CN111980151A - Cast-in-place square column precast square beam concrete frame node - Google Patents

Abstract

The invention discloses a concrete frame joint of cast-in-place square columns and prefabricated square beams. Top longitudinal reinforcement, upper cast-in-place area of multiple superimposed square beams. The cast-in-place concrete square column and two precast concrete square beams are connected by pouring concrete, the upper cast-in-place area of the superimposed square beam is connected with the precast concrete square beam by pouring concrete, and the bottom longitudinal bars of multiple beams pass through the unbonded anti-buckling sleeve A plurality of unbonded anti-buckling sleeves are located at the bottom of the precast concrete square beam, and a plurality of beam top longitudinal bars are located in the upper cast-in-place area of the superimposed square beam and the cast-in-place concrete square column. The invention uses the unbonded anti-buckling sleeve at the end of the prefabricated laminated square beam to lengthen the free elongation distance of the steel bar, thereby increasing the length of the plastic hinge, thereby improving the rotational ductility of the end of the square beam, and overcoming the reciprocating load of the structure when the structure is subjected to reciprocating load. , the problem of buckling of the steel bar in the sleeve.

Description

A cast-in-place square column prefabricated square beam concrete frame joint

technical field

The invention relates to the technical field of building structures, in particular to a concrete frame joint of cast-in-place square columns and prefabricated square beams.

Background technique

During the earthquake, the concrete at the beam end of the concrete frame cracks under the action of tensile force, resulting in a sharp increase in the strain of the steel bar at the cracked concrete. The hinge length improves the rotational ductility of the beam end. But under seismic reciprocating loads, the rebar will buck within the PVC casing when under pressure.

SUMMARY OF THE INVENTION

Purpose of the invention: The purpose of the present invention is to provide a concrete frame joint of cast-in-place square columns and prefabricated square beams. The length of the plastic hinge improves the rotational ductility of the square beam end and prevents the buckling of the reinforcement inside the sleeve.

Technical scheme: In order to achieve the purpose of the present invention, the technical scheme adopted in the present invention is: a concrete frame node of a cast-in-place square column and a prefabricated square beam, the node includes a cast-in-place concrete square column (1) and two precast concrete square beams (2), the inner bottom end of the precast concrete square beam (2) is provided with a plurality of beam bottom longitudinal bars (21) and an unbonded anti-buckling sleeve (22), and the unbonded anti-buckling sleeve (22) One end of the beam is coplanar and connected to one surface of the precast concrete square beam (2), and the longitudinal reinforcement (21) at the bottom of each beam extends out of the precast concrete square beam (2) through an unbonded anti-buckling sleeve (22). ), and the extended part of the longitudinal reinforcement (21) at the bottom of the beam is bent;

The two precast concrete square beams (2) are opposite to each other, and the bent portion of the longitudinal reinforcement (21) at the bottom of the beam of each precast concrete square beam (2) is in close contact with the opposite side of the other precast concrete square beam (2). A concrete square column (1) vertically connected to the two precast concrete square beams (2) is formed by pouring between the two precast concrete square beams (2), and the two precast concrete square beams (2) have a plurality of beams at their outer tops The top longitudinal reinforcement (3), and each beam top longitudinal reinforcement (3) is respectively connected to the two prefabricated concrete square beams (2), and a concrete layer (4) is poured on the outer top of the concrete square beam (2); and the two The two precast concrete square beams (2), the concrete layer (4) and the concrete square column (1) are integrally connected; one end of the cast-in-place concrete square column (1) is located above the two precast concrete square beams (2), and the other end is located above the two precast concrete square beams (2). It is located below the two precast concrete square beams (2); the bent part of the longitudinal reinforcement (21) at the bottom of the beam is located inside the cast-in-place concrete square column (1).

The non-bonded anti-buckling sleeve (22) is a steel pipe and is coated with lubricating grease on the inside and outside. The inner diameter of the steel pipe is 2-4mm larger than the diameter of the longitudinal rib (21) at the bottom of the beam, the thickness of the steel pipe is 3-5mm, and the length of the steel pipe is 20-30 times the diameter of the longitudinal rib (21) at the bottom of the square beam.

The part of the bottom longitudinal rib (21) of the square beam passing through the unbonded anti-buckling sleeve is coated with lubricating grease.

There is no bond between the precast concrete square beam (2), the unbonded buckling sleeve (22) and the bottom longitudinal reinforcement (21) of the square beam.

Beneficial effects: compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

The invention uses the non-bonded anti-buckling sleeve to lengthen the free elongation distance of the steel bar, thereby increasing the length of the plastic hinge, thereby improving the rotational ductility of the square beam end, and avoiding the disadvantage of the buckling of the steel bar at the square beam end under the seismic reciprocating load .

Description of drawings

Fig. 1 is the concrete frame joint schematic diagram of cast-in-place square column prefabricated square beam of the present invention;

Fig. 2 is the prefabricated laminated square beam schematic diagram of the present invention;

In the picture: 1- cast-in-place concrete square column, 2- precast concrete square beam, 21- beam bottom longitudinal reinforcement, 22- unbonded anti-buckling sleeve, 3- beam top longitudinal reinforcement, 4- concrete layer.

