A subway station ring beam and supporting steel prefabricated assembly construction method

Abstract

The application discloses a subway station ring beam and supporting steel bar prefabricated assembly construction method, which comprises the following steps: step 1, mold processing; step 2, steel bar processing; step 3, steel bar cage prefabrication; step 4, prefabricated steel bar cage installation; step 5, adjusting segment steel bar binding; and step 6, closed segment steel bar binding. The application has high assembly rate, can realize 24-hour continuous operation, effectively solves the problem of concentrated labor shortage, realizes balanced and safe production, solves the problems of dense and crossed steel bars at complex nodes and installation failure due to steel bar collision, increases the fault tolerance of prefabricated assembly steel bar butt joint through local on-site binding mode, makes the steel bar butt joint simple and convenient, is more beneficial to the operability of steel bar prefabricated assembly, and has the characteristics of more flexibility and light weight compared with reinforced concrete prefabricated assembly, and is safer and more reliable during installation.

Description

Technical Field

[0001] This invention belongs to the field of building engineering technology, and in particular relates to a method for prefabricating and assembling ring beams and supporting steel bars for subway stations. Background Technology

[0002] Currently, rail transit has become the preferred mode of transportation for people and has entered a period of rapid development. Construction standards and requirements are becoming increasingly stringent, and construction speed is accelerating. The construction time for the ring beams and supports of subway stations is lengthy. To save construction time, effectively reduce on-site rebar tying time, and lower the safety hazards of on-site cutting and welding, this invention proposes a factory-prefabricated rebar on-site installation scheme. This scheme shifts most of the on-site rebar tying work for ring beams and support beams to a digital centralized processing plant, significantly improving the working environment for rebar workers. Simultaneously, relying on digitally controlled processing equipment improves rebar processing accuracy, reduces rebar cage installation errors, shortens rebar construction time, and accelerates the overall station construction progress.

[0003] Traditionally, a steel bar processing shed is erected on-site, equipped with steel bar cutting machines, threading machines, and bending machines. The raw steel bars are mechanically cut, threaded, and bent according to the design dimensions. These bars are then carried to the foundation pit by steelworkers. Various types and sizes of steel bars are then tied and welded on-site according to the ring beam and support design drawings. This requires a large number of steelworkers working simultaneously, resulting in concentrated work and disrupting balanced production. In the event of an emergency, this can easily lead to mass casualties and major or catastrophic safety accidents. The on-site tying process is time-consuming, delaying construction and hindering balanced production. To expedite construction, extra steelworkers are often hired temporarily, resulting in significant waste and cost increases of over 20%. Finding a large number of steelworkers quickly is also difficult. Therefore, the construction cycle for ring beams and support beams typically exceeds one to two months, preventing the rapid establishment of production capacity for the next stage of construction. Summary of the Invention

[0004] The purpose of this invention is to provide a prefabrication and assembly construction method for ring beams and supporting steel bars in subway stations that can overcome the above-mentioned technical problems. The method of this invention includes the following steps:

[0005] Step 1, Mold processing: Make a precise positioning mold for the reinforcing bars according to the spacing of the main reinforcing bars of the ring beam and the support beam. The mold consists of four hot-dip galvanized square tubes with positioning holes drilled in them. The square tubes are connected by bolts through connecting plates. Drill holes in the middle of the square tubes according to the positioning spacing of the reinforcing bars. The diameter of the positioning hole is 2mm larger than the diameter of the reinforcing bar to facilitate the reinforcing bar to be inserted into the mold for positioning.

[0006] Step 2, Rebar Processing: Thread both ends of the main reinforcing bar, with one end threaded to the length of a sleeve and the other end threaded to half the length of a sleeve. Install the connecting sleeve at the end with the length of a sleeve thread, and protect the thread at the other end with a plastic protective sleeve; bend and process the reinforcing bar stirrups according to the actual size requirements.

