Prefabricated primary and secondary beam connecting joint and connecting method thereof

Abstract

The invention belongs to the technical field of prefabricated buildings, and particularly discloses a prefabricated primary and secondary beam connecting joint and a connecting method thereof, and the prefabricated primary and secondary beam connecting joint comprises a prefabricated primary beam, a connecting device and a prefabricated secondary beam. The prefabricated main beam is provided with a first external longitudinal bar, the connecting device is placed at the position, provided with the first external longitudinal bar, of the prefabricated main beam, the connecting device comprises a heavy frame and a supporting formwork set, and the heavy frame is placed on the prefabricated main beam; the two supporting formwork sets are arranged at the two ends of the heavy frame in a one-to-one correspondence mode and located on the two sides of the prefabricated main beam correspondingly. Each supporting formwork set comprises two vertical plates and a transverse plate, and the transverse plate and the two vertical plates are of an integrated structure to form a U-shaped groove. The number of the prefabricated secondary beams is two, and the end portions of one ends of the two prefabricated secondary beams are placed in the U-shaped grooves in a one-to-one correspondence mode. Extra supporting scaffolds and wood formworks do not need to be erected and dismantled in the installation process, the construction period is greatly shortened, construction steps and labor cost are reduced, and the assembly rate of prefabricated parts is increased.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of prefabricated buildings, and particularly relates to a prefabricated main and secondary beam connecting joint and a connecting method thereof. BACKGROUND

[0002] In a prefabricated structure, the installation mode of the main and secondary beam joint significantly affects the progress and assembly rate of the overall structure assembly, which involves the production, hoisting, steel collision and cast-in-place formwork support of prefabricated components. In order to meet the stress performance requirements of large-span prefabricated beams, the rigid connection of the main and secondary beam joint needs to be ensured. Compared with the steel sleeve connection, the prefabricated main and secondary beam connecting joint adopts the method of steel lap joint combined with concrete post-casting, which is the most mature and economical construction method for rigid connection of the main and secondary beam joint due to its simple design and fast construction. However, the traditional prefabricated main and secondary beam steel lap joint joint with post-cast concrete requires consideration of the lap length and lap operation space of the lower longitudinal reinforcement of the secondary beam, resulting in an excessively long cast-in-place section that requires additional formwork and scaffold support, greatly prolonging the construction period and reducing the overall project assembly rate.

[0003] In actual prefabricated frame structures, the prefabricated main and secondary beam connecting joint post-cast construction scheme mainly includes two schemes: main beam reserved slot post-cast joint and secondary beam end post-cast joint. The main beam reserved slot post-cast joint requires a certain depth of post-cast slot reserved on the main beam, which causes the main beam, as the main load-bearing component, to have insufficient stiffness. In addition, the interface between the lower thin wall of the prefabricated main beam and the cast-in-place part after slotting is prone to crack risk. The secondary beam end post-cast joint has the characteristics of good integrity and large stiffness, allowing it to be designed as a rigid joint in structural design. Therefore, the construction method of the secondary beam end post-cast joint of the prefabricated main and secondary beam is widely used.

[0004] According to the national building standard design drawing set "Prefabricated concrete structure connecting joint construction", even if the secondary beam does not need to consider seismic action, the steel reinforcement binding lap length is at least l = 1.2 x 35d = 840mm. In order to ensure sufficient steel lap length and construction space, the traditional secondary beam end post-cast joint scheme requires a post-cast concrete length of more than 1300mm, which increases the workload of supporting the formwork for post-casting, significantly reduces the assembly rate and increases the labor cost and construction period.

