Method for tying together reinforced concrete framework for precast box girders

Abstract

This provides a method for tying together reinforced concrete frames for precast box girders. [Solution] The reinforcing steel frame for the girder is divided into multiple reinforcing mesh sheets and steel strip mesh sheets. Here, the reinforcing mesh is directly processed into the desired shape, and the reinforcing mesh sheets are directly placed in predetermined positions on the tying stage, and subsequent tying is performed manually. For extra-large standard mesh sheets and irregularly shaped mesh sheets, one reinforcing bar is first processed in the form of a steel strip mesh and then placed in the desired position, and the steel strip mesh is used to arrange, lay, and tie the through-reinforcements.

Description

Technical Field

[0001] The present invention relates to the technical field of railway construction, and specifically to a binding construction method for the steel bar framework of precast box girders.

Background Art

[0002] The precast of box girders for high-speed railways includes main processes such as steel bar manufacturing and installation, formwork polishing, concrete pouring, prestress tensioning, mortar pressing in holes, girder body concrete curing, rough finishing and sealing of anchor holes, and spray coating of waterproof paint at the girder ends. Other processes except for steel bar manufacturing and installation have achieved technical breakthroughs in terms of smart construction. Conventional steel bars for box girders are numerous in types and quantities, with a large workload. Taking a 32m box girder as an example, the steel bars include 6 diameters, 103 types of shapes, with a total weight of 52t, and the number of steel bar indirect connection joints reaches 70,000. The connection forms are complex and diverse, and the process is old, with unstable quality and low efficiency.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The object of the present invention is to provide a binding construction method for the steel bar framework of precast box girders, which divides the box girder into multiple steel bar meshes and steel strip meshes, processes them respectively, and then performs overall assembly, so as to reduce the manual operation process, save manpower, stabilize quality, and greatly improve efficiency.

Means for Solving the Problems

[0004] Based on the above object, the present invention uses the following technical solutions.

[0005] A method for tying together a reinforced steel frame for a precast box girder, wherein the reinforced steel frame for the girder is divided into multiple reinforced steel mesh sheets and steel strip mesh sheets, in which the reinforced steel mesh is directly processed into the desired shape, and the reinforced steel mesh sheets are directly placed in predetermined positions on a tying stage, and subsequent tying is performed manually, and for extra-large standard mesh sheets and irregularly shaped mesh sheets, one reinforcement is first processed in the form of a steel strip mesh and then placed in the desired position, and the through reinforcement is then placed, laid and tied using the steel strip mesh.

[0006] Preferably, the assembly steps for the reinforcing steel mesh sheet and the steel strip mesh sheet are as follows: Step 1: Transport the N12 reinforcing bars of the base plate one by one to the binding stage and place them in the designated positions. Step 2, Place the steel strip mesh on the bottom plate. Step 3: Place the steel strip mesh on one side of the web, Step 4, Place the steel strip mesh on the other side of the web, Step 5, Place the mesh sheet of the base plate in the designated position. Step 6, Place the web mesh sheet in place. Step 7, Place the reinforcing bars of the top plate in the designated position. Step 8: After placing the reinforcing mesh at the bottom of the top plate into the formwork, place the steel strip mesh. Step 9: After precasting the reinforcement at the top of the top plate in a mesh pattern offline, place it in the formwork. Step 10: Position the mesh sheets on both sides of the top plate in their designated locations.

[0007] Preferably, the welding process for the reinforcing mesh sheet is as follows: Step 1: The raw materials for the reinforcing bars are transported from the storage area to the coil reinforcing bar straightening and feeding area, where the reinforcing bars are pulled, cushioned, straightened, cut to the required length, and then cut. Step 2: The horizontal reinforcing bars are transported to the horizontal reinforcing bar feeding area, and the horizontal reinforcing bars are dropped using a chain system. Step 3: Transport to the welding area and form by resistance welding. Step 4: After molding, fold one side of the reinforcing mesh sheet at a time in the in-line bending area.

[0008] Preferably, the direction of the bend is upward.

[0009] Preferably, the method for processing the steel strip mesh is as follows: Step 1: For each of the longitudinal (and transverse) reinforcing bars required for the precast box girder, the through-reinforcing bars are straightened in-line based on the set data using a numerically controlled reinforcing bar straightening means, and then straightened one by one according to the set feed pitch and transported one by one. Step 2, the reinforcing bars and steel strips are wrapped in a cross shape and welded together to form a mesh. Step 3: After welding is complete, the mesh sheet is fed forward, bent in the direction of the steel strip's cross-section, automatically wound up, and the finished steel strip coil is automatically transported to a tray.

