Exploring the Complete Equipment Steel Structure: In-depth Analysis from Basics to Frontiers- Jiaxing Dingshi Machinery Manufacturing Co., Ltd.

1. Basic Knowledge of Complete Equipment Steel Structure

1.1 Definition and Composition

The Complete Equipment Steel Structure is a building structure system that uses steel as the main load-bearing component and is combined through a specific connection method. It has the remarkable characteristics of high strength, light weight, and convenient construction, and has been widely used in the field of modern construction. Its constituent elements mainly include various types of steel and the way to connect these steels.

In the selection of steel, there are rich and diverse types. Common ones are carbon structural steel, such as Q235, which has moderate strength, good plasticity and weldability, and relatively low cost. It is widely used in general building structures, such as ordinary industrial plants, warehouses, etc. Low-alloy high-strength steel is also a common type, such as Q345, which improves the strength and corrosion resistance of steel by adding a small amount of alloy elements. It is suitable for buildings that bear large loads or have high requirements for structural durability, such as large-span bridges and high-rise buildings. There are also stainless steels, such as 304, 316, etc., which have excellent corrosion resistance and are often used in humid and highly corrosive environments, such as marine engineering and chemical equipment. High-strength steels such as Q550 and Q690 have tensile strengths exceeding conventional steels, which can effectively reduce the amount of steel used, reduce the deadweight of the structure, and improve the stability of the building. They play an important role in some projects with extremely high requirements for structural performance.

The connection method plays a key role in the fully equipped steel structure and directly affects the integrity and stability of the structure. Weld connection is one of the most important connection methods for modern steel structures. It has many advantages, simple structure, and any form of components can be directly connected without complex connectors; economical materials, will not weaken the cross-section of the components, and save steel; convenient manufacturing and processing, easy to realize automated operation, high production efficiency, reliable quality; good connection tightness, can effectively improve the rigidity of the structure. However, weld connections also have some disadvantages. In the heat-affected zone near the weld, the metallographic structure of the steel will change, causing the local material to become brittle; welding residual stress and residual deformation will reduce the bearing capacity of the compressed member; welded structures are more sensitive to cracks. Once local cracks appear, they are easy to extend to the whole structure. The cold brittleness problem is more prominent in low-temperature environments; and the material requirements are high, the welding procedures are strict, and the quality inspection workload is large. Bolt connections are divided into ordinary bolt connections and high-strength bolt connections. Ordinary bolts are divided into three levels: A, B, and C. Grades A and B are refined bolts, and grade C is rough bolts. Ordinary bolt connections are easy to install and disassemble, simple to operate, and low in cost. They are suitable for some parts that have relatively low requirements for connection accuracy and strength, such as temporary structures or connections of secondary components. High-strength bolt connections transmit shear forces by applying pre-tension to generate friction between the connecting parts. They have the advantages of tight connection, good force performance, fatigue resistance, and simple installation. They are widely used in important structural connections, such as frame nodes of high-rise buildings and steel beam connections of bridges.

Rivet connections were widely used in steel structures in the past. Although they are used less now, they are still used in some heavy structures and structures that directly bear dynamic loads. Riveted steel structures have good plasticity and toughness, are easy to check for quality, have reliable connections, good resistance to dynamic loads, and have relatively low requirements for the material of the main steel. However, its structure is complex, and the process of making holes and riveting is labor-intensive. The nail holes will weaken the cross-section of the main material, increasing the cost and construction difficulty.

1.2 Comparison with traditional building structures

There are obvious differences between fully equipped steel structures and traditional building structures in terms of performance, cost, construction cycle, etc., and each shows unique characteristics.

In terms of performance, fully equipped steel structures have significant strength advantages. Steel has high strength and high elastic modulus. Compared with concrete and wood, its density to yield strength ratio is relatively low. This makes the steel structure have a small cross-section and light weight under the same stress conditions, but can withstand greater loads, making it very suitable for building large-span, ultra-high, and ultra-heavy buildings, such as large stadiums and ultra-high-rise office buildings. At the same time, steel has good toughness and plasticity, uniform material, high structural reliability, can withstand impact and dynamic loads well, and has excellent seismic resistance. When natural disasters such as earthquakes occur, steel structures can absorb energy through their own deformation, effectively reduce the degree of structural damage, and ensure the safety of life and property. However, traditional concrete structures have heavy weight and large cross-sectional dimensions of components. In large-span and super-high buildings, they will exert great pressure on the foundation, and their seismic resistance is relatively weak. They are prone to serious damage such as cracks and collapse in earthquakes.

