Large-span Complex Steel Structure Construction Characteristics

SAFS Steel Structure Engineering Co. LTD would like to introduce the construction characteristics of large-span complex steel structures here.

Firstly, it is of a high construction difficulty. For engineering projects that apply large-span complex steel structures, they usually have the characteristics of large space ratio, large project scale, huge workload of related projects, and large amount of engineering materials and components required and so on. This shows the difficulty and complexity in engineering construction. Due to different material components, there are many differences in structure, form, size, etc., so it will be more difficult to set out in specific construction.

Secondly, it requires high installation accuracy. Under normal circumstances, the large-scale large-span complex steel structure project is mostly a project undertaken by the government, which means that the project completion degree of the project will be reflected in the society as a kind of construction level, so the requirements for the construction of related projects are numerous and strict. For example, in the installation and processing of components, the accuracy of the relevant steps must be refined within the relevant regulations, and the joint construction must be carried out in strict accordance with the national welding seam indicators, so as to ensure that the welding seam effect and installation accuracy.

Large-span complex steel structure projects have strict requirements on construction materials in modern buildings, because they involve many aspects. In order to carry out the normal orderly construction work, the quality and strength of the steel are increasingly stringent in the steel selection process.

Large-span steel structures also require prestressing technical support. In the construction industry, prestressing technology is a vital technology to ensure the quality of design and construction work. In large space and complex steel structures, prestressing technology is mainly used in cable-membrane, cable dome, and overall expansion and contraction in innovative structural buildings.

Steel structure space frame building - the pillar of future construction technology

       A new type of building system of steel structure building has the industry boundaries between the real estate industry, construction industry and metallurgical industry, and is integrated into a new industrial system. This is the steel structure building system that is generally optimistic about the industry.

Compared with traditional concrete buildings, steel structure buildings replace reinforced concrete with steel plates or profiled steels, which have higher strength and better earthquake resistance. And because the components can be manufactured in factories and installed on site. Therefore, the construction period is greatly reduced. Due to the reusability of steel, construction waste can be greatly reduced, and it is more green and environmentally friendly. Therefore, it is widely used by countries all over the world and is used in industrial buildings and civil buildings.

Take the stadium space frame as an example. The stadium refers to a 400-meter runway (including a football field in the center) with fixed road teeth. Outdoor track and field venues with more than 6 runways and fixed stands. The site area is huge, and the roof is usually a transparent semi-closed structure. The stadium space frame structure has good integrity, high rigidity and good seismic performance, and can create a large-span column-free space, which is widely used in small and medium-sized stadium projects. In large-scale stadium projects, it is necessary to form a composite structural system with other types of structures to play their respective advantages. After careful and strict anti-corrosion and fire-proof treatment, the space frame parts are basically maintenance-free within the service life, and the cost performance is very high.

At present, the application of steel structure buildings in high-rise buildings is becoming more and more mature, and it has gradually become the mainstream construction technology, which is the development direction of future buildings.

Precautions for construction of steel structure fireproof paint

      1. The steel structure fire protection spraying protection should be constructed by a professional construction team that has passed the training and has the corresponding construction qualifications. Strict construction plans are formulated according to project characteristics and product selection. The physical and chemical properties of coatings can be sampled according to the needs of the project according to the specified proportion before the project is carried out. For intumescent fire retardant paint, different parts should be selected to test the foaming performance during construction.

2. The surface cleaning of the base material of fire retardant paint should be strictly inspected as a process. Remove dust, iron filings, rust, grease and other substances that hinder adhesion, and do a good job of anti-rust treatment of the substrate. The primer and surface coatings in the fireproof paint shall be matched accordingly, and the primer shall not corrode the steel.

3. The thickness of the coating should reach the design value, and the joint parts should be thickened. The requirements of spraying site, surface treatment of components, filling of joints, paint preparation, number of spraying times, quality control and acceptance, etc., shall all comply with the current national standard "Technical Specification for Application of Fireproof Paint for Steel Structures" (CECS24). The coating thickness should be checked during construction (measured with a thickness gauge). If the cracks in the coating are common and the width is large, it should be studied and analyzed whether the process is correct and whether the mixing ratio of the coating is reasonable.

