According to the architectural characteristics of steel structure residences, fire is the main safety hazard of steel structure buildings. This article proposes that coating and spraying methods are the most common solutions for steel structure fire protection, and how to determine the fire resistance grade of steel structures, with engineering examples. Explain the important role and construction technology of GF fireproof board in steel structure fireproofing.
With the development of science and technology, new materials are used more and more widely, among which steel is a commonly used one. Buildings with steel structures as the main body are the mainstream of the development of modern spatial structures. It is of great significance and value to explore modern steel structure buildings. Fire is the main safety hazard of steel structure buildings. It is proposed that cladding and spraying methods are the most common solutions for steel structure fire protection, and how to determine the fire resistance grade of steel structures. It also explains the important role and construction of GF fireproof boards in steel structure fire protection. Craftsmanship. At present, new technologies, new processes, and new products in steel production in our country are increasing day by day, making the building structure full of the flavor of the modern era. It has actually been proved that steel structure buildings have broad development prospects in our country.
Ⅰ.Architectural characteristics of modern steel structures
1.High degree of pre-engineering, reduced construction costs and shortened construction period
The coordinated and unified standards for steel structure building modules have achieved industrialized mass production of buildings, improved building pre-engineering, and made building components of different materials, shapes and manufacturing methods have a certain degree of versatility and interchangeability. At the same time, the pre-engineering of steel structure buildings integrates material processing and installation, which greatly reduces construction costs; it also speeds up the construction speed, shortening the construction period by more than 40%, thus speeding up the capital turnover speed of real estate developers, making the building more efficient. Put into use earlier.
2.The design and function of the building and structure are integrated to make the building more functional.
In steel structure buildings, structure has become an important factor in the image composition. The shape, components, and nodes of the structure lead to and restrict the image of the building to a large extent. Only by integrating the design and functions of buildings and structures can the building be more functional so that subsequent design links can be carried out, creating a steel structure building that integrates technology and art.
3.Steel structure buildings can meet the requirements of super height and super span
Steel has a uniform structure, close to isotropic homogeneous body, high strength and high elastic modulus. The ratio of its density to strength is much smaller than that of masonry, concrete, and wood. Under the same stress, the steel structure has a small self-weight, so it can be made into structures with larger spans and higher heights as well as flexible structural shapes. The National Stadium “Bird’s Nest” steel structure project has a large number of complex truss columns, main trusses, and secondary structure welding nodes. The welds are crisscrossed and the construction is very difficult. Now humans have the ability to build super-large domes with a span of more than 1,000 meters and super-tall buildings with a height of more than 1,000 meters and up to 4,000 meters. Moreover, the combination of steel cables and membrane structures to form a cable-membrane structure system can better meet the span requirements of the building, making this type of building a landmark building. The building height is high, the structure span is large, and the seismic performance design requires high welding quality of the main steel structure. For example: the connection welds between frame beams and columns, the connection welds between shear plates and columns, the connection welds between beam webs and columns, and column splicing welds, etc., are all main parts of the structure and are basically slopes. It has first-level penetration of welds and 100% ultrasonic flaw detection, which requires very high welding quality. There are many varieties and specifications of steel used, and more and more low-alloy high-strength structural steels and large-thickness steels are used. With the continuous improvement of steel production technology, cast steel, austenitic stainless steel, and composite steel plates are also increasingly used. Many applications. Therefore, before on-site construction, it is required to conduct real-time weldability tests of new steel types based on the delivery status of the steel used, explore scientific welding process parameters, and formulate corresponding welding process measures.
4.Raw materials can be recycled, contributing to environmental protection and sustainable development
The development of steel structures is of particular significance to my country, which is very short of resources and energy, because China is the world’s largest country of brick and concrete buildings. Steel is a high-strength and high-performance material with high recycling value. The scraps are also valuable and do not require molding construction. At present, internationally eye-catching new residential products have been introduced into our country. Its environmental protection and energy-saving characteristics are mainly reflected in two aspects: (1) This type of residence adopts a fully enclosed thermal insulation and moisture-proof system, with small temperature changes and low heat loss. No matter winter or summer, it has a comfortable living environment. When the outdoor temperature is 0 degrees Celsius, the indoor temperature can still remain above 17 degrees Celsius; when the outdoor temperature reaches 30 degrees Celsius, the indoor temperature is only about 21 degrees Celsius. (2) Compared with brick-concrete structure residences, it can save more than 60% of energy, air conditioning equipment can save more than 30% of electricity consumption in winter and summer, and the waste utilization of the structure is 100%. Compared with brick-concrete structure, under the same floor height condition, The steel structure maintains a small wall area, saving energy required for air conditioning and reducing maintenance costs.