In terms of cost, the cost structure of fully equipped steel structures is relatively complex. On the one hand, the price of steel itself is relatively high, especially some high-performance steels, such as high-strength steel and stainless steel, which makes the material cost of steel structures account for a large proportion of the initial investment. Moreover, the processing and production of steel structures requires professional equipment and technology, and the processing cost cannot be ignored. However, from the perspective of the full life cycle cost, steel structures also have their advantages. Due to the fast construction speed of steel structures, the construction period can be greatly shortened, and the time cost in the construction process is reduced. For some projects that are urgently needed to be put into use, such as commercial buildings and industrial plants, the economic benefits brought by early operation may exceed the increase in initial investment. The maintenance cost of steel structure is relatively low, and its structural durability is good. Under normal maintenance conditions, it has a long service life, which reduces the cost of later maintenance and replacement. Although the material cost of traditional concrete structure is relatively low, a large amount of auxiliary materials such as formwork and scaffolding are required during the construction process, and the construction process is complex and the labor cost is high. At the same time, concrete structure is prone to cracks, leakage and other problems during use, and regular maintenance and repair are required, and the later maintenance cost is high.

In terms of construction cycle, fully equipped steel structure has obvious advantages. The components of steel structure are usually prefabricated in the factory, and advanced automation equipment can be used in the production process, which has high precision and high production efficiency. After the prefabricated components are transported to the construction site, they are quickly assembled by mechanized lifting equipment, and the construction speed is fast, which can greatly shorten the construction period. For example, some large steel structure factories may only take a few months from foundation construction to completion of the main structure. Traditional building structures, such as concrete structures, require a series of processes such as on-site formwork construction, steel bar binding, and concrete pouring. The construction process is greatly affected by factors such as weather and workers' technical level, and the construction period is long. The pouring and curing of concrete alone takes a lot of time. For example, the construction of a multi-story residential building may take a year or even longer.

2. The advantages of fully equipped steel structures are fully demonstrated

2.1 Excellent strength and stability

With its excellent strength and stability, fully equipped steel structures have shown unparalleled advantages in the field of construction and have become the preferred structural form for many large buildings and landmark projects.

In terms of strength, steel has extremely high tensile, compressive and bending strength. Taking the common Q345 low-alloy high-strength steel as an example, its yield strength is not less than 345MPa, and its tensile strength is between 470-630MPa. This means that under the same stress conditions, steel structural components can withstand greater loads than other traditional building materials. For example, when building a long-span bridge, the steel structure can achieve a larger span and reduce the number of bridge piers by virtue of its high strength characteristics, thereby reducing construction costs and the impact on the space under the bridge. Like the famous Hangzhou Bay Cross-sea Bridge, its main structure adopts a large amount of steel structure. The high-strength steel of the main bridge steel beam enables the bridge to cross the vast sea area, withstand huge traffic loads and natural forces, and show strong bearing capacity.

In terms of stability, the performance of steel structure is also excellent. The material of steel is uniform, the elastic modulus is high, and the reliability of the structure is strong. Its structural system can effectively disperse and transfer loads through reasonable design and connection methods to ensure that the structure remains stable under various complex working conditions. For example, in super high-rise buildings, the frame system of steel structure works with lateral force-resistant components such as core tubes to resist the influence of horizontal forces such as wind loads and earthquakes, and ensure the safety of buildings. The Shanghai Tower, with a total height of 632 meters, adopts a giant frame-core tube-cantilever truss structure system. The application of steel structure enables the building to remain stable in the face of natural disasters such as strong winds and earthquakes, becoming an outstanding representative of world construction projects.

In the construction of some industrial plants, the strength and stability advantages of fully equipped steel structures have also been fully reflected. For large-scale machinery manufacturing plants, heavy equipment and frequent lifting operations are required. Steel structures can easily meet these load requirements and ensure the structural safety and normal use of the plant. At the same time, the stability of the steel structure is also reflected in its good fatigue resistance. It can adapt to the frequent vibration and load changes in industrial production and extend the service life of the plant.

2.2 Convenient and efficient construction

The fully equipped steel structure shows remarkable convenience and efficiency during the construction process, which makes it popular in modern construction projects, which can greatly shorten the construction period and reduce construction costs.

The convenience of steel structure construction is first reflected in the prefabrication of components. Steel structure components are processed and manufactured in the factory through advanced automation equipment, which can achieve high-precision production. For example, the dimensional accuracy of components such as steel beams and steel columns can be controlled at the millimeter level, which provides a strong guarantee for rapid assembly on site. In the factory production environment, the components can also be pre-painted and fireproofed, etc., which reduces the process and time of on-site construction. Taking a large steel structure commercial complex project as an example, after the steel structure components are prefabricated in the factory, they are transported to the construction site and assembled by large tower cranes and other lifting equipment, which greatly improves the construction efficiency.

