A construction method for cantilever casting the straight section of the side span by closing the middle span first and then the side span

Abstract

The present application discloses a method for cantilever casting the straight section of the side span by closing the middle span first and then the side span, which comprises the following steps: S1, building brackets on both sides of the bridge pier to construct the initial cantilever box beam; S2, after the initial cantilever box beam construction is completed, removing the brackets; S3, assembling the hanging basket on the initial cantilever box beam; S4, using the hanging basket to construct the cantilever box beam in sections; S5, carrying out the closing section construction; S6, after the closing section construction is completed, installing a supporting device for supporting the hanging basket and the side span section on the bridge tower crossbeam; S7, carrying out the side span section construction; S8, after the side span section construction is completed, removing the hanging basket and the supporting device to complete the construction. The present application has the effect of improving construction efficiency and construction safety.

Description

Technical Field

[0001] The present application relates to the technical field of bridge construction, and in particular to a construction method for cantilever casting a side span straight section by closing a middle span first and then a side span. Background Art

[0002] A suspension bridge is a bridge that uses cables (or steel chains) suspended from towers and anchored on both banks (or both ends of the bridge) as the main load-bearing components of the upper structure. The ends of a suspension bridge are generally continuous steel structures, and the middle is a steel box girder structure, where the continuous steel structure consists of piers and concrete box girders set on the piers. Concrete box girders are generally constructed using climbing formwork, and steel box girder structures are generally constructed using cable cranes.

[0003] Suspension bridges are mostly built across rivers and canyons, where the terrain on both sides is complex. Therefore, when constructing continuous steel structures, the distances between adjacent piers and between piers and bridge towers are often inconsistent. When constructing concrete box girders, in order to stabilize the force on the piers, cantilever box girders are often cast and constructed simultaneously from both sides of the piers. However, due to the inconsistent distances between adjacent piers and between piers and bridge towers, it is easy for the cantilever box girder to be constructed to the point where the cantilever box girder on the other side of the pier has not yet been constructed to the location of the bridge tower when the cantilever box girder needs to be closed.

[0004] In view of the above situation, if the closing section is constructed first and then the side span section, the closing section will be subjected to upward bending moment during the side span construction, which will cause the closing section to easily arch or even break, posing a great safety hazard. In order to avoid the above situation, in actual construction, the side span construction is often carried out first and then the closing section construction, but because the closing section has not been constructed yet, the continuous steel structure is disconnected, which makes it difficult to transport materials. Materials can only be transported by hoisting, which seriously affects the construction period. Summary of the invention

[0005] In order to improve construction efficiency and eliminate the construction risks caused by first constructing the closing section and then the side span section, the present application provides a cantilever casting side span straight section construction method for closing the middle span first and then the side span.

[0006] The present application provides a construction method for first closing the middle span and then the side span to cantilever cast the side span straight section, which adopts the following technical solution:

[0007] A construction method for first closing the middle span and then the side span to cantilever cast the side span straight section comprises the following steps:

[0008] S1. Build brackets on both sides of the bridge pier to carry out the initial cantilever box girder construction;

[0009] S2. After the construction of the initial cantilever box girder is completed, remove the bracket;

[0010] S3. Assemble the hanging basket on the initial cantilever box beam;

[0011] S4. Use hanging basket to construct cantilever box beam in sections;

[0012] S5, carry out the closing section construction;

[0013] S6. After the construction of the closing section is completed, a support device for supporting the hanging basket and the side span section is installed on the bridge tower beam;

[0014] S7, carry out side span construction: when the hanging basket moves forward to the right position, the hanging basket is supported by the supporting device, and then the inner mold is arranged in the mold cavity of the hanging basket and the steel bars are tied, and then the concrete is poured and vibrated;

[0015] S8. After the construction of the side span is completed, remove the hanging basket and supporting device to complete the construction.

[0016] By adopting the above technical solution, the present application first carries out the construction of the closing section, thereby facilitating the handling of materials and goods and effectively improving construction efficiency. When the side span section is being constructed, the hanging basket moves forward, and then the hanging basket is towed by the support device, and then the side span section is constructed. During this period, since the hanging basket is towed by the support device, the support device provides support for the hanging basket and the side span section, thereby offsetting most of the gravity of the side span section, so that the closing section will not be arched due to bending, effectively improving construction safety.

[0017] Preferably, before the side span section is constructed, a counterweight is arranged on the closing section.

