The prefabricated prefabricated volumetric construction (PPVC) means that the building is divided into several space modules. All equipment, pipelines, decoration and fixed furniture in the modules have been completed, and the facade decoration can also be completed. These modules are transported to the construction site and assembled together like “building blocks”.
In foreign countries, modular warehouse offices are rapidly becoming a trend. In the 20th century, Le Corbusier put forward the idea that “architecture is a living machine”, hoping that buildings can get rid of the limitations of materials and structures and become more space products that meet human needs.
China has also created a modular high-rise building technology, called “stainless steel living building technology”, which was developed by the Steel Structure Research Institute of the school of civil engineering, Hunan University.
In Changsha, Hunan Province, the developers once showed how to “turn the building into a living building”. An 11 storey apartment rose in less than 29 hours. To be exact, the apartment was completed in 28 hours and 45 minutes. It was amazing. Such a lightning speed once again shocked the world.
This building is not only the building with the shortest construction period in history, but also its biggest feature is that the whole building does not use any steel and cement. Is this building really solid?
How did this happen?
What is the stainless steel movable building technology
The reason why it is called the living building is that the building is modular assembly. The movable columns and beams are made of thick wall stainless steel profiles. The structure, wall windows, electromechanical and decoration are all manufactured by the factory. The living building modules are transported in 40 foot standard containers, which can be transported to all parts of the world without obstacles and at low cost.
We can see from the media reports that the living building has 11 floors, with a total construction area of about 3000 square meters. The columns and beams of the whole building are made of stainless steel channel steel and square tubes without any concrete. On site, only bolts are used to tighten the modules and plug in water and electricity.
The reason why it can be used for 1000 years is that the stainless steel core plate exclusively developed in China, which is the first in the industry, has creatively solved the core technology of core plate structure applied in the construction industry.
Core technology in stainless steel core plate
As we all know, compared with ordinary steel, rusted steel material has the advantages of good durability, corrosion resistance and low maintenance cost, and the R & D personnel have developed stainless steel core plate based on the honeycomb plate structure which is widely used in the aviation field.
The stainless steel core plate adopts S304 stainless steel sheet as the upper and lower panels, and S304 stainless steel thin-walled core tubes are densely distributed between the upper and lower panels according to a certain distance, and then the panel and core tubes are connected into a solid whole through copper brazing.
The stainless steel core plate is welded by the exclusively invented hot air copper brazing technology. Brazing refers to the method of using a metal material with a lower melting point than the base metal as the filler metal, heating the weldment and filler metal to a temperature higher than the melting point of the filler metal, wetting the base metal with liquid filler metal, filling the joint gap, and diffusing with the base metal to connect the weldment.
The brazing process of stainless steel core plate is as follows: add copper filler metal between stainless steel panel and stainless steel core tube, send it into the brazing furnace as a whole, slowly raise the temperature to above 1000 ℃, then maintain it at above 1000 ℃ for one hour, finally slowly cool it to room temperature, and finally form the stainless steel core plate.
With this brazing process, the final stainless steel core plate is not only 10 times lighter than the traditional structure, but also 100 times stronger in toughness, and can resist super earthquakes and typhoons. It is the material with the highest strength and the largest toughness currently used in the construction field. According to the test, to achieve the same strength, if carbon steel needs 4 tons, then stainless steel core plate only needs 1 ton. At the same time, it is more than 95 times more resistant to corrosion than carbon steel. As a result, the service life of stainless steel core plate is 20 times that of reinforced concrete buildings.
At the same time, the stainless steel core plate structure has the advantages of honeycomb sandwich structure, such as light weight and high strength, good anti vibration effect, good sound insulation effect, etc; It also has the advantages of corrosion resistance of stainless steel, low maintenance cost and low life cycle cost.
How did China’s “stainless steel living building” technology accomplish the construction of 11 floors in 29 hours?
In addition, because of the stainless steel structure, the building adopts 22cm rock wool insulation and 3-4 layers of glass to bring high insulation. Even if the indoor and outdoor temperature difference is more than 10 ℃, the load of air conditioning is only 10% – 20%. The stainless steel core plate is far beyond the 60 year service life of concrete, and also avoids the garbage pollution after the concrete buildings are abandoned.
What are the advantages
In conclusion, such buildings have such advantages. First, stainless steel is extremely durable, earthquake resistant and has strong vitality. Second, adopt thick insulation, multi glass windows and fresh air heat recovery, reducing carbon by 80%~90% compared with traditional buildings. Third, the layout of building units and houses is very flexible, and can be demolished and rebuilt in other places.
Is it possible for such a technology to be commercially available on a large scale? In fact, the Korean version of “huoshenshan” hospital in 2020 adopted this technology from China, because it adopted the most advanced prefabricated construction technology in the industry, and maximized the use of assembled industrialized products and modular core board components, which can improve the production, installation, logistics and labor efficiency by 6-10 times, subvert the traditional construction mode and greatly reduce the workload of field operations, Two Korean versions of “huoshenshan hospital” were built in two days.
In recent years, modularization technology has developed very rapidly. Modularization is to decompose complex systems into independent components through the process of module decomposition and module concentration on the basis of division of labor and knowledge, and then connect the independent components into a complete system through the plug and play interface. The concept of modular design was applied in the field of mechanical design as early as the early 20th century. Due to the limitations of technology and new materials at that time, modular technology has not become the leading technology in production activities.
In recent years, with the development of science and technology, modular production mode has begun to develop. For example, computer production, world petroleum engineering construction, urban rail vehicle electrical wiring modular assembly process, etc. have begun to adopt modular technology, and even chip design and manufacturing are moving towards modularization.
The factory assembly line produces building modules, and the workers assemble them on site. The factory prefabrication mode also makes the building type, apartment type, room type and the number of floors more flexible. The prefabrication of 30 ㎡ modules can be easily changed to 60 ㎡, 90 ㎡, 120 ㎡… Some intelligent application scenarios will even become standard in the future modular buildings. Intelligent interfaces and parts are prefabricated in the building structure in advance, It is easy to realize intelligent home application. This can be said to be the development trend in the future.