Construction method of formwork prefabricated part and cast-in-place structure connecting joint

Abstract

The invention discloses a construction method of a formwork prefabricated part and a cast-in-place structure connecting joint. The construction method comprises the following steps that formwork prefabricated parts and cast-in-place connecting joint steel bars are designed; simulation analysis is conducted according to steel bar overturning samples and steel bar construction sequences of different types of connection nodes, and the steel bar problem existing at the positions of the connection nodes is avoided in advance through three-dimensional visualization verification and steel bar collision detection; according to BIM modeling analysis, the model, positioning and lap joint modes of the steel bars are determined, the length of the steel bars is reserved, and formwork prefabricated parts are produced; and finally carrying out on-site construction. Precise sample turning of the steel bars at the connecting joints is conducted through BIM modeling, and the problems of steel bar collision, lap joint waste, steel bar mistakes and omissions and the like are avoided. The construction sequence of steel bars in a cast-in-place connection node area is simulated through BIM modeling, the problems that the steel bars are placed disorderly and cannot be bound, and steel bar conflicts exist are solved, the field construction efficiency is improved, and quick installation of formwork components is achieved.

Description

Technical Field

[0001] This invention belongs to the field of prefabricated building construction, and in particular relates to a construction method for the connection node between prefabricated formwork components and cast-in-place structures. Background Technology

[0002] With traditional construction methods revealing numerous insurmountable flaws, prefabricated construction has become a new direction for the construction industry due to its advantages such as high construction efficiency, good quality, and short construction period. Compared with cast-in-place structures, prefabricated building components are standardized and manufactured in factories, then transported to the construction site for hoisting and installation. This greatly improves construction efficiency and reduces on-site wet work. However, with the rapid development of prefabricated structural systems, the connection nodes between these structures and cast-in-place structures have revealed prominent problems of insufficient structural load-bearing capacity.

[0003] Addressing the pain points of prefabricated structural systems, the precast concrete structure system offers a novel approach. This system utilizes high-strength concrete slabs as the outer shell in a factory, creating a hollow interior. After the shell is transported to the construction site and assembled, concrete is poured into the cavity. This structural system is widely adopted in residential projects due to its advantages, including good integrity, simple and convenient on-site installation, and the elimination of formwork supports.

[0004] The cavity of the precast formwork component is fixed with a steel cage. In the area where it connects with the lower structure, the construction method of the steel reinforcement is different from that of the traditional cast-in-place structure and also different from that of the ordinary prefabricated structure system. For example, how to make the steel reinforcement in the connection area during construction, the steel reinforcement reserved in the cast-in-place structure, and the construction of the steel reinforcement reserved for vertical connection between precast formwork components are all problems that need to be solved in the current process of promoting the precast formwork structure system.

[0005] If the rebar is reserved according to the traditional construction sequence of cast-in-place walls and columns, there will be collisions and conflicts between the rebar reserved in the lower structure and the rebar in the upper formwork structure. This will require the construction team to constantly try to adjust the position of the rebar on site, and there will be disorder in the placement of the rebar in the connection area with the lower structure. This will cause inconvenience to construction and pose a risk of delays in the construction period. Summary of the Invention

[0006] The purpose of this invention is to provide a construction method for the connection node between precast formwork components and cast-in-place structures, which can solve the problems of difficulty in rebar detailing, rebar collision, and disordered rebar placement in the connection area between the formwork structure and the cast-in-place structure, so as to achieve the purpose of rapid installation of formwork structure components.

[0007] This invention is implemented as follows: a construction method for the connection node between a precast molded component and a cast-in-place structure, the construction method comprising the following steps: Reinforcement design for precast formwork components and cast-in-place connection nodes: Design the thickness of the formwork, concrete strength grade, and reinforcement of the cast-in-place connection nodes for the precast formwork components, specifying the type, quantity, location of the main reinforcement and stirrups, as well as the anchorage length and lap splice form of the main reinforcement. BIM Modeling Analysis: Based on the design drawings, simulation analysis is conducted on the rebar detailing and rebar construction sequence for different types of connection nodes. Firstly, the reserved lap length, reserved lap location, and anchorage method of the vertical and horizontal rebars in the precast formwork components are determined. Secondly, the location, lap length, bending angle, and potential conflicts with the vertical rebars of the precast formwork components are determined. Through BIM modeling simulation analysis, 3D visualization verification, and rebar collision detection, rebar problems at connection node locations are avoided in advance, facilitating on-site construction. Production of precast formwork components: Based on BIM modeling and analysis, determine the type, location, lap splicing method, and reserved length of reinforcing bars; then proceed with the production of precast formwork components. On-site construction: During the construction process, technical personnel need to be present throughout the process and provide technical guidance, while also conducting technical verification of the rebar binding at the connection nodes.

