A method for converting construction of a single-tower self-anchored suspension bridge with beams first and cables later

Abstract

The present application belongs to the technical field of self-anchored suspension bridge construction, in particular to a method for converting the system of a single-tower self-anchored suspension bridge with beams first and cables later. The method first prepares for the system conversion construction; then codes the whole bridge's suspenders into R1 area suspenders, R2 area suspenders, R3 area suspenders and R4 area suspenders; then respectively pulls the R1 area suspenders to the control force value at one time, pulls the R2 area suspenders to the control force value in stages, pulls the R3 area suspenders to the control force value at one time, and pulls the R4 area suspenders to the control force value; finally removes the temporary support of the main beam, applies the secondary dead load, and completes the system conversion. The present application avoids repeatedly pulling most of the suspenders and frequently moving and installing and removing the pulling equipment in a large range, thereby speeding up the connection of the pulling process, improving the construction efficiency, saving the cost of temporary facilities, and shortening the construction period.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of self-anchored suspension bridge construction, in particular to a method for converting the system of a single-tower self-anchored suspension bridge with beams first and cables later. BACKGROUND

[0002] The construction method of self-anchored suspension bridge with beams first and cables later refers to first erecting temporary supports to install the main beam, then erecting the main cable and installing the suspension cable, and finally completing the system conversion by tensioning the suspension cable. Compared with the construction method of erecting the main cable first and then the main beam, it has two advantages. First, the construction process is relatively simple, and the main cable does not need to be temporarily anchored, so the construction efficiency is high. Second, the main beam is erected above the temporary supports, which does not occupy large mechanical equipment and is beneficial to the construction control of the main beam. The core process of the construction method with beams first and cables later is to realize the system conversion of the whole bridge by actively tensioning the suspension cable. In the system conversion process, determining the reasonable sequence, batch and control force value of the suspension cable tensioning, the number of main cable saddle pushing and the timing are important guarantees for the safety of the components such as the main cable, main beam, suspension cable and bridge tower during the construction stage, and are also the basis for realizing the reasonable bridge completion state. There are the following problems in the common system conversion process:

[0003] (1) Some suspension cable forces are too large during the tensioning process, resulting in low safety redundancy. It is a common phenomenon that the current suspension cable force is too large when tensioning the suspension cable, which is caused by improper tensioning batch and tensioning control force.

[0004] (2) Short suspension cables are prone to collide with the cable guide pipe, causing safety hazards. Due to the large displacement characteristics of the main cable in the longitudinal direction of the bridge and the compression characteristics of the main beam, the initial installation of the suspension cable has an inclination angle. If the short suspension cable is installed and tensioned before the early stage of system conversion, it is prone to collision with the cable guide pipe.

[0005] (3) The number and length of the extension rods required during the tensioning process of the suspension cable are large, which is economically poor. If the suspension cable at the bridge tower is tensioned first, the length of the extension rod used will increase, and if the cycle step distance of the batch tensioning of the suspension cable increases, the number of extension rods will also increase.

[0006] (4) The construction efficiency of the system conversion is low. The repeated tensioning adjustment of the suspension cable in batches requires constant changes in the position of the tensioning platform and the installation and removal of the tensioning equipment, which significantly reduces the construction efficiency and increases the construction period of the system conversion. SUMMARY

[0007] In view of the above problems, the purpose of the present application is to provide a method for converting the system of a single-tower self-anchored suspension bridge with beams first and cables later. By dividing the tensioning of the suspension cable of the whole bridge, the repeated tensioning of most suspension cables and the frequent large-scale movement and installation and removal of tensioning equipment are avoided, thereby accelerating the connection of the tensioning process, improving the construction efficiency, saving the cost of temporary facilities, and shortening the construction period.

