Keywords

1 Introduction

1.1 Small Steel Structure Prefabricated Building

Low-rise housing has long been criticized for its traditional cheap and low-skilled construction. With the technological progress of the industry, the values of consumers and practitioners have changed, the small steel structure prefabricated buildings have gradually entered the public life. Under the background of building industrialization, small steel structure prefabricated buildings can achieve quality improvement, efficiency improvement, technology upgrading, resource conservation, and environmental friendly demand is one of the best construction methods [1, 2].

Compared with concrete structure, it is found that the steel structure prefabricated building only has higher material consumption and construction tool usage costs, but has obvious advantages in labor costs and construction period input. In addition, the prefabricated structure building site construction is simple, the construction speed is fast, the construction efficiency is high, and it can be recycled, which can play a lot of economic benefits for on-site cost control and has a broader economic benefit prospect [3, 4] (Table 1).

Table 1. Proportion of prefabricated residential construction cost of the project [5].
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1.2 Status of Small Prefabricated Residential Buildings

Southwest China is mostly mountainous and hilly, with a large rural area. With the improvement of living standards, in the process of urban-rural integration development, consumers have put forward different levels of demand for small residential buildings, diversified product designs and prosperous markets. Through the team's investigation, it is found that the common small prefabricated houses in southwest China have the following problems:

The construction is arbitrary, causing a certain degree of damage to the ecological environment. Some small residential buildings directly choose local building materials, the construction is arbitrary, there is no planning, increase construction waste and pollution emissions, and have a greater impact on the ecological environment.

The interior space structure is single, and additional interior decoration is required. The indoor space combination and scale of small houses are relatively single, and they are blindly seeking large. At the same time, after the completion of construction, more interior space decoration is required, and the construction period is extended.

Building safety and weather resistance are uneven, and the living function is not perfect. The construction technology content is low, the building weather resistance is poor, the use comfort is poor, and the occupants have a bad experience.

Poor economy, insufficient sustainability of building resource utilization. Today's products are expensive, require high maintenance, and have low reusability. When changes or adjustments are required for objective reasons, it is difficult to reorganize and use, and the green ecological sustainability is not strong.

2 Small Prefabricated Housing Design Strategies

2.1 Adapt to the Site and Respect Nature

Southwest China is mountainous with many high slopes, rugged roads, great climate change, cold winters and hot summers. Most of the local houses originated from the dry column type, and the building complex varied from place to place, forming a rich courtyard layout, including: stilt building, concave shape, one seal and one zigzag. The building complex is built along the mountain, does not pay attention to strict orientation and geometric symmetry, and has a flexible layout; Focusing on ecology and nature, it embodies the concept of “the unity of nature and man” [6, 7].

2.2 Recycling and Ecological Protection

Small steel structure prefabricated buildings, in the process of construction and use, pay attention to the combination with the ecological environment, to avoid continuous damage to the environment; The construction period is short, and the assembly and decoration are convenient; Building safety guarantee, can provide a comfortable living experience; The recycling of building resources is highly sustainable. In addition, considering the differences in different construction conditions, it also takes into account the characteristics of standardized design and mass production [8].

2.3 Standard Space and Perfect Function

Carefully analyze the function of residential buildings, design standard modules such as living room, bedroom, kitchen, bathroom and balcony, and the modules can be independently spliced in combination with the design theme, which can be extended horizontally and widened horizontally, and can also be heightened vertically. At the same time, the building itself light control system, water supply system and sewage treatment system and other functions are combined with design.

In the process of combining space modules, it can also be adapted to the different use objects of the room by replacing furniture and soft furnishings, such as redefining its use function; Lightweight partition walls can also be used to change the position of the original wall door openings in the room, so that the function of the room can be changed to adapt to different stages of the family [9].

2.4 High Security and Diverse Styles

The main body of the steel structure prefabricated building structure should have good force performance, easy to disassemble and replace, and fatigue resistance; Pay attention to the small thermal conductivity of the roof and wall, and the thermal insulation performance should be good. While taking into account the comfort and aesthetic effect, reduce construction waste and avoid environmental pollution. In addition, by choosing a combination of various styles, the transformation of exterior design, material and interior decoration can be realized, forming a personalized and independent style effect, avoiding the dilemma of single similarity.