[0008] Furthermore, after the precast components of the formwork are produced, the upper and lower precast components need to be pre-assembled in the factory to avoid problems caused by the vertical ribs of the lower precast components colliding with the vertical ribs of the upper precast components, which would prevent on-site installation.

[0009] Furthermore, before construction, a visual technical briefing is conducted for construction workers using a combination of text and graphics and BIM model interpretation. This clarifies the lap length of the vertical reinforcement to be reserved in the lower structure and the bending requirements of the vertical reinforcement, the hoisting process of the precast formwork components, the lap form and lap length of the reinforcement in the upper and lower precast formwork components, and the construction sequence of the reinforcement at the connection nodes between the precast formwork components and the cast-in-place structure.

[0010] Furthermore, during the detailed design phase, Revit software was used to conduct detailed designs for different cage-like structural components and to perform BIM modeling, clarifying the placement of reinforcing bars in the cavity area of ​​the precast components and the length of reserved reinforcing bars at the bottom and top of the components.

[0011] Furthermore, during the construction phase, Revit software was used to create BIM models for different connection nodes of the precast formwork components, and to perform reinforcement detailing and reinforcement reservation analysis for the connection nodes.

[0012] Furthermore, for the straight connection nodes between the formwork wall and the cast-in-place structure and the L-shaped connection nodes between the formwork wall: the horizontal connecting bars and horizontal stirrups configured in the node area are prone to collision with the horizontal bars on the side of the formwork wall. Before producing the formwork wall, the problem of rebar detailing in the connection section is analyzed through BIM modeling, and the horizontal bars of the formwork wall and the horizontal connecting bars and horizontal stirrups of the cast-in-place structure are simulated to clarify the starting distance and vertical spacing, so as to avoid collision.

[0013] Furthermore, for the straight connection node with one side being a formwork wall and the other side being a cast-in-place structure, and the L-shaped connection node between formwork walls: first, the reinforcement of the cast-in-place structure is tied, then the formwork wall is hoisted, the horizontal reinforcement of the formwork wall is inserted into the cast-in-place structure, and finally, U-shaped horizontal connecting bars are inserted on site. The horizontal connecting bars are set as open type, and the length of the extension into the formwork wall is 1.2LaE. The overall construction sequence of the reinforcement of the connection node section is as follows: reinforcement tying of the cast-in-place structure, hoisting of the formwork wall, tying of the horizontal reinforcement of the formwork wall with the longitudinal reinforcement of the cast-in-place structure, insertion of horizontal connecting bars, adjustment of the position of the horizontal connecting bars, tying of the horizontal connecting bars with the longitudinal reinforcement of the cast-in-place structure, formwork support and joint treatment of the cast-in-place structure, and pouring of concrete. For a straight connection node with formwork walls on both sides and cast-in-place structure in the middle: first, tie the cast-in-place structure reinforcement. During the process of tying the stirrups, simultaneously place closed horizontal connecting bars, with each end extending into the formwork wall by a length of 1.2LaE. The horizontal connecting bars are not tied at first. Then, hoist the formwork walls at both ends. After the walls are in place, adjust the position of the horizontal bars of the walls and the stirrups of the cast-in-place structure. Finally, tie the horizontal connecting bars, avoiding collisions between the horizontal connecting bars and the stirrups and the reserved horizontal bars of the walls. The overall construction sequence of the reinforcement in the connection node section is as follows: cast-in-place vertical bars, stirrup tying, hoisting the formwork walls, adjusting the position of the formwork walls and stirrups, tying the horizontal bars of the formwork walls and the longitudinal bars of the cast-in-place structure, tying the horizontal connecting bars, formwork support and joint treatment of the cast-in-place structure, and pouring concrete.