[0008] The technical scheme of the present application is: a tower-cable conversion construction method of a single-tower self-anchored suspension bridge system with a beam first and a cable later, comprising the following steps:

[0009] S1: system conversion construction preparation, specifically: complete the main tower construction of the bridge tower, erect the main beam temporary support, complete the main beam erection at the predetermined elevation position, complete the installation of the main cable saddle and the spreader saddle, the spreader sleeve and the main cable erection, and complete the installation of the cable clamp and the sling;

[0010] S2: regional coding of the full-bridge sling, specifically: R1 region sling, R2 region sling, R3 region sling and R4 region sling, wherein the R2 region sling is the sling that needs to be batched and tensioned, the R3 region sling is the sling close to the bridge tower and can be tensioned to the control force value at one time, and the R4 region sling is the sling close to the two side anchor spans; the R1 region sling is the sling between the R2 region sling and the R4 region sling;

[0011] S3: tension the R1 region sling to the control force value at one time, and intersperse the main cable saddle jacking construction during the tensioning process, and jack the main cable saddle to the design position in batches;

[0012] S4: tension the R2 region sling to the control force value in stages;

[0013] S5: tension the R3 region sling to the control force value at one time;

[0014] S6: tension the R4 region sling to the control force value;

[0015] S7: remove the main beam temporary support, apply the secondary dead load, and complete the system conversion.

[0016] In the step S2, the full-bridge sling is regionally coded, and the length of the R4 region sling < the length of the R1 region sling < the length of the R2 region sling < the length of the R3 region sling.

[0017] In the step S3, the main cable saddle jacking construction is performed in three times, and the difference between the three jacking amounts is within 40%.

[0018] In the step S4, the R2 region sling is tensioned in stages, specifically: three-stage tensioning, and the cycle step distance of each stage of tensioning is 3 or 1 sling.

[0019] In the step S4, after the R2 region sling is tensioned, the full-bridge of the suspension bridge is evenly counterweighted along the longitudinal bridge direction, and the counterweight includes the sidewalk board and the guardrail.

[0020] In the steps S3-S6, the length of the lengthening rod used in the process of tensioning the R1 region sling, the R2 region sling, the R3 region sling and the R4 region sling is < 2.5m, and the number of the lengthening rods is ≤ 8.

[0021] The strength safety factor of the R1 zone sling, the R2 zone sling, the R3 zone sling and the R4 zone sling in any working condition should be greater than 2.5, and the maximum tension control range is less than or equal to 2500kN.

[0022] In steps S3-S5, the R1 zone sling, the R2 zone sling and the R3 zone sling are respectively tensioned according to the tensioning sequence of the two lateral bridge towers.

[0023] In step S6, the longer sling is tensioned first and then the shorter sling is tensioned when the R4 zone sling is tensioned.

[0024] The technical effects of the present application are as follows: 1. The present application avoids repeated tensioning of most slings and frequent large-scale movement and installation and disassembly of tensioning equipment by partitioning and tensioning the full-bridge slings, thereby speeding up the tensioning process, improving construction efficiency, saving temporary facility costs and shortening the construction period; 2. The present application can keep the main tower top deflection and the main tower bottom stress within a safe and reasonable range during system conversion, and can ensure that the bridge alignment of the main cable and the main beam meets the design requirements after the system conversion is completed, the main tower returns to the vertical state, and the sling internal force error is within the allowable deviation range; 3. The present application requires fewer lengthening rods with shorter lengths, thereby achieving the purpose of saving temporary facility costs; 4. The present application encodes the full-bridge slings by regions, the length of the R4 zone sling is less than the length of the R1 zone sling, the length of the R2 zone sling and the length of the R3 zone sling, thereby avoiding the risk of some slings having a large cable force during construction and reducing the safety redundancy, and avoiding the risk of collision between short slings and cable pipes.

[0025] Avoiding the risk of some slings having a large cable force during construction and reducing the safety redundancy, and avoiding the risk of collision between short slings and cable pipes.

[0026] The following will be further described with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a bridge type structure schematic diagram of the embodiment of the present application.

[0028] Figure 2 It is a structure schematic diagram of the construction step S3 of the embodiment of the present application.

[0029] Figure 3 It is a structure schematic diagram of the construction step S4 of the embodiment of the present application.

[0030] Figure 4This is a structural schematic diagram of construction step S5 of a construction method for converting a single-tower self-anchored suspension bridge system using a beam-to-cable conversion method according to an embodiment of the present invention.

[0031] Figure 5 This is a structural schematic diagram of construction step S6 of a construction method for converting a single-tower self-anchored suspension bridge system using a beam-to-cable conversion method according to an embodiment of the present invention.

[0032] Figure 6 This is a structural schematic diagram of construction step S7 of a construction method for converting a single-tower self-anchored suspension bridge system using a beam-to-cable conversion method according to an embodiment of the present invention.

