Prefabricated primary and secondary beam joint cut-off waist bar double-straight-thread sleeve connecting process

Abstract

The invention discloses a prefabricated primary and secondary beam joint cut-off waist bar double-straight thread sleeve connecting process which comprises the following specific steps: S1, preparation work: preparing required tools and materials including a double-straight thread sleeve, steel bar cutting equipment, welding equipment, a template required for pouring concrete and a supporting pile body; during steel bar blanking, waist bars on the side faces of a main beam are cut off according to requirements, the full length of bottom bars at the ends of secondary beams is kept, and the cut-off steel bars are cleaned and derusted; s3, treating a notch of the main beam; s4, a double-straight-thread sleeve is installed; s5, arranging in a staggered manner; s6, welding treatment is conducted; step S7, construction acceptance; and S8, final pouring is conducted. During operation, space limitation is not prone to occurring, the connecting part is convenient to reinforce, construction is inconvenient, the connecting quality, stability and safety of the prefabricated main beam and secondary beam joints can be improved, and meanwhile structural integrity can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of building construction, and particularly relates to a process for connecting prefabricated primary and secondary beam nodes with truncated waist reinforcement using double straight thread sleeves. Background Art

[0002] According to the national architectural standard design atlas, "Joint Construction of Prefabricated Concrete Structures," the existing prefabricated primary and secondary beam connection process utilizes a pre-embedded mechanical joint technique for the bottom reinforcement of the secondary beam. This technique involves screwing the end longitudinal reinforcement into the pre-embedded sleeve after the secondary beam is in place. The connection structure is primarily formed through pre-embedded and mechanical joints. During construction, the secondary beam's bottom longitudinal reinforcement typically uses two rows of six bars, d = 25 mm, HRB400 steel, and six bars, d = 16 mm, HRB400 steel, for the side longitudinal reinforcement. Using this pre-embedded mechanical joint method, all 11 longitudinal bars in the secondary beam model are cut at the same cross-section. This method is designed to ensure that the secondary beam is hoisted vertically into the notch of the primary beam. This can cause the bottom longitudinal reinforcement of the secondary beam to collide with the waist reinforcement at the notch, preventing the secondary beam from being properly installed. While theoretically feasible, aligning the secondary beam from the side of the primary beam during hoisting is difficult to control due to the inertia of the secondary beam, making it prone to side impact with the primary beam, posing a safety risk. While this method solves the problem of hoisting the primary and secondary beam joints, the fact that all longitudinal reinforcement in the secondary beam is cut off also easily creates a weak surface at the junction of the primary and secondary beams, reducing the joint connection stiffness. Furthermore, due to limited working space, some joints are difficult to connect or tighten with the reinforcement, making construction inconvenient. This results in failure to fully meet the requirements of the atlas and specifications, affecting project quality. To address these issues, the present invention proposes a prefabricated primary and secondary beam joint connection process using double straight threaded sleeves with cut waist reinforcement. Summary of the Invention

[0003] (1) Technical problems solved

[0004] In view of the shortcomings of the existing technology, the present invention provides a double straight thread sleeve connection process for truncated waist reinforcement at the nodes of prefabricated primary and secondary beams, which solves the problems of reduced stiffness of the nodes of prefabricated primary and secondary beams and inconvenience in construction.

[0005] (2) Technical solution

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] The technical solution of the present invention is: a double straight thread sleeve connection process for truncated waist reinforcement at prefabricated primary and secondary beam nodes, the specific steps of which include the following:

[0008] Step S1, preparation: prepare the necessary tools and materials, including double straight thread sleeves, steel bar cutting equipment, welding equipment, formwork required for pouring concrete, and supporting piles;

[0009] Step S2, steel bar pretreatment: when cutting steel bars, cut off the side waist bars of the main beam as required, keep the bottom bars at the ends of the secondary beams continuous, and clean and derust the cut steel bars;

[0010] Step S3, main beam notch processing: expand the post-casting notch reserved for the main beam by 300 mm on both sides to ensure space and position for sleeve connection; check the size and flatness of the notch, and perform trimming and cleaning;

[0011] Step S4, installing the double straight thread sleeve: insert the double straight thread sleeve into the main beam notch to ensure that the sleeve is positioned accurately and firmly; use a first-level mechanical joint to connect the sleeve to the main beam cut waist reinforcement and tighten it;