[0014] Furthermore, regarding the connection nodes between the upper formwork column and the lower cast-in-place column: First, the reinforcement details of the upper formwork column are created using BIM modeling. Then, based on the positions of the vertical bars and stirrups of the upper formwork column, the reinforcement details of the lower cast-in-place column are created. To facilitate the lap joint of the vertical bars of the upper and lower columns and avoid collisions, the top of the vertical bars of the lower cast-in-place column needs to be bent inwards at a 1:6 angle to avoid the vertical bars of the upper formwork column. The reserved vertical bars of the lower cast-in-place column need to be anchored into the reinforcement cage of the upper formwork column by ≥1.0LaE. Finally, simulation... The reinforcement construction process, the reinforcement construction sequence of the connection area between the upper formwork column and the lower cast-in-place column is as follows: before pouring the lower cast-in-place column, the positioning and verification of the reserved vertical reinforcement of the lower cast-in-place column is checked; the reserved vertical reinforcement of the lower cast-in-place column is bent inward at a ratio of 1:6; the column top stirrups of the lower cast-in-place column are tied; the positioning stirrups are welded on the reserved reinforcement; the lower cast-in-place column is poured; the positioning of the reserved vertical reinforcement is checked again; the upper formwork column is hoisted; the longitudinal reinforcement of the formwork column is installed; the stirrups are tied to the reserved vertical reinforcement; the bottom of the upper formwork column is supported; and the concrete is poured.

[0015] Furthermore, regarding the connection node between the upper variable cross-section formwork column and the lower cast-in-place column: First, simulate and detail the reinforcement of the upper and lower columns using BIM modeling. When the reinforcement extending from the lower cast-in-place column cannot extend into the upper variable cross-section formwork column, the ends of the reinforcement should be anchored to the top surface of the beam with an anchor plate ≥0.5LaE. When the reserved vertical reinforcement of the lower cast-in-place column conflicts with the vertical reinforcement of the upper variable cross-section formwork column, the reserved vertical reinforcement of the lower cast-in-place column should be bent inward at a 1:6 angle to avoid the vertical reinforcement of the upper variable cross-section formwork column. The reserved vertical reinforcement of the lower cast-in-place column must be anchored into the upper formwork and upper variable cross-section formwork column with an anchor plate ≥1.0LaE. At the variable cross-section location, when the horizontal distance of the reserved vertical reinforcement of the lower cast-in-place column bent inward is >1 / 6h, the reserved vertical reinforcement should not be bent into the upper variable cross-section formwork column. It can extend to the top of the column and then be anchored with an anchor plate. For the vertical reinforcement of the upper-level formwork column with variable cross-section, vertical dowel bars are pre-reserved in the lower-level cast-in-place column. The anchorage section of the vertical dowel bars is 1.2LaE, extending into the upper-level formwork column with variable cross-section by 1.6LaE. After the reinforcement of the upper and lower columns is detailed, the construction process of the reinforcement of the connection node is simulated. The construction sequence of the reinforcement of the connection node between the upper-level formwork column with variable cross-section and the lower-level cast-in-place column is as follows: verification of the positioning of the reserved vertical reinforcement before the lower-level cast-in-place column is poured; bending the reserved vertical reinforcement inward at a ratio of 1:6; adding additional dowel bars at the variable cross-section position; tying the column top stirrups of the lower-level cast-in-place column; welding positioning stirrups on the reserved vertical reinforcement of the lower-level cast-in-place column; pouring the lower-level cast-in-place column; re-verification of the positioning of the reserved vertical reinforcement of the lower-level cast-in-place column; hoisting the upper-level formwork column with variable cross-section; longitudinal reinforcement of the formwork column; tying the stirrups and reserved vertical reinforcement; setting up the bottom formwork of the upper-level formwork column with variable cross-section; and pouring concrete.

[0016] The construction method provided by this invention has at least the following advantages compared with the prior art: 1. By using BIM modeling, the rebar at the connection node can be accurately detailed, avoiding problems such as rebar collision, waste of reserved rebar lap splices, and rebar omission caused by on-site rebar workers relying on experience for detailing.

