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THREE-DIMENSIONAL PRINTING TECHNOLOGY IN CIVIL ENGINEERING

Авторы:
Город:
Петрозаводск
ВУЗ:
Дата:
17 февраля 2019г.

The contemporary customer demand for housing is constantly increasing due to the expedient growth of human population. The widely practiced conventional approach in housing development and economic challenges experienced by the bigger portion of human population call for new ideas in civil engineering and construction technologies. Introduction of innovative technologies into the area of civil engineering should increase the speed of housing construction significantly. It sounds strange today, but 3- D printing construction technology may become basic soon.

According to the latest statistics, around 7 billion people inhabit the Earth today and about 4,5 billion of them reside in big cities. Therefore, more than 50% percent of the total population are urban citizens. If all goes the way it does now, 9.2 billion people will inhabit the planet by 2050. Most probably, they will choose to live in huge urban centers because of the proximity to their work places and due to the possibility to enjoy a more comfortable life. Agglomerations all around the world will grow like newer seen before. The number of people looking for accommodation to work and live in will grow exponentially. It looks like a real problem waiting for its quick solution.

This challenge can be considered as a new opportunity come up with new approaches and to formulate new concepts on how new cities should be planned and developed. Such cities should generate less garbage and carbon dioxide, become smart and sustainable, ecologically friendly and safe.

The solution for many countries is to rebuild and expand existing residential developments. Some countries are already testing these ideas to be realized in the nearest future. They are, for example, South Korea (New Songdo City), China (Tianjin Eco-City), Abu Dhabi (Masdar City). Such innovative projects are very demanding and require huge financial investments and human intellectual abilities.

When a country becomes wealthier, it has the opportunity to build cities from scratch or, so to say, from ground zero, while the race of salaries comes along. At a certain point, the thoughtful and skillful implementation of the system involving cooperation of machines and construction technologies starts bringing considerable profit. Today numerous countries and their institutions are involved in the research of mechanized system’s usage. The employment of new construction technologies in civil engineering industry can make the process of large settlements’ development much cheaper. Some countries such as USA, Japan, and China invest a lot of money and human capital into the realization of this ambitious goal.

The basic idea of such innovative projects is to rely on methods on which 3D-printing process is based. For example, to print a tea cup we have to, first, make a virtual 3D-model of this object. Later the model will be materialized by a special printing machine layer by layer.

Modern prototypes of the concrete-using 3D-printers are able to build dynamic shapes of house-walls.

The so called Contour crafter is a first 3D printer able to print houses in field conditions in a short period of time. Even though most of the Contour crafter operations are controlled by the built in computer system, this machine is not fully autonomous A team of highly skilled workers is required to serve and maintain all the mechanisms involved into the process of construction.

In addition this technology requires the use of special construction vehicles

The 3D constriction starts with the process of site leveling, afterwards, the craftsmen lay a solid concrete foundation. The Contour crafter runs on specially constructed rails. The machine is placed on top of them with the help of a truck crane.

To reach a specific point in the three-dimensional space and to provide movement of the 3-D printer three axes X, Y, and Z are required. The X-axis is defined by the direction of the rails. The Y-axis is defined by the height of the crane arm: 3D-printer becomes higher and higher during the process of construction. The maximal construction height reaches 6 m, which correlates with a 2-level house. The last axis is defined by the cross beam, which is connected to a print-head of the Counter crafter.

The 3D printing technology requires the use of special construction materials. In house construction industry it is a fast drying concrete. A construction machine (a mixer) brings it to the construction site, and then the material is put into a special container connected to a print-head by special tubes. A computerized system of the

Counter crafter controls all movements of the print-head.

The print head of the contour crafter machine is very mobile and can be twisted into different positions. The 3D-printer is used to build up both load-bearing and standard walls. Both types of the walls have numerous holes and openings, which can be used for different installments and nets. Such

“unconventional” wall structure saves them from drilling. The print-head runs from one side of the wall to another, applying construction material layer by the layer.

Upon finishing the first level of the structure, such elements as doors and window lintels are installed. That

is the moment when a robotic arm of the special crane comes into play. It can grab, transfer and build in the above mentioned elements. The robotic arms are also involved into the process of floor installment. Such traditional contraction elements as concrete plates, concrete slabs or special metal structures rolled by mechanized robotic arms are part of the 3D construction process. Thereafter, a layer of concrete is poured on top of this metal structure to make a monolithic floor. Upon this procedure the 3D-printer is ready to continue its work. The machine work is complete after preparing the base for the future roof; thereafter, the team of craftsmen starts finishing the house.

Let’s look at the economic effectiveness of the 3D-printing technology on the example of the 2-level house with the accumulative floor space of 110 square meters. This house is compared to the same size structure built with the use of traditional construction technologies and a team of 4 brick layers.

Table 1

 

Characteristics

Brick layer (workers)

3D-printer operator

Number of workers

4

1

Productivity

6 cubic meters of bricks per shift

1 house per shift

Duration of work

20 shifts

1 shift

Salary

150 000 RUB

<<150 000 RUB

 

A team of 4 brick layers is needed to construct a house of the targeted size. At the same time, only one 3D- printer operator is employed in the similar type of work.

A team of 4 workers lays 6 cubic meters of bricks per shift and finishes the work in 20 shifts. Only one 3D- printer operator erects a complete house during one shift.

The income of the team of workers exercising traditional construction technologies amounts to 150 000 rubbles. The salary of the operator is not defined yet, but if to approach this question technically and to divide the salary of the brick layers’ team by 20 shifts then 1 shift of the 3D-printer operator might cost about 7 500 rubbles.

In is essential to mention that this technology has both advantages and disadvantages.

Table 2

 

Advantages

Disadvantages

Challenges

The increase in the speed of house

construction development.

The limited height of the building

Rising       unemployment     among

construction workers.

 

The decrease in the working costs

 

Specially organized construction site

A       need      to      develop      new

construction materials fitting for 3D-printer.

A     great     potential    for    future

construction                technologies’

evolvement

 

Typical architectural structure of the buildings

 

High skilled workers

 

This technology increases the speed of house construction and reduces cost of erected houses. On the other hand elevates the number of unemployed people and asks for workers with special engineering skills. In addition it requires development of the special construction site and elaboration of modernized construction materials fitting for 3D printing technology. At this stage of its development 3D printing construction technology can provide people with typical and limited in size and height structure, but it definitely has a great potential in solving housing problems of the growing population.

Based on everything mentioned above we can ascertain that this construction technologies has a promising future for every developing country including Russia.

The final construction products are typical by the looks.



References

 

1.        Canadian Wood Frame House Construction: Canada Mortgage and Housing Corporation, 3d edition, revised, 2014. - 351 p.

2.        Low income housing [Электронный ресурс] // CONTOUR CRAFTING Robotic Construction Systems URL:    http://www.contourcrafting.org/low-income-housing

3.        Top    ten     construction    technologies     [Электронный     ресурс]    //     URL:     https://www.raconteur.n et/business/top-ten-construction-innovations

4.        Ten          futuristic          construction          technologies          [Электронный ресурс]  //          URL: https://science.howstuffworks.com/engineering/structural/10-futuristic-construction-technologies1.htm