[0010] Preferably, the hooks of the hoop reinforcement N15 inside the web are 90° right-angle hooks to facilitate welding / binding to the transverse reinforcement at the bottom of the top plate.

[0011] Preferably, a 135° or 90° hook is provided at the end of the reinforcing bar N35 in the upper layer of the bottom plate, or an anchor plate is provided at the end of N35.

[0012] Preferably, the N14 reinforcing bars in the lower layer of the top plate are welded / tied to the N15, and anchor plates are provided at the ends of the N14 reinforcing bars. [Effects of the Invention]

[0013] The present invention has the following beneficial effects compared to the prior art.

[0014] In the construction method of the present invention, the box girder skeleton is divided into a plurality of steel bar meshes and steel strip meshes, processed respectively, and then assembled as a whole. For the steel materials, from supply, transportation, sizing, cutting, mesh welding to bending forming into a mesh sheet, a line-integrated numerical control composite processing machine such as a mesh welding device, a shearing line, and a bending center can be used. With a single mesh sheet, it is easy to realize mechanized processing. Some steel bars are manually inserted, which greatly improves the overall automation rate, reduces the manual operation process, saves manpower, stabilizes the quality, and significantly improves the efficiency.

Brief Description of the Drawings

[0015] [Figure 1] It is a flowchart of the assembly of the mesh sheet. [Figure 2] It is a layout diagram of the steel bar mesh sheet. [Figure 3] It is a schematic diagram of the hook of the hoop bar inside the web. [Figure 4] It is a schematic diagram of the hook of the anchor end of the steel bar N35 in the upper layer of the bottom plate. [Figure 5] It is a schematic diagram of the end anchor plate of the steel bar N35 in the upper layer of the bottom plate. [Figure 6] It is a schematic diagram of the hook of the anchor end of the steel bar N35 in the upper layer of the bottom plate. [[ID=2,5]]

Embodiments for Carrying Out the Invention

[0016] Hereinafter, referring to FIGS. 1 to 6, a method for binding a precast box girder steel reinforcement framework according to an embodiment of the present invention will be described. In the description of this embodiment, "first" and "second" are merely for the purpose of explanation and do not indicate relative importance or implicitly indicate the number of the specified technical features. Therefore, the features defined by "first" and "second" may mean including at least one feature (that is, one or more features) explicitly or implicitly. In the description of the present invention, "plurality" means at least two (for example, two, three, etc.) unless otherwise limited. When a certain feature is described as "including one or more" of other features, it indicates that, unless otherwise specified, it does not exclude other features and may further include other features.

[0017] In the description of this embodiment, the description referring to terms such as "one embodiment", "several embodiments", "exemplary embodiments", "example", "specific example", "several examples", etc. means that the specific features, structures, materials or characteristics described in relation to the said embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the general expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0018] As shown in FIGS. 1 to 6, the present invention is a method for binding a precast box girder steel reinforcement framework. In the said construction method, the steel reinforcement framework for the girder is divided into a plurality of steel bar mesh sheets and steel strip mesh sheets. Here, the steel bar mesh is directly processed into a desired shape, and the steel bar mesh sheet is directly placed at a predetermined position on the binding stage, and subsequent binding is performed manually. For the extra-large standard mesh sheet and the irregular-shaped mesh sheet, in the form of a steel strip mesh, first, one steel bar is processed and then placed at the desired position, and then, using the steel strip mesh, the arrangement, laying and binding of the longitudinal bars are carried out.

[0019] Preferably, the assembly steps of the said steel bar mesh sheet and the steel strip mesh sheet are as follows.

[0020] Step 1: Transport the N12 reinforcing bars of the base plate one by one to the binding stage and place them in the designated positions. Step 2, Place the steel strip mesh on the bottom plate. Step 3: Place the steel strip mesh on one side of the web, Step 4, Place the steel strip mesh on the other side of the web, Step 5, Place the mesh sheet of the base plate in the designated position. Step 6, Place the web mesh sheet in place. Step 7, Place the reinforcing bars of the top plate in the designated position. Step 8: After placing the reinforcing mesh at the bottom of the top plate into the formwork, place the steel strip mesh. Step 9: After precasting the reinforcement at the top of the top plate in a mesh pattern offline, place it in the formwork. Step 10: Position the mesh sheets on both sides of the top plate in their designated locations.