4. The spraying of fireproof paint should master the consistency of the paint, the pressure of the air compressor and the distance between the spray port and the component during spraying. The main observation during construction is that there are many splashes indicating that the construction parameters are unreasonable and should be adjusted. The amount of diluent in the coating should not be too much, otherwise the normal construction viscosity of the coating will be reduced, and the coating cannot be attached to the surface of the steel structure.

5. In the process of coating construction, it must be done after the previous coating is basically dried and cured. The protection method of the coating, the number of construction times and the thickness of the protective layer should be determined according to the construction design requirements. The coating thickness of each pass should be moderate, and it should not be too thick or not rolled evenly, so as not to affect the coating quality. Strictly follow the painting process, and do not leave safety hazards to the building in order to rush the construction period.

6. After the project is completed, it is not only possible to measure the thickness of the coating, but also to detect the color of the coating and the leakage and cracks by visual method. Tap the coating with a 0.75-1kg hammer to test its strength. Use a 1m ruler to check the flatness of the coating.

The role of the glass dome

      In order to create a comfortable urban leisure space and give full play to the affinity of urban public space, with the official appearance of the glass dome, the urban renewal of the "facade" of the Bund has added landmark buildings.China's distinctive glass dome is undoubtedly the China Port Museum in Ningbo, Zhejiang, and the adjacent national underwater cultural heritage protection base Ningbo Base. The 3 modules of the three glass domes above the roof consist of an irregular elliptical spherical hyperboloid structure.

The main frame of the glass dome is an aluminum alloy frame, and the stress frame is a steel structure. The panel is made of ultra-white tempered laminated glass and external glass. The decorative frame consists of aluminium alloy tubes of different sizes. According to the structure, it can be divided into mesh dome, tension dome, suspension dome and load-bearing dome. According to the material, it can be divided into brick dome, metal dome, film dome, glass dome and wooden dome.The ramps allow visitors to "symbolically rise above the heads of their room representatives".A "lightweight sculpture" at the center reflects the horizon into the interior, while sun visors track the sun's path to block sun gain and glare. The overall image makes people even more admire the greatness of steel structure construction engineers.

The importance of fire fighting equipment in steel structure buildings

In recent years, with the development of urban construction and the increase of high-rise buildings, the development of steel structure buildings in my country is very rapid. During the construction of steel structure buildings, construction waste and construction noise are reduced to a minimum. In addition, steel structure buildings have high seismic performance, easy reconstruction and demolition, and high recycling and reuse rate of materials. It is a green industry with harmonious and sustainable development between man and nature. Please do not ignore the related issues such as fire protection and anti-corrosion.

Due to the many shortcomings of concrete structure buildings, with the advancement of modern technology and the improvement of environmental protection awareness, steel structure buildings have been greatly developed. Whether it is for industrial or civil use, many builders tend to use steel structures. All kinds of steel structure houses stand in the alleys of big cities, which also indicates that a new round of changes in construction has come. Many construction parties strive to make the steel structure to meet the predetermined functional requirements such as safety, applicability and durability under the specified conditions and period of use at the lowest cost. But please don't ignore the firefighting facilities of the steel structure building in the later use. The following points should be paid attention to: the property rights unit, user unit or property management unit of civil public buildings shall implement unified management of the building, and can conduct regular inspections on each steel structure building to facilitate timely discovery of problems and active rectification. In the case of residential buildings, due to their private nature, it is difficult for management units to conduct long-term home inspections. Once the fire protection layer of the steel structure is damaged or fails due to aging, it cannot be found in time, resulting in long-term hidden dangers.

Destruction of fire protection layer of steel structure platform by decoration. Some owners usually renovate the building before use, even if fire protection measures are taken during the construction, due to the lack of professional knowledge of the owners and the importance of it, they did not protect it during the renovation process. Once the protective layer of the steel structure is damaged or even peeled off, it is often not repaired. Once a fire occurs, it will affect the safety of the main structure of the building and cause loss of life and property.