[0007] Step 3: Precast steel cage:

[0008] Step 3.1: Model the steel reinforcement cages according to the standard customized length of the steel reinforcement profiles using BIM technology. Divide the ring beam and support beam steel reinforcement cages into standard sections, special sections and adjustment sections. Simulate the collision between the support beam and the lattice column, and between the steel reinforcement cage and the anchor reinforcement of the pile to determine the position of the anchor reinforcement.

[0009] Step 3.2: Standard segment steel cages are divided according to factory-made lengths to avoid cutting and save materials. Corner sections are defined as special segments. The steel bars are prefabricated and hoisted or tied on site. Adjusted segments are used at the joints between closed sections and ring beams and support beams. Adjusted segments are tied on site.

[0010] Step 3.3: Install the steel cage formwork in the digital steel bar processing plant according to the BIM 3D model, and tie the precast steel cage reinforcement of the ring beam and support beam onto the steel cage formwork;

[0011] Step 3.4: At the intersection of the ring beam and the pile, the stirrups are processed into hook-shaped stirrups, and the hook-shaped stirrups are used for connection on site; the stirrups between the piles are directly tied in place by the stirrups in the steel bar processing plant, and an additional reinforcing stirrup is added with φ16 steel bars to enhance the rigidity during hoisting and reduce the deformation of the steel cage during hoisting; the precast steel cage of the support beam is prefabricated by directly tying the stirrups in the digital processing plant.

[0012] Step 4: Installation of precast steel cage:

[0013] Step 4.1: Set up 8 lifting points on the precast steel cage. Use No. 10 channel steel to make crossbeams at the lifting points. Place the crossbeams below the upper main reinforcement of the precast steel cage. Use clamps to fix the steel cage and crossbeams with the steel wire rope for lifting the steel cage. Use a bridge crane at the steel processing plant to lift the precast steel cage onto a transport flatbed truck and transport it to the installation site. Use a 25T crane to lift and lower it on site.

[0014] Step 4.2 Before hoisting and lowering the steel cage, use an ink line to mark the position lines of the ring beam and support beam steel bars on the concrete cushion layer. Check whether the anchor steel bars at the top of the pile collide or conflict with the steel bars of the beam. Adjust the anchor steel bars to be straight and not to collide with the ring beam steel bars.

[0015] Step 4.3: Determine the starting point of the first section installation and draw a line. During installation, ensure that the starting point line and the end face of the steel reinforcement in the steel cage are on the same cross section. Align the anchoring steel reinforcement at the pile position and slowly lower the ring beam steel cage to ensure that the anchoring steel reinforcement enters the ring beam steel cage accurately. Then lower the steel reinforcement into place and make fine adjustments. At the joint of the steel cage, use a torque wrench to tighten the steel reinforcement connector from one end to the other and install the hook reinforcement at the pile position.

[0016] Step 4.4: In the foundation pit, hoist the steel reinforcement cage of the support beam onto the concrete cushion of the support beam, and weld the lattice column connecting plate at the lattice column location to make the lattice column and the support beam firmly connected;

[0017] Step 5: Adjust the segmental reinforcement binding:

[0018] Step 5.1: Install the standard segments of the precast steel cage sequentially from the starting point to both ends. At the corners and special segments, use on-site binding. Install a movable steel positioning mold at the ends of the steel bars to ensure that the next standard segment is accurately connected to the special segment.

[0019] Step 5.2: The adjustment segments at the intersection of the support beam and the ring beam are all tied on site. After the standard segment steel cage of the support beam is installed, there are adjustment segments between the two ends of the support beam steel cage and the ring beam. Anchor the node steel bars of the adjustment segment to the ring beam, then put the stirrups of the adjustment segment into the main bars of the adjustment segment, and screw the threaded sleeve on the support beam steel cage into the main bars of the adjustment segment. First connect the soil-facing side and the lower main bars, then connect the main bars on the side near the foundation pit and the upper main bars. Finally, tie the stirrups and hook bars of the adjustment segment to complete the connection between the standard segment, the adjustment segment, and the ring beam.