The on-site assembly process is also very efficient. The connection methods of steel structures, such as bolt connection and welding, are relatively simple to operate and can quickly connect components. Bolt connection is easy to install and disassemble, and the connection operation can be completed quickly at the construction site, and it is convenient for later maintenance and modification. Welding can provide a firm connection to ensure the integrity of the structure. During the construction process, construction personnel can choose the appropriate connection method according to the actual situation on site to improve the construction progress. At the same time, the construction of steel structures is less affected by natural factors such as weather. Unlike processes such as concrete pouring, which require specific temperature and humidity conditions, it can continue to construct under various weather conditions, further ensuring the construction progress.

Due to the fast construction speed of steel structures, the construction period of the project can be greatly shortened. This is of great significance for some projects with urgent time requirements, such as commercial buildings and emergency relief projects. The earlier the commercial building opens, the earlier the economic benefits can be generated; emergency relief projects can be quickly built to provide timely shelter for the affected people.

2.3 New choice for environmental protection and energy saving

Under the background of increasing requirements for environmental protection and energy saving in today's society, fully equipped steel structures have become a new choice for environmental protection and energy saving in the construction field with their outstanding performance in many aspects, which is in line with the concept of sustainable development.

From the perspective of environmental protection, steel structures have the characteristics of being recyclable. Steel is a recyclable material. After the service life of the building ends, the steel structure components can be recycled and reprocessed and put back into new construction projects. According to statistics, the steel recycling rate after the demolition of steel structure buildings is as high as more than 90%, which greatly reduces the generation of construction waste and reduces the pressure on the environment. In contrast, the large amount of construction waste generated after the demolition of traditional concrete structures is difficult to handle and causes great pollution to the environment. For example, in urban renewal projects, the demolition and reuse of steel structure buildings are more convenient, which can effectively reduce the emission of waste and realize the recycling of resources.

During the construction process, steel structures also have environmental advantages. Since steel structure components are prefabricated in the factory, there is less wet work on site, which reduces dust, noise and other pollution on the construction site. Compared with traditional construction, the construction waste generated by steel structure construction can be reduced by more than 80%. At the same time, the construction machinery used in the steel structure construction process is relatively small, the energy consumption is low, and the impact on the surrounding environment is small. In some construction projects in the central area of the city, the low pollution and low noise characteristics of steel structure construction can reduce the interference with surrounding residents and commercial activities.

In terms of energy saving, steel structure buildings have low energy consumption during use. The thermal insulation performance of steel structure buildings can be effectively improved through reasonable design and the selection of efficient thermal insulation materials. For example, the use of thermal insulation rock wool boards, polyurethane foam boards and other materials on the exterior walls and roofs of steel structure buildings can effectively reduce the transfer of heat and reduce the energy consumption of buildings during winter heating and summer cooling. The internal space layout of steel structure buildings is relatively flexible, which is conducive to the use of natural lighting and ventilation design, further reducing the use time of artificial lighting and air conditioning systems and reducing energy consumption.

Some green building projects using steel structures have achieved energy self-sufficiency or partial self-sufficiency by adopting new energy technologies such as solar photovoltaic panels and ground source heat pumps, greatly reducing dependence on traditional energy and reducing carbon emissions. These projects have not only achieved remarkable results in environmental protection and energy conservation, but also provided useful practical experience for promoting the sustainable development of the construction industry.

3. Application fields shine

3.1 The preferred choice of industrial buildings

In the field of industrial buildings, fully equipped steel structures have become the preferred structural form for buildings such as factories and warehouses with their unique advantages, providing a solid foundation for the efficient operation of industrial production.

In factory construction, fully equipped steel structures have shown excellent adaptability. For large-scale machinery manufacturing plants, they need to bear the load of heavy equipment and frequent lifting operations. The high-strength characteristics of steel structures enable them to easily cope with these challenges. For example, in large automobile manufacturing plants, various large stamping equipment, welding robots, etc. need to be installed in the workshop. The frame and crane beam system of the steel structure can provide stable support for these equipment to ensure the safety and efficiency of the production process. At the same time, the large span capacity of the steel structure can create a spacious, column-free interior space, which is convenient for the layout of equipment and the arrangement of process flow, and improves the utilization rate of production space.

The fast construction speed of the steel structure is of great significance for some factory projects that are in urgent need of production. In a highly competitive market environment, enterprises that can start production as soon as possible can seize the market opportunity.