[0018] The adoption of the above technical solution is helpful to eliminate the bending moment generated during the construction of the subsequent side span section, thereby ensuring that the closing section will not arch.

[0019] Preferably, the support device is provided with two groups, and the two groups of support devices are respectively located on both sides of the length direction of the cantilever box beam. The support device includes a fixed beam anchored on the bridge tower cross beam, and the fixed beam extends along the width direction of the bridge tower cross beam. A hydraulic cylinder is provided at one end of the fixed beam close to the cantilever box beam, and the hydraulic cylinder is vertically arranged to the fixed beam, and the piston rod of the hydraulic cylinder is connected to the support beam.

[0020] By adopting the above technical solution, when the side span section is being constructed, the hanging basket moves forward, and then the support beam is pulled up by the hydraulic cylinder so that the support beam abuts against the bottom of the hanging basket, thereby providing support for the hanging basket, and then the side span section can be constructed. Since the support device provides support for the hanging basket and the side span section, the closing section will not be arched. At the same time, since the support beam can move in the vertical direction, it will not hinder the movement of the hanging basket.

[0021] Preferably, the support beam includes a connecting section and a supporting section, the connecting section is connected to the piston rod of the hydraulic cylinder, the supporting section is hinged to the connecting section, and the connecting section is provided with a driving member for driving the supporting section to be hinged; the supporting section rotates in a horizontal plane under the action of the driving member.

[0022] By adopting the above technical solution, the hydraulic cylinder will not hinder the movement of the hanging basket, so that the side span section can be connected with the bridge tower cross beam. At the same time, the support beam includes a connection section and a support section. When the support beam is lowered into place, the driving member drives the support section to rotate relative to the connection section until the end of the support section away from the connection section is toward the center line of the cantilever box beam, so as to provide support for the side span section in the future. After the construction of the side span section is completed, the support section is retracted by the driving member, and the support device can be disassembled, which is conducive to reuse, thereby helping to reduce construction costs.

[0023] Preferably, the fixed beam is fixedly connected to one end close to the cantilever box beam with a guide beam, the guide beam is fitted with the side wall of the bridge tower crossbeam, and the connecting section is provided with a guide block at one end away from the supporting section, and the guide block is slidably connected with the guide beam.

[0024] By adopting the above technical solution, the guide beam cooperates with the guide block to guide the support beam, making the support beam more stable during movement. At the same time, when the support beam is stressed, the guide beam can also withstand a certain bending moment, so that the hydraulic cylinder is not easily damaged.

[0025] Preferably, the connecting section is hingedly arranged with the guide block, a limiting block is slidably arranged on the side of the guide beam facing away from the bridge tower cross beam, the limiting block is located below the guide block, and the piston rod of the hydraulic cylinder is fixedly connected to the limiting block; when installing the support beam, a lifting device for lifting the support beam is installed on the bridge tower cross beam, the lifting device is connected to the connecting section, and then the guide block is plugged into the guide beam, and then the support beam is slowly lowered by using the lifting device until the connecting section abuts against the limiting block.

[0026] By adopting the above technical solution, due to the long length of the support beam, when installing the support beam, the cantilevered part of the support beam is long, which makes installation difficult, and the construction workers need to stand on the edge of the bridge tower beam to carry out construction, which poses a great construction risk. Therefore, this application hinges the connecting section with the guide block, and provides a lifting device for lifting the support beam on the bridge tower beam. When installing the support beam, first connect the support beam with the lifting device on the bridge tower beam, then plug the connecting block with the guide beam, then push the support beam out of the bridge tower beam to make the support beam fall, and then use the lifting device to slowly lower the support beam until the support beam abuts against the limit block, that is, the installation of the support beam is completed. The entire installation process is simple and efficient, and the construction workers do not need to stand on the edge of the bridge tower beam to carry out construction, which significantly reduces the construction risk.

[0027] Preferably, the hoisting device comprises a winch, a chain is wound on a winding shaft of the winch, and a free end of the chain is fixedly connected to the connecting section.

[0028] By adopting the above technical solution, it is convenient to lift or lower the support beam, which is conducive to improving construction efficiency. In addition, during the construction of the side span section, the lifting device also provides support for the support beam, which is conducive to reducing the load of the hydraulic cylinder, making the hydraulic cylinder less likely to be damaged, and significantly improving the support capacity of the side span section, further reducing the possibility of arching of the closing section.

