The mainly material of the so-called "steel building homes" is a steel structure frame supplemented by colored metal profiled steel plates. Its architectural performance is descendent from the portal steel frame. Generally speaking, light steel residential buildings are recognized by all walks of life for their simplicity and clarity.
To solve the housing shortage problem, some European countries have adopted a highly industrialized steel structure building system, built a large number of prefab houses, and formed a batch of complete and standard steel structure housing systems. In Finland, Sweden, Denmark, France and other countries, steel structure building systems are very popular. Sweden's steel structure, especially light steel structure, is the most developed, and light steel structure residential prefabricated components account for 95%. At the same time, Sweden is also the world's largest manufacturer of metal building homes.
The load-bearing structure adopts cold-formed thin-walled light steel framework, adopts high-strength, anti-corrosion steel coil (yield strength 550Mpa, zinc-aluminum alloy coating thickness 270g/m2), and steel thickness is 0.75mm. Through computer-aided manufacturing special equipment, according to design requirements, directly rolled into various types of structural components. The vertical load-bearing members adopt close-packed columns, with the maximum column center distance of 600mm. Plane load-bearing components: the roof adopts a stringer mesh with a grid size of 600X600mm.
The floor (ground) surface adopts truss beams with a maximum middle distance of 1200mm, and the lintels of doors and windows adopt small truss beams. The wall enclosure structure adopts light-weight high-strength enclosure material or fiber cement board. The roof, floor, inner and outer walls are made of waterproof and thermal insulation materials. The roofing and floor system adopts waterproof glass fiber tiles, waterproof coiled materials, thermal insulation material cotton, stringers, and hanging fireproof gypsum board.
The production of steel structure adopts computer-aided manufacturing technology, and the whole process of production is completed with professional equipment controlled by computer software to ensure that the accuracy of component manufacturing is within half a millimeter that is difficult to achieve by humans. Except for the foundation construction, the rest are all dry work construction and installation.
The cold-formed thin-wall pre engineered metal building system is a mature technology in Australia. Special CAD technology-light steel structure construction design software is used in the design, and the design file generated from this can be directly input to the processing equipment for automatic processing.
The stable supply of steel causes little price fluctuations. The wall with thin-walled light steel structure can maintain an excellent plane, which means that the wall will not rebound or shrink and break when you nail the nail. Because the material can be cut to the required length in advance, waste is reduced to a great extent. Besides, the scrap of steel can also be sold, which greatly reduces waste. The basic treatment is simple and suitable for a wide range of geological conditions, and the basic part can save 50% of the cost of traditional buildings. Reasonable wall thickness makes the user's house acquisition rate about 8% higher than that of general existing buildings, and because of the fast construction, the capital turnover period is shortened, the capital flow rate is accelerated, and the cost is correspondingly reduced.
The metal frame homes originated in the United States. Its background is the destruction of forests caused by excessive felling of trees, which in turn led to the deterioration of the entire global environment. In this situation where the world is advocating the protection of forests, the technology of light steel structure was jointly developed by 13 American companies and quickly spread in the United States. Due to environmental protection, reasonable design, fast completion speed, and excellent seismic performance, it was built in Japan after the Great Hanshin Earthquake in 1995 and is becoming more and more popular.
The light steel frame house is a construction method that replaces the wooden frame of the traditional wooden house with a section steel frame. The material used is 100% steel. The parts are connected by screws and nails, and no welding or adhesive is used. So there is no need to worry about the harm to the human body caused by the use of medicines in the construction process. Besides, the construction site will not pollute the surrounding environment caused by a large amount of dust and noise.
The profiles of light steel structure houses are mass-produced in the factory, and the skeleton is assembled in the factory and assembled on site. Only 1 professional on-site guidance and 7 installation workers are required to complete the construction of the skeleton of a house within the normal design time.
Residential steel buildings are light in weight, and their structural weight is only 1/5 of the weight of traditional brick-concrete structures, which greatly reduces the load received during earthquakes and has high safety. Besides, high-strength screws and bolts imported from Japan are used to connect and fix the skeleton and the frame, and the installation is scientific and fast. At the same time, structural calculations are made for each building during design, and the foundation and overall structure of the building are designed based on structural calculations. Structural calculations are the crystallization of tests and practices in the United States and Japan, with patented technology rights and national certificates.