In warehouse construction, fully equipped steel structures also have significant advantages. The rapid development of the modern logistics industry has put forward higher requirements for warehouse space and carrying capacity. Steel structure warehouses can achieve large-span designs to meet the large-scale storage needs of goods. For example, warehouses in large logistics distribution centers use steel structure grids or portal frame structures.The steel structure is light in weight and has relatively low requirements for the bearing capacity of the foundation. In some areas with poor geological conditions, it can also reduce the cost of infrastructure construction.

Steel structure warehouses also have good scalability. With the development of the business, the scale of the warehouse may need to be expanded. The connection method of the steel structure facilitates the disassembly and addition of components, which can easily realize the expansion of the warehouse. In addition, the durability of the steel structure is good. Under normal maintenance conditions, it can ensure the long-term and stable use of the warehouse, reducing the cost of later maintenance and replacement.

3.2 The unique charm of commercial buildings

In the field of commercial buildings, the fully equipped steel structure has given a unique charm to buildings such as shopping malls and office buildings with its unique advantages, meeting the diversified needs of commercial space and becoming an ideal choice for modern commercial buildings.

For shopping malls, fully equipped steel structures can provide flexible and open space layout. The interior of the shopping mall needs to be divided into different functional areas, such as shopping areas, dining areas, entertainment areas, etc. The large span characteristics of the steel structure allow the internal space to be freely divided according to business needs, without a large number of load-bearing walls, providing merchants with more display and business space. For example, large shopping malls usually use steel structure frame systems, with spacious and bright interior spaces that can accommodate various large commercial facilities and numerous businesses, creating a comfortable and convenient shopping environment. At the same time, the steel structure has a fast construction speed, which can shorten the construction period of the shopping mall, enable the shopping mall to open as soon as possible, seize the market opportunity, and bring faster returns to investors.

In terms of appearance design, the steel structure has strong plasticity and can achieve various unique architectural shapes to meet the commercial building's pursuit of individuality and attractiveness. Some modern shopping malls use steel structures to create unique facades and roof shapes, becoming the city's landmark buildings and attracting consumers' attention.

As an important place for commercial office, office buildings also have high requirements for spatial flexibility and structural stability. Fully equipped steel structure office buildings can provide open office space, which is convenient for enterprises to carry out personalized decoration and layout according to their own needs. The open office area and flexible partition design can meet the office mode and team collaboration needs of different enterprises. Moreover, the steel structure has good seismic performance, which can ensure the safety of office personnel and the integrity of office facilities when natural disasters such as earthquakes occur. For example, in some earthquake-prone areas, many high-rise office buildings are built with steel structures. Through reasonable structural design and strengthening measures, the earthquake resistance of the building is improved, providing a safe and reliable office environment for enterprises and employees.

Steel structure office buildings also have good sustainability. The recyclable characteristics of steel are in line with modern environmental protection concepts. After the service life of the building,

the steel structure components can be recycled and reused, reducing the generation of construction waste. At the same time, steel structure buildings have low energy consumption during use. By adopting energy-saving equipment and optimizing the building envelope structure, energy consumption can be further reduced and the operating costs of enterprises can be reduced.

3.3 The shining stage of public buildings

In the field of public buildings, fully equipped steel structures have become the shining stage of buildings such as gymnasiums and exhibition halls with their unique advantages and excellent performance. They not only provide people with a fully functional public activity space, but also show the artistic charm of modern architecture.

As a venue for large-scale activities such as sports events and cultural performances, gymnasiums have extremely high requirements for space and structural performance. Fully equipped steel structures play a key role in the construction of gymnasiums. Its high strength and large span can realize the design of large column-free space, meeting the needs of sports competitions and spectators. At the same time, the good seismic resistance and structural toughness of steel structure enable it to maintain structural stability and safety in the face of natural disasters such as earthquakes and strong winds.

In terms of design, the flexibility of steel structure allows the gymnasium to present various unique appearances. For example, the "Ice Ribbon" speed skating hall of the Beijing Winter Olympics uses a saddle-shaped cable net roof composed of 22 domestic high-vanadium closed cables with a span of 198 meters. The amount of steel used is only 1/4 of that of traditional steel structures. It not only achieves lightweight and efficient force-bearing design, but its unique shape also symbolizes the track left by athletes when they slide across the ice at high speed. It is full of dynamic and artistic sense and has become one of the landmark buildings of the Beijing Winter Olympics.

As an important place for displaying cultural, artistic, scientific and technological achievements, the exhibition hall is also inseparable from the support of fully equipped steel structure. Steel structure can provide flexible exhibition space, which is convenient for dividing and adjusting space according to the content and scale of the exhibition. Large exhibition halls usually need to display a variety of large exhibits, and the large span and high load-bearing capacity of steel structures can easily meet these needs.