[0017] 2. By simulating the construction sequence of steel reinforcement in the cast-in-place connection node area through BIM modeling, problems such as misplacement of steel reinforcement, inability to tie, and steel reinforcement conflict are avoided, which improves on-site construction efficiency and saves steel reinforcement costs, and enables rapid installation of formwork structure components. Attached Figure Description

[0018] Figure 1a This is a structural schematic diagram of the straight connection node between the formwork wall and the cast-in-place structure provided in this embodiment; Figure 1b This is a detailed drawing of the reinforcement of the straight connection node between the formwork wall and the cast-in-place structure provided in this embodiment; Figure 1c This is a schematic diagram of a straight connection node provided in this embodiment, where the two sides are formwork walls and the middle is a cast-in-place structure; Figure 1dThis is a detailed drawing of the reinforcement of a straight connection node with formwork walls on both sides and a cast-in-place structure in the middle, as provided in this embodiment. Figure 2a This is a structural schematic diagram of the L-shaped connection node between the formwork walls provided in this embodiment; Figure 2b This is a detailed drawing of the reinforcement of the L-shaped connection node between the formwork walls provided in this embodiment; Figure 3a This is a structural schematic diagram of the connection node between the upper mold shell column and the lower cast-in-place structural column provided in this embodiment; Figure 3b This is a detailed drawing of the reinforcement of the connection node between the upper formwork column and the lower cast-in-place structural column provided in this embodiment; Figure 4a This is a structural schematic diagram of the connection node between the upper variable cross-section molded column and the lower cast-in-place column provided in this embodiment; Figure 4b This is a detailed drawing of the reinforcement of the connection node between the upper variable cross-section molded column and the lower cast-in-place column provided in this embodiment. Detailed Implementation

[0019] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0020] This embodiment provides a construction method for the connection node between precast mold components and cast-in-place structures, including the following steps: Reinforcement design for precast formwork components and cast-in-place connection nodes: During the design phase, the thickness of the formwork, the concrete strength grade, and the reinforcement of the cast-in-place connection nodes of the formwork components are designed according to relevant standards, specifications, and drawings. Revit software is used to carry out detailed design and BIM modeling for different cage formwork structural components, clarifying the type, quantity, and location of the main reinforcement and stirrups, as well as the anchorage length and lap splice form of the main reinforcement, such as the placement of reinforcement in the cavity area of ​​the formwork component and the length of reserved reinforcement at the bottom and top of the component.

[0021] BIM modeling and analysis: Based on the design drawings, simulation analysis was conducted on the rebar detailing and rebar construction sequence for different connection nodes. Firstly, the reserved lap length, reserved lap location, and anchorage method of the vertical and horizontal rebars in the precast formwork components were determined. Secondly, the location, lap length, bending angle, and potential conflicts with the vertical rebars of the lower structure's top were determined. Through BIM modeling and simulation analysis, and via 3D visualization verification and rebar collision detection, rebar problems at connection node locations were proactively avoided, facilitating on-site construction.

[0022] Production of precast formwork components: Based on BIM modeling analysis and detailing, determine the steel bar type, positioning, lap splicing method, and reserved steel bar length, etc., to produce precast formwork components. At the same time, communicate with the prefabrication factory in advance. After the formwork components are produced, the upper and lower layers of formwork components need to be pre-assembled in the factory to avoid collisions between the reserved vertical bars of the lower layer formwork components and the vertical bars of the upper layer formwork components due to problems in the production process, which would prevent on-site installation.

[0023] On-site construction: The reinforcement at the connection nodes described in this example is quite dense, posing significant technical challenges for on-site construction. Prior to construction, a visual technical briefing was conducted for the construction personnel using a combination of text and graphics, along with BIM model interpretation. This briefing clarified the required lap length and bending requirements for the vertical reinforcement in the lower structure, the hoisting process for the precast formwork components, the lap form and length of the reinforcement in the upper and lower formwork components, and the construction sequence of reinforcement at the connection nodes between the formwork components and the cast-in-place structure. During construction, technical personnel were required to be present throughout the process to provide technical guidance and to conduct technical verification of the reinforcement binding at the connection nodes.