3 Application Case of Small Steel Structure Prefabricated House – “Four Seasons of Heshan”

Located in the Heshan Four Seasons project located in Heshanping, Jiangjin, Chongqing, the main body of the building adopts a small steel structure assembly building, which has the advantages of fast and environmental protection, free and efficient, safe and comfortable, and strong sustainability (Fig. 1).

Fig. 1.
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General layout of the project.

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This paper takes this project as an example to explain the practical application of small steel structure prefabricated buildings in southwest China.

3.1 Build Quickly and Protect the Environment

The architecture of Heshan Four Seasons implements the design concept of modularization and lightweight into the whole process of design and production, maximizing industrialization, convenient transportation, and rapid assembly, so as to adapt to the topographic characteristics of the mountains in southwest China.

Through full investigation and practice summary, the structural design of the project imitates the traditional dry-column building in the southwest region, applies the traditional building frame structure system to the prefabricated building, is based on independent small piles, and uses steel square pipe as the structural frame, forming an overall overhead building form, without ground hardening, without occupying surface green space, so as to adapt to various complex terrain and landforms in southwest China. In addition, under the condition that the overhead height of the building is sufficient, the overhead layer can continue to cultivate, or form a semi-open flexible space, which can be used for drinking tea and resting after work, and further meet the daily life needs of residents on the basis of protecting the natural environment.

3.2 Free Space and Diversified Decoration

Through the subdivision of functions, five basic modules are formed: living room module, bedroom module, kitchen module, bathroom module and balcony module, which are spliced horizontally and vertically independently in combination with the design theme. In addition, the interior and exterior decoration insulation composite integrated board is used as the maintenance system, and the interior and exterior wall decoration is realized synchronously through one installation and basic molding. While ensuring comfort and aesthetics, avoid the cost and environmental pressure caused by secondary renovations.

At the same time, in the process of design and production, the project combines local cultural characteristics, shows the charm of local cultural characteristics, and becomes a beautiful local cultural landscape (Figs. 2 and 3).

Fig. 2.
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Courtyard renderings 1.

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Fig. 3.
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Courtyard renderings 2.

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3.3 High Security and Perfect Functions

The project building is based on steel structure, which has good force performance, removable and replaceable, and fatigue resistance; All steel structure surface thermosetting powder coating anti-corrosion treatment, oxidation corrosion resistance, can guarantee the design service life of more than 50 years.

Fig. 4.
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Real scene of project courtyard.

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Fig. 5.
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Interior decoration.

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The building itself integrates the whole house intelligent light control system, water supply system and sewage treatment system, and at the same time can be integrated into energy (solar energy, wind energy), heating (floor heating, radiator), weak current (remote control system), artificial intelligence and other humanized scientific and technological details according to demand, intelligent cameras, intelligent door locks, etc. are unified into the building's IOT system, which is convenient and safe. After installation, you can move in, making it easy to achieve a comfortable and smart living experience (Figs. 4 and 5).

3.4 Resource Circulation and Strong Sustainability

The whole system of the small steel structure assembly building of Heshan Four Seasons is composed of frame structure system, wall system, roof system and ground system, each of which is an independent system, and the structure is a large frame structure, bolts are actively connected, few connection points, and easy and quick disassembly. The main steel adopts a large size, thickness and strength, which ensures the complete rate of disassembly.

According to statistics, in the process of dismantling such buildings, the damage rate of floor and roof decoration materials is about 10%, and the damage rate of floor and roof base slabs is less than 5%. Therefore, the overall disassembly damage rate is about 10%, which reflects the advantages of relocation and reuse.

4 Conclusion

Through research and comparison, the paper expounds the advantages of steel structure in the prefabricated construction industry. Combined with the common problems of small prefabricated buildings in southwest China, four design strategies for small steel structure prefabricated buildings are proposed. Finally, taking the project “Heshan Four Seasons” in Chongqing, China as an example, the practical application of methods such as fast construction, environmental protection, free space, diversified decoration, high safety, perfect function, and strong sustainability of resource circulation is expounded, and strives to provide a reference for the application of small steel structure prefabricated buildings in southwest China.