[0020] Step 6: Binding of the closed section reinforcement. A closed section must be set at the end of the precast steel cage of the station ring beam to adjust the cumulative construction error that occurs during the entire installation process. This section needs to be bound on-site to reduce the difficulty of precast connection construction. The binding length of the closed section at the end should be controlled at 2-3m to eliminate the deviation generated during the assembly of the precast steel cage of the station ring beam. Before binding the closed section reinforcement on-site, the main reinforcement of the closed section should be measured on-site. The main reinforcement should be cut and threaded according to the actual measured length. When binding, the stirrups should be put into the main reinforcement of the closed section and the threaded sleeves on the already installed ring beam steel cage should be screwed into the main reinforcement of the closed section. First connect the main reinforcement of the soil-facing side and the lower part, then connect the main reinforcement of the side near the foundation pit and the upper part. Finally, bind the stirrups of the closed section to complete the precast installation of the entire station ring beam.

[0021] Furthermore, in step 5.1, in order to ensure accurate connection between the next standard segment and the special segment, standard segments are installed first at both ends of the special segment, and the special segments are tied together on site. When tying the special segment, the stirrups of the special segment are first put onto its main reinforcement, and the threaded sleeve on the standard segment is then screwed into the anchoring joint of the main reinforcement of the special segment. First, the soil-facing side and the lower main reinforcement are connected, then the main reinforcement on the side near the foundation pit and the upper main reinforcement are connected. Then, the stirrups of the special segment are tied in sequence to complete the connection between the standard segment and the special segment.

[0022] The method described in this invention has the following beneficial effects:

[0023] 1. This invention mainly uses prefabricated standard parts, resulting in a high assembly rate. Standard parts are easy to manufacture in a standardized and centralized manner in a factory. Factory operations are not limited by climate conditions and on-site environmental conditions, enabling continuous 24-hour operation. The factory operation has good airtightness and minimal interference with the outside world.

[0024] 2. After the prefabrication and assembly of ring beams and support beams is realized, most of the steel reinforcement work can be carried out in the factory in advance without affecting other construction procedures on site. Steelworkers can start steel reinforcement work in advance, which effectively solves the problem of concentrated labor shortage and achieves balanced and safe production.

[0025] 3. The use of on-site binding in some areas effectively solves the problems of dense and intersecting steel bars at complex nodes, as well as the inability to install them due to steel bar collisions. At the same time, the on-site binding method increases the tolerance of precast steel bar splicing, making steel bar splicing simple and convenient, and more conducive to the operability of precast steel bar assembly.

[0026] 4. Precast steel assembly is more flexible than precast reinforced concrete assembly, and its precast components are lighter than precast reinforced concrete components, eliminating the need for large hoisting equipment and making transportation and installation safer and more reliable. Attached Figure Description

[0027] Figure 1 This is a flowchart of the prefabrication and assembly construction method for the ring beam and supporting steel bars of the subway station as described in this invention. Detailed Implementation

[0028] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0029] like Figure 1 As shown, the method of the present invention includes the following steps:

[0030] Step 1, Mold processing: Make a precise positioning mold for the reinforcing bars according to the spacing of the main reinforcing bars of the ring beam and the support beam. The mold consists of four hot-dip galvanized square tubes with positioning holes drilled in them. The square tubes are connected by bolts through connecting plates. Drill holes in the middle of the square tubes according to the positioning spacing of the reinforcing bars. The diameter of the positioning hole is 2mm larger than the diameter of the reinforcing bar to facilitate the reinforcing bar to be inserted into the mold for positioning.

[0031] Step 2, Rebar Processing: Thread both ends of the main reinforcing bar, with one end threaded to the length of a sleeve and the other end threaded to half the length of a sleeve. Install the connecting sleeve at the end with the length of a sleeve thread, and protect the thread at the other end with a plastic protective sleeve; bend and process the reinforcing bar stirrups according to the actual size requirements.

[0032] Step 3: Precast steel cage:

[0033] Step 3.1: Model the steel reinforcement cages according to the standard customized length of the steel reinforcement profiles using BIM technology. Divide the ring beam and support beam steel reinforcement cages into standard sections, special sections and adjustment sections. Simulate the collision between the support beam and the lattice column, and between the steel reinforcement cage and the anchor reinforcement of the pile to determine the position of the anchor reinforcement.