[0024] Specifically, during the construction phase, Revit software was used to create BIM models for different connection nodes of the precast formwork components, and analyses were performed on the connection node reinforcement details and reinforcement reservations. The main connection nodes were represented by the following four models: (1) For the model of the straight connection node between the formwork wall and the cast-in-place structure, please refer to Figure 1a , Figure 1c ; (2) Model of L-shaped connection node between the shell walls, see Figure 2a ; (3) Model of the connection node between the upper shell column and the lower cast-in-place column, see Figure 3a ; (4) Model of the connection node between the upper variable cross-section molded column and the lower cast-in-place column, see Figure 4a ; For the straight connection nodes between formwork wall 1 and cast-in-place structure 2, and the L-shaped connection nodes between formwork walls 1, the U-shaped horizontal connecting bars a and horizontal stirrups b configured in the node area are prone to collision with the horizontal bars on the side of formwork wall 1. Before producing formwork wall 1, the rebar detailing problem in the connection section is analyzed through BIM modeling. The horizontal bars of formwork wall 1 and the U-shaped horizontal connecting bars a and horizontal stirrups b of cast-in-place structure 2 are simulated, and the starting distance and vertical spacing are clarified to avoid collision. Then, the on-site rebar construction process is simulated. Specifically, for the straight connection nodes with formwork wall 1 on one side and cast-in-place structure 2 on the other side, and the L-shaped connection nodes between formwork walls 1: first, the rebar of cast-in-place structure 2 is tied, then formwork wall 1 is hoisted, the horizontal bars of formwork wall 1 are inserted into cast-in-place structure 2, and finally, U-shaped horizontal connecting bars a are inserted on-site. U-shaped horizontal connecting bars a are set to open type and extend into formwork wall 1 by a length of 1.2LaE. The overall construction sequence for the reinforcement of the connecting node section is as follows: binding of the reinforcement of cast-in-place structure 2 → hoisting of formwork wall 1 → binding of the horizontal reinforcement of formwork wall 1 to the longitudinal reinforcement of cast-in-place structure 2 → insertion of the U-shaped horizontal connecting bar a → adjustment of the position of the U-shaped horizontal connecting bar a → binding of the U-shaped horizontal connecting bar a to the longitudinal reinforcement of cast-in-place structure 2 → formwork erection and joint treatment of cast-in-place structure 2 → pouring of concrete. For the straight-line connecting node with formwork wall 1 on both sides and cast-in-place structure 2 in the middle, see... Figure 1c First, the reinforcement of cast-in-place structure 2 is tied. During the tying of the stirrups, closed-shaped horizontal connecting bars c are placed simultaneously, extending 1.2LaE into the formwork wall 1 at each end. The closed-shaped horizontal connecting bars c are not tied initially. Then, the formwork walls at both ends are hoisted. After the walls are in place, the positions of the horizontal reinforcement bars of the walls and the horizontal stirrups b of cast-in-place structure 2 are adjusted. Finally, the closed-shaped horizontal connecting bars c are tied, avoiding collisions with the horizontal stirrups b and the reserved horizontal reinforcement bars in the walls. The overall construction sequence of reinforcement in the connection node section is as follows: tying of vertical reinforcement and horizontal stirrups b of the cast-in-place structure (simultaneous insertion of closed-shaped horizontal connecting bars c) → hoisting of formwork wall 1 → adjusting the positions of formwork wall 1 and horizontal stirrups b → tying of horizontal reinforcement bars of formwork wall 1 to longitudinal reinforcement of cast-in-place structure 2 → tying of closed-shaped horizontal connecting bars c → formwork erection and joint treatment of cast-in-place structure 2 → pouring of concrete. See the detailed reinforcement drawings below. Figure 1b , Figure 1d , Figure 2b .

[0025] For the connection node between the upper formwork column 3 and the lower cast-in-place column 4: First, the reinforcement of the upper formwork column 3 is detailed using BIM modeling. Then, the reinforcement of the lower cast-in-place column 4 is detailed according to the position of the vertical reinforcement e and stirrup f of the upper formwork column 3. In order to facilitate the lap of the vertical reinforcement of the upper and lower columns and avoid collision, the top of the vertical reinforcement of the lower cast-in-place column 4 needs to be bent inward at 1:6 to avoid the vertical reinforcement e of the upper formwork column 3. The reserved vertical reinforcement e1 of the lower cast-in-place column 4 needs to be anchored into the reinforcement cage of the upper formwork column 3 by ≥1.0LaE. Finally, simulating the rebar construction process, the rebar construction sequence for the connection area between the upper formwork column 3 and the lower cast-in-place column 4 is as follows: Before pouring the lower cast-in-place column 4, the positioning and verification of the reserved vertical reinforcement e1 is performed → the reserved vertical reinforcement e1 of the lower cast-in-place column 4 is bent inwards at a ratio of 1:6 → the top stirrups of the lower cast-in-place column 4 are tied → positioning stirrups are welded onto the reserved vertical reinforcement e1 → the lower cast-in-place column 4 is poured → the positioning of the reserved vertical reinforcement e1 is verified again → the upper formwork column 3 is hoisted → the vertical reinforcement e and stirrup f of the formwork column are tied to the reserved vertical reinforcement e1 → the bottom of the upper formwork column 3 is supported with formwork and concrete is poured. See the detailed rebar drawing. Figure 3b .

