Restricted type steel tube concrete member

Abstract

A restricted type steel tube concrete member jointly consists of a longitudinal bar (1), a stirrup (2), a steel tube (3), core concrete (4) and a boundary layer (5), and is characterized in that the steel tube (3) is filled with the core concrete (4); the boundary layer (5) is arranged between the steel tube (3) and the core concrete (4); one or more than one pressure reducing notch (6) is formed in the surface of the steel tube (3); the length of each pressure reducing notch (6) equals the annular periphery of the member in the perimeter direction; the depth of each pressure reducing notch (6) is greater than or equals 80% of the thickness of the steel tube (3) and smaller than the thickness of the steel tube (3); the sum of widths of the pressure reducing notches (6) is not smaller than 2% of the length of the member; a fiber reinforced composite material (7) is arranged in each pressure reducing notch (6); and a fiber direction of the fiber reinforced composite material (7) is along the ring direction of the member. The technical shortcoming that the steel tube in a common steel tube concrete structure mainly bears vertical stress and is easy to bend is overcome. The restricted type steel tube concrete member is suitable to be a vertical load-bearing member 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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