Low high beam and common high beam same platform construction method

Abstract

A method for co-constructing low-height and high-strength box girder beams, belonging to the field of railway box girder prefabrication construction technology, utilizes a combination of pipe piles and raft slab concrete, pre-embedded U-bolts, steel supports, wedge-shaped adjusting blocks, and a liftable bottom formwork to create a co-located production platform for both high-height and low-height beams. This allows for the synchronous lifting of the box girder bottom formwork, achieving the goal of increasing the formwork height. Through a combination of processes—including the overall hoisting of reinforcing bars for high-strength beams and the overall entry of hydraulic inner formwork—and the separate hoisting of reinforcing bars and segmented hoisting of wooden inner formwork for low-height beams, the method achieves the goal of batch production of high-strength beams while rapidly converting to the production of low-height beams from the same beam-making platform. This method is highly practical, simple in construction, economical, easy to operate, and easy to master, enabling efficient co-location production of box girders of different heights.

Description

Technical Field

[0001] This invention belongs to the field of railway box girder prefabrication construction technology, specifically relating to a method for constructing low-slender beams and ordinary-slender beams on the same platform. Background Technology

[0002] Currently, bridges account for a large proportion of railway engineering applications. Post-tensioned box girders have been widely used due to their advantages such as good stress resistance, simple structure, and factory construction. For the same line, the design will use standard box girders of different heights due to the influence of topography, subsequent planning, existing high-grade buildings, and important pipelines. Conventionally, ordinary high-height girders are used. When the height does not meet the requirements, cast-in-place low-height girders are used. Due to the limitations of site conditions, cast-in-place low-height girders have relatively high safety risks, construction costs, and construction cycles. On-site prefabrication requires a separate girder casting platform, and the number of low-height girders prefabricated is extremely low. In some sections, only one span may be used. The economic feasibility of setting up a separate platform is poor. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a method for constructing low-slender beams and ordinary high-slender beams on the same platform. This method has the characteristics of simple structure, low cost, easy operation, good safety, and good versatility, which improves efficiency and achieves the goal of quickly converting the production of low-slender beams to the production of ordinary high-slender beams in batches on the same beam-making platform.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for constructing low-slender beams and ordinary-slender beams on the same platform, characterized by comprising: S100: Construction preparation: All co-location platforms, formwork, tools, lifting equipment, concrete conveying equipment, tensioning equipment, beam lifting machines, etc. are prepared in place and have passed inspection; S200: Precast ordinary high beams, grind the templates and spray release agent, tie the reinforcing bars at the reinforcing bar tying platform according to the bottom web and top slab as a whole, use two gantry cranes with special lifting tools to lift the whole beam into the common platform template of the beam fabrication platform, install embedded parts, etc. S300: The hydraulic inner mold is moved from the inner mold platform to the steel reinforcement of the beam-making platform by the formwork transfer machine, and the inner mold end mold is installed. Concrete pouring is carried out by a combination of a conveying pump and a concrete placing machine. After the concrete is poured, the formwork is removed and pre-tensioning is carried out when the strength reaches the design value. After the pre-tensioning is completed, the beam is lifted out of the beam-making platform by a tire-type beam lifting machine. S400: Platform Conversion: Set up 5 rows of jacks in 3 longitudinal positions and fix them on the concrete foundation. Connect them all in series on the pump station. Lift the jacks to 5cm below the bottom longitudinal beam. Remove the bolts to release the constraint between the bottom formwork and the side formwork. Lift the bottom formwork as a whole to the design height of the low-high beam. After the level instrument is used to check that it is qualified, adjust the wedge adjustment blocks to fix the formwork. Rivet the arc connecting plate to the bottom formwork and the side formwork. Install the support wooden pads to support the bottom formwork and the side formwork. Pull the bottom formwork and the side formwork together to fix them. The platform is converted to the low-high beam production mode. S500: The template is polished and sprayed with release agent. The bottom web plate and top plate reinforcement are tied separately at the reinforcement tying platform. After the tying is completed, two gantry cranes are used with special lifting tools to lift the bottom web plate into the common platform template of the beam making platform. The wooden inner mold is processed in sections according to the inner box size of the low and high beams. The wooden inner mold is then lifted and fixed in the order from the middle to both ends by gantry cranes. After inspection and approval, the end mold is installed. The top plate reinforcement is lifted and connected to the bottom web plate reinforcement. The embedded parts are installed. S600: Concrete pouring is carried out by a combination of a conveying pump and a concrete placing machine. After the concrete is poured and the strength reaches the design value, the inner formwork is manually removed and pre-tensioning is carried out. After the pre-tensioning is completed, the beam is lifted out of the beam-making platform by a tire-type beam lifting machine. S700: After all the low-rise beams are produced, the platform is converted. The operation is reversed according to step S400. The bottom formwork of the platform template is lowered to the height of the ordinary high-rise beam to reinforce the template. After the bottom formwork anti-arch dimension is qualified, the hydraulic inner formwork is hoisted to the inner formwork platform to carry out the normal process of ordinary high-rise beam prefabrication production.