The steel is a non-combustible material, and is protected by deep galvanizing, which can prevent corrosion and termites, and can automatically repair the damage of the coating.
The external heat insulation method used in steel framing systems utilizes the unique properties of thin-walled light steel structures. The frame is tightly covered from the outside with a thin plastic heat insulation and moisture-proof material, and a layer of heat insulation material is added. There is an air layer outside the thermal insulation material, and various materials can be used for various exterior wall treatments according to the customer's requirements for the exterior wall of the building. The external heat insulation method does not require heat insulation treatment inside the skeleton, and the inside can be directly treated as an inner wall. The principle is similar to a thermos bottle. Therefore, based on not increasing the construction cost, the excellent energy-saving and thermal insulation effect is achieved through the treatment of the building structure, and the disadvantages of moisture and insects caused by condensation are overcome. Therefore, the external heat insulation method has quickly replaced the internal heat insulation method, thus ensuring the characteristics of the thin-walled metal structure that it is warm in winter and cool in summer. When the outdoor temperature is 0 degrees, the room can still maintain 17.2 degrees of natural air convection to regulate the indoor temperature.
steel structure homes make full use of the superior characteristics of steel, which is in line with the current mainstream selection of building materials. Because the thin-walled light steel structure building uses steel, it will not age with the loss of time. Besides, 100% of the waste steel can be recycled. At the same time, thin-walled light steel structure buildings can also use recycled steel. In the United States, every 5 to 6 waste cars can build a 180 square meter house.
Prefab metal homes are similar to wood structures. Under the same construction requirements, the labor time and cost of skilled workers with thin-walled light steel structures are much lower than those of wooden structures. The thin-walled light steel structure profiles are mass-produced in the factory. The skeleton can be assembled in the factory and installed on the construction site. Only 1 on-site guidance and 7 installation workers are required to complete the construction of a house skeleton. Because the profiles are thin and light, they can be built by hand.
There are many choices of material size and thickness, which provides a lot of space for designers to consider whether they are designing for cost or designing for efficiency.
The floor surface of the metal building houses is composed of cold-formed thin-walled steel frame or composite beam, floor OSB structural plate, supports, connectors, etc. The materials used are oriented strand board, cement fiber board, and plywood. Each square meter on these lightweight floors can bear a load of 316 to 365 kilograms. The weight of the floor structure system of the light steel structure residence is only one-fourth to one-sixth of the traditional concrete floor system, but its floor structure height is 100-120 mm higher than that of ordinary concrete slabs.
The steel built home roof system is composed of roof truss, structural OSB panel, waterproof layer, light roof tiles (metal or asphalt shingles). The roof of light steel structure can have a variety of combinations and materials. Under the premise of ensuring the waterproof technology, there are more options for appearance.
The walls of steel structure house are mainly composed of wall frame columns, wall top beams, wall bottom beams, wall supports, wall panels and connectors. Light steel structure houses generally use internal transverse walls as structural load-bearing walls, and wall columns are C-shaped light steel components. The wall thickness is determined according to the load, usually 0.84 to 2 mm, and the distance between wall posts is generally 400 to 600 mm. The wall structure arrangement method of the light steel structure house can effectively bear and reliably transmit the vertical load, and the arrangement is convenient, but the steel residence wall structure cannot bear the horizontal load.
To ensure the thermal insulation effect of the prefab steel homes, the thermal insulation materials used in the outer walls and roofs of the buildings can be used for a long time and can keep warm. In prefab steel structure homes, in addition to filling glass fiber between the wall columns, a layer of insulation material is attached to the outside of the wall, which effectively cuts off the thermal bridge from the wall columns to the external wall panels. The joists between the floors are filled with glass fiber to reduce the heat transfer through the floors; all the wall columns of the inner walls are filled with glass fiber to reduce the heat transfer between the household walls.
One of the most critical issues for steel house construction is the application of fire protection technology. The fire resistance rating of steel construction is level 4. In light steel structure houses, fire-resistant gypsum boards are pasted on both sides of the walls and the ceiling of the floor. For ordinary firewalls and household walls, 25.4 mm thick (1 inch) gypsum boards are used to protect them to meet the fire protection requirement of 1 hour. Besides, the glass fiber is filled between the wall columns and the floor joists.