For the fire protection facilities of other civil buildings, such as fire alarm systems and automatic sprinkler systems, the national fire protection regulations have relatively clear requirements. Residential buildings have long been regarded as large-scale and wide-ranging economic buildings with relatively low cost and investment standards. Except for the high-rise residential buildings with a height of more than 100 meters and the high-rise residential buildings belonging to the first-class high-rise buildings, which should be equipped with automatic sprinkler systems, other types of multi- and high-rise residential buildings only need fire hydrant systems. It can be seen that, such as civil buildings that also use steel structure systems, the fire safety factor of residential buildings is relatively low because the regulations do not require the installation of automatic sprinkler systems. I hope everyone will not ignore the importance of fire protection in steel structure buildings.

Installation steps of steel structure columns

The installation of steel structure columns is one of the difficulties in the construction of the radiant chamber of the heating furnace, and ensuring the verticality of each column is the key to the installation of the columns. In order to ensure the construction quality of the column, the "cross reinforcement symmetrical erection method" is used for installation during the construction. Specific steps are as follows:

1. Use a 50t truck to hang the first column on the ring beam at the bottom of the furnace. After aligning with two theodolites from two vertical directions, use four steel wire ropes to seal and temporarily fix it from four directions, and weld the column feet to the ring beam at the bottom of the furnace.

2. After erecting the second column in the same way in the symmetrical direction, use two seamless steel pipes (with connecting plates in the middle) to connect the two columns at about 2/3 of the height and reinforce them into sheets.

3. Use the same method to erect the third and fourth uprights in the vertical direction, and use two steel pipes to reinforce them horizontally. After connecting the four uprights into a frame, remove all the reinforcing cords.

4. With these four columns as the support, a 50t truck is used to erect the other 12 columns in turn. For each erected one, complete the installation and spot welding of the reinforcing ring beam below the cross reinforcement with the previous column at the same time. Then erect the next one in the same way until all are erected.

A 50t truck can be used to hang the hoarding. According to the layout plan, along the mesh steel skeleton from the lower ring to the upper ring of the hoarding. Before the hoarding, according to the arrangement of the board, there is no reinforcing ring beam at the upper and lower ends of the board, and a circle of wall bars can be temporarily set up to facilitate the hoarding and ensure the quality.

Testing method for bolt ball of steel structure space frame

       1. Bolt balls and materials needed to manufacture bolt ball joints. Its varieties, specifications, performance, etc. should meet the national product standards and design requirements.

Inspection method: Check the product's quality qualified documents, Chinese signs and inspection reports.

2. The bolt ball shall not have burning, cracks and folds.

Inspection method: Check a part of the bolt ball of each specification, observe with a 10x magnifying glass and inspect the surface.

3. The bolt ball thread size and thread tolerance should comply with the current national standards.

Inspection method: Check a part of the bolt ball of each specification and measure it with a standard thread gauge.

4. The size and allowable deviation of bolt ball diameter, roundness, and the angle between the center lines of two adjacent bolt holes should comply with the "Code for Acceptance of Construction Quality of Steel Structure Engineering".

Inspection method: Check a part of the bolt ball of each specification, and check whether it meets the specified value with a caliper and an indexing head instrument.

The above four are the detection methods of bolt balls for steel structure space frame. We can apply them to the actual inspection to improve the overall quality of the project.

Technical requirements for the production of space frame steel structure accessories

The current space frame and steel structure accessories include blanking plates, grid rods, bolt balls, high-strength bolts, cone, non-groove nuts and other products. There are high requirements for the production technology of these accessories. Improving production skills can improve the performance of the product is beneficial for the accessories to ensure the entire safety and stability of the building during construction. The following SAFS Steel Structure Space Frame Engineering Co., Ltd. will give you a detailed introduction.

For space frame steel structure accessories, it is necessary to gradually improve the performance of the product. It is very important to add the content of production technology. In the traditional production process, there are many impurities in the produced product, which affects the later use of the product., and the time of use will also be reduced. For the entire project construction, the overall project quality and safety factor will also be reduced, so for space frame steel structure buildings, they will have higher requirements for space frame accessories. The emergence of these situations also forces manufacturers to upgrade their production technology.