[0005] Furthermore, the height difference of the bottom formwork during the platform conversion is less than ±3mm, the height difference at the four corners of the support plate is less than ±1mm, and the height difference between the reverse arch and the designed reverse arch is less than ±2mm.

[0006] Furthermore, the deviation during the separate hoisting of the reinforcing bars is less than ±10cm.

[0007] Furthermore, the inner mold storage rack is bolted and movable, and the mold transfer machine is mobile.

[0008] Furthermore, the inner mold of the low-rise beam is made of wood and is manufactured in sections. After the sections are hoisted, they are connected by rigid connection of square timber.

[0009] The pedestal structure is as follows: the pipe pile (1) is rigidly connected to the concrete foundation (2) by steel bars, the U-bolt (3) is embedded in the concrete foundation (2) and bolted to the steel support (4), the wedge-shaped adjustment block (7) is bolted to the steel support (4) below and the bottom longitudinal beam (8) above, the bottom longitudinal beam (8) is welded to the bottom template (9), the arc connecting plate (12) is riveted to the bottom template (9) and the side template (10), the supporting pad (11) is supported below the arc connecting plate (12), and the pump station (6) is connected in series with all the jacks (5) through oil pipes.

[0010] The diameter and length of the pipe pile (1), the reinforcement and structural dimensions of the concrete foundation (2) are determined by calculation.

[0011] The pre-embedded U-bolts (3) are U-shaped round steel with 8cm exposed on the concrete surface. The exposed part is a threaded structure. Two U-bolts are set at each point with a spacing of 45cm×45cm. Three rows are set horizontally and the longitudinal spacing is 4m.

[0012] The steel support (4) is a circle with upper and lower steel plates closed.

[0013] The wedge-shaped adjusting block (7) is a steel diagonal wedge block with two finely threaded steel bars on both sides, which can be tightened or loosened by bolts.

[0014] The beneficial effects of this invention are: The bearing capacity of the foundation is improved by combining pipe piles with raft concrete. U-bolts are pre-embedded in the concrete foundation and bolted to the steel supports, so as to achieve a fast, stable and detachable connection between the foundation and the superstructure, and realize the purpose of a stable foundation and reusable box girder bearing support.

[0015] By simultaneously lifting the bottom longitudinal beam with jacks, the height of the bottom formwork is raised synchronously as a whole. After reaching the desired height, the height is adjusted by tightening the steel wedge-shaped adjustment blocks and bolting them to the steel support pier below and the bottom longitudinal beam above, thus achieving the purpose of raising the bottom formwork of the box girder synchronously as a whole.

[0016] The invention provides a co-location production platform and construction method for both high-strength and low-strength box girder beams. This platform is formed by combining pipe piles, raft slab concrete, pre-embedded U-bolts, steel supports, wedge-shaped adjusting blocks, and a liftable bottom formwork. This allows for the synchronous lifting of the box girder bottom formwork, achieving a higher formwork height. Through a combination of processes—including the overall hoisting of reinforcing bars for high-strength box girder beams and the overall entry of the hydraulic inner formwork—and the separate hoisting of reinforcing bars and segmented hoisting of wooden inner formwork for low-strength box girder beams—the invention achieves the goal of simultaneously producing high-strength box girder beams in batches while rapidly converting to the production of low-strength box girder beams from the same beam-making platform. Attached Figure Description

[0017] Figure 1 This is a process flow diagram of the present invention.

[0018] Figure 2 This is a schematic diagram of the prefabrication construction of ordinary high-rise beams.

[0019] Figure 3 This is a schematic diagram of the prefabrication construction of low-rise beams.

[0020] Figure 4 This is a front view of the co-positioning platform device.

[0021] Figure 5 This is a side view of the co-positioning platform device.

[0022] Among them, 1 is the pipe pile, 2 is the concrete foundation, 3 is the pre-embedded U-bolt, 4 is the steel support pier, 5 is the jack, 6 is the pump station, 7 is the wedge-shaped adjusting block, 8 is the bottom longitudinal beam, 9 is the bottom formwork, 10 is the side formwork, 11 is the supporting pad, and 12 is the arc connecting plate. Detailed Implementation

[0023] The invention will be further described below with reference to the accompanying drawings and working principle.

