The application of steel tube in the concrete structure
We often see the water-cooled steel structure system. This is by using the specially designed structure to make the water with rust-roof and freeze-proofing material to be a liquid circulation channel, and then by decreasing the temperature to improve the fire resistance characteristics of the steel pipe. the steel pipe. Only the steel pipe can be used to make the closed channel.
Concrete filled steel tube is the concrete composite column by pouring concrete into the thin-walled steel pipe. The core concrete can prevent the loss of stability of the pipe and the rust of the inner surface, steel pipe BJ can prevent concrete filled steel tube to longitudinal compressive lateral expansion, and it is a kind of composite structure materials by combing steel and concrete with superior performance and easy construction.
The innovation of steel concrete structure generates very fast. Demand for steel, concrete structure is not only the number is big, also eager to them on the varieties, specifications and performance and the development of structure in sync. The development of the concrete structure promotes the innovation of the steel used in reinforced concrete and prestressed concrete used all kinds of new progress in steel.
Composite applications of steel tube
What are the applications of steel pipe structure? steel pipe includes all kinds of welded pipe and seamless pipe, because of the ideal circular cross section, the ability that resistance to local buckling is very strong, and it is the best light component to bear the radial pressure inside and outside. Made from steel tube column and beam element, it can not only separate used in structure, but also can be combined into frame, truss structure types, rack, etc. In the steel and concrete composite structure, is being rolled steel pipe concrete column, has become the new domain of effective application of steel tube.
It is very popular used for space truss structure. Steel bar is the best choice for the ball nodes or screw tied node space truss structure. It is also very common for tall structures, for the steel pipe section has superior performance, and the outer surface of the circular arc can significantly reduce the role of wind load. By using the steel tube mast or mast tower, can make these advantages into full play.
The performance and application of steel tube concrete structure
Steel tube concrete structure is the structure formed by filling concrete. According to the cross section shape, the steel tube concrete can be divided into square steel tube concrete, round steel tube concrete and polygons steel tube concrete. It takes advantage of both steel tube and concrete material combination between role in mechanical process, fully play the advantages of these two kinds of material, and it has greatly improve the plasticity and toughness of concrete, and can prevent or delay the onset steel pipe local buckling, make steel tube concrete with high bearing capacity, good plasticity and toughness, good economic benefits and convenient construction.
Although steel tube concrete is made up of two kinds of materials, it is seen as a kind of new material, the so-called “composite material” (no longer distinguish between steel tube and concrete). And under the different load combinations, the change of the performance is continuous and uniform; Performance of steel tube concrete components with geometric parameters, such as the steel ratio, slenderness ratio, and hollow rate, the change is continuous and uniform; Performance as the physical parameters of steel tube concrete components, such as the strength of the steel and concrete,the change is continuous and uniform; The performance of the concrete filled steel tubular members with the cross section shape, such as round, polygons, octagon, hexagon and a square of the change is continuous and uniform, etc.
In the steel pipe concrete unification theory, the study on mechanical property of high strength steel tube concrete and the fire resistance and fire protection performance had been analyzed.
High strength steel tube concrete performance research is a hot topic of scholars in recent years. This kind of high strength concrete are high intensity that can save cement and decrease the size of member section, reduce weight, and it is used to load a large structure, such as high-rise buildings, underground engineering and the pillar of large-span structure, etc. However, weakness of high strength concrete is brittle with big ductile difference, this will hinder it in the practical engineering application, especially in the complex stress state, the structure is controlled by the brittle failure, its working reliability is reduced greatly. If filled the steel tube with the high strength concrete, the ductility will be greatly enhanced for the restrain of the steel tube. In addition, under the complex stress state, the steel pipe has a great ability of shear and torsion. In this way, through the combination of the two, it can effectively overcome the shortcoming of high strength concrete with big brittleness, make the engineering application of high strength concrete is able to realize, to give full play to the economic benefit. A large number of examples show that compared with the ordinary strength concrete and steel column, steel tube high strength concrete can save 50% steel; Compared with reinforced concrete column, it does not need the template, and can save concrete by more than 50%, reduce the weight of more than 50%, and the steel consumption and cost slightly more or approximately equal.
Adopt high strength concrete filled in steel tube concrete, Except the other advantages of ordinary strength concrete, at least it can save concrete by more than 60% and reduce the weight of more than 60%.
Because the concrete filled steel tube is a new type of structure, the current domestic have not yet set the class structure of fire protection standard, which not only restricts the promotion of the structure, and the structure of the refractory examination have been completed lack the necessary scientific basis. Therefore, further study of fireproof property of the concrete filled steel tube, determine the fire prevention design method and the standard is very important.