[0021] Preferably, the welding process for the reinforcing mesh sheet is as follows:

[0022] Step 1: The raw materials for the reinforcing bars are transported from the storage area to the coil reinforcing bar straightening and feeding area, where the reinforcing bars are pulled, cushioned, straightened, cut to the required length, and then cut. Step 2: The horizontal reinforcing bars are transported to the horizontal reinforcing bar feeding area, and the horizontal reinforcing bars are dropped using a chain system. Step 3: Transport to the welding area and form by resistance welding. Step 4: After molding, fold one side of the reinforcing mesh sheet at a time in the in-line bending area.

[0023] Preferably, the direction of the bend is upward.

[0024] Preferably, the method for processing the steel strip mesh is as follows:

[0025] Step 1: For each of the longitudinal (and transverse) reinforcing bars required for the precast box girder, the through-reinforcing bars are straightened in-line based on the set data using a numerically controlled reinforcing bar straightening means, and then straightened one by one according to the set feed pitch and transported one by one. Step 2, the reinforcing bars and steel strips are wrapped in a cross shape and welded together to form a mesh. Step 3: After welding is complete, the mesh sheet is fed forward, bent in the direction of the steel strip's cross-section, automatically wound up, and the finished steel strip coil is automatically transported to a tray.

[0026] Preferably, the hooks of the hoop reinforcement N15 inside the web are 90° right-angle hooks to facilitate welding / binding to the transverse reinforcement at the bottom of the top plate.

[0027] Preferably, a 135° or 90° hook is provided at the end of the upper reinforcing bar N35 of the bottom plate, or an anchor plate is provided at the end of N35.

[0028] Preferably, the N14 reinforcement bars in the lower layer of the top plate are welded / tied to the N15 bars, and anchor plates are provided at the ends of the N14 reinforcement bars.

[0029] To further clarify the purpose, technical proposal, and advantages of the present invention, the technical proposal of the present invention will be described in detail below. However, the following examples represent only some, and not all, examples of the present invention. All other examples that can be obtained by those skilled in the art without any creative work based on the examples of the present invention are within the scope of the protection of the present invention.

[0030] <Example 1> This method involves tying together the reinforced steel frame for precast box girders. The reinforced steel frame for the girder is divided into multiple reinforced steel mesh sheets and steel strip mesh sheets. In this method, the reinforced steel mesh is directly processed into the desired shape, and workers operate overhead cranes and lifting equipment to directly position the reinforced steel mesh sheets in predetermined locations on the tying stage. Due to interference during the mesh sheet assembly process, some 32-meter-long through-reinforcements cannot be directly welded to the mesh sheet and must be manually positioned in advance. After the mesh sheet is placed in the formwork, subsequent tying is performed manually. In the case of extra-large standard mesh sheets (over 6m wide) or irregularly shaped mesh sheets (N12 large U-shaped reinforced steel mesh sheet), they cannot be processed in the shape of reinforced steel mesh. Instead, they are processed in the shape of steel strip mesh, meaning that one member such as N12 is first processed and then positioned in the predetermined location, and then the through-reinforcements are placed and laid through the steel strip mesh.

[0031] Using Charpy as an example, the entire reinforced steel frame for the girder is divided into 14 mesh sheets, including 10 reinforcing mesh sheets and 4 steel strip mesh sheets, and then assembled and welded. The specific steps are as follows:

[0032] Step 1: Transport the N12 reinforcing bars of the base plate one by one to the binding stage and place them in the designated positions. Step 2, Place the steel strip mesh on the bottom plate. Step 3, Place the steel strip mesh 1 on one side of the web, Step 4, Place the steel strip mesh 2 on the other side of the web, Step 5, Place the mesh sheet of the base plate in the designated position. Step 6, Place the web mesh sheet in place. Step 7, Place the reinforcing bars of the top plate in the designated position. Step 8: After placing the reinforcing mesh at the bottom of the top plate into the formwork, place the steel strip mesh. Step 9: After precasting the reinforcement at the top of the top plate in a mesh pattern offline, place it in the formwork. Step 10: Position the mesh sheets on both sides of the top plate in their designated locations.