[0005] At present, the method of bending the longitudinal reinforcement at the bottom of the secondary beam for the prefabricated main and secondary beam connecting joint can reduce the post-cast length, allowing the post-cast concrete to be controlled within 400mm. However, due to the long post-cast length, the existing construction method of the prefabricated main and secondary beam steel lap post-cast joint still requires the construction steps of supporting scaffolding and wooden formwork, and the main and secondary beam connecting site formwork has problems such as complicated construction steps, difficult positioning and long construction period. SUMMARY

[0006] In view of the above problems, the present application aims to provide a prefabricated primary and secondary beam connecting node and a connecting method thereof, which can realize unified pouring of subsequent composite slabs and prefabricated nodes, and does not require additional support scaffolding and formwork during construction, thus having the advantages of "fast assembly" and "precise positioning".

[0007] The technical solution of the present application is: a prefabricated primary and secondary beam connecting node, comprising a prefabricated primary beam, a connecting device, and a prefabricated secondary beam. The prefabricated primary beam has a first external longitudinal reinforcement, the connecting device is placed at the position of the prefabricated primary beam where the first external longitudinal reinforcement is arranged, the connecting device comprises a load-bearing frame and a support formwork set, the load-bearing frame is placed on the prefabricated primary beam; the support formwork set has two sets, the two sets of support formwork sets are correspondingly arranged at the two ends of the load-bearing frame and are respectively located on the two sides of the prefabricated primary beam; each set of support formwork sets comprises two vertical plates and a horizontal plate, the two vertical plates are oppositely distributed, and one side of the upper end of each vertical plate is movably connected to the load-bearing frame; the horizontal plate is arranged at the lower end of the two vertical plates, the horizontal plate and the two vertical plates are an integral structure, forming a U-shaped groove, and the opening direction of the U-shaped groove is perpendicular to the length direction of the prefabricated primary beam. There are two prefabricated secondary beams, one end of each prefabricated secondary beam is correspondingly placed in the U-shaped groove, the end of the prefabricated secondary beam placed in the U-shaped groove has a second external longitudinal reinforcement, the second external longitudinal reinforcement is connected to the first external longitudinal reinforcement, and a concrete layer is further arranged in the U-shaped groove.

[0008] Further, the load-bearing frame comprises load-bearing rods and connecting rods. The load-bearing rods are arranged in parallel to each other, and the vertical plates are movably connected to the ends of the load-bearing rods. The connecting rods are arranged between the two load-bearing rods along the length direction of the load-bearing rods, and the two ends of each connecting rod are connected to the two load-bearing rods.

[0009] Further, the ends of the load-bearing rods are provided with first connecting rings, and the vertical plates are provided with second connecting rings, and the first connecting rings and the second connecting rings are connected by bolts and nuts.

[0010] Further, the connecting device further comprises a steel framework, which is fixed to the vertical plates and the horizontal plate and located on the inner side of the U-shaped groove, and is used for reinforcing the vertical plates and the horizontal plate.

[0011] Further, the steel framework comprises four first edge steel bars and four second edge steel bars. The four first edge steel bars form a rectangular structure and are arranged on the horizontal plate, and two opposite first edge steel bars are in one-to-one correspondence with the two vertical plates. The four second edge steel bars are arranged in pairs on the two vertical plates, and each pair of second edge steel bars forms a triangular structure with the first edge steel bar of the vertical plate in contact.

[0012] Further, the triangular structure is a right-angled triangular structure.

[0013] Further, the first outer longitudinal rib is a mouth-shaped structure, and the middle section of the bottom edge of the mouth-shaped structure is embedded in the prefabricated main beam.

[0014] Further, the end of the prefabricated secondary beam placed in the U-shaped groove is provided with a groove.

[0015] A connecting method of a prefabricated main-secondary beam connecting node, the connecting node is connected, and specifically comprises the following steps: The prefabricated main beam is hoisted on the building structure, the force bearing frame is placed on the prefabricated main beam part, and the accuracy of the placement position is determined by the level, then two groups of supporting templates are set at both ends of the force bearing frame in one-to-one correspondence, and the two prefabricated secondary beams are simultaneously hoisted and placed in the U-shaped groove.