Ⅱ.Fire protection construction methods in architectural design of steel structures
Structural fire protection problems of buildings are generally easier to solve on reinforced concrete structures, but more factors need to be considered on steel structure buildings. The following are two commonly used fire protection measures: one is to use the coating method, and the coating method is to use bricks. , concrete, calcium silicate board and other materials to wrap the steel structure to form a protective layer and improve the fire resistance limit of the components; the second is to use spraying method, using thick or thin fire retardant coatings according to different parts of the steel structure. It is to apply a layer of fire retardant coating on the surface of the steel structure to form a protective film, thereby improving the fire resistance limit of the building components. It is divided into thick and thin types. Different thicknesses of coatings have different fire resistance limits.
1.GF fireproof board
The construction and application of new fireproof board GF-1100 super calcium silicate fireproof board (hereinafter referred to as GF fireproof board) in steel structure building fireproof technology. This fire protection technology is a new steel structure building fire protection technology jointly developed by Laigang Construction Co., Ltd. and Laizhou Mingfa Insulation Materials Co., Ltd.
(1) Main components of GF fireproof board. GF fireproof board uses CaO and SiO2 as the main raw materials, and undergoes high-temperature and high-pressure chemical reactions. It is supplemented with reinforcing fibers and inorganic auxiliary materials. (2) Fireproof board-GF board manufacturing method and device. The key points of the manufacturing method and equipment of GF fireproof board are to prepare the slurry as required, keep it in the gelling tank at 80-140°C for 3-30 hours, perform gelling reaction, and input the resulting slurry into the plate making machine to make the plate. The plates are then steamed, dried, and cut into finished products. (3) Performance of GF fireproof board: GF fireproof board is an inorganic non-combustible board, which is a semi-permanent material. It has excellent properties such as high heat resistance, strong thermal insulation performance, low bulk density, high specific strength, and good durability. The maximum operating temperature can reach 1100°C. It does not produce toxic gases under high temperature and fire conditions. It is a green and environmentally friendly building material.
2.Fire protection construction technology for steel structure residential buildings
The main body of this project adopts steel structure design, and the foundation adopts concrete raft foundation. The main body is a steel frame-shear wall structural system, the beams are hot-rolled H-shaped steel beams, and the support columns are made of welded spiral steel pipes.
According to the design requirements, the fire resistance level of the main structure is Level 2, that is, the fire resistance limit of the beam is 1.5h; the fire resistance limit of the column is 2h. This project uses 20mm thick (fire resistance limit 2h) and 25mm thick (fire resistance limit 3h) GF fireproof boards, which can fully meet the fireproof design requirements.
(1) How to install GF fireproof board on steel beams
The steel beam is made of 20mm thick GF fireproof board. Determine the installation position and cutting size of the keel on the steel beam that needs fire protection, and cut the keel according to the size. Configure the high-temperature adhesive powder and glue into a high-temperature adhesive, and coat the contact surface between the keel and the steel beam. Apply high-temperature adhesive and then bond it to the steel beam.
After the high-temperature adhesive solidifies, the GF fire-proof board can be cut according to the size of the steel beam, and the cut GF fire-proof board can be fixed on the keel with air nails (T50).
(2) How to install GF fireproof board on steel columns
The steel columns are made of 25mm thick GF fireproof board. Determine the position of the vertical keel (the keel is made of C75 light steel keel) and mark it. The vertical keels against the wall are directly fixed on the wall with steel nails, and the keels that are not against the wall are fixed between the upper and lower floor slabs with steel nails. Determine the size of the horizontal keels (C50 light steel keels) based on the fixed vertical keels. The distance between the horizontal keels shall not be greater than 500mm. The connection between the horizontal keels and the vertical keels shall be connected with rivets (see Figure 2). Determine the size of the GF fireproof board according to the fixed keel size and cut the material. Use air nails (T50) to fix the cut GF fireproof board on the keel.
Ⅲ.Conclusion
Using GF fireproof panels to protect steel structures to improve their fire resistance is an ideal and simple measure. GF fireproof board is not only an excellent fireproof material, but also a decorative material, which can compensate for the displacement deviation of steel beams and columns and improve the aesthetics of factory interior decoration. The surface of GF fireproof board can be directly sprayed, pasted and other interior decorations can meet the decoration requirements of different parts.