[0029] Preferably, one end of the fixed beam away from the cantilever box beam is fixedly connected with a back-support beam, and the back-support beam abuts against the side wall of the bridge tower cross beam.

[0030] By adopting the above technical solution, the fixed beams, the counter-support beams and the guide beams form a gantry structure and are buckled onto the bridge tower cross beams, so that when the side span section is constructed, the bridge tower cross beams serve as bending-resistant members, further improving the supporting capacity and preventing the supporting device from failing.

[0031] In summary, the present application includes at least one of the following beneficial technical effects:

[0032] 1. This application first carries out the construction of the closing section and then the side span section, which is convenient for carrying construction materials, thereby improving construction efficiency. At the same time, a support device for supporting the hanging basket and the side span section is set on the bridge tower beam to offset most of the gravity of the side span section, so that the closing section will not be arched due to bending, thereby ensuring construction safety;

[0033] 2. This application facilitates the installation of the support beam by arranging a lifting device for lifting the support beam on the bridge tower crossbeam, and the lifting device can provide supporting force to the support beam, thereby enhancing the bearing capacity of the support beam and preventing the support device from failing. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the structure during the construction of the side span section in this application;

[0035] Figure 2 It is a structural schematic diagram of the supporting device in this application.

[0036] Description of reference numerals:

[0037] 1. Cantilever box girder; 2. Hanging basket; 3. Bridge tower crossbeam; 4. Fixed beam; 5. Guide beam; 6. Reverse support beam; 7. Slide; 8. Guide block; 9. Limit block; 10. Support beam; 101. Connecting section; 102. Supporting section; 103. Electric cylinder; 11. Hydraulic cylinder; 12. Mounting plate; 13. Connecting rod; 14. Connecting groove; 15. Lifting device; 151. Winch; 152. Chain. DETAILED DESCRIPTION

[0038] The following is combined with Figure 1-2 This application is described in further detail.

[0039] The present application embodiment discloses a construction method for cantilever casting a side span straight section by closing the middle span first and then the side span, comprising the following steps:

[0040] S1. Build supports on both sides of the pier to carry out the initial cantilever box girder construction.

[0041] S2. After the construction of the initial section of the cantilever box girder is completed, remove the support.

[0042] S3. Assemble hanging basket 2 on the initial cantilever box girder on both sides of the pier.

[0043] S4. Two groups of hanging baskets 2 synchronously and sectionally carry out the construction of the cantilever box girder 1 in opposite directions.

[0044] S5. When the hanging basket 2 on one side of the pier is constructed to the position of the closing section and the hanging basket 2 on the other side of the pier is constructed to the position of the side span section, the closing section is constructed first.

[0045] S6. After the construction of the closing section is completed, a support device for supporting the hanging basket 2 and the side span section is installed on the bridge tower cross beam 3. Then the materials are transported to the location of the side span section, and then a counterweight block is arranged on the closing section according to the weight of the side span section.

[0046] Reference Figure 1 and Figure 2 , two groups of support devices are provided, and the two groups of support devices are respectively located on both sides of the bridge tower cross beam 3. When the side span section is formed, the two groups of support devices are respectively located on both sides of the length direction of the side span section. The support device includes a fixed beam 4 anchored on the bridge tower cross beam 3 by an anchor rod, and the fixed beam 4 extends along the width direction of the bridge tower cross beam 3. The end of the fixed beam 4 close to the cantilever box beam 1 is vertically fixedly connected with a guide beam 5, and the guide beam 5 abuts against the side wall of the bridge tower cross beam 3; the end of the fixed beam 4 away from the cantilever box beam 1 is vertically fixedly connected with a back-support beam 6, and the back-support beam 6 and the guide beam 5 are located on the same side of the fixed beam 4, and the back-support beam 6 abuts against the side wall of the bridge tower cross beam 3. The fixed beam 4, the back-support beam 6 and the guide beam 5 are integrally formed and constitute a gantry structure and are buckled on the bridge tower cross beam 3, so that the connection is more stable, and at the same time it is conducive to enhancing the bearing capacity of the support device.

[0047] A slide groove 7 is recessed on the side of the guide beam 5 away from the bridge tower cross beam 3. The cross section of the slide groove 7 is T-shaped. The slide groove 7 runs through the upper end surface of the guide beam 5. A limit block 9 and a guide block 8 are slidably connected in the slide groove 7. The guide block 8 is located above the limit block 9. The limit block 9 extends out of the slide groove 7 on the side away from the bridge tower cross beam 3.