[0033] The welding process for the reinforcing mesh sheet is as follows:

[0034] Step 1: The raw materials for the reinforcing bars are transported from the storage area to the coil reinforcing bar straightening and feeding area, where the reinforcing bars are pulled, cushioned, straightened, cut to the required length, and then cut. Step 2: The horizontal reinforcing bars are transported to the horizontal reinforcing bar feeding area, and the horizontal reinforcing bars are dropped using a chain system. Step 3: Transport to the welding area and form by resistance welding. Step 4: After forming, in the inline bending area, both sides of the rebar mesh sheet must be bent one by one. After bending, the mesh sheet must be transported by a roller device. The vertical rebars are moved forward according to the set mesh pitch, and the horizontal rebars are positioned one by one before welding. Therefore, the bending direction is upward. Otherwise, the hook points would interfere with the transport rollers, making transport impossible. As a result, since a single rebar (horizontal rebar) may be located above or below the through-reinforcement, the device must be able to accommodate both of the above feeding modes.

[0035] The method for processing the steel strip mesh described above is as follows:

[0036] First, the longitudinal (and transverse) reinforcing bars required for the precast box girder are straightened in-line according to set data using a numerically controlled reinforcing bar straightening device, preparing them for use. Then, each bar is straightened and transported one by one according to a set feed pitch. The reinforcing bars and steel strips are then wrapped in a cross shape and welded to form a mesh. After welding is complete, the mesh sheet is fed forward, bent in the direction of the cross-section of the steel strip, automatically wound up, and the finished steel strip coil is automatically transported to a tray. The steel strip mesh welding apparatus mainly consists of devices such as an automatic straightening device, an automatic feeding device, an automatic fixed-length dropping device, and an automatic winding device, enabling a fully automated steel strip mesh welding process.

[0037] The process flow of the aforementioned steel strip mesh welding apparatus is as follows: straightening and cutting of raw materials to a fixed length → stepwise supply of vertical reinforcing bars → dropping of vertical reinforcing bars → supply of steel strips → welding by the apparatus → winding → lifting of the finished steel strip mesh.

[0038] The process flow for processing U-shaped reinforcing bars in the aforementioned precast box girder is as follows: automatic supply of raw materials → cutting to a fixed length and dropping in an aligned manner → bending and shaping of large U-shaped reinforcing bars → transport of large U-shaped reinforcing bars to a positioning device → lifting of the finished product to an assembly jig.

[0039] The hooks of the hoop reinforcement N15 inside the web are changed from 135° hooks to flat hooks, thereby facilitating welding / binding of the flat hooks of N15 to the lateral reinforcement of the top and bottom plates, forming the overall reinforced steel framework.

[0040] A 135° hook is provided at the end of the upper reinforcing bar N35 of the base plate, reducing the length of the reinforcing bar by 320 mm, thereby avoiding interference with the reinforcing bars on the outside of the web.

[0041] The N14 reinforcing bars in the lower layer of the top plate are welded / tied to the N15 bars, and the hooks at their ends are omitted. An anchor plate is provided to facilitate construction.

[0042] The construction process adopted in this embodiment offers the following advantages for rebar mesh fabrication: (1) High fabrication accuracy and standardized finished products. (2) Improved work efficiency through robotic feeding. (3) Easy to modify and low operational failure rate. (4) Reduced manpower and lower labor intensity. Improved work efficiency: Manpower for a single girder is reduced by 20%, the number of workers is reduced from 4 to 2, and labor costs are reduced by 440 yuan.

[0043] The aforementioned steel strip mesh welding has the following advantages: (1) It is an innovation of conventional technology, easy and quick to install. (2) It has high work efficiency and low labor intensity. (3) It has a short production cycle and high economic effect. (4) It has good man-machine interaction and a low failure rate. Improved work efficiency: The man-hours for a single girder are reduced by 20%, the number of workers is reduced from 4 to 2, and labor costs are reduced by 440 yuan.

[0044] The U-shaped rebar processing process described above has the following advantages: (1) It is easy to operate, safe and reliable, and has high production efficiency. (2) The bending and flexing process of large U-shaped rebars is performed in the initial stage. (3) They can be arranged sequentially and precisely positioned. (4) The fully automated process flow reduces the workload of workers. Improved work efficiency: The number of man-hours per girder is reduced by 80%, the number of workers is reduced from 6 to 1, and labor costs are reduced by 1087.5 yuan.

[0045] <Example 2> This is a tying construction process for a reinforced steel frame for a precast box girder, wherein a 90° hook is provided at the end of the upper layer of reinforcing bars N35 of the bottom plate, reducing the length of the reinforcing bars by 320 mm, thereby avoiding interference with the reinforcing bars on the outside of the web. Otherwise, it is the same as in Example 1.