[0034] Step 3.2: Standard segment steel cages are divided according to factory-made lengths to avoid cutting and save materials. Corner sections are defined as special segments. The steel bars are prefabricated and hoisted or tied on site. Adjusted segments are used at the joints between closed sections and ring beams and support beams. Adjusted segments are tied on site.

[0035] Step 3.3: Install the steel cage formwork in the digital steel bar processing plant according to the BIM 3D model, and tie the precast steel cage reinforcement of the ring beam and support beam onto the steel cage formwork;

[0036] Step 3.4: At the intersection of the ring beam and the pile, the stirrups are processed into hook-shaped stirrups, and the hook-shaped stirrups are used for connection on site; the stirrups between the piles are directly tied in place by the stirrups at the steel bar processing plant, and an additional reinforcing stirrup is added with φ16 steel bars to enhance the rigidity during hoisting and reduce the deformation of the steel cage during hoisting; the precast steel cage of the support beam is prefabricated by directly tying and processing with all stirrups in the digital processing plant.

[0037] Step 4: Installation of precast steel cage:

[0038] Step 4.1: Set up 8 lifting points on the precast steel cage. Use No. 10 channel steel to make crossbeams at the lifting points. Place the crossbeams below the upper main reinforcement of the precast steel cage. Use clamps to fix the steel cage and crossbeams with the steel wire rope for lifting the steel cage. Use a bridge crane at the steel processing plant to lift the precast steel cage onto a transport flatbed truck and transport it to the installation site. Use a 25T crane to lift and lower it on site.

[0039] Step 4.2 Before hoisting and lowering the steel cage, use an ink line to mark the position lines of the ring beam and support beam steel bars on the concrete cushion layer. Check whether the anchor steel bars at the top of the pile actually collide or conflict with the steel bars of the beam. Adjust the anchor steel bars to be straight and not to collide with the ring beam steel bars.

[0040] Step 4.3: Determine the starting point of the first section installation and draw a line. During installation, ensure that the starting point line and the end face of the steel reinforcement in the steel cage are on the same cross section. Align the anchoring steel reinforcement at the pile position and slowly lower the ring beam steel cage to ensure that the anchoring steel reinforcement enters the ring beam steel cage accurately. Then lower the steel reinforcement into place and make fine adjustments. At the joint of the steel cage, use a torque wrench to tighten the steel reinforcement connector from one end to the other and install the hook reinforcement at the pile position.

[0041] Step 4.4: In the foundation pit, hoist the steel reinforcement cage of the support beam onto the concrete cushion of the support beam, and weld the lattice column connecting plate at the lattice column location to make the lattice column and the support beam firmly connected;

[0042] Step 5: Adjust the segmental reinforcement binding:

[0043] Step 5.1: Install standard segments of the precast steel cage sequentially from the starting point to both ends. At the corners, special segments are connected by on-site binding. Install movable steel bar positioning molds at the ends of the steel bars to ensure accurate connection between the next standard segment and the special segment. Alternatively, standard segments can be installed first at both ends of the special segment, and then the special segments can be connected by on-site binding. When binding the special segment, first insert the stirrups of the special segment onto its main reinforcement. Then screw the threaded sleeves on the standard segment into the anchoring steel bar joints of the special segment's main reinforcement. First connect the soil-facing side and the lower main reinforcement, then connect the main reinforcement on the pit side and the upper main reinforcement. Subsequently, bind the stirrups of the special segment sequentially to complete the connection between the standard segment and the special segment.

[0044] Step 5.2: The adjustment segments at the intersection of the support beam and the ring beam are all tied on site. After the standard segment steel cage of the support beam is installed, there are adjustment segments between the two ends of the support beam steel cage and the ring beam. Anchor the node steel bars of the adjustment segment to the ring beam, then put the stirrups of the adjustment segment into the main bars of the adjustment segment, and screw the threaded sleeve on the support beam steel cage into the main bars of the adjustment segment. First connect the soil-facing side and the lower main bars, then connect the main bars on the side near the foundation pit and the upper main bars. Finally, tie the stirrups and hook bars of the adjustment segment to complete the connection between the standard segment, the adjustment segment, and the ring beam.

