by In recent days, Mr.
Mao Hongbin’s masterpiece “let precast buildings die” has caused a sensation.
Such an emotional article that lacks basic understanding of the concept, national standard definition, historical evolution and technical principles of precast buildings has read hundreds of thousands and won many praise, indicating that it is not an individual phenomenon that the industry does not know enough about precast buildings, It also reflects the resistance and disgust of people in the industry caused by the strong promotion of precast buildings in some areas regardless of the actual local situation.
I believe that anyone has the right to question, criticize and oppose precast buildings.
I admire Mr.
Mao’s sense of responsibility for the safety of people’s lives and the courage to express his views.
Any questioning voice about precast buildings, no matter for what purpose, is a good thing! At least, it has attracted everyone’s attention and attention, which is more conducive to the promotion and solution of the problem.
Mr.
Xu Demin specially wrote the article “questioning precast buildings is a good thing” for this purpose.
You can go and see it.
Here, I mainly respond to and discuss Mr.
Mao Hongbin’s lack of understanding of the connotation and specific technical details of precast buildings, and even the wrong places.
If there is anything wrong, everyone has different opinions, and you are welcome to criticize and discuss.
If you know what is a precast building, you won’t let it die.
What is a precast building? In short, precast buildings refer to buildings built by precast components through reliable connection.
According to the classification of structural materials, precast buildings mainly include concrete structure, steel structure, wood structure and composite structure.
In history, there are stone structure, iron structure and other building structures with less contemporary application.
Mr.
Mao Hongbin’s “let precast buildings die” generally refers to whether he wants all precast buildings to die? Obviously not, but he exaggerated the problem of attacking all precast buildings.
If you know the definition of precast building in the national standard, you won’t let it die.
According to the definition of three national standards of precast building (concrete structure, steel structure and wood structure precast building standard), Precast building is “a building in which precast components are integrated as the main parts of structural system, peripheral protection system, interior decoration system, equipment and pipeline system”.
The national standard further explains in the article description: the precast building is a systematic project, which is a building that integrates the precast components through modular coordination, module combination, interface connection, node structure and construction method, so as to assemble efficiently and reliably on the construction site, and achieve the integration of building envelope, main structure and electromechanical decoration.
From this, we can see that the precast building should not only pay attention to whether the structure is assembled or not, but also pay attention to the system integration and full decoration, which is in line with the gist and direction of realizing the industrialization of new buildings.
Is it wrong to implement system integration and full decoration? Mr.
Mao Hongbin’s “let the precast building die” is to let the precast building defined in the national standard die? Obviously not, but he used the question of denying all precast buildings very loosely.
If you know the history of precast buildings, you won’t talk about letting them die.
Human beings evolved from primates.
Like all primates, human beings have no architectural instinct.
Human demand for buildings and the ability to build buildings are formed in the process of evolution.
According to archaeological findings, the earliest man-made residence of mankind was about 2 million years ago, almost at the same time as mankind began to use fire.
Perhaps the most direct reason for the origin of “architecture” is the lifestyle around the fire pond and the protection of the fire from being extinguished by wind and rain.
The origin of architecture can be traced far back.
Some animals earlier than primates, that is, animals that appeared earlier than 60 million years ago, are the ancestors of various buildings.
Some animals are born architects.
They can build excellent cast-in-situ “buildings”, precast “buildings” and cave “buildings” without entering the architecture department, mastering structural knowledge and learning construction technology.
The ancestors of cast-in-situ buildings are bees, desert termites and swifts.
Bees use beeswax to build beehives.
There is a kind of desert stone bee, which uses saliva and small grains of sand to mix into “bee concrete” to build a honeycomb.
The process of making paper honeycomb is the same as that of making paper honeycomb with honey bee’s saliva and fiber.
There is a kind of desert termite in Australia.
It mixes feces and sand into “ant concrete”, which can build a 3M high ant nest.
Compared with its body length, such a high ant nest is equivalent to a human skyscraper of more than km, which is higher than the world’s tallest building – the 828m high Burj Khalifa in Dubai.
Swifts use saliva, wet mud and fluffy feathers to build valuable bird’s nests.
The principle of these “bird made concrete” is the same as that of reinforced concrete.
Branches or feathers bear tensile stress, and the gel formed after drying wet mud and saliva bears compressive stress.
There is a kind of bird in South America called stove bird.
The process of building bird’s nest with soft mud is like 3D printing.
The ancestor of cave building is the instinct of earthworms, snakes and rats; Some rats and badgers either dig holes in the soil or gnaw holes in old trees.
Polar bears will use ice holes in the ice or trim out ice holes to live in the holes.
The ancestors of precast buildings are red ants, gardeners and crows.
Red ants build large ant nests with pine needles, twigs, bark, leaves and straw.
They are concave “buildings” with roofs.
There is a kind of gardener in South America.
It uses branches to build houses with courtyards.
It is common for crows to build nests on trees with branches.
Figure 1 the bird’s nest built with branches is the source of precast “architecture”, which is not a new concept and new thing.
Even birds can build precast buildings..