[0016] The upper longitudinal reinforcement of the prefabricated main beam and the upper longitudinal reinforcement of the prefabricated secondary beam are bound, and after the hoisting of the superimposed plate, the cast-in-place concrete is poured together.

[0017] Compared with the prior art, the beneficial effects of the present application are that the prefabricated main beam and the prefabricated secondary beam are connected together by the connecting device, which greatly shortens the horizontal length of the curved longitudinal reinforcement of the cast-in-place area of the prefabricated main beam and the prefabricated secondary beam, and the horizontal length is not more than 200mm, and the connecting device acts as a cast-in-place area template and a supporting device for connecting the prefabricated main beam and the prefabricated secondary beam, thereby eliminating the need for additional supporting scaffolds and wooden templates during the entire main-secondary beam connecting node installation process, greatly shortening the construction period, reducing the construction steps and labor cost, and improving the assembly rate of prefabricated components.

[0018] The whole scheme has the advantages of "fast assembly" and "precise positioning", and because the positioning is accurate and simple, the construction process is greatly simplified, and the obvious advantage of short construction period is obtained. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the overall structure schematic diagram of the present application; Figure 2 is the structure schematic diagram of the prefabricated main beam of the present application; Figure 3 is the structure schematic diagram of the connecting device of the present application; Figure 4 is the structure schematic diagram of the prefabricated secondary beam of the present application; Figure 5 is the local structure schematic diagram of the connecting device of the present application; Figure 6 is the connecting structure schematic diagram of the prefabricated main beam and the connecting device of the present application; Figure 7 is the size diagram of the traditional cast-in-place main-secondary beam connecting node and the prefabricated main-secondary beam connecting node of the experimental example of the present application; Figure 8 This is a cross-sectional view of the main beam of the traditional cast-in-place main and secondary beam connection node in the experimental example of this invention; Figure 9 This is a cross-sectional view of the secondary beam of the traditional cast-in-place main and secondary beam connection node in the experimental example of this invention; Figure 10 This is an experimental example of finite element numerical analysis of the present invention.

[0020] Among them, 1-precast main beam, 10-first external longitudinal reinforcement, 2-connecting device, 20-U-shaped groove, 21-support frame, 211-support rod, 212-connecting rod, 213-first connecting ring, 22-support template group, 221-vertical plate, 222-horizontal plate, 223-second connecting ring, 23-steel frame, 231-first edge steel bar, 232-second edge steel bar, 3-precast secondary beam, 30-second external longitudinal reinforcement, 300-groove. Detailed Implementation

[0021] The following is in conjunction with the appendix Figure 1 To the attached Figure 10 The specific embodiments of the present invention will be described in detail below. In the description of the present invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0022] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0023] Example like Figure 1 The diagram illustrates a precast main-secondary beam connection node, comprising a precast main beam 1, a connecting device 2, and a precast secondary beam 3. (Example:) Figure 2 As shown, the precast main beam 1 has a first external longitudinal reinforcement 10, as... Figure 1 , Figure 6 As shown, the connecting device 2 is placed at the location where the first external longitudinal reinforcement 10 is set on the precast main beam 1, as follows. Figure 2As shown, the connecting device 2 includes a support frame 21 and a support template assembly 22. The support frame 21 is placed on the precast main beam 1. There are two sets of support template assemblies 22, which are arranged one-to-one at both ends of the support frame 21, located on both sides of the precast main beam 1. Each support template assembly 22 includes two vertical plates 221 and a horizontal plate 222. The two vertical plates 221 are distributed opposite each other, with their upper sides movably connected to the support frame 21. The horizontal plate 222 is located at the lower end of the two vertical plates 221. The horizontal plate 222 and the two vertical plates 221 are an integral structure, forming a U-shaped groove 20. The opening direction of the U-shaped groove 20 is perpendicular to the length direction of the precast main beam 1. Figure 2 , Figure 3 As shown, there are two precast secondary beams 3. The ends of one end of each precast secondary beam 3 are placed in the U-shaped groove 20. The end of the precast secondary beam 3 located in the U-shaped groove 20 has a second external longitudinal reinforcement 30. The second external longitudinal reinforcement 30 is connected to the first external longitudinal reinforcement 10. A concrete layer is also provided in the U-shaped groove 20.