Detailed ways

Below in conjunction with accompanying drawing, the technical scheme of the present invention is described in further detail:

The invention provides a concrete frame joint of cast-in-place square columns and prefabricated square beams. The joint comprises a cast-in-place concrete square column (1) and two prefabricated concrete square beams (2). The inner bottom ends of the prefabricated concrete square beams (2) are There are a plurality of beam bottom longitudinal bars (21) and an unbonded anti-buckling sleeve (22), one end of the unbonded anti-buckling sleeve (22) is on the same surface as one surface of the precast concrete square beam (2) and Connected, the longitudinal reinforcement (21) at the bottom of each beam protrudes from the surface of the precast concrete square beam (2) through an unbonded anti-buckling sleeve (22), and the longitudinal reinforcement (21) at the bottom of the beam protrudes partially bent;

The two precast concrete square beams (2) are opposite to each other, and the bent portion of the longitudinal reinforcement (21) at the bottom of the beam of each precast concrete square beam (2) is in close contact with the opposite side of the other precast concrete square beam (2). A concrete square column (1) vertically connected to the two precast concrete square beams (2) is formed by pouring between the two precast concrete square beams (2), and the two precast concrete square beams (2) have a plurality of beams at their outer tops The top longitudinal reinforcement (3), and each beam top longitudinal reinforcement (3) is respectively connected to the two prefabricated concrete square beams (2), and a concrete layer (4) is poured on the outer top of the concrete square beam (2); and the two The two precast concrete square beams (2), the concrete layer (4) and the concrete square column (1) are integrally connected; one end of the cast-in-place concrete square column (1) is located above the two precast concrete square beams (2), and the other end is located above the two precast concrete square beams (2). It is located below the two precast concrete square beams (2); the bent part of the longitudinal reinforcement (21) at the bottom of the beam is located inside the cast-in-place concrete square column (1).

Further, the non-bonded anti-buckling sleeve (22) is a steel pipe, and both inside and outside are coated with lubricating grease.

Further, the inner diameter of the non-bonded anti-buckling sleeve (22) is 2-4mm larger than the diameter of the longitudinal reinforcement (21) at the bottom of the beam, the thickness of the non-bonded anti-buckling sleeve (22) is 3-5 mm, and the non-bonded anti-buckling sleeve (22) has a thickness of 3-5 mm. The length of the anti-buckling sleeve (22) is 20-30 times the diameter of the longitudinal reinforcement (21) at the bottom of the square beam beam.

Further, the part of the steel bar at the bottom of the square beam passing through the unbonded anti-buckling sleeve is coated with lubricating grease.

Further, there is no bond between the precast concrete square beam (2), the unbonded buckling sleeve (22) and the longitudinal reinforcement (21) at the bottom of the beam.

Referring to Fig. 1 to Fig. 2, the manufacturing method of the present invention comprises the following steps:

Step 1: First make the prefabricated concrete square beam 1, the manufacturing steps are as follows, and then apply a lubricating grease coating to the area inside the unbonded anti-buckling sleeve 22 with the longitudinal bars 21 at the bottom of the beam, and then apply the unbonded anti-buckling sleeve 22 Apply lubricating grease coating on the inside and outside, then pass the non-bonded anti-buckling sleeve 22 through the longitudinal reinforcement 21 at the bottom of the beam to the position shown in the figure, bend the longitudinal reinforcement 21 at the bottom of the beam, bind the reinforcement cage, and finally pour concrete to make a precast concrete square. beam.

Step 2: Hoist the precast concrete square beams 2 on both sides, and bind the longitudinal bars 3 at the top of the beams to the precast concrete square beams 2 .

Step 3: binding the reinforcement cage of the cast-in-place concrete square column 1, and pouring the cast-in-place concrete square column 1 and the stacked concrete layer 4 to form an integral connection.

The above are only some embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (3)

1. A cast-in-place square column prefabricated square beam concrete frame node, the node comprises a cast-in-place concrete square column (1) and two prefabricated concrete square beams (2), characterized in that: the prefabricated concrete square beam (2) The inner bottom end is provided with a plurality of beam bottom longitudinal bars (21) and an unbonded anti-buckling sleeve (22), and one end of the unbonded anti-buckling sleeve (22) is connected to one surface of the precast concrete square beam (2). On the same plane and in communication, the longitudinal reinforcement (21) at the bottom of each beam protrudes from the surface of the precast concrete square beam (2) through an unbonded anti-buckling sleeve (22), and the longitudinal reinforcement (21) at the bottom of the beam ) the protruding part is bent; The two precast concrete square beams (2) are opposite to each other, and the bent portion of the longitudinal reinforcement (21) at the bottom of the beam of each precast concrete square beam (2) is in close contact with the opposite side of the other precast concrete square beam (2). A concrete square column (1) vertically connected to the two precast concrete square beams (2) is formed by pouring between the two precast concrete square beams (2), and the two precast concrete square beams (2) have a plurality of beams at their outer tops The top longitudinal reinforcement (3), and each beam top longitudinal reinforcement (3) is respectively connected to the two prefabricated concrete square beams (2), and a concrete layer (4) is poured on the outer top of the concrete square beam (2); and the two The two precast concrete square beams (2), the concrete layer (4) and the concrete square column (1) are integrally connected; one end of the cast-in-place concrete square column (1) is located above the two precast concrete square beams (2), and the other end is located above the two precast concrete square beams (2). are located under two precast concrete square beams (2); the bent portion of the longitudinal reinforcement (21) at the bottom of the beam is located inside the cast-in-place concrete square column (1); the unbonded anti-buckling sleeve (22) is a steel pipe , and has a lubricating grease coating on the inside and outside. 2 . The cast-in-place square column prefabricated square beam concrete frame joint according to claim 1 , wherein the steel bars at the bottom of the square beam are coated with a lubricating grease coating through the part of the unbonded anti-buckling sleeve. 3 . 3. A cast-in-place square column prefabricated square beam concrete frame joint according to claim 1 or 2, characterized in that the prefabricated concrete square beam (2), the unbonded buckling sleeve (22) and the beam bottom There is no bond between the longitudinal ribs (21).

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