the left in this pic is part of this demonstration. It appears that they are printing the roof of one of the more finished of the three buildings that they printed. The article did say that they even printed the roof. I’m sure there is some scaffolding as well as some flat supports under where they are printing the roof. And I’m also sure that they are printing the reinforcement for the roof structure right into the roof itself.
That’s the wonderful thing about 3D printing, and also the wonderful thing about composites. Using these materials and means of making things out of them offers up an infinite number of possibilities to the designer. What it really takes to pull something off like what was done here is to have good people thinking all the way through how to do this and taking a systems or holistic view of the entire construction process.
And, from the image to the right of that top set, it appears that they have appointed the third building which is a “fisherman’s house” rather nicely. There’s another pic in the article that shows an overhead view of the bathroom, but I decided not to use that one in my newsletter.
Moving on, some of the most beautifully shaped bridges are possible using 3D printing. Of course, with composites you can get any shape you want, and with 3D printing you don’t even need a mold to produce really gorgeous functional structures. The two pics on the bottom right and the one in the center right are all 3D printed. And, they are made out of a variety of 3D printed materials. The bridge in the center right pic is a 3D printed steel bridge with printed in reinforcements and structure that it not only very appealing the eye, but structurally sound as well. Those supports between the bridge deck and the lower support members have a very unique shape. If there are any engineers out there, those appear to be extremely efficient structures. They are loaded primarily in compression and bending, so having each end of the thin supports being quite a bit fatter and faired into the structure makes it so that there won’t be any stress concentrations. Sorry about the little engineering mechanics treatise here, but since I’m a composites guy I sort of think this way.
Finally, I wanted to talk about the picture to the right. These structures are being built as we speak in a number of locations around the US and abroad. The shape of them reminds me of a yurt, which as most of us know is an ancient structural design, but very efficient. And the entire structure is 3D printed with the exception of the little white structure you see as a roof on both of these attached yurts. This may be one of the solutions to the global housing crisis, because the materials for building these things can be locally sourced, and the quality of things like the sand and aggregate that goes into them can be quite a bit inferior to what is required by the Uniform Building Code for the 100+ story steel and concrete monoliths that are built in the big cities of the world. Sourcing local will make this affordable for nearly all of humanity.
I for one am excited to see this technology take off. We desperately need something to house the billions of people who don’t have adequate shelter.
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