[0048] A support beam 10 is provided on the side of the guide block 8 away from the bottom of the slide groove 7. The support beam 10 includes a connecting section 101 and a supporting section 102. One end of the connecting section 101 is hinged to the guide block 8. The rotation plane of the connecting section 101 is vertically arranged. The connecting section 101 is overlapped on the limit block 9. The other end of the connecting section 101 is hinged to the support beam 10. The rotation plane of the support beam 10 is perpendicular to the rotation plane of the connecting section 101. A driving member for driving the support beam 10 to be hinged is provided on the connecting section 101. The driving member is an electric cylinder 103. The cylinder body of the electric cylinder 103 is hinged to the connecting section 101. The piston rod of the electric cylinder 103 is hinged to the supporting section 102. Under the drive of the electric cylinder 103, the supporting section 102 rotates relative to the connecting section 101.

[0049] A hydraulic cylinder 11 is also provided near the fixed beam 4 to the cantilever box beam 1. A mounting plate 12 for mounting the hydraulic cylinder 11 is fixedly connected to the side of the fixed beam 4. The cylinder body of the hydraulic cylinder 11 is mounted on the mounting plate 12. The piston rod of the hydraulic cylinder 11 is fixedly connected to a connecting rod 13. The connecting rod 13 extends toward the direction of the guide beam 5. A connecting groove 14 is opened along the length direction of the guide beam 5. The connecting groove 14 is connected to the slide groove 7. The connecting rod 13 passes through the connecting groove 14 and is fixedly connected to the limit block 9.

[0050] A lifting device 15 for lifting the support beam 10 is also provided on the bridge tower cross beam 3. The lifting device 15 includes a winch 151 installed on the bridge tower cross beam 3. A chain 152 is wound on the winding shaft of the winch 151. The free end of the chain 152 is fixedly connected to the end of the connecting section 101 away from the guide block 8.

[0051] When installing the support device, put the limit block 9 into the slide groove 7 in advance, and connect the piston rod of the hydraulic cylinder 11 with the limit block 9. Then use the anchor rod to anchor the fixed beam 4 to the bridge tower beam 3. Then install the winch 151 on the bridge tower beam 3. When installing the winch 151, ensure that the winding shaft of the winch 151 is located above the fixed beam 4. Then fix the free end of the chain 152 to the end of the connecting section 101 away from the supporting section 102, then stand up the support beam 10 and put the guide block 8 into the slide groove 7, then push the support beam 10 out of the bridge tower beam 3 to make the support beam 10 tilt, then use the lifting device 15 to slowly lower the support beam 10 until the connecting section 101 abuts against the limit block 9, and complete the installation of the support member. The entire installation process is simple and efficient, which is conducive to improving construction efficiency; and construction personnel do not need to stand on the edge of the bridge tower beam 3 to perform construction, which is conducive to improving construction safety.

[0052] S7, carry out the side span construction: when the hanging basket 2 moves forward to the position, the supporting device is used to support the hanging basket 2. Specifically, when the hanging basket 2 moves forward to the position, the electric cylinder 103 drives the supporting section 102 until the supporting section 102 and the connecting section 101 are arranged at 90 degrees, and the end of the supporting section 102 away from the connecting section 101 needs to face the center line of the cantilever box beam 1. Then the hydraulic cylinder 11 is used to drive the limit block 9 to move upward, and the limit block 9 moves upward to drive the guide block 8 and the support beam 10 to move upward synchronously until the support section 102 abuts against the bottom of the hanging basket 2, and finally the winch 151 is used to reel in the chain 152 until the chain 152 is tightened. Afterwards, the inner mold is arranged in the mold cavity of the hanging basket 2 and the steel bars are tied, and then the concrete is poured and vibrated. Since the supporting device provides support for the hanging basket 2 and the side span section, thereby offsetting most of the gravity of the hanging basket 2 and the side span beam, and cooperating with the counterweight block arranged on the closing section, the bending moment received by the closing section is completely handled within the bearing range, thereby eliminating the possibility of arching of the closing section and ensuring construction safety.

[0053] S8. After the construction of the side span is completed, remove the support device and the hanging basket 2 to complete the construction. Specifically, remove the support device first, and then remove the hanging basket 2. When removing the support device, the winch 151 loosens the chain 152, and then the hydraulic cylinder 11 drives the limit block 9 to move downward, and the support beam 10 and the guide block 8 move downward synchronously, and then the electric cylinder 103 drives the support section 102 to rotate so that the support section 102 is reset. Then the winch 151 reels the chain 152 to make the support beam 10 vertical, and then the connecting block is pulled out of the slide 7 through the support beam 10. The hanging basket 2 can be removed in the conventional way, which will not be described in detail here.

