Professor of Industrial & Systems Engineering, Dr. Behrokh Khoshnevis discusses Contour Crafting: Automated Construction at TEDxOjai event (Transcript).
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Dr. Behrokh Khoshnevis – The inventor of Contour Crafting
Maslow, the renowned American psychologist, identified the pyramid of human needs, at the base of which are the two essentials: food and shelter. So shelter is the topic of my presentation tonight.
At the dawn of the 21st century, unfortunately this is the condition of shelter for nearly 1 billion people in our world. These slums are the breeding ground for disease, crime, illiteracy, and over-population. Naturally governments are after solutions. They are after finding ways to change the situation.
However, what they’re facing is a problem of conventional construction, the current construction methods that we employ. They are generally slow. They are labor-intensive and inefficient. If you look around yourself, pretty much everything is made automatically today. Your shoes, your clothes, your home appliances, your car. The only thing we still build by hand are these buildings.
Construction is the most hazardous job. It is more dangerous than mining and agriculture. In this country it kills 10,000 people every year, and there are about 400,000 injuries every year. Eventually these translate into costs to the society and homeowners. Construction, the way it’s done today, is very wasteful, and generates a lot of emissions. And because of all the different trades that are involved in there, and the difficulty of the management process in construction, the process is pretty corruption prone. It is very costly, and is always over budget.
So, what we have been focusing on is finding a solution to this problem. And our solution basically benefits from advanced technology. I named this process ‘Contour Crafting’, and it is essentially a way of streamlining the process of construction by benefiting from the experience that we have gained in the domain of manufacturing.
In manufacturing, there’s a process called CAD/CAM. Computer Aided Design, Computer Aided Manufacturing. A lot of things that you see are designed on computers and without any human interference, are sent to the production machinery that automatically make those products that you use. So we want to scale up those processes and bring them to the realm of construction.
This, of course, has been the desire of a lot of engineers, and technologists. There have been problems, there have been difficulties in such a transition. Recently, there has been development in the field of fabrication. You probably heard about 3D printing of 3D objects. So Contour Crafting is basically scaling up 3D printing to the scale of buildings.
What we are hoping to generate are entire neighborhoods that are dignified, at a fraction of the cost, at a fraction of the time, far more safely, and with architectural flexibility that would be unprecedented. So the buildings that will be built, of course, will not be as homogenous as these. Every building can be very different. They do not have to look like tract houses, because all you have to change is a computer program. The architectural design is basically sent to the machine directly.
This animation shows the concept. The material, which is cementitious materials, initially concrete, is deposited through a nozzle, and the building is built layer by layer. In the process, a lot of things can be done, including automatic reinforcement, automatic plumbing, automatic electrical network installation.
And once the basic structure is done, there could be other automated processes that would do auxiliary operations such as finish work, tiling, and even painting using ink-jet printers, the kind that print billboards. So, in the end, the whole building can be ready in an unprecedented time. We anticipate an average house, a 2,500 square foot house, can be built in about 20 hours, custom design.
The model that you see here is pretty simplified, because I didn’t want to make the animation difficult for my students. But you can imagine that the walls do not have to necessarily be rectilinear. They can use any kind of curve, therefore you can really execute very exotic, beautiful architectural features, without incurring additional costs.
This clip shows how reinforcement, plumbing, and electrical installation can be done. So rather than using continuous rebars, we can have segments of rebar automatically inserted and assembled inside the building. So this wall is being reinforced by a two-dimensional mesh of steel.
Likewise, plumbing elements could be installed while the building is being erected. As you know, currently every one of these activities involve their own trade. So for electrical network installations you can have these polymeric blocks with conductors that carry electricity, and communication signals.
This is one of the machines that we’ve developed. As you see, the nozzle is secreting pretty dense concrete. This concrete is high performance, and it is mixed with fibers, composite fibers. It gives you pretty good strength. This particular wall has a 10,000-psi strength. The average concrete structures that you see typically are about 3,000 psi, pounds per square inch.