[0045] Step 6: Binding of the closed section reinforcement. A closed section must be set at the end of the precast steel cage of the station ring beam to adjust the cumulative construction error that occurs during the entire installation process. This section needs to be bound on-site to reduce the difficulty of precast connection construction. The binding length of the closed section at the end should be controlled at 2-3m to eliminate the deviation generated during the assembly of the precast steel cage of the station ring beam. Before binding the closed section reinforcement on-site, the main reinforcement of the closed section should be measured on-site. The main reinforcement should be cut and threaded according to the actual measured length. When binding, the stirrups should be put into the main reinforcement of the closed section and the threaded sleeves on the already installed ring beam steel cage should be screwed into the main reinforcement of the closed section. First connect the main reinforcement of the soil-facing side and the lower part, then connect the main reinforcement of the side near the foundation pit and the upper part. Finally, bind the stirrups of the closed section to complete the precast installation of the entire station ring beam.

[0046] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for prefabricating and assembling ring beams and supporting steel bars for subway stations, characterized in that, Includes the following steps: Step 1, Mold processing: Make a precise positioning mold for the reinforcing bars according to the spacing of the main reinforcing bars of the ring beam and the support beam. The mold consists of four hot-dip galvanized square tubes with positioning holes drilled in them. The square tubes are connected by bolts through connecting plates. Drill holes in the middle of the square tubes according to the positioning spacing of the reinforcing bars. The diameter of the positioning hole is 2mm larger than the diameter of the reinforcing bar. Step 2, Rebar Processing: Thread both ends of the main reinforcing bar, with one end threaded for the length of a sleeve and the other end threaded for half the length of a sleeve. Install the connecting sleeve on the end with the length of the sleeve thread, and protect the thread on the other end with a plastic protective sleeve; bend and process the reinforcing bar stirrups according to actual requirements. Step 3: Precast steel cage: Step 3.1: Model the steel reinforcement cages according to the standard customized length of the steel reinforcement profiles using BIM technology. Divide the ring beam and support beam steel reinforcement cages into standard sections, special sections and adjustment sections. Simulate the collision between the support beam and the lattice column, and between the steel reinforcement cage and the anchor reinforcement of the pile to determine the position of the anchor reinforcement. Step 3.2: Standard segment steel cages are divided according to factory-made dimensions and lengths. Corner sections are defined as special segments. The steel bars are prefabricated and hoisted or tied on-site. Adjusted segments are used at the joints between closed sections and ring beams and support beams. Adjusted segments are tied on-site. Step 3.3: Install the steel cage formwork in the digital steel bar processing plant according to the BIM 3D model, and tie the precast steel cage reinforcement of the ring beam and support beam onto the steel cage formwork; Step 3.4: At the intersection of the ring beam and the pile, the stirrups are processed into hook-shaped stirrups and connected on site using hook-shaped stirrups; the stirrups between the piles are directly tied in place at the steel bar processing plant, and an additional reinforcing stirrup is added using φ16 steel bars; the precast steel cage of the support beam is prefabricated in the digital processing plant by directly tying and prefabricating it using the full stirrup method. Step 4: Installation of precast steel cage; Step 5: Adjust the segmental reinforcement binding; Step 6: Binding of the closed section reinforcement. A closed section must be set at the end where the precast reinforcement cage of the station ring beam is connected end to end. This is to adjust the cumulative construction error that occurs during the entire installation process of the precast reinforcement cage of the ring beam. This section needs to be bound on site to reduce the difficulty of precast connection construction.

