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Fireproof property of steel structure

Date:2016-10-24 22:06:05 Visits:

Steel is a kind of building material which will not burn, it has the characteristic of earthquake resistance, bending resistance and so on. In practical application, steel can increase the load capacity building relative, can also meet the needs of architectural design modeling, but also to avoid the defects of concrete building materials cannot bend, stretch, so the steel construction industry has been favored, monolayer, multilayer, skyscrapers, factories, warehouses, waiting rooms, lounges etc. the steel is very common. However, there are some defects in the fire protection of steel as building materials, the mechanical properties, such as yield point, tensile and elastic modulus and so on will be due to the increase of temperature and a sharp decline. The steel structure is generally 450 to 650 degrees Celsius in temperature will lose the bearing capacity, big deformation, resulting in steel column and beam bending, the results caused by excessive deformation can't continue to use, generally without steel structure fireproof limit protection for 15 minutes. The length of the time is also related to the speed of the heat absorption of the component. In order to overcome the deficiency of fire protection in the practical application, the steel structure material must be treated by fire prevention. The purpose is to increase the fire resistance limit of the steel structure to the limit range of the design code. To prevent the deformation of steel structure in heating in the fire quickly, the measure is varied, the key is to adopt different methods according to different situations, such as the use of thermal insulation and refractory material directly blocking flame burning steel structure, reduce the heat transfer rate of temperature rise, steel structure to postpone the weakening time. But no matter what the method, its principle is the same. The following introduces several different steel structure fire protection measures. First, the outsourcing layer. Is in the steel structure outside the appearance of the added outsourcing layer, can be cast molding, can also use the spray method. Cast in situ concrete encased concrete is usually reinforced with steel wire mesh or reinforcement to limit shrinkage cracks and to ensure the strength of the casing. The spraying method can at the construction site of the steel structure to form a protective layer coated on the surface of sand, sand lime can be cement or gypsum mortar, can also be mixed with perlite or asbestos. At the same time, outsourcing layer can also made of prefabricated gypsum or pearlite, asbestos, asbestos cement, lightweight concrete, the adhesive, nails, bolts in steel structure. Two, water filling (water). Hollow steel structure inner water filling is the most effective protection measures against fire. This method can make the steel structure in the fire to maintain a low temperature, water circulation in the steel structure, absorbing the heat of the material itself. By cooling the heated can be recycled, or by introducing cold water pipe to replace the heated water. Three, shielding. The steel structure arranged in the refractory wall or ceiling, or the gap between two pieces of components concealed in the wall, as long as a little increase or increase the refractory material that can achieve the purpose of fire prevention. This is one of the most economical way to fire the fire. Four, expansion material. The fire protection steel structure, this method has the advantages of fire insulation performance, construction steel structure is not affected by the geometric constraints, generally do not need to add auxiliary facilities, and the coating quality light, there is a beautiful decorative effect, advanced fire prevention techniques to the modern. At present, the high-rise steel structure building is increasing, especially some super high-rise buildings, the steel structure material is more extensive. The high-rise building fire accident, the fire is not in a short period of time can be put out, which requires us to design a building, increase the fire protection for building materials, in order to enhance its fire resistance, and formulate the emergency plan necessary within the building, to reduce casualties and property losses.