[0024] Because this embodiment connects the precast main beam 1 and the precast secondary beam 3 together through the connecting device 2, the horizontal length of the bent longitudinal reinforcement in the cast-in-place area of ​​the precast main beam 1 and the precast secondary beam 3 is greatly shortened, with the horizontal length not exceeding 200mm. Therefore, the precast main and secondary beam connection node proposed in this embodiment shortens the concrete post-pouring strip of the traditional precast main and secondary beam reinforcement lap joint from 400mm to 200mm. The entire main and secondary beam installation process does not require the erection and dismantling of additional supporting scaffolding and wooden formwork, greatly shortening the construction period, reducing construction steps and labor costs, and improving the assembly rate of precast components.

[0025] After the second external longitudinal reinforcement 30 is connected to the first external longitudinal reinforcement 10, concrete is poured in the U-shaped groove 20 to form a concrete layer, so that the precast main beam 1 and the precast secondary beam 3 form an integrated structure.

[0026] Preferred, such as Figure 3 As shown, the support frame 21 includes support rods 211 and connecting rods 212. There are two support rods 211, arranged parallel to each other, and a vertical plate 221 is movably connected to the end of the support rod 211. There are multiple connecting rods 212, which are arranged sequentially between two support rods 211 along the length of the support rod 211, with each end of the connecting rod 212 connected to one of the two support rods 211. In this embodiment, the dimensions of the support frame 211 are 300mm*60mm*15mm, and the dimensions of the connecting rods 212 are 105mm*60mm*15mm. Both the support rods 211 and the connecting rods 212 are made of Q355 steel. The vertical plate 221 and the horizontal plate 222 are also made of Q355 steel, and both the vertical plate 221 and the horizontal plate 222 are 15mm thick.

[0027] Preferred, such as Figure 3As shown, the end of the force bar 211 is provided with a first connecting ring 213, and the vertical plate 221 is provided with a second connecting ring 223, and the first connecting ring 213 and the second connecting ring 223 are connected by bolts and nuts.

[0028] Preferably, as shown in Figure 3 , Figure 5 The connecting device 2 further comprises a steel framework 23, which is fixed on the vertical plate 221 and the horizontal plate 222 and located inside the U-shaped groove 20, and is used for reinforcing the vertical plate 221 and the horizontal plate 222.

[0029] Preferably, as shown in Figure 3 , Figure 5 The steel framework 23 comprises four first edge steel bars 231 and four second edge steel bars 232. The four first edge steel bars 231 form a rectangular structure and are arranged on the horizontal plate 222, and two opposite first edge steel bars 231 correspondingly contact two vertical plates 221. The four second edge steel bars 232 are arranged in pairs on the two vertical plates 221 respectively, and each group of four second edge steel bars 232 and the first edge steel bars 231 of the vertical plate 221 in contact form a triangular structure.

[0030] Preferably, the triangular structure is a right-angled triangular structure.

[0031] Preferably, as shown in Figure 2 The first outer longitudinal reinforcement 10 is a mouth-shaped structure, and the middle section of the bottom edge of the mouth-shaped structure is embedded in the prefabricated main beam 1.

[0032] Preferably, as shown in Figure 4 The end of the prefabricated secondary beam 3 placed in the U-shaped groove 20 is provided with a groove 300.

