High-strength reinforcing steel bar self-compaction steel fiber ultrahigh-strength concrete transfer girder

Abstract

The invention provides a high-strength reinforcing steel bar self-compaction steel fiber ultrahigh-strength concrete transfer girder and relates to a reinforcing steel bar concrete transfer girder. The high-strength reinforcing steel bar self-compaction steel fiber ultrahigh-strength concrete transfer girder overcomes the defect that the common reinforced concrete transfer girder has high self-weight, is difficult to construct and cannot apply the high-strength reinforcing steel bar, the defects that a profile steel concrete transfer girder and a combined transfer girder cannot apply the high-strength reinforcing steel bar and has complex connecting nodes with a concrete frame supporting column, and the defect that the wing edge of a steel girder is easy to buckle under the negative bending moment action of the combined transfer girder. The high-strength reinforcing steel bar self-compaction steel fiber ultrahigh-strength concrete transfer girder consists of a high-strength longitudinal reinforcing steel bar, a high-strength closed hooping and self-compaction steel fiber ultrahigh-strength concrete, restrains the hooping spacing of the whole concrete comprising a concrete protective layer to be 60 to 80 mm, and restrains the hooping spacing of the longitudinal reinforcing steel bar to be 80 to 150 mm, wherein the outer surface of the whole concrete is in level with the outer surface of the transfer girder. The high-strength reinforcing steel bar self-compaction steel fiber ultrahigh-strength concrete transfer girder organically combines the self-compaction steel fiber ultrahigh-strength concrete, the high-strength hooping and the high-strength longitudinal reinforcing steel bar and completely exerts the advantages of different materials, so that the earthquake resistance of the transfer girder is greatly improved and the transfer girder has a wide application prospect in high-rise and super high-rise structures.

Description

technical field [0001] The invention belongs to a building structure component and relates to a concrete transfer beam. Background technique [0002] Due to the functional requirements of the building, there is a large space in the lower part, and the vertical components in the upper part cannot be directly connected to the ground, but are connected to the vertical components in the lower part through a horizontal conversion structure. The beams supporting the upper columns or shear walls are called transfer beams. Compared with other types of transfer structures, the transfer beam has the advantages of clear and quick force transmission path, reliable operation and simple structure. [0003] At present, there are several types of transfer beams: 1. Reinforced concrete transfer beams; 2. Steel concrete transfer beams; 3. Steel-concrete composite transfer beams. [0004] At present, the yield strengths of the profiled steel, longitudinally loaded steel bars and transversely...

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Problems solved by technology

[0005] At present, the strength of concrete used in transfer beams in my country is lower than C50, mainly because the low yield strength of stirrups cannot effectively restrain high-strength and ultra-high-strength concrete

[0006] The reinforced concrete transfer beam has its own weight: it weighs hundreds of tons, and it is difficult to support the formwork and pour concrete; the yield strength of the longitudinally stressed steel bars and transversely loaded steel bars is lower than 500 MPa, and the steel bars in the beam are crowded, which is not convenient for construction; concrete protection The layer is not effectively restrained. Under the action of reciprocating earthquake force, the concrete protective layer is easy to crush and fall off at the places where the beam mid-span and the beam end have large bending moments, which is not conducive to the formation of plastic hinges and is not conducive to the seismic resistance of the transfer beam; , the concrete protective layer is the weak link in the concrete under shear compression. The concrete protective layer that is not effectively restrained is easy to be crushed, which is not good for the ductility of the component; because the basis for the joint work of steel bars and concrete is the strain coordination, the yield strength exceeds 700 M The strain of steel bars with Pa reaches 3,500 microstrains when they yield in compression, and the ultimate compressive strain of concrete is 3,300 microstrains. There is a difference in deformation between high-strength steel bars and concrete, and cracks occur. In this way, high-strength steel bars with a yield strength of more than 700 MPa When the concrete is damaged, it cannot yield, and its advantages of high yield strength have not been brought into play, so it is not easy to be popularized and applied in engineering.

[0007] The steel-concrete transfer beam needs to carry out steel structure construction and reinforced concrete structure construction at the same time, and the construction is difficult, and the joint structure with the frame pillar is complicated, and the joint construction is difficult; the yield strength of the section steel, longitudinal stress reinforcement and transverse stress reinforcement are all lower than 500 M The concrete cover is not effectively restrained, and under the action of reciprocating earthquake force, the concrete cover is easily crushed in the middle of the beam span and where the bending moment at the beam end is large, which is not conducive to the formation of plastic hinges. , which is not conducive to the seismic resistance of the transfer beam; when the shear compression is damaged, the concrete cover is the weak link in the concrete under shear compression, and the concrete cover that is not effectively restrained is easy to be crushed, which is not good for the ductility of the component; because the steel bar and concrete can work together The basis of the work is strain coordination. The steel bar with a yield strength of more than 700 MPa has a strain of more than 3,500 microstrains when it is subjected to compression, and the ultimate compressive strain of concrete is 3,300 microstrains. There is a deformation difference between high-strength steel bars and concrete, resulting in Cracks, such high-strength steel bars with a yield strength exceeding 700 MPa cannot yield when the concrete is damaged, and the advantages of high yield strength cannot be brought into play, which is not convenient for popularization and application in engineering

[0008] The steel-concrete composite transfer beam, like the steel-concrete transfer beam, belongs to the type of composite beam, and the structure of the connecting node with the frame pillar is complicated, and the construction of the node is difficult; the yield strength of the steel is lower than 500 MPa, and the steel is heavy; under the action of the earthquake force, the mid-span Under the action of negative bending moment, the flange of the steel beam is easy to buckle; the concrete protective layer is not effectively restrained, and under the action of reciprocating earthquake force, the concrete protective layer is easily crushed at the beam end and the beam mid-span where the bending moment is large, which is not conducive to conversion Beam anti-seismic; when the shear compression fails, the concrete cover is the weak link in the concrete under shear compression, and the concrete cover that is not effectively restrained is easy to be crushed, which is not good for the ductility of the component; because the basis for the joint work of steel bars and concrete is Strain coordination, when the steel bar with a yield strength of more than 700 MPa is under compression, the strain reaches more than 3500 micro-strains, and the ultimate compressive strain of concrete is 3300 micro-strains. High-strength steel bars with a strength of more than 700 MPa cannot yield when the concrete is damaged, and the advantages of high yield strength cannot be brought into play, which is not convenient for popularization and application in engineering

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