[0026] For the connection node between the upper variable cross-section formwork column 5 and the lower cast-in-place column 4: First, simulate and detail the reinforcement of the upper and lower columns using BIM modeling. When the reserved vertical bar e1 extending from the lower cast-in-place column 4 cannot extend into the upper variable cross-section formwork column 5, the end of the reserved vertical bar e1 is anchored to the top surface of the beam with an anchor plate h and ≥0.5LaE. When the reserved vertical bar e1 conflicts with the vertical bar e of the upper variable cross-section formwork column 5, the reserved vertical bar e1 is bent inward at a 1:6 ratio to avoid the vertical bar e of the upper variable cross-section formwork column 5. The reserved vertical reinforcement e1 needs to be anchored into the upper variable cross-section formwork column 5 by ≥1.0LaE. At the variable cross-section location, if the reserved vertical reinforcement e1 is bent inwards by a horizontal distance >1 / 6h, the reserved vertical reinforcement e1 should not be bent and extended into the upper variable cross-section formwork column 5. It can extend to the top of the column and then be anchored with an anchor plate g. Simultaneously, at the location of the vertical reinforcement in the upper variable cross-section formwork column 5, a vertical dowel bar should be pre-reserved in the lower cast-in-place column 4. The anchorage section of the vertical dowel bar is 1.2LaE, extending into the upper variable cross-section formwork column 5 by 1.6LaE (see...). Figure 4b The construction process for the connection node reinforcement is simulated after the reinforcement detailing of the upper variable cross-section formwork column 5 is completed. The construction sequence of the reinforcement for the connection node between the upper variable cross-section formwork column 5 and the lower cast-in-place column 4 is as follows: Before pouring the lower cast-in-place column 4, the positioning and verification of the reserved vertical reinforcement e1 is completed → the reserved vertical reinforcement e1 is bent inward at a ratio of 1:6 → additional dowel bars are added at the variable cross-section location → the top stirrups of the lower cast-in-place column 4 are tied → positioning stirrups are welded onto the reserved vertical reinforcement e1 → the lower cast-in-place column 4 is poured → the positioning of the reserved vertical reinforcement e1 of the lower cast-in-place column 4 is verified again → the upper variable cross-section formwork column 5 is hoisted → the vertical reinforcement e and stirrup f of the upper variable cross-section formwork column 5 are tied to the reserved vertical reinforcement e1 → the bottom formwork of the upper variable cross-section formwork column 5 is erected and concrete is poured. See the detailed reinforcement drawing. Figure 4b .

[0027] In summary, this embodiment provides a precise, efficient, and convenient method for constructing reinforcing bars in the connection area between the formwork structure and the cast-in-place structure. This method solves problems such as difficulties in rebar detailing, bar collisions, and disordered bar placement in the connection area, thus achieving the goal of rapid installation of formwork structure components.

[0028] Compared with the prior art, this embodiment has at least the following beneficial effects: 1. By using BIM modeling, the rebar at the connection node can be accurately detailed, avoiding problems such as rebar collision, waste of reserved rebar lap splices, and rebar omission caused by on-site rebar workers relying on experience for detailing.

[0029] 2. By simulating the construction sequence of steel reinforcement in the cast-in-place connection node area through BIM modeling, problems such as misplacement of steel reinforcement, inability to tie, and steel reinforcement conflict are avoided, which improves on-site construction efficiency and saves steel reinforcement costs, and enables rapid installation of formwork structure components.