[0054] The implementation principle of the construction method of the embodiment of the present application for closing the middle span first and then the side span to cantilever cast the straight section of the side span is as follows:

[0055] The present application first carries out the construction of the closing section and then the side span section, which is convenient for carrying construction materials and thus helps to improve construction efficiency. At the same time, a supporting device for supporting the hanging basket 2 and the side span section is arranged on the bridge tower crossbeam 3 to offset most of the gravity of the side span section, so that the closing section will not be arched due to bending, thereby ensuring construction safety.

[0056] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A construction method for cantilever casting the straight section of the side span by closing the middle span first and then the side span, characterized in that: The following steps are involved: S1. Build brackets on both sides of the bridge pier to carry out the initial construction of the cantilever box girder (1); S2, after the initial construction of the cantilever box girder (1) is completed, the bracket is removed; S3, assembling the hanging basket (2) on the initial section of the cantilever box beam (1); S4, using the hanging basket (2) to construct the cantilever box beam (1) in sections; S5, carry out the closing section construction; S6. After the construction of the closing section is completed, a supporting device for supporting the hanging basket (2) and the side span section is installed on the bridge tower cross beam (3); S7, carrying out the side span construction: when the hanging basket (2) moves forward to the right position, the hanging basket (2) is supported by the supporting device, and then the inner mold is arranged in the mold cavity of the hanging basket (2) and the steel bars are tied, and then the concrete is poured and vibrated; S8, after the construction of the side span is completed, the hanging basket (2) and the supporting device are removed to complete the construction; The support device is provided in two groups, and the two groups of support devices are respectively located on both sides of the length direction of the cantilever box beam (1). The support device comprises a fixed beam (4) anchored on the bridge tower cross beam (3), and the fixed beam (4) extends along the width direction of the bridge tower cross beam (3). A hydraulic cylinder (11) is provided at one end of the fixed beam (4) close to the cantilever box beam (1), and the hydraulic cylinder (11) is arranged perpendicular to the fixed beam (4). The piston rod of the hydraulic cylinder (11) is connected to the support beam (10), and the support beam (10) comprises a connecting section (101) and a supporting section (102); The end of the fixed beam (4) close to the cantilever box beam (1) is fixedly connected to a guide beam (5), the guide beam (5) is in contact with the side wall of the bridge tower cross beam (3), and the end of the connecting section (101) away from the supporting section (102) is provided with a guide block (8), and the guide block (8) is slidably plugged with the guide beam (5); The connecting section (101) is hingedly arranged with the guide block (8); a limit block (9) is slidably moved on the side of the guide beam (5) away from the bridge tower cross beam (3); the limit block (9) is located below the guide block (8); and the piston rod of the hydraulic cylinder (11) is fixedly connected with the limit block (9); when installing the support beam (10), a lifting device (15) for lifting the support beam (10) is installed on the bridge tower cross beam (3); the lifting device (15) is connected with the connecting section (101); then the guide block (8) and the guide beam (5) are plugged in; and then the support beam (10) is slowly lowered by using the lifting device (15) until the connecting section (101) abuts against the limit block (9); The hoisting device (15) comprises a winch (151), a chain (152) is wound on a winding shaft of the winch (151), and a free end of the chain (152) is fixedly connected to the connecting section (101).

2. The method of cantilever casting the straight section of the side span by closing the middle span first and then the side span according to claim 1 is characterized in that: Before the side span section is constructed, counterweights are placed on the closing section.

3. The method for cantilever casting the straight section of the side span by closing the middle span first and then the side span according to claim 1 is characterized in that: The connecting section (101) is connected to the piston rod of the hydraulic cylinder (11), the supporting section (102) is hinged to the connecting section (101), and a driving member for driving the supporting section (102) to be hinged is provided on the connecting section (101); the supporting section (102) rotates in a horizontal plane under the action of the driving member.

4. The method for cantilever casting the straight section of the side span by closing the middle span first and then the side span according to claim 1 is characterized in that: One end of the fixed beam (4) away from the cantilever box beam (1) is fixedly connected to a back-support beam (6), and the back-support beam (6) abuts against the side wall of the bridge tower cross beam (3).

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