[0033] Attached reference numerals: 1-Bridge tower; 2-Main girder; 3-Main cable; 4-Suspension cable; 41-R1 zone suspension cable; 42-R2 zone suspension cable; 43-R3 zone suspension cable; 44-R4 zone suspension cable; 5-Scattered cable saddle; 6-Scattered cable sleeve; 7-Main girder temporary support; 8-Main cable saddle. Implementation

[0034] A construction method for converting a single-tower self-anchored suspension bridge system using a beam-to-cable conversion method includes the following steps:

[0035] S1: Prepare for system conversion construction, specifically as follows: Figure 1 As shown, the main tower construction of bridge tower 1 is completed, the temporary support 7 for the main beam is erected, the main beam 2 is erected at the predetermined elevation, the main cable saddle 8, the cable saddle 5, the cable sleeve 6 are installed and the main cable 3 is erected, and the cable clamps and suspenders 4 are installed.

[0036] S2: Divide the entire bridge's suspension cables into regional codes, such as... Figure 1 As shown, they are specifically numbered as follows: R1 zone suspender 41, R2 zone suspender 42, R3 zone suspender 43, and R4 zone suspender 44. Among them, R2 zone suspender 42 is the suspender that needs to be tensioned in batches, R3 zone suspender 43 is the suspender that is close to bridge tower 1 and can be tensioned to the control force value in one go, and R4 zone suspender 44 is the suspender that is close to the anchor spans on both sides; R1 zone suspender 41 is the suspender between R2 zone suspender 42 and R4 zone suspender 44.

[0037] S3: As Figure 2 As shown, the R1 zone suspender cable 41 is tensioned to the control force value in one go, and the main cable saddle 8 is pushed into place during the tensioning process. The main cable saddle 8 is pushed into the design position in stages.

[0038] S4: As Figure 3 As shown, the sling in zone R2 is tensioned in stages 42 to the control force value;

[0039] S5: As Figure 4 As shown, the R3 zone sling 43 is tensioned to the control force value in one go;

[0040] S6: As Figure 5As shown, the R4 region cable 44 is tensioned to a control force value;

[0041] S7: as shown, the temporary support 7 of the main beam is removed, the secondary dead load is applied, and the system conversion is completed. Figure 6

[0042] The present application encodes the full-bridge cable by region, specifically: R1 region cable 41, R2 region cable 42, R3 region cable 43 and R4 region cable 44. By tensioning the full-bridge cable by region, repeated tensioning of most cables and frequent large-scale movement and installation and removal of tensioning equipment are avoided, thereby accelerating the connection of the tensioning process, improving construction efficiency, saving temporary facility costs and shortening the construction period.

[0043] In the step S2, the full-bridge cable is encoded by region, and the length of the R4 region cable 44 is < the length of the R1 region cable 41 < the length of the R2 region cable 42 < the length of the R3 region cable 43.

[0044] In the step S2, the full-bridge cable is encoded by region, and the length of the R4 region cable 44 is < the length of the R1 region cable 41 < the length of the R2 region cable 42 < the length of the R3 region cable 43.

[0045] In the step S3, the pushing construction of the main cable saddle 8 is performed in three times, and the difference between the three pushing amounts is within 40%.

[0046] In the step S3, the pushing construction of the main cable saddle 8 is performed in three times, and the difference between the three pushing amounts is within 40%.

[0047] In the step S4, the R2 region cable 42 is tensioned in stages, specifically: three-stage tensioning, and the cycle step distance of each stage of tensioning is 3 or 4 cables.

[0048] In the step S4, the R2 region cable 42 is tensioned in stages, specifically: three-stage tensioning, and the cycle step distance of each stage of tensioning is 3 or 4 cables.

[0049] In the step S4, after the R2 region cable 42 is tensioned, the full-bridge of the suspension bridge is evenly counterweighted along the longitudinal bridge direction, and the counterweight includes a sidewalk plate and a guardrail. ​

[0050] After the R2 region cable 42 is tensioned, the full bridge of the suspension bridge is evenly counterweighted along the longitudinal direction of the bridge, and the footpath board and guardrail can be installed in advance in this working condition, thereby further shortening the construction period.