[0046] <Example 3> A method for tying together the reinforced steel frame for a precast box girder, wherein anchor plates are provided at the ends of the upper layer of reinforcing bars N35 of the bottom plate, reducing the length of the reinforcing bars by 320 mm, thereby avoiding interference with the reinforcing bars on the outside of the web. Otherwise, it is the same as in Example 1.

[0047] The above describes only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modification or substitution that a person skilled in the art can easily conceive within the scope of the art disclosed by the present invention should be included within the scope of protection of the present invention. Accordingly, the scope of protection of the present invention shall be the same as that of the claims.

Claims

1. A method for tying together reinforced concrete frames for precast box girders, The reinforcing steel framework for the girder is divided into multiple reinforcing mesh sheets and steel strip mesh sheets. Here, the reinforcing mesh is directly processed into the desired shape, and the reinforcing mesh sheets are directly placed in the designated position on the tying stage, and subsequent tying is performed manually. For extra-large standard mesh sheets and irregularly shaped mesh sheets, one reinforcing bar is first processed in the form of a steel strip mesh and then placed in the desired position, and the through-reinforcements are then placed, laid, and tied using the steel strip mesh. A method for tying together a reinforced steel frame for precast box girders, characterized by the features described above.

2. The assembly steps for the aforementioned reinforcing steel mesh sheet and steel strip mesh sheet are as follows: Step 1: Transport the N12 reinforcing bars of the base plate one by one to the binding stage and place them in the designated positions. Step 2, Place the steel strip mesh on the bottom plate. Step 3: Place the steel strip mesh on one side of the web. Step 4, Place the steel strip mesh on the other side of the web. Step 5, Place the mesh sheet of the base plate in the designated position. Step 6, Place the web mesh sheet in the designated position. Step 7, Place the reinforcing bars of the top plate in the designated position. Step 8: After placing the reinforcing mesh at the bottom of the top plate into the formwork, place the steel strip mesh. Step 9, After precasting the reinforcement at the top of the top plate in a mesh pattern offline, place it in the formwork. Step 10, Position the mesh sheets on both sides of the top plate in the designated locations. The method for tying together a reinforcing steel frame for a precast box girder according to feature 1.

3. The welding process for the aforementioned reinforcing mesh sheet is as follows: Step 1: The raw materials for the reinforcing bars are transported from the storage area to the coil reinforcing bar straightening and feeding area, where the reinforcing bars are pulled, cushioned, straightened, cut to the required length, and then cut. Step 2: The horizontal reinforcing bars are transported to the horizontal reinforcing bar feeding area, and the horizontal reinforcing bars are dropped using a chain system. Step 3: Transport to the welding area and form by resistance welding. Step 4: After molding, in the inline bending area, bend one bar at a time on both sides of the reinforcing mesh sheet. The method for tying together a reinforcing steel frame for a precast box girder according to feature 1.

4. The direction of the bend is upward. The method for tying together a reinforcing steel frame for a precast box girder according to feature 3.

5. The method for processing the steel strip mesh described above is as follows: Step 1: For each of the longitudinal (and transverse) reinforcing bars required for the precast box girder, the through-reinforcing bars are straightened in-line based on the set data using a numerically controlled reinforcing bar straightening means, and then straightened one by one according to the set feed pitch and transported one by one. Step 2, the reinforcing bars and steel strips are wrapped in a cross shape and welded together to form a mesh. Step 3: After welding is complete, the mesh sheet is fed forward, bent in the direction of the steel strip's cross-section, automatically wound up, and the finished steel strip coil is automatically transported to a tray. The method for tying together a reinforcing steel frame for a precast box girder according to feature 1.

6. The hooks of the hoop reinforcement N15 inside the web are 90° right-angle hooks to facilitate welding / binding to the transverse reinforcement at the bottom of the top plate. The method for tying together a reinforcing steel frame for a precast box girder according to feature 2.

7. The ends of the reinforcing bars N35 in the upper layer of the base plate are provided with hooks at a 135° or 90° angle, or anchor plates are provided at the ends of N35. The method for tying together a reinforcing steel frame for a precast box girder according to feature 2.

8. The N14 reinforcing bars in the lower layer of the top plate are welded / tied to N15, and anchor plates are provided at the ends of the N14 reinforcing bars. The method for tying together a reinforcing steel frame for a precast box girder according to feature 2.

Images