In terms of appearance design, exhibition halls can use the plasticity of steel structures to create an architectural image that is creative and culturally rich. For example, the "rounded double gravel" shape of the Guangzhou Opera House realizes an irregular hyperbolic roof through the steel structure shell. The unique architectural form is integrated with the surrounding environment, showing the perfect combination of modern architecture and art, and has become a symbol of urban culture and a landmark building.

4. In-depth analysis of the core technology

4.1 Careful selection of materials

In the construction of fully equipped steel structures, the selection of materials is crucial and directly related to the performance, safety and durability of the structure. There are many types of steel suitable for fully equipped steel structures, each with its own unique characteristics and applicable scenarios.

Carbon structural steel is one of the common types of steel, among which Q235 is widely used. It has good comprehensive performance, moderate strength, and a yield strength of about 235MPa, which can meet the bearing requirements of general building structures. It has good plasticity and toughness, can produce certain deformation without sudden fracture when subjected to stress, and has good weldability, which is convenient for welding connection at the construction site. It has relatively low cost and is an ideal choice for ordinary industrial plants, warehouses and other buildings.

Low-alloy high-strength steel such as Q345 has significantly improved its strength by adding a small amount of alloying elements (such as manganese, vanadium, etc.), and its yield strength reaches 345MPa and above. At the same time, it also has good corrosion resistance and weldability, and plays an important role in projects with high requirements for structural strength and durability such as long-span bridges and high-rise buildings. For example, in some cities' iconic high-rise buildings, Q345 steel is widely used to construct the main structural frame to ensure the stability of the building when it is subjected to huge vertical loads and horizontal wind loads.

High-strength steel such as Q550, Q690, etc., has a tensile strength far exceeding that of conventional steel. The tensile strength of Q550 can reach 690-830MPa, and the tensile strength of Q690 is even higher. This type of steel is suitable for special buildings with extremely high requirements for structural performance, such as large-span roof structures of large stadiums and core tube structures of super-high-rise buildings. The use of high-strength steel can effectively reduce the amount of steel used, reduce the weight of the structure, and improve the stability and safety of the building. In the construction of some large-scale sports venues, steel trusses made of Q690 high-strength steel have achieved large-span space spans, providing spectators with a wide column-free viewing space.

Stainless steels such as 304 and 316 are known for their excellent corrosion resistance. 304 stainless steel contains 18% chromium and 8% nickel, has good corrosion resistance and oxidation resistance, and can maintain stable performance in humid and corrosive environments. On this basis, 316 stainless steel adds molybdenum to further improve its ability to resist pitting and crevice corrosion. Therefore, stainless steel is often used in fields such as marine engineering and chemical equipment that have strict requirements for corrosion resistance. In the construction of offshore platforms, stainless steel is used to make key structural components and connectors to resist long-term erosion by seawater.

The selection criteria for steel are strict and multiple factors need to be considered comprehensively. Steel with appropriate strength grade should be selected according to the stress characteristics and design load of the structure. For components that bear large loads, high-strength steel should be selected; for components that are generally less stressed, steel with moderate strength can be selected to achieve economical and reasonable purposes. The environmental conditions in which the structure is located should be considered. For example, in humid and corrosive environments, stainless steel or weathering steel should be preferred; in cold areas, the low-temperature impact toughness of steel should be considered to ensure that the steel will not suffer brittle fracture in low-temperature environments.

The weldability of steel is also one of the important considerations. Welding is a common way to connect steel structures. Good weldability can ensure the quality and performance of welded joints. For welded structures, steel with good weldability should be selected, and its weldability should be evaluated based on the chemical composition and carbon equivalent of the steel. Factors such as the processing performance, supply status and cost of steel should also be considered to ensure that the selected steel can not only meet the performance requirements of the structure, but also be easy to process, manufacture and purchase in actual projects, while controlling costs.

4.2 Ingenuity of design

The design of fully equipped steel structure is a complex and delicate work, which requires full consideration of the safety, functionality and economy of the structure. Among them, structural design and node design are key links, which embody the ingenuity of designers.

In terms of structural design, it is necessary to select a suitable structural system based on factors such as the use function, load conditions and site conditions of the building. Common steel structure systems include frame structure, truss structure, grid structure, cable suspension structure, etc. Each system has its unique force characteristics and scope of application.

The frame structure consists of beams and columns, which are connected by nodes to form a spatial skeleton. It has the advantages of flexible plane layout and high space utilization, and is suitable for multi-story and high-rise buildings. In buildings such as office buildings and teaching buildings, the frame structure can provide spacious indoor space, which is convenient for functional zoning and layout.