[0033] Since the connecting device 2 is arranged to connect the prefabricated main beam 1 and the prefabricated secondary beam 3 and acts as a cast-in-place area formwork and a supporting device. The first outer longitudinal reinforcement 10 and the second outer longitudinal reinforcement 30 inside the connecting device 2 are alternately arranged, which can ensure good anchoring and stress transfer between the prefabricated main beam and the prefabricated secondary beam, and the cast-in-place area between the prefabricated main beam 1 and the prefabricated secondary beam 3 is not more than 200mm, which greatly shortens the horizontal length of the curved longitudinal reinforcement of the cast-in-place area of the prefabricated main beam 1 and the prefabricated secondary beam 3.

[0034] Therefore, the prefabricated main and secondary beam connecting joint provided in the embodiment shortens the concrete post-cast strip of the traditional prefabricated main and secondary beam reinforcing lap joint from 400mm to 200mm, and the entire main and secondary beam installation process does not need to set up and remove additional supporting scaffolds and wooden formworks, which greatly shortens the construction period, reduces the construction steps and labor cost, and improves the assembly rate of prefabricated components.

[0035] A connecting method of a prefabricated main and secondary beam connecting node, the connecting node proposed in the embodiment is connected, and specifically includes the following steps: The prefabricated main beam 1 and the prefabricated secondary beam 2 are manufactured in a prefabricated factory, and the outer longitudinal reinforcement at the bottom of the prefabricated main beam 1 and the prefabricated secondary beam 2 is bent by 90° for secondary processing to form the first outer longitudinal reinforcement 10 and the second outer longitudinal reinforcement 30, respectively. The outer longitudinal reinforcement of the prefabricated main beam 1 is bound by iron wire to form a mouth-shaped closed shape, and the prefabricated concrete end of the prefabricated secondary beam 2 is provided with a preset groove 300 so as to increase the bonding area of the prefabricated concrete and the cast-in-place concrete.

[0036] The prefabricated main beam 1 is hoisted on the building structure, the load-bearing frame 21 is placed on the prefabricated main beam 1, and the accuracy of the placement position is determined by using a level, then two groups of support formwork groups 22 are correspondingly arranged at two ends of the load-bearing frame 21, and two prefabricated secondary beams 3 are simultaneously hoisted and placed in the U-shaped groove 20, and the concrete end of the prefabricated secondary beam 2 is ensured to abut against the first edge steel bar 231.

[0037] The upper longitudinal reinforcement of the prefabricated main beam 1 and the upper longitudinal reinforcement of the prefabricated secondary beam 3 are bound, and after the superimposed slab is hoisted, the cast-in-place concrete is poured together.

[0038] Experimental example The prefabricated main and secondary beam connecting node proposed in the embodiment 1 is prepared, and a control group is arranged, the control group adopts a traditional cast-in-place main and secondary beam connecting node. The sizes of the traditional cast-in-place main and secondary beam connecting node and the prefabricated main and secondary beam connecting node are shown in Figure 7 . The sectional view of the traditional cast-in-place main and secondary beam connecting node is shown in Figure 8 , Figure 9 . The basic parameters of the cast-in-place main and secondary beam connecting node and the prefabricated main and secondary beam connecting node are shown in Tables 1 and 2. The bending resistance test is performed on the prepared traditional cast-in-place main and secondary beam connecting node, and the finite element numerical analysis results of the traditional cast-in-place main and secondary beam connecting node and the prefabricated main and secondary beam connecting node are shown in Figure 10 . It can be seen that the bending resistance performance of the prefabricated main and secondary beam connecting node designed in the design example is better than that of the traditional cast-in-place node.