[0024] like Figure 1 , 2 As shown in Figure 3, a method for constructing low-slender beams and ordinary-slender beams on the same platform includes: S100: Construction preparation: All co-location platforms, formwork, tools, lifting equipment, concrete conveying equipment, tensioning equipment, beam lifting machines, etc. are prepared in place and have passed inspection.

[0025] S200: Precast ordinary high beams, grind the formwork and spray release agent, tie the reinforcing bars as a whole at the reinforcing bar tying platform according to the bottom web and top slab, use two gantry cranes with special lifting tools to lift the whole beam into the common platform formwork of the beam making platform, and install embedded parts, etc.

[0026] S300: The hydraulic inner mold is moved from the inner mold platform to the steel reinforcement of the beam-making platform using a formwork transfer machine, and the inner mold end mold is installed. Concrete pouring is carried out using a combination of a conveying pump and a concrete placing machine. After the concrete reaches the design strength, the formwork is removed and pre-tensioning is performed. After the pre-tensioning is completed, the beam is lifted out of the beam-making platform using a tire-mounted beam lifting machine.

[0027] S400: Platform Conversion: Install jacks in 5 rows (3 jacks per row, 3 longitudinally) on the concrete foundation, connecting them in series to the pump station. Lift the jacks to 5cm below the bottom longitudinal beam. Remove bolts to release the constraint between the bottom and side forms. Lift the entire bottom formwork to the designed height for the low-high beam. After verifying its accuracy with a level, adjust the wedge-shaped adjusting blocks to fix the formwork. Rivet the arc-shaped connecting plate to the bottom and side forms. Install supporting wooden blocks below the arc-shaped connecting plate and secure the bottom and side forms with tie rods. This converts the platform to a low-high beam production mode.

[0028] S500: The template is ground and sprayed with release agent. The reinforcing bars are first tied separately at the reinforcing bar tying platform for the bottom web and top slab. After tying, two gantry cranes are used with special lifting equipment to lift the bottom web to the common platform template of the beam fabrication platform. Wooden inner molds are processed in sections according to the dimensions of the inner box of the low-high beam. The wooden inner molds are then lifted and fixed in sequence from the middle to both ends using gantry cranes. After inspection and approval, the end molds are installed. The top slab reinforcing bars are then lifted and connected to the bottom web reinforcing bars. Embedded parts are installed, etc.

[0029] S600: Concrete pouring is carried out by a combination of a conveying pump and a concrete placing machine. After the concrete is poured and the strength reaches the design value, the inner formwork is removed manually and pre-tensioning is carried out. After the pre-tensioning is completed, the beam is lifted out of the beam-making platform by a tire-type beam lifting machine.

[0030] S700: After all the low-rise beams are produced, the platform is converted. The operation is reversed according to step S400. The bottom formwork of the platform template is lowered to the height of the ordinary high-rise beam to reinforce the template. After the bottom formwork anti-arch dimension is qualified, the hydraulic inner formwork is hoisted to the inner formwork platform to carry out the normal process of ordinary high-rise beam prefabrication production.

[0031] like Figure 4 , 5 As shown, the specific device includes: the pipe pile 1 is rigidly connected to the concrete foundation 2 by steel bars; the pre-embedded U-bolt 3 is pre-embedded in the concrete foundation 2 and bolted to the steel support 4; the wedge-shaped adjusting block 7 is bolted to the steel support 4 below and the bottom longitudinal beam 8 above; the bottom longitudinal beam 8 is welded to the bottom formwork 9; the arc connecting plate 12 is riveted to the bottom formwork 9 and the side formwork 10; the supporting wooden pad 11 is supported below the arc connecting plate 12; and the pump station 6 is connected to all the jacks 5 through oil pipes.

[0032] Pipe pile 1, the diameter and length of the pipe pile 1, the reinforcement and structural dimensions of the concrete foundation 2 are determined by calculation.

[0033] The U-shaped bolts 3 are embedded in the concrete surface. The U-shaped round steel is exposed for 8cm. The exposed part is threaded. Two U-shaped bolts are set at each point with a spacing of 45cm×45cm. They are arranged in three rows horizontally and with a longitudinal spacing of 4m.

[0034] Steel support 4, wherein the steel support 4 is a circle enclosed by upper and lower steel plates.

[0035] The wedge-shaped adjusting block 7 is a steel diagonal wedge-shaped block with two finely threaded steel bars on both sides, which can be tightened or loosened by bolts.

