A Confined Steel Tube Concrete Member

Abstract

A constrained concrete-filled steel tube component, which is composed of longitudinal bars (1), stirrups (2), steel tubes (3), core concrete (4), and interface layer (5), is characterized in that the core concrete (4) is filled in Inside the steel pipe (3), an interface layer (5) is provided between the steel pipe (3) and the core concrete (4), and one or more decompression notches (6) are provided on the surface of the steel pipe (3), and each decompression The length of the notch (6) is along the circumferential direction of the component, and the depth of the decompression notch (6) is greater than or equal to 80% of the thickness of the steel pipe (3) and less than the thickness of the steel pipe (3). The decompression notch ( 6) The sum of the widths is not less than 2% of the component length, and fiber-reinforced composite material (7) is arranged in the decompression notch (6), and its fiber direction is along the circumferential direction of the component. The invention overcomes the technical defect that the steel pipe mainly bears the vertical stress and is easy to buckle in the common steel pipe concrete structure, and is suitable for vertical load-bearing components of various bridges and buildings.

Description

technical field [0001] The invention relates to a restrained steel pipe concrete component, which is applied to various bridges and column structures of buildings, and belongs to the field of civil engineering. Background technique [0002] In the CFST structure, steel and concrete work together to give full play to their respective advantages, so that the member has good ductility, especially excellent seismic performance. At the same time, the CFST structure has the advantages of convenient construction and high rigidity. However, CFST The structure still has its own inherent deficiencies: 1) The steel pipe must bear both vertical stress and lateral stress, and the steel pipe mainly bears vertical stress; 2) The effect of vertical stress makes the steel pipe inevitably buckle locally failure mode, which reduces the ductility of the CFST structure, and the buckling is difficult to repair. [0003] Under the conditions of commonly used design parameters in engineering, the ...

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Problems solved by technology

[0002] In the CFST structure, steel and concrete work together to give full play to their respective advantages, so that the member has good ductility, especially excellent seismic performance. At the same time, the CFST structure has the advantages of convenient construction and high rigidity. However, CFST The structure still has its own inherent deficiencies: 1) The steel pipe must bear both vertical stress and lateral stress, and the steel pipe mainly bears vertical stress; 2) The effect of vertical stress makes the steel pipe inevitably buckle locally failure mode, which reduces the ductility of the CFST structure, and the buckling is difficult to repair

[0003] Under the conditions of commonly used design parameters in engineering, the compressive bearing capacity of conventional steel tube concrete structures is slightly greater than the simple superposition of the vertical bearing capacity of steel tubes and core concrete. The reason is that the steel tubes have a certain restraint on the core concrete. It is equivalent to increasing the vertical bearing capacity of the steel pipe directly by about 1.3 times. If the steel of the steel pipe is completely used as a restraint, it is equivalent to an ordinary restraint stirrup, which can increase the vertical bearing capacity of the steel pipe directly by about 2.0 times. However, conventional concrete-filled steel tube structures cannot exert this effect. Traditional technologies tend to strengthen the integrity of steel tubes and concrete. For example, Chinese Patent No. "201210580378.4" discloses "a kind of SCS steel tube concrete Structure", using shear nails to strengthen the bond between steel pipe and core concrete, and Chinese Patent No. "201320034226.4", which discloses a steel pipe concrete column, which improves the grip strength of steel pipe and concrete by welding threaded steel bars inside the steel pipe, These technologies make the steel pipe more focused on the role of vertical bearing, rather than the effect of circumferential restraint. Simply opening notches on the surface of the steel pipe, the steel pipe still bears a large load due to the bonding and friction between the steel pipe and the core concrete. vertical stress, and the steel pipe at the notch will undoubtedly buckle in advance, forming a weak section

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