Nine prefabricated building problems that you are concerned about

The prefabricated building is the intuitive manifestation of the prefabricated construction link in the building industrialization, and is the prefabricated parts and components produced by the factory assembled on the construction site, and the whole process should be standardized design, factory production, assembly construction, integrated decoration, information management and intelligent application.

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Prefabricated buildings have the advantages of stable quality, low energy consumption, low pollution, high production efficiency, reduced safety accidents, low labor intensity, and good working conditions.

Recently, many fans have left messages, asking Xiaozhu many related questions about prefabricated buildings,

Today, Xiaozhu sorted out 9 questions that everyone is concerned about from the message to answer.

Q1: Is the quality and safety of the prefabricated building guaranteed? Is it sturdy?

In the design process, through the simulation of various calculation models, diversified and all-round physical experiments, and the practice of a large number of projects at home and abroad, it is proved that the quality and safety of the house can stand the test, and the technology is mature and reliable.

Due to the fact that a large number of parts and components are produced in factories, the ability to control the quality of prefabricated buildings is far greater than that of traditional cast-in-place on-site wet operations.

Q2: Are all prefabricated buildings concrete?

At this stage, there are three main ways of industrialized production of construction in China:

Precast concrete prefabricated building (PC building)

A building built with prefabricated concrete components as the main components, assembled and connected and partially cast-in-place concrete structures;

Steel structure building

The steel structure is the main structure, combined with the industrial floor slab and internal and external wall system, to form a complete building system, which has the advantages of wide application range, light weight, energy saving and environmental protection;

Timber frame assembly building

Due to the limitations of resources and environmental conditions, there is a long way to go to promote it nationwide.

Q3: Can it resist earthquakes?

At present, the seismic performance of China's prefabricated building structure is basically equivalent to the seismic performance of cast-in-place structure, and even some performance exceeds the seismic performance of cast-in-place structure building, which can meet the fortification requirements of Beijing earthquake level 8.

One of the key technologies that can resist earthquakes: the connection technology of prefabricated nodes.

At present, the technology mainly used in Beijing was born in the United States in the 70s and introduced to Japan in 72, the sleeve is prefabricated in the component, and the other end of the steel bar is connected by high-strength grouting at the construction site.

Steel bar filling sleeve connection technology, last century slurry sleeve connection in Japan and the United States has been a lot of practice, including sleeve stress-strain curve, cyclic tensile fatigue test, such a technology after long-term experiments, and after the test of strong earthquakes, the United States and Japan have concluded that it can be used boldly in high-rise buildings.

In addition, prefabricated buildings can also enhance seismic performance by introducing seismic isolation measures.

Q4: In the past, there were large board houses, why do you want to promote prefabricated buildings now?

In the 80s of the last century, the focus of China's capital construction shifted from production to life, and in order to quickly solve the people's housing needs, prefabricated large-slab buildings began to appear and develop rapidly. Since the beginning of the 90s, the slab building "suddenly died".

The reasons for this phenomenon are as follows:

First, the market requires diversified house types and personalized decoration, and the large plate structure system fails to solve the contradiction between design standardization and diversification, resulting in an increase in the difficulty of factory production and an increase in costs;

Second, the large plate structure system failed to solve the waterproof problem well, and a large number of leaks occurred in about 15 years after completion;

Third, the cast-in-place concrete construction technology (such as large formwork technology) has developed rapidly, migrant workers have entered the city, and the labor cost is low, which has accelerated the demise of the large slab structure system;

Fourth, with the urgency of China's demographic dividend reduction and environmental pollution, the 18th National Congress of the Communist Party of China put forward the requirements of "ecological civilization construction", the construction industry must take the industrialization road of saving resources and energy and reducing environmental pollution, combined with domestic and foreign experience, the use of prefabricated buildings is one of the main means.

Q5: How about the sound insulation?

The prefabricated building floor slab adopts a superimposed floor slab, which is different from the hollow floor slab in the past, which is a layer of concrete floor slab reproduced on the basis of the prefabricated floor slab, so as to form a solid prefabricated monolithic floor slab.