The truss structure is composed of rods connected by nodes. It is generally a plane or space structure composed of triangular units. It has reasonable force and can give full play to the strength of the material. It is suitable for large-span roof structures and bridge structures. For example, the roofs of some large industrial plants adopt truss structures, which can achieve larger spans, reduce internal support, and provide a wide space for production.

Grid structure is a spatial grid structure composed of multiple rods according to a certain rule. It has the characteristics of spatial force, high rigidity, and good integrity. It is suitable for large-span public buildings such as gymnasiums and exhibition halls. The roof of the National Aquatics Center "Water Cube" adopts a new polyhedral space rigid frame grid structure, with a steel consumption of only 120kg/m2, which achieves efficient coverage of large-span spaces and shows a unique architectural shape.

The cable-suspended structure is mainly composed of cables, towers and anchors. It uses the tension of the cable to bear the load. The structure is light and suitable for bridges and buildings with super-large spans. For example, the famous Golden Gate Bridge has a main span of 1,280 meters and uses a cable-suspended structure to cross the strait, becoming a classic of world bridge construction.

In the process of structural design, accurate mechanical analysis and calculation are also required. Through the knowledge of structural mechanics, material mechanics, etc., the internal forces and deformations of the structure under various loads are calculated to ensure that the structure meets the requirements of strength, stiffness and stability. With the help of advanced structural analysis software, such as SAP2000, Midas, etc., complex structures can be simulated and analyzed more accurately, providing a reliable basis for design.

Node design is an important part of steel structure design, which directly affects the integrity and reliability of the structure. Node connection methods include welding connection, bolt connection, bolt-welding mixed connection, etc. Each connection method has its advantages and disadvantages and applicable scenarios. Welding connection is one of the commonly used connection methods in steel structure. Its advantages are simple structure, tight connection, reliable force transmission, and steel saving. Welding can make the components form a whole and improve the stiffness and stability of the structure. In some parts with high requirements for structural integrity, such as the connection between steel beams and steel columns, welding connections are often used. However, welding also has some disadvantages, such as welding residual stress and deformation will be generated during welding, which will have a certain impact on the performance of the structure; welding quality is greatly affected by welding process and welder technical level, and welding defects are prone to occur.

Bolt connections are divided into ordinary bolt connections and high-strength bolt connections. Ordinary bolt connections are simple to construct, easy to disassemble and assemble, and have low costs. They are suitable for some secondary structures or temporary structures that do not require high connection strength. High-strength bolt connections transmit shear forces by applying pre-tension to generate friction between the connecting parts. They are tightly connected, have good force performance, and are fatigue-resistant. They are widely used in important structural connections. High-strength bolt connections are widely used in frame nodes of high-rise buildings, steel beam connections of bridges, and other parts.

Bolt-weld hybrid connections combine the advantages of welding and bolt connections and are widely used in some complex node designs. For example, in the connection between steel beams and steel columns, welding connections can be used first to ensure the integrity and rigidity of the nodes, and then high-strength bolt connections can be used to improve the reliability and detachability of the nodes.

In node design, the size and structure of the nodes should be reasonably determined according to the force characteristics and connection methods of the nodes. For example, for welded nodes, the form, size and length of the weld should be determined to ensure the strength and quality of the weld; for bolted nodes, the diameter, number and arrangement of the bolts should be determined to ensure the reliability of the bolt connection. It is also necessary to consider the processing technology of the nodes and the feasibility of construction and installation, so that the node design is easy to process and install on site.

4.3 Continuous improvement of construction technology

The construction technology of fully equipped steel structure is a key link to ensure the quality and safety of the structure. It is necessary to strictly follow the scientific construction process and strive for excellence in each process to achieve the expected effect of the design.

The construction process usually includes steps such as construction preparation, foundation construction, component production and transportation, on-site installation, connection and fixation, painting and protection.

In the construction preparation stage, a detailed construction organization design should be carried out, a construction plan and schedule should be formulated, and the tasks and requirements of each construction stage should be clarified. The construction site should be leveled, measured and laid out to create conditions for subsequent construction. At the same time, the construction personnel should be organized to conduct technical briefings and safety training to ensure that the construction personnel are familiar with the construction technology and safety operating procedures.

Foundation construction is an important foundation for steel structure construction, and its quality directly affects the stability of the entire structure. According to the design requirements, the foundation excavation, pouring and maintenance work should be carried out. For large steel structure buildings, the foundation is usually reinforced concrete foundation. It is necessary to ensure that the size, position and strength of the foundation meet the design requirements. During the foundation construction process, attention should be paid to controlling the flatness and verticality of the foundation.Provide good basic conditions for the installation of steel columns.