[0030] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not 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 this invention. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A construction method for the connection node between a precast molded component and a cast-in-place structure, characterized in that, The construction method includes the following steps: Reinforcement design for precast formwork components and cast-in-place connection nodes: Design the thickness of the formwork, concrete strength grade, and reinforcement of the cast-in-place connection nodes for the precast formwork components, specifying the type, quantity, location of the main reinforcement and stirrups, as well as the anchorage length and lap splice form of the main reinforcement. BIM Modeling Analysis: Based on the design drawings, simulation analysis is conducted on the rebar detailing and rebar construction sequence for different types of connection nodes. Firstly, the reserved lap length, reserved lap location, and anchorage method of the vertical and horizontal rebars in the precast formwork components are determined. Secondly, the location, lap length, bending angle, and potential conflicts with the vertical rebars of the precast formwork components are determined. Through BIM modeling simulation analysis, 3D visualization verification, and rebar collision detection, rebar problems at connection node locations are avoided in advance, facilitating on-site construction. Production of precast formwork components: Based on BIM modeling and analysis, determine the type, location, lap splicing method, and reserved length of reinforcing bars; then proceed with the production of precast formwork components. On-site construction: During the construction process, technical personnel need to be present throughout the process and provide technical guidance, while also conducting technical verification of the rebar binding at the connection nodes.

2. The construction method according to claim 1, characterized in that, After the precast components of the formwork are produced, the upper and lower precast components need to be pre-assembled in the factory to avoid problems caused by the vertical ribs of the lower precast components colliding with the vertical ribs of the upper precast components, which would prevent on-site installation.

3. The construction method according to claim 1, characterized in that, Before construction, a visual technical briefing was conducted for construction workers using a combination of text and graphics and BIM model interpretation. This briefing clarified the lap length and bending requirements of the vertical reinforcement to be reserved in the lower structure, the hoisting process of the precast formwork components, the lap form and lap length of the reinforcement in the upper and lower precast formwork components, and the construction sequence of the reinforcement at the connection nodes between the precast formwork components and the cast-in-place structure.

4. The construction method according to claim 1, characterized in that, During the detailed design phase, Revit software was used to conduct detailed designs for different cage-like structural components and to perform BIM modeling, clarifying the placement of reinforcing bars in the cavity area of ​​the precast components and the length of reserved reinforcing bars at the bottom and top of the components.

5. The construction method according to claim 1, characterized in that, During the construction phase, Revit software was used to create BIM models of different connection nodes of the precast formwork components, and to perform reinforcement detailing and reinforcement reservation analysis of the connection nodes.

6. The construction method according to claim 5, characterized in that, For the straight connection nodes between the formwork wall and the cast-in-place structure and the L-shaped connection nodes between the formwork wall: the horizontal connecting bars and horizontal stirrups configured in the node area are prone to collision with the horizontal bars on the side of the formwork wall. Before producing the formwork wall, the problem of rebar detailing in the connection section is analyzed through BIM modeling. The horizontal bars of the formwork wall and the horizontal connecting bars and horizontal stirrups of the cast-in-place structure are simulated, and the starting distance and vertical spacing are clearly defined to avoid collision.

7. The construction method according to claim 6, characterized in that, For a straight connection node with a formwork wall on one side and a cast-in-place structure on the other, and an L-shaped connection node between formwork walls: first, the reinforcement of the cast-in-place structure is tied; then, the formwork wall is hoisted; the horizontal reinforcement of the formwork wall is inserted into the cast-in-place structure; finally, U-shaped horizontal connecting bars are inserted on site. The horizontal connecting bars are set to be open type, and the length of the bars extending into the formwork wall is 1.2LaE. The overall construction sequence of reinforcement in the connection node section is as follows: reinforcement tying of the cast-in-place structure, hoisting of the formwork wall, tying of the horizontal reinforcement of the formwork wall to the longitudinal reinforcement of the cast-in-place structure, insertion of horizontal connecting bars, adjustment of the position of the horizontal connecting bars, tying of the horizontal connecting bars to the longitudinal reinforcement of the cast-in-place structure, formwork support and joint treatment of the cast-in-place structure, and pouring of concrete. For a straight connection node with formwork walls on both sides and cast-in-place structure in the middle: first, tie the cast-in-place structure reinforcement. During the process of tying the stirrups, simultaneously place closed horizontal connecting bars, with each end extending into the formwork wall by a length of 1.2LaE. The horizontal connecting bars are not tied at first. Then, hoist the formwork walls at both ends. After the walls are in place, adjust the position of the horizontal bars of the walls and the stirrups of the cast-in-place structure. Finally, tie the horizontal connecting bars, avoiding collisions between the horizontal connecting bars and the stirrups and the reserved horizontal bars of the walls. The overall construction sequence of the reinforcement in the connection node section is as follows: cast-in-place vertical bars, stirrup tying, hoisting the formwork walls, adjusting the position of the formwork walls and stirrups, tying the horizontal bars of the formwork walls and the longitudinal bars of the cast-in-place structure, tying the horizontal connecting bars, formwork support and joint treatment of the cast-in-place structure, and pouring concrete.