The wear resistance and anti-corrosion requirements of steel structure space frame accessories are relatively high. At the same time, due to these accessories are used in the construction industry, they have high requirements for the overall safety factor, because they need to be used after the completion of the large-span space frame project. , If the safety factor does not meet the standard, it will have a great impact on the later use of the building, and affect the service life of the building. Many real estate development industries have the highest requirements for the quality of space frame products, even if the price of the product is relatively expensive, but they are also willing to buy more products, so for space frame manufacturers, they need to learn from foreign production technology and join domestic product production, so that they can have an absolute competitive advantage in the market competition.

How to use steel structure for large-span roof construction

Large-span roof construction is very important for buildings, so what is the process of using steel structure for large-span roof construction? Is there anything to pay attention to? China SAFS steel structure takes everyone to learn together. The space frame manufacturer analyzes the steps of steel structure roof construction:

①When laying glass wool roll felt, the veneer should face the indoor side, perpendicular to the purlin, leave about 20 cm of rolled felt at the eaves of one side, and fix it on the outermost purlin with a special clamp or double-sided tape;

② Ensure that the roll is aligned and tensioned when unwinding, lay the glass wool roll felt on the other side of the eaves, also leave 20 cm of roll felt, and fix it on the outermost purlin with a special clamp or double-sided tape;

③ The two rolls of cotton are connected together by binding with a stapler on the veneer flash;

④ Install the roof color steel plate, remove the fixtures at the eaves on both sides, and use the reserved 20 cm veneer to close the edge of the glass wool;

⑤ Pay attention to maintaining the tension and alignment of the glass wool roll felt, and the joint between the rolls is tight. When the longitudinal overlap is required, the overlap joint should be arranged at the purlin;

⑥ According to the needs of the project, in order to avoid the generation of cold bridges, some hard thermal insulation materials can be considered on the purlins.

The space frame company analyzes three installation methods for the structure of a single-story industrial plant

       SAFS Steel Structure Space Frame analyzes three installation methods for single-story industrial plant structures: piece-by-piece hoisting method, inter-node hoisting method and comprehensive hoisting method.

1. Piece hoisting method

The hoisting method in parts is that when the plant structure is hoisted, only one or two components are hoisted each time the crane is hoisted. Generally, all components are hoisted in three times. The first time to hoist the column, and to correct and fix it; the second time to hoist the crane beam, the connecting beam and the inter-column support; the third time to hoist the roof truss, skylight frame, roof panel and roof support between sections.

Part-to-piece hoisting method, the same type of components are hoisted every time the crane is used. The crane can be selected according to the weight and installation height of the components. Different types of cranes are selected for different components, which can give full play to the working performance of the crane. During the hoisting process, the number of rigging changes is small, the hoisting speed is fast, and the efficiency is high, which can provide sufficient time for component correction, welding and fixing, and concrete pouring and curing.

2. Comprehensive hoisting method

The comprehensive hoisting method means that part of the components in the building (columns, inter-column supports, crane beams and other components) are hoisted by the separate hoisting method. Part of the components (all the components of the roof) are hoisted by the internode hoisting method. The comprehensive hoisting method absorbs the advantages of the piece hoisting method and the inter-node hoisting method. Therefore, this method is mostly used in structural hoisting.

3. Inter-node hoisting method

The inter-node hoisting method means that in one operation of the crane during the hoisting process, all or most of the various types of components are hoisted between the sub-nodes. The advantage is that the crane has a short walking route, and the working surface can be created for the next process according to the interval in time. However, it is required to choose a crane with a larger lifting capacity. The performance of the crane cannot be fully exerted, the rigging is frequently replaced, the installation speed is slow, the supply of components and the layout are complex, and the time for component correction and post-fixing is urgent. This method is generally not used for the hoisting of reinforced concrete structure workshops, and is only suitable for the installation of steel structure workshops and gantry structures.