[0012] Step S5, staggered arrangement: stagger the double straight thread sleeves symmetrically to ensure that the area percentage of the steel bar joints meets the requirements, check the arrangement and connection quality of the sleeves to ensure that the connection is firm and stable;

[0013] Step S6: welding the connection parts to ensure a firm and sealed connection;

[0014] Step S7, construction acceptance: After the connection is completed, the construction acceptance is carried out to check the quality and compliance of the connection parts, and to conduct quality inspection and record;

[0015] Step S8, final pouring: set up formwork and supporting piles around the connection part to prepare for the final concrete pouring work.

[0016] As a further preferred embodiment of the present invention, the sleeve has a diameter of M16, M20, M24, or M30, a length of 100 mm, 150 mm, or 200 mm, and is made of carbon steel or alloy steel.

[0017] As a further preferred embodiment of the present invention, step S2 also includes threading the steel bars, marking the position of the waist bars on the side of the main beam, determining the length to be cut, and using a steel bar cutter to cut the waist bars on the side of the main beam according to the marked position to ensure that the cut is smooth. According to the sleeve and connection requirements, before rolling and threading the ends of the cut steel bars, the steel bars must be cleaned first to ensure that there are no impurities on the surface.

[0018] As a further preferred embodiment of the present invention, in step S2, during the threading process, the threading depth is a ratio of the sleeve diameter, which is 0.2-0.3 times the diameter, and is 3-4 mm according to the thread specification of the sleeve. The speed of the threading machine is 45-180 r / min.

[0019] (3) Beneficial effects

[0020] The present invention provides a double straight thread sleeve connection process for truncated waist reinforcement at prefabricated primary and secondary beam nodes. It has the following beneficial effects:

[0021] The present invention is not easily subject to space restrictions during operation, the connection parts are easy to reinforce, the construction is inconvenient, and the connection quality, stability and safety of the prefabricated primary and secondary beam nodes can be improved, while also helping to improve the overall performance of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the connection structure of the existing prefabricated main beam and the main and secondary beams;

[0023] Figure 2 This is a schematic diagram of another existing connection structure of prefabricated main beams and main and secondary beams;

[0024] Figure 3 It is a schematic diagram of the construction process of the present invention;

[0025] Figure 4 A schematic diagram of a structure in which a post-casting notch is reserved for the beam of the present invention and extends 300 mm on both sides;

[0026] Figure 5 The present invention relates to a connection structure of a prefabricated main beam and main and secondary beams. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] See also Figure 1-5 The embodiment of the present invention provides a technical solution: a process for connecting prefabricated primary and secondary beam nodes with truncated waist reinforcement using double straight thread sleeves, the specific steps of which include the following:

[0029] Step S1, preparation: prepare the necessary tools and materials, including double straight thread sleeves, steel bar cutting equipment, welding equipment, formwork required for pouring concrete, and supporting piles;

[0030] Step S2, steel bar pretreatment: when cutting steel bars, cut off the side waist bars of the main beam as required, keep the bottom bars at the ends of the secondary beams continuous, and clean and derust the cut steel bars;

[0031] Step S3, main beam notch processing: expand the post-casting notch reserved for the main beam by 300 mm on both sides to ensure space and position for sleeve connection; check the size and flatness of the notch, and perform trimming and cleaning;

[0032] Step S4, installing the double straight thread sleeve: insert the double straight thread sleeve into the main beam notch to ensure that the sleeve is positioned accurately and firmly; use a first-level mechanical joint to connect the sleeve to the main beam cut waist reinforcement and tighten it;

[0033] Step S5, staggered arrangement: stagger the double straight thread sleeves symmetrically to ensure that the area percentage of the steel bar joints meets the requirements, check the arrangement and connection quality of the sleeves to ensure that the connection is firm and stable;

[0034] Step S6: welding the connection parts to ensure a firm and sealed connection;

[0035] Step S7, construction acceptance: After the connection is completed, the construction acceptance is carried out to check the quality and compliance of the connection parts, and to conduct quality inspection and record;

[0036] Step S8, final pouring: set up formwork and supporting piles around the connection part to prepare for the final concrete pouring work.