2. The method for prefabricating and assembling ring beams and supporting steel bars for subway stations according to claim 1, characterized in that, Step 4 includes the following steps: Step 4.1: Set up 8 lifting points on the precast steel cage. Use No. 10 channel steel to make crossbeams at the lifting points. Place the crossbeams below the upper main reinforcement of the precast steel cage. Use clamps to fix the steel cage and crossbeams with the steel wire rope for lifting the steel cage. Use a bridge crane at the steel processing plant to lift the precast steel cage onto a transport flatbed truck and transport it to the installation site. Use a 25T crane to lift and lower it on site. Step 4.2: Before hoisting and lowering the reinforcing cage, mark the positions of the ring beam and support beam reinforcing bars on the concrete foundation with an ink line; Step 4.3: Determine the starting point of the first section installation and draw a line. During installation, ensure that the starting point line and the end face of the steel reinforcement in the steel cage are on the same cross section. Align the anchoring steel reinforcement at the pile position and slowly lower the ring beam steel cage to ensure that the anchoring steel reinforcement enters the ring beam steel cage accurately. Then lower the steel reinforcement into place and make fine adjustments. At the joint of the steel cage, use a torque wrench to tighten the steel reinforcement connector from one end to the other and install the hook reinforcement at the pile position. Step 4.4: In the foundation pit, hoist the steel reinforcement cage of the support beam onto the concrete cushion of the support beam, and weld the lattice column connecting plate at the lattice column location to make the lattice column and the support beam firmly connected.

3. The prefabrication and assembly construction method for ring beams and supporting steel bars of a subway station according to claim 1, characterized in that, Step 5 includes the following steps: Step 5.1: Install the standard segments of the precast steel cage sequentially from the starting point to both ends. At the corners, special segments are passed by on-site binding. Install the movable steel positioning mold at the ends of the steel bars so that the next standard segment can be accurately connected to the special segment. Step 5.2: The adjustment segments at the intersection of the support beam and the ring beam are all tied on-site. After the standard segment reinforcement cage of the support beam is installed, there are adjustment segments between the two ends of the support beam reinforcement cage and the ring beam. Anchor the node reinforcement of the adjustment segment to the ring beam, then put the stirrups of the adjustment segment onto the main reinforcement of the adjustment segment, and screw the threaded sleeve on the support beam reinforcement cage into the main reinforcement of the adjustment segment. First connect the soil-facing side and the lower main reinforcement, then connect the main reinforcement on the side near the foundation pit and the upper main reinforcement. Finally, tie the stirrups and hook bars of the adjustment segment to complete the connection between the standard segment, the adjustment segment, and the ring beam.

4. The prefabrication and assembly construction method for the ring beam and supporting steel reinforcement of a subway station according to claim 3, characterized in that, In step 5.1: In order to ensure that the next standard segment can be accurately connected to the special segment, standard segments are installed first at both ends of the special segment, and the special segments are tied together on site. When tying the special segment, the stirrups of the special segment are first put onto its main reinforcement, and the threaded sleeve on the standard segment is then screwed into the anchoring joint of the main reinforcement of the special segment. First, the soil-facing side and the lower main reinforcement are connected, then the main reinforcement on the side near the foundation pit and the upper main reinforcement are connected. Then, the stirrups of the special segment are tied in sequence to complete the connection between the standard segment and the special segment.

5. The method for prefabricating and assembling ring beams and supporting steel bars for subway stations according to claim 1, characterized in that, In step 6, the binding length of the end closure section is controlled at 2-3m to eliminate the deviations generated during the assembly of the precast steel cage of the entire station ring beam.

6. The prefabrication and assembly construction method for ring beams and supporting steel bars of a subway station according to claim 1, characterized in that, In step 6: Before binding the reinforcing bars of the closed section on site, the main reinforcing bars of the closed section are measured on site. The main reinforcing bars are cut and threaded according to the actual measured length. When binding, the stirrups are put on the main reinforcing bars of the closed section and the threaded sleeves on the already installed ring beam reinforcing cage are screwed into the main reinforcing bars of the closed section. First, the main reinforcing bars on the soil-facing side and the lower part are connected, then the main reinforcing bars on the side near the foundation pit and the upper part are connected. Finally, the stirrups of the closed section are bound to complete the prefabrication and installation of the ring beam of the whole station.

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