[0039] Table 1 Basic parameters of the main beam 1 of the cast-in-place main and secondary beam connecting node and the prefabricated main and secondary beam connecting node Table 2 Basic parameters of the secondary beam 3 of the cast-in-place main and secondary beam connecting node and the prefabricated main and secondary beam connecting node The above-described specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application, and it should be understood that the above-described specific embodiments are merely examples of the present application and do not limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A precast primary and secondary beam connection node, characterized in that, include: The precast main beam (1) has a first external longitudinal reinforcement (10); The connecting device (2) is placed at the location where the first external longitudinal reinforcement (10) is set on the precast main beam (1). The connecting device (2) includes: a support frame (21) placed on the precast main beam (1); a support template group (22) with two groups, which are respectively set at both ends of the support frame (21) and located on both sides of the precast main beam (1); each support template group (22) includes: two vertical plates (221) distributed opposite to each other, with one side of the upper end movably connected to the support frame (21); and a horizontal plate (222) set at the lower end of the two vertical plates (221). The horizontal plate (222) and the two vertical plates (221) are an integral structure, forming a U-shaped groove (20). The opening direction of the U-shaped groove (20) is perpendicular to the length direction of the precast main beam (1). There are two precast secondary beams (3). The ends of the two precast secondary beams (3) are placed in the U-shaped groove (20) one by one. The ends of the precast secondary beams (3) located in the U-shaped groove (20) have second external longitudinal bars (30). The second external longitudinal bars (30) are connected to the first external longitudinal bars (10). A concrete layer is also provided in the U-shaped groove (20).

2. The precast primary and secondary beam connection node as described in claim 1, characterized in that, The support frame (21) includes: There are two load-bearing rods (211) arranged in parallel to each other, and the vertical plate (221) is movably connected to the end of the load-bearing rod (211); There are multiple connecting rods (212). Multiple connecting rods (212) are arranged sequentially between two load-bearing rods (211) along the length direction of the load-bearing rod (211). The two ends of the connecting rods (212) are respectively connected to the two load-bearing rods (211).

3. A precast primary and secondary beam connection node as described in claim 2, characterized in that, The end of the support rod (211) is provided with a first connecting ring (213), and the vertical plate (221) is provided with a second connecting ring (223). The first connecting ring (213) and the second connecting ring (223) are connected by bolts and nuts.

4. A precast primary and secondary beam connection node as described in claim 1, characterized in that, The connecting device (2) also includes a steel frame (23), which is fixed on the vertical plate (221) and the horizontal plate (222) and located inside the U-shaped groove (20) to reinforce the vertical plate (221) and the horizontal plate (222).

5. A precast primary and secondary beam connection node as described in claim 4, characterized in that, The steel frame (23) includes: Four first edge steel bars (231) form a rectangular structure and are set on the horizontal plate (222). Two opposite first edge steel bars (231) are in contact with two vertical plates (221) in a one-to-one correspondence. Four second edge steel bars (232) are set in pairs on two vertical plates (221). The four second edge steel bars (232) in each pair form a triangular structure with the first edge steel bar (231) in contact with the vertical plate (221).

6. A precast primary and secondary beam connection node as described in claim 5, characterized in that, The triangle structure is a right-angled triangle structure.

7. A prefabricated primary and secondary beam connection node as described in claim 1, characterized in that, The first external longitudinal reinforcement (10) is a square-shaped structure, and the middle section of the bottom edge of the square-shaped structure is embedded in the precast main beam (1).

8. A precast primary and secondary beam connection node as described in claim 1, characterized in that, The precast secondary beam (3) has a groove (300) at the end placed in the U-shaped groove (20).

9. A method for connecting precast primary and secondary beam connection nodes, characterized in that, Connecting any of the connection nodes described in claims 1-8 specifically includes the following steps: The precast main beam (1) is hoisted onto the building structure, the support frame (21) is placed on the precast main beam (1), and the accuracy of the placement position is determined by a level. Then, two sets of support templates (22) are set one by one at both ends of the support frame (21), and two precast secondary beams (3) are hoisted and placed in the U-shaped groove (20) at the same time. The upper longitudinal reinforcement of the precast main beam (1) and the upper longitudinal reinforcement of the precast secondary beam (3) are tied, and the cast-in-place concrete is poured together after the composite slab is hoisted.

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