[0037] The sleeve has diameters of M16, M20, M24, and M30, lengths of 100mm, 150mm, and 200mm, and is made of carbon steel or alloy steel.

[0038] Step S2 also includes threading the steel bars, marking the position of the waist bars on the side of the main beam, determining the length to be cut, and using a steel bar cutter to cut the waist bars on the side of the main beam according to the marked position to ensure that the cut is smooth. According to the sleeve and connection requirements, before rolling and threading the ends of the cut steel bars, the steel bars must be cleaned first to ensure that there are no impurities on the surface.

[0039] In step S2, during the threading process, the threading depth is a ratio of the sleeve diameter, which is 0.2-0.3 times the diameter, and is 3-4 mm according to the thread specification of the sleeve. The speed of the threading machine is 45-180 r / min.

[0040] In Example 1, a double-threaded sleeve connection process for truncated waist reinforcement at prefabricated primary and secondary beam nodes was used. The bottom reinforcement at the secondary beam end remained continuous, and the pre-cast notch in the main beam was extended 300mm to each side. The side waist reinforcement of the main beam was truncated (cut during cutting and threaded by rolling) using a centrally symmetrical, staggered arrangement. The truncated waist reinforcement of the main beam was then connected using a double-threaded sleeve (Class I sleeve). The double-threaded sleeves used a Class I mechanical joint. After staggering, they met the requirements for the percentage of joint area within the same section. The sleeve size was selected in accordance with the "Technical Specification for Mechanical Connection of Steel Bars" (JGJ 107-2016).

[0041] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all perspectives, the embodiments should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims, not the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be included within the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0042] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A double straight thread sleeve connection process for truncated waist reinforcement at prefabricated primary and secondary beam nodes, characterized in that: The specific steps include the following: Step S1, preparation: prepare the necessary tools and materials, including double straight thread sleeves, steel bar cutting equipment, welding equipment, formwork required for pouring concrete, and supporting piles; Step S2, steel bar pretreatment: when cutting steel bars, cut off the side waist bars of the main beam as required, keep the bottom bars at the ends of the secondary beams continuous, and clean and derust the cut steel bars; Step S3, main beam notch processing: expand the post-casting notch reserved for the main beam by 300 mm on both sides to ensure space and position for sleeve connection; check the size and flatness of the notch, and perform trimming and cleaning; Step S4, installing the double straight thread sleeve: insert the double straight thread sleeve into the main beam notch to ensure that the sleeve is positioned accurately and firmly; use a first-level mechanical joint to connect the sleeve to the main beam cut waist reinforcement and tighten it; Step S5, staggered arrangement: stagger the double straight thread sleeves symmetrically to ensure that the area percentage of the steel bar joints meets the requirements, check the arrangement and connection quality of the sleeves to ensure that the connection is firm and stable; Step S6: welding the connection parts to ensure a firm and sealed connection; Step S7, construction acceptance: After the connection is completed, the construction acceptance is carried out to check the quality and compliance of the connection parts, and to conduct quality inspection and record; Step S8, final pouring: set up formwork and supporting piles around the connection part to prepare for the final concrete pouring work.

2. The process for connecting prefabricated primary and secondary beam nodes with double straight thread sleeves by cutting waist reinforcement according to claim 1 is characterized in that: The sleeve has diameters of M16, M20, M24, and M30, lengths of 100mm, 150mm, and 200mm, and is made of carbon steel or alloy steel.

3. The process for connecting prefabricated primary and secondary beam nodes with truncated waist reinforcement using double straight thread sleeves according to claim 2, characterized in that: Step S2 also includes threading the steel bars, marking the position of the waist bars on the side of the main beam, determining the length to be cut, and using a steel bar cutter to cut the waist bars on the side of the main beam according to the marked position to ensure that the cut is smooth. According to the sleeve and connection requirements, before rolling and threading the ends of the cut steel bars, the steel bars must be cleaned first to ensure that there are no impurities on the surface.

4. The process for connecting prefabricated primary and secondary beam nodes with truncated waist reinforcement using double straight thread sleeves according to claim 3, characterized in that: In step S2, during the threading process, the threading depth is a ratio of the sleeve diameter, which is 0.2-0.3 times the diameter, and is 3-4 mm according to the thread specification of the sleeve. The speed of the threading machine is 45-180 r / min.

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