Lightweight concrete interior partition walls are usually made of lightweight slats or concrete products, etc., and their materials themselves have superior sound insulation properties. Its light steel keel partition wall usually adds sound insulation materials such as rock wool or insulation board in the middle, which meets the national standard in terms of sound insulation standards.

In terms of sound insulation standards, it is not only consistent with the cast-in-place floor slab, but also has good flatness, saves formwork and facilitates construction.

Q6: The joints of the prefabricated building are glued together, how to avoid frost heave, corrosion, rain and snow leakage and other problems?

At present, the prefabricated building solves the problem of water leakage through three ways: structural waterproofing, structural waterproofing, and material waterproofing.

Structural waterproofing: vertical joints cast-in-place concrete pouring, the structure is self-waterproof.

Waterproof structure: Horizontal seam anti-sill structure prevents water from flowing into the room.

Material waterproofing: The exterior wall joints are made of "improved silicone glue" for material waterproofing.

Q7: Is the cost of prefabricated buildings high?

In essence, the construction technology of the prefabricated and cast-in-place construction methods is quite different, the construction process is different, the organization and management methods are different, and the economic, social and environmental benefits brought by the two are also different, and the "cost" between the two should not be simply compared.

Generally speaking, the increase in the cost of prefabricated buildings mainly includes: prefabricated component products and transportation costs, on-site installation and hoisting costs, large machinery leasing fees, wall and floor joint treatment and related material costs;

The cost reduction mainly includes: the steel and concrete works are carried out in the prefabricated component factory, which reduces the cost of on-site masonry, reduces the cost of plastering, and also reduces the cost of on-site support and formwork.

In addition, at present, the state vigorously promotes prefabricated buildings, and will increase policy support to reduce the incremental cost of prefabricated buildings through area incentives, the implementation of full decoration to shorten the construction period, technical training of industrial workers, reduce labor costs, and reduce construction costs in the construction industry.

Q8: What is the status of prefabricated buildings in foreign countries?

 

Europe

Europe is the origin of modern industrial reform, and the industrial production of housing is no exception, especially in the Nordic region due to the cold climate, short construction period, and high labor costs. Europe is the first region to emerge the "factory prefabrication, on-site assembly" residential production and construction mode, among which Finland, Sweden, Norway and other countries have a building prefabrication rate of more than 70%.

Japan

70% of Japan's urban residences are single-family villa buildings, most of which are light steel and wood structure systems, and there are many high-rise residences in large cities, most of which are "prefabricated frame structure systems", and the technical characteristics of the system are "prefabricated frame structures + exterior wall hanging boards", which generally carry out the main construction, and then carry out the installation of hanging boards.

United States, Canada, Australia

The United States, Canada, Australia due to the small population density, ordinary houses are mainly independent villas, coupled with the pursuit of rich wood resources and individualization, generally rarely use concrete structure, the structural system of villas is mostly light steel structure or wood structure, the required parts have been completely standardized and combined, can realize factory production, and even residents can buy all kinds of building materials needed in the supermarket, and they can complete the construction of the house.

Q9: Is there a market for prefabricated buildings in China?

At present, most of the national government's affordable housing is built in prefabricated buildings, which has been greatly improved in terms of quality, housing scale and household standardization.

In addition to government affordable housing, commercial housing in the field of prefabricated buildings has also gradually expanded, from the newly adopted "13th Five-Year Plan" prefabricated building action plan, by 2020, the proportion of prefabricated buildings in the country will reach more than 15%, of which the key promotion areas will reach more than 20%, actively promote the area to reach more than 15%, and encourage the promotion of the area to reach more than 10%.

Establish and improve the prefabricated building policy system, planning system, standard system, technical system, product system and supervision system, form a number of large-scale production enterprises and general contracting enterprises of prefabricated building design, construction and parts, form a professional team of prefabricated buildings, comprehensively improve the quality, efficiency and quality of prefabricated buildings, and realize the comprehensive development of prefabricated buildings.

We believe that in the future, prefabricated buildings will become a major gospel of the domestic construction industry.