The components are made in the factory. Through advanced processing equipment and technology, the steel is processed into the shape and size required by the design. In the process of component production, the processing accuracy must be strictly controlled to ensure that the dimensional deviation of the components is within the allowable range. For example, the length, width, height and other dimensional accuracy of components such as steel beams and steel columns must be controlled at the millimeter level to ensure the smooth installation on site. The components are pre-treated as necessary, such as rust removal and anti-corrosion, to improve the durability of the components.

After the components are made, they must be transported and stored. During transportation, effective protective measures must be taken to prevent the components from collision and damage. According to the progress requirements of the construction site, the transportation time and sequence of the components should be reasonably arranged to ensure that the components arrive at the construction site on time. When storing, a dry and ventilated site should be selected, the components should be stored in categories, and appropriate support and fixing measures should be taken to prevent deformation of the components.

On-site installation is the core link of steel structure construction, and professional lifting equipment and technology are required. According to the weight, size and installation location of the components, select appropriate lifting equipment, such as tower cranes, truck cranes, etc. During the hoisting process, the construction plan must be strictly followed to ensure that the lifting, positioning and installation of the components are accurate. When installing the steel column, first align the bottom of the steel column with the embedded bolts of the foundation, then slowly lower it, adjust the verticality and position of the steel column, and finally tighten the bolts to fix it. The installation of the steel beam is usually carried out from one end to the other. First install the main beam, then install the secondary beam, and firmly connect the steel beam and the steel column through the connecting plate and bolts.

Connection and fixation are key steps to ensure the integrity of the steel structure. For welding connections, operations must be carried out in accordance with the requirements of the welding process, select appropriate welding materials and welding parameters, and control the welding quality. During the welding process, attention should be paid to prevent welding deformation and defects, and necessary inspections and tests should be carried out on the welding joints, such as appearance inspection, ultrasonic flaw detection, etc. For bolt connections, operations should be carried out in accordance with the pre-tension and tightening torque required by the design to ensure the reliability of the bolt connection. When tightening the bolts, tools such as torque wrenches should be used to tighten them in the prescribed order and method.

Coating and protection are important measures to improve the durability of steel structures. After the steel structure is installed, the surface of the component should be painted to form a protective film to prevent the steel from corrosion and oxidation. Before painting, the surface of the component should be thoroughly derusted to ensure the adhesion of the coating. According to the use environment and requirements of the structure, choose the appropriate type of coating and coating process. Under normal circumstances, ordinary anti-rust paint can be used for painting; in a highly corrosive environment, it is necessary to use a coating with better corrosion resistance, such as epoxy zinc-rich paint, polyurethane paint, etc. The thickness and number of layers of the coating must also meet the design requirements. Generally, multiple layers of primer, intermediate paint and topcoat are required to ensure the protective effect.

5. Future Outlook and Trend Forecast

5.1 Integration of New Technologies

In the future, the field of fully equipped steel structures will usher in a wave of new technology integration, and the application of intelligent technology and new materials will bring new opportunities and changes to its development.

The application prospects of intelligent technology in fully equipped steel structures are broad. With the rapid development of technologies such as the Internet of Things, big data, and artificial intelligence, steel structure buildings will achieve intelligent design, production, and management. In the design stage, with the help of building information modeling (BIM) technology, designers can create three-dimensional digital models to accurately design and simulate and analyze every detail of the steel structure. Through BIM technology, collaborative design between different professions can be achieved, effectively avoiding design conflicts and errors, and improving design efficiency and quality. Using artificial intelligence algorithms, design schemes can also be optimized, and multiple feasible schemes can be automatically generated according to different design requirements and constraints. The best scheme can be selected through data analysis and simulation evaluation.

In the production process, intelligent technology will realize the automated production and quality monitoring of steel structure components. Through automated production lines, process parameters such as cutting, welding, and processing of steel can be accurately controlled to improve production efficiency and product accuracy. Using sensors and Internet of Things technology, the production process can be monitored in real time, problems in production can be discovered and solved in a timely manner, and the stability of product quality can be ensured. For example, during the welding process, the quality of the weld is monitored in real time through sensors. Once defects are found, the welding parameters are automatically adjusted or production is stopped for repair.