[0036] The specific device includes: the pipe pile 1 is rigidly connected to the concrete foundation 2 by steel bars; the U-bolt 3 is embedded in the concrete foundation 2 and bolted to the steel support 4; the wedge-shaped adjusting block 7 is bolted to the steel support 4 below and the bottom longitudinal beam 8 above; the bottom longitudinal beam 8 is welded to the bottom formwork 9; the arc connecting plate 12 is riveted to the bottom formwork 9 and the side formwork 10; the supporting wooden pad 11 is supported below the arc connecting plate 12; and the pump station 6 is connected to all the jacks 5 through oil pipes.

[0037] Pipe pile 1, the diameter and length of the pipe pile 1, the reinforcement and structural dimensions of the concrete foundation 2 are determined by calculation.

[0038] The U-shaped bolts 3 are embedded in the concrete surface. The U-shaped round steel is exposed for 8cm. The exposed part is threaded. Two U-shaped bolts are set at each point with a spacing of 45cm×45cm. They are arranged in three rows horizontally and with a longitudinal spacing of 4m.

[0039] Steel support 4, wherein the steel support 4 is a circle enclosed by upper and lower steel plates.

[0040] The wedge-shaped adjusting block 7 is a steel diagonal wedge-shaped block with two finely threaded steel bars on both sides, which can be tightened or loosened by bolts.

[0041] After calculating the number of pipe piles based on the design bearing capacity, the pipe piles are constructed. The pipe piles are rigidly connected to the subsequently poured concrete foundation via pre-embedded reinforcing bars. During concrete foundation construction, U-shaped bolts are pre-embedded at approximately 4m intervals in three horizontal rows. After the dimensions and positions of the pre-embedded bolts are verified as qualified, steel supports are installed and the bolts are tightened. Self-leveling mortar is poured into the area where the steel supports are not in close contact with the concrete surface. Wedge-shaped adjusting blocks and bottom longitudinal beams are installed above the steel supports and securely bolted. Bottom formwork is installed on the bottom longitudinal beam. After adjusting the arch according to the design, the bottom longitudinal beam is welded securely to the bottom formwork. Side formwork and other formwork are then installed. After all installation is complete, standard box girders are poured, and low-rise beams are required. At that time, the jacks were set up in 5 rows of 3 longitudinal jacks and fixed on the concrete foundation. All of them were connected in series on the pump station. The jacks were lifted to 5cm below the bottom longitudinal beam. The bolts between the wedge-shaped adjusting blocks and the bottom longitudinal beam were removed, and the constraints between the bottom formwork and the side formwork were released. After the inspection was completed, the pump station was operated to lift the bottom formwork to the design height of the low-high beam. After the level was checked and found to be qualified, the wedge-shaped adjusting blocks were adjusted to reach the height of the bottom longitudinal beam and the bolts were tightened to fix it. The jacks were lowered. After the bottom formwork reached the design elevation for the second time, the arc connecting plate was riveted to the bottom formwork and the side formwork. Supporting wooden blocks were installed under the arc connecting plate to fix the bottom formwork and the side formwork with pulls. After the overall height of the beam-making platform formwork is increased, the steel cage is hoisted, the end formwork is installed, the inner formwork is installed, the box girder concrete is poured, and after pre-tensioning, the beam is lifted off the platform to carry out the prefabrication of the next box girder. After the production quantity of low-high beams is reached, the beam-making platform is lowered in reverse order to the height of ordinary high beams to continue the production of standard box girders, so as to realize the production of ordinary high beams and low-high beams on the same platform.