8. The construction method according to claim 5, characterized in that, For the connection node between the upper formwork column and the lower cast-in-place column: First, the reinforcement details of the upper formwork column are created using BIM modeling. Then, the reinforcement details of the lower cast-in-place column are created based on the positions of the vertical bars and stirrups of the upper formwork column. To facilitate the lap joint of the vertical bars of the upper and lower columns and avoid collisions, the top of the vertical bars of the lower cast-in-place column needs to be bent inward at a 1:6 angle to avoid the vertical bars of the upper formwork column. The reserved vertical bars of the lower cast-in-place column need to be anchored into the reinforcement cage of the upper formwork column by ≥1.0LaE. Finally, the reinforcement is simulated. The construction process, the construction sequence of the reinforcement in the connection area between the upper formwork column and the lower cast-in-place column is as follows: before pouring the lower cast-in-place column, the positioning and verification of the reserved vertical reinforcement is checked; the reserved vertical reinforcement of the lower cast-in-place column is bent inward at a ratio of 1:6; the column top stirrups of the lower cast-in-place column are tied; the positioning stirrups are welded on the reserved reinforcement; the lower cast-in-place column is poured; the positioning of the reserved vertical reinforcement is checked again; the upper formwork column is hoisted; the longitudinal reinforcement of the formwork column is installed; the stirrups are tied to the reserved vertical reinforcement; the bottom of the upper formwork column is supported; and the concrete is poured.

9. The construction method according to claim 5, characterized in that, For the connection node between the upper variable cross-section formwork column and the lower cast-in-place column: First, simulate and detail the reinforcement of the upper and lower columns using BIM modeling. When the reinforcement extending from the lower cast-in-place column cannot extend into the upper variable cross-section formwork column, the ends of the reinforcement should be anchored to the top surface of the beam with an anchor plate ≥0.5LaE. When the reserved vertical reinforcement of the lower cast-in-place column conflicts with the vertical reinforcement of the upper variable cross-section formwork column, the reserved vertical reinforcement of the lower cast-in-place column should be bent inward at a 1:6 ratio to avoid the vertical reinforcement of the upper variable cross-section formwork column. The reserved vertical reinforcement of the lower cast-in-place column must be anchored into the upper formwork and upper variable cross-section formwork column with an anchor plate ≥1.0LaE. At the variable cross-section location, when the horizontal distance of the reserved vertical reinforcement of the lower cast-in-place column bent inward is >1 / 6h, the reserved vertical reinforcement should not be bent into the upper variable cross-section formwork column. It can extend to the top of the column and then be anchored with an anchor plate. For the vertical reinforcement of the variable cross-section formwork column, vertical dowel bars are pre-reserved in the lower cast-in-place column. The anchorage section of the vertical dowel bars is 1.2LaE, extending into the upper variable cross-section formwork column by 1.6LaE. After the reinforcement of the upper and lower columns is detailed, the construction process of the connection node reinforcement is simulated. The construction sequence of the reinforcement of the connection node between the upper variable cross-section formwork column and the lower cast-in-place column is as follows: verification of the positioning of the reserved vertical reinforcement before the lower cast-in-place column is poured; bending the reserved vertical reinforcement inward at a ratio of 1:6; adding additional dowel bars at the variable cross-section position; tying the column top stirrups of the lower cast-in-place column; welding positioning stirrups on the reserved vertical reinforcement of the lower cast-in-place column; pouring the lower cast-in-place column; re-verification of the positioning of the reserved vertical reinforcement of the lower cast-in-place column; hoisting the upper variable cross-section formwork column; longitudinal reinforcement of the formwork column; tying the stirrups and reserved vertical reinforcement; setting up the bottom formwork of the upper variable cross-section formwork column; and pouring concrete.

Images