In the operation and management stage of steel structure buildings, intelligent technology also plays an important role. Through various sensors installed in the building structure, the force, deformation, temperature and other data of the structure are collected in real time, and the health status of the structure is evaluated and predicted through big data analysis and artificial intelligence algorithms. When the structure is abnormal, the system can issue an early warning in time, provide decision-making basis for managers, take corresponding maintenance and reinforcement measures, and ensure the safe use of the building. The intelligent property management system can also realize real-time monitoring and management of building energy consumption, equipment operation status, etc., and improve the operation efficiency and energy saving level of the building.

The application of new materials will also bring new breakthroughs to fully equipped steel structures. In addition to traditional steel, some high-performance steel and composite materials will gradually be widely used. High-strength steels such as Q890 and Q1100 have higher yield strength and tensile strength, which

can further reduce the deadweight of the structure and improve the bearing capacity of the structure. In some super-high-rise buildings and large-span bridges, the use of high-strength steel can reduce the amount of steel used, reduce the project cost, and improve the stability and safety of the structure.

Weathering steel is also a new type of material with broad application prospects. It adds alloy elements such as phosphorus, copper, chromium, and nickel to ordinary carbon steel to form a dense protective film on the surface of the steel. It has good atmospheric corrosion resistance and can be used for a long time without painting. In some outdoor steel structures, such as bridges and towers, the use of weathering steel can reduce maintenance costs and extend the service life of the structure.

The application of composite materials in fully equipped steel structures has also received more and more attention. For example, the steel-concrete composite structure combines the light weight and high strength of the steel structure with the compressive and fire-resistant properties of the concrete structure. It has good mechanical properties and economic benefits and has been widely used in high-rise buildings, bridges and other fields. The combination of fiber reinforced composite materials (FRP) and steel also provides new ideas for the development of steel structures. FRP has the advantages of light weight, high strength, corrosion resistance, and fatigue resistance. After being compounded with steel, it can significantly improve the seismic performance and durability of the structure. It is suitable for building structures in earthquake-prone areas and harsh environments.

5.2 Outlook on Development Direction

In the direction of sustainable development and multifunctionality, fully equipped steel structures have shown a clear development trend and will make important contributions to the transformation and progress of the construction industry.

Sustainable development is an important direction for the future development of fully equipped steel structures. As the world's attention to environmental protection and resource conservation continues to increase, the advantages of steel structure buildings in environmental protection and energy conservation will become more prominent. The recyclable characteristics of steel structure buildings are in line with the concept of sustainable development. After the service life of the building, the steel can be recycled and reprocessed to reduce the generation of construction waste. In the future, steel structure buildings will pay more attention to green design and construction, adopt renewable energy and energy-saving equipment, and reduce the energy consumption of buildings during use. In the building envelope, use efficient thermal insulation materials to reduce heat transfer and improve the energy efficiency of the building. Use new energy technologies such as solar photovoltaic panels and ground source heat pumps to achieve self-sufficiency or partial self-sufficiency in building energy, reduce dependence on traditional energy, and reduce carbon emissions.

In the design stage, the harmonious coexistence of buildings and the environment will also be fully considered, and eco-friendly design concepts will be adopted to reduce the impact on the natural environment. For example, rationally plan the layout and orientation of the building, make full use of natural lighting and ventilation, and reduce the use of artificial lighting and air-conditioning systems. Set up green landscapes and rainwater collection systems around the building to achieve the recycling of water resources and improve the ecological environment.

Multifunctionality is also one of the development trends of fully equipped steel structures. With the continuous improvement of people's demand for building functions, steel structure buildings will have more functions and characteristics. In architectural design, attention will be paid to the flexibility and variability of space so that the building can adapt to different usage needs. By adopting movable partitions and furniture, the free combination and adjustment of indoor space can be achieved to meet the personalized needs of different users. Steel structure buildings will also integrate multiple functions, such as office, residence, business, leisure, etc., to create a comprehensive building space. In some large-scale complex projects in some cities, steel structure buildings organically combine functional areas such as office areas, commercial areas, and residential areas to form a fully functional, convenient and efficient urban living space.

In the functional design of buildings, attention will also be paid to intelligence and humanization, equipped with advanced intelligent control systems, to achieve intelligent management of building equipment, environment, etc., and provide users with a comfortable and convenient living and working environment. In some public buildings, steel structures will have better acoustic, optical and thermal performance, providing people with a more comfortable activity space. For example, in gymnasiums, exhibition halls and other buildings, the acoustic effect is improved by using sound-absorbing materials and reasonable space design, which enhances the experience of audiences and visitors. In the lighting design of buildings, advanced lighting technology and materials are used to maximize natural lighting while ensuring indoor temperature and comfort.

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Exploring the Complete Equipment Steel Structure: In-depth Analysis from Basics to Frontiers