Claims

1. A method for constructing low-slender beams and ordinary-slender beams on the same platform, characterized in that, include: S100： Construction preparation: All equipment, including the platform, formwork, tools, lifting equipment, concrete conveying equipment, tensioning equipment, and beam lifting machine, are in place and have passed inspection. S200: Precast ordinary high beams, grind the templates and spray release agent, and tie the reinforcing bars at the reinforcing bar tying platform according to the bottom web and top slab as a whole. Use two gantry cranes with special lifting tools to lift the whole beam into the common platform template of the beam fabrication platform and install the embedded parts. S300: The hydraulic inner mold is moved from the inner mold platform to the steel reinforcement of the beam-making platform by the formwork transfer machine, and the inner mold end mold is installed. Concrete pouring is carried out by a combination of a conveying pump and a concrete placing machine. After the concrete is poured, the formwork is removed and pre-tensioning is carried out when the strength reaches the design value. After the pre-tensioning is completed, the beam is lifted out of the beam-making platform by a tire-type beam lifting machine. S400: Platform Conversion: Set up 5 rows of jacks in 3 longitudinal positions and fix them on the concrete foundation. Connect them all in series on the pump station. Lift the jacks to 5cm below the bottom longitudinal beam. Remove the bolts to release the constraint between the bottom formwork and the side formwork. Lift the bottom formwork as a whole to the design height of the low-high beam. After the level instrument is used to check that it is qualified, adjust the wedge adjustment blocks to fix the formwork. Rivet the arc connecting plate to the bottom formwork and the side formwork. Install the support wooden pads to support the bottom formwork and the side formwork. Pull the bottom formwork and the side formwork together to fix them. The platform is converted to the low-high beam production mode. S500: The template is polished and sprayed with release agent. The bottom web plate and top plate reinforcement are tied separately at the reinforcement tying platform. After the tying is completed, two gantry cranes are used with special lifting tools to lift the bottom web plate into the common platform template of the beam making platform. The wooden inner mold is processed in sections according to the inner box size of the low and high beams. The wooden inner mold is then lifted and fixed in the order from the middle to both ends by gantry cranes. After inspection and approval, the end mold is installed. The top plate reinforcement is lifted and connected to the bottom web plate reinforcement. The embedded parts are installed. S600: Concrete pouring is carried out by a combination of a conveying pump and a concrete placing machine. After the concrete is poured and the strength reaches the design value, the inner formwork is manually removed and pre-tensioning is carried out. After the pre-tensioning is completed, the beam is lifted out of the beam-making platform by a tire-type beam lifting machine. S700: After all the low-rise beams are produced, the platform is converted. The operation is reversed according to step S400. The bottom formwork of the platform template is lowered to the height of the ordinary high-rise beam to reinforce the template. After the bottom formwork anti-arch dimension is qualified, the hydraulic inner formwork is hoisted to the inner formwork platform to carry out the normal process of ordinary high-rise beam prefabrication production.

2. The method for constructing low-slender beams and ordinary-slender beams on the same platform according to claim 1, characterized in that, The height difference of the bottom formwork during the platform conversion is less than ±3mm, the height difference of the four corners at the support plate position is less than ±1mm, and the height difference between the reverse arch and the designed reverse arch is less than ±2mm.

3. The method for constructing low-slender beams and ordinary-slender beams on the same platform according to claim 1, characterized in that, When hoisting steel bars in separate sections, the deviation should be less than ±10cm.

4. The method for constructing low-slender beams and ordinary-slender beams on the same platform according to claim 1, characterized in that, The inner mold storage rack is bolted and movable, and the mold transfer machine is movable.

5. The method for constructing low-slender beams and ordinary-slender beams on the same platform according to claim 1, characterized in that, The inner mold of the low-rise beam is made of wood and is made in sections. After the sections are hoisted, they are connected by rigid connection of square timber.

6. A method for constructing low-slender beams and ordinary-slender beams on the same platform according to claim 1, characterized in that, The pedestal structure is as follows: the pipe pile (1) is rigidly connected to the concrete foundation (2) by steel bars, the U-bolt (3) is embedded in the concrete foundation (2) and bolted to the steel support (4), the wedge-shaped adjustment block (7) is bolted to the steel support (4) below and the bottom longitudinal beam (8) above, the bottom longitudinal beam (8) is welded to the bottom template (9), the arc connecting plate (12) is riveted to the bottom template (9) and the side template (10), the supporting pad (11) is supported below the arc connecting plate (12), and the pump station (6) is connected in series with all the jacks (5) through oil pipes.

7. A production platform for co-positioning high-strength beams and low-strength beams according to claim 6, characterized in that, The diameter and length of the pipe pile (1), the reinforcement and structural dimensions of the concrete foundation (2) are determined by calculation.

8. A production platform for co-positioning high-strength beams and low-strength beams according to claim 6, characterized in that, The pre-embedded U-bolts (3) are U-shaped round steel with 8cm exposed on the concrete surface. The exposed part is a threaded structure. Two U-bolts are set at each point with a spacing of 45cm×45cm. Three rows are set horizontally and the longitudinal spacing is 4m.

9. A production platform for co-positioning high-strength beams and low-strength beams according to claim 6, characterized in that, The steel support (4) is a circle with upper and lower steel plates closed.

10. A production platform for both high-strength and low-strength beams as described in claim 6, characterized in that, The wedge-shaped adjusting block (7) is a steel diagonal wedge block with two finely threaded steel bars on both sides, which can be tightened or loosened by bolts.

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