The light steel frame home is filled with glass wool between the inner and outer walls and the floor joists, which effectively prevents audio transmission through the air. As for the impact sound propagating through solids, the following structural treatment is done: for the household wall, two wall columns are used to form two walls with intermediate spaces. For the small keel used to fix the gypsum board for the ceiling, an elastic structure with small cut grooves is used to effectively reduce the transmission of structure-borne sound between floors.
The metal structure buildings have fast on-site construction and are completely industrially assembled. The dry construction method is adopted for construction, which will not cause waste of water materials. Besides, it saves costs, has low labor loss, and can completely achieve civilized construction. The construction speed is rapid. The construction of the same volume is only 1/4 of the construction time of traditional buildings. The construction speed of traditional concrete and brick-concrete structures is slow, wet work is carried out, and the labor loss is excessive.
Light steel structure houses are environmentally-friendly and sustainable products. All materials are environmentally-friendly and can be recycled and reused. Compared with traditional brick-concrete buildings, it can avoid resource depletion caused by clay bricks. Compared with reinforced concrete buildings, because light steel structure steel can be recycled in the future, but concrete cannot be recycled, it will be construction waste in the future, causing environmental pressure.
The light weight of the steel house, the metal material properties and the necessary shear wall structure determine the inherent seismic performance of the light steel structure system. Since the seismic activity is left and right and up and down, the light steel structure connected by fasteners forms a safe and stable box, which will not cause the wall to collapse or the floor fall to endanger personal safety due to the shaking of the earthquake. The poor seismic performance of brick-concrete buildings is recognized by most people, and the Sichuan earthquake is already a good example. To achieve the same seismic performance of concrete buildings requires higher structural material costs. On the contrary, it will increase the overall construction cost and increase the difficulty of construction and design.
The flexible combination of structural materials and the matching of various supporting decorative materials in prefab steel houses can faithfully and perfectly restore the architectural design plan, which can give architectural designers more imagination and provide flexible design options. The limited range of steel frame building design options for traditional building structures will bring more design constraints to architectural designers. If the building is of the same complex type, the cost of traditional building materials will be higher than the construction cost of light steel structure.
The reason why prefab villas have been widely concerned by the market and sustained development is that light steel structures have outstanding results in many indicators such as energy conservation and environmental protection. Let's take a look at the aspects of its highlights.
The CO2 emission from the construction of steel frame houses is about 480kg/m2, which is more than 35% lower than the traditional concrete carbon emission of 740.6kg/m2.
The weight of light steel residential high-rise buildings is about 900-1000kg/m2, and traditional concrete is about 1500-1800kg/m2, and its weight is reduced by about 40%. It can greatly reduce the consumption of cement, sand and other resources, thereby greatly reducing the carbon emissions in the process of mineral excavation, smelting and transportation; there is no need for wooden formwork and scaffolding during the construction of steel building homes. If its market share increases by 5 percentage points, it can reduce timber logging equivalent to 9,000 hectares of forest; reduce building weight and save about 30% of underground pile foundations.
Residential steel homes are mainly assembled on site, which can greatly reduce sewage discharge during the construction process. If its market share increases by 5 percentage points, it will reduce sewage discharge equivalent to the total water volume of 10 West Lake.
CCA lightweight grouting wall has a good self-insulation function, which is three times the thermal insulation performance of traditional brick walls, which greatly reduces operating energy consumption.
The "tall, light and strong" feature of steel structure makes it easy to realize high-rise buildings and can improve the efficiency of land use per unit area. The indoor housing acquisition rate can increase by 5%-8%, and the underground garage parking space can increase by 10%-20%. Nowadays, when the problem of small amount of money and difficulty in parking is highlighted, its socio-economic value is particularly prominent.
Assembly construction reduces noise disturbance, waste water discharge and dust pollution at the construction site; reduces sand and gravel mining and construction waste discharge, protects the environment, and creates a new era of architectural civilization.
When the building is demolished, the recycling rate of the main structural material of the light steel frame houses is above 90%, which is about 60% less than the traditional concrete waste discharge. Reduce the occupation of land resources by construction waste landfill and the pollution of surface and groundwater sources by harmful substances in waste (construction waste accounts for about 40% of the total social waste). Resource utilization of industrial waste: industrial waste is the main material in the composite wall; waste is turned into treasure: the CCA wallboard is mainly made of quartz sand tailings; the light grouting filler is mainly made of industrial waste such as fly ash .