The Vertical Printing Technology (VPT) startup has invented a method of using 3D printers in multi-story construction. Unlike current technologies that only allow “3D printing” single-floor structures, this printer can be used for erecting high-rises. Printing out the most expensive and labor-intensive part will reduce in half the cost and time of erecting monolithic frames. Invest Foresight discussed the novelty with a co-founder of the company, Alexander Titov, at the Digital Construction Forum.
Alexander Titov was on the team working on the Novovoronezh nuclear power plant from Atomenergoproekt, an engineering unit of Rosatom state corp, which was the general contractor for the project. The company was constantly failing to meet project deadlines because of its subcontractors who said they did not have enough people due to low pay; even when they did have enough people, they often showed substandard work. This happens at any construction site – failure to meet deadlines and the ever-growing construction costs are the biggest problems. So Titov and his colleagues had an idea to try and automate part of the process, possibly by using a 3D printer to do part of the work.
“Construction printers now available on the market can actually produce walls, but they cannot produce floor slabs. Neither can they lay reinforcement or install steel bars, which is absolutely needed for high-rise construction. The existing technology cannot be replicated to become widespread. What cities need is multi-story construction,” Alexander Titov says.
VPT claims to have solved this problem by inventing a way to simultaneously “print” vertical columns and floor slabs and lay reinforcement. Everything else – the walls and the roof – can be made in the conventional way or using 3D printers now available on the market, such as the one from Spetsavia, a Yaroslavl company. VPT can also print the roof if it is flat. They cannot print floor slabs along with the walls yet, because their 3D printers do additive layering printing and cannot work in the thin air: layers need support.
What is vertical 3D printing technology? Vertical support columns and floor slabs are fabricated using a movable formwork and a printer that positions tensioning cables and porous concrete in layers for the whole height of the building.
VPT uses the pre-tensioned concrete technology, with reinforcing cables inserted into the concrete and then tensioned; as a result, a compressive tension is created that holds the slab structure together, making it more durable than conventional reinforcement, and saves both concrete and fittings. Such concrete is used in nuclear projects and bridge construction.
The startup founders took the existing technologies of pretension concrete and movable formwork, combined them and made processes automated and robotized, which resulted in a hybrid technology that allows “printing” floor slabs and support columns, and inserts the fittings automatically during the printing process. The printer forms columns and floor slabs in layers in bulk, separates them with special splitters, and places the fittings with hooks. The slabs are made vertically; after the concrete sets, they rotate to a horizontal position thus forming the building frame. The technology allows organizing a construction conveyor system at the construction site. According to Titov, this results in a twofold reduction in the time and costs of building frame assembly, while the number of employed workers can be reduced fourfold.
The proposed solution allows constructing not only single-floor structures but high-rise buildings as well. Titov believes that introducing the 3D vertical printing technology will lead to radical changes in the global construction industry.
“The technology largely resembles the traditional slip-form casting technology but uses the automation of the concreting/reinforcement process”, says G&E Engineering company’s chief engineer Timur Yezhov. “The major know-how is turning floor slabs after the printing process and concrete setting. It is hard to say without making estimations, but it appears initially that as the upper floor slabs turn the building frame looks unstable, which may result in a designer having to place heavy-gauge columns – which means excess use of materials. In addition, the technology does not allow constructing complicated buildings – and labor efficiency of creating complicated architectural forms is to a great extent is an impetus for development of construction printing”.
The Vertical Printing Technology company is now seeking investments of $900,000 to create a pilot printer able to print the first building, and an industry partner that needs this device. VTP is likely to find investors and partners among construction companies interested in economizing on costs or equipment manufacturers.
The company does not plan to build a 3D construction printer plant but intends to sell licenses to use its technology. The startup already has a patent for slab turning technology, and new ones may be created during the development process. The technology might be purchased by construction equipment manufacturers such as Komatsu and Mitsubishi or construction companies such as Strabag and others.
3D printing technologies are gradually becoming popular in Russia, with a 3D car part printing factory to be built in Moscow, construction printers developed by the Betonator company, and numerous startups that make use of this technology.
By Natalia Kuznetsova