[0051] In the steps S3 to S6, a lengthening rod is used in the process of tensioning the R1 region cable 41, the R2 region cable 42, the R3 region cable 43 and the R4 region cable 44, the length of the lengthening rod is < 2.5 m, and the number of the lengthening rods is ≤ 8.

[0052] In the process of tensioning the R1 region cable 41, the R2 region cable 42, the R3 region cable 43 and the R4 region cable 44, a lengthening rod is used, and the tensioning sequence of the cables in the R1-R2-R3-R4 regions is followed. Since the lengthening rod required for tensioning the R1 region cable is relatively short, and the main cable is obviously displaced downward after the R1 region cable is tensioned, the length of the lengthening rod required for tensioning the R2 region cable is obviously reduced, and the length of the lengthening rod required for tensioning the R3 region cable is also obviously reduced after the R2 region cable is tensioned. Therefore, the same lengthening rod can be used in the process of tensioning the R1 region cable 41, the R2 region cable 42, the R3 region cable 43 and the R4 region cable 44, the number of the lengthening rods is greatly reduced, the processing is facilitated, and the number of the lengthening rods is ≤ 8.

[0053] In the steps S3 to S6, the safety factor of the strength of the R1 region cable 41, the R2 region cable 42, the R3 region cable 43 and the R4 region cable 44 in any working condition should be > 2.5, and the maximum tension control range is ≤ 2500 kN.

[0054] In the steps S3 to S5, the R1 region cable 41, the R2 region cable 42 and the R3 region cable 43 are respectively tensioned according to the tensioning sequence of the two side towers 1.

[0055] The R1 region cable 41, the R2 region cable 42 and the R3 region cable 43 are respectively tensioned according to the tensioning sequence of the two side towers 1, so that the risk of the safety redundancy being reduced due to the cable force being too large in the construction stage of some cables is avoided, and the risk of the short cable colliding with the cable pipe is also avoided.

[0056] In the step S6, when the R4 region cable 44 is tensioned, the longer cable is first tensioned, and then the shorter cable is tensioned.

[0057] The R4 region cable is relatively short, and is finally installed and tensioned. After the cables in other regions are tensioned, the longitudinal deformation of the main cable and the compression of the main beam are basically completed, the R4 region cable is installed in a nearly vertical state, the space between the cable and the cable guide pipe is sufficient, and the construction difficulty is greatly reduced.

[0058] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for converting construction of a self-anchored suspension bridge system with a single tower and a cable after a girder, characterized in that: The method comprises the following steps: S1: system conversion construction preparation, specifically: complete the main tower construction of the bridge tower (1), erect the main beam temporary support (7), complete the main beam (2) erection at the predetermined elevation position, complete the installation of the main cable saddle (8) and the spreader saddle (5), the spreader sleeve (6) and the main cable (3) erection, complete the installation of the cable clamp and the sling (4); S2: the full-bridge sling is coded in regions, specifically coded as: R1 region sling (41), R2 region sling (42), R3 region sling (43) and R4 region sling (44), wherein, the R2 region sling (42) is the sling that needs to be tensioned in batches, the R3 region sling (43) is the sling close to the bridge tower (1) and can be tensioned to the control force value at one time, the R4 region sling (44) is the sling close to the two side anchor spans; the R1 region sling (41) is the sling between the R2 region sling (42) and the R4 region sling (44), in the step S2, the full-bridge sling is coded in regions, the length of the R4 region sling (44) < the length of the R1 region sling (41) < the length of the R2 region sling (42) < the length of the R3 region sling (43); S3: the R1 region sling (41) is tensioned to the control force value at one time, and the main cable saddle (8) jacking construction is completed in the tensioning process, the main cable saddle (8) is jacked to the design position in batches; S4: the R2 region sling (42) is tensioned to the control force value in stages, in the step S4, the R2 region sling (42) is tensioned in stages, specifically three-stage tensioning, and the tensioning cycle step distance is 3 or 4 slings; S5: the R3 region sling (43) is tensioned to the control force value at one time; S6: the R4 region sling (44) is tensioned to the control force value; S7: remove the main beam temporary support (7), apply the secondary dead load, and complete the system conversion.

2. The method according to claim 1, wherein the method is characterized in that: In the step S3, the main cable saddle (8) jacking construction is carried out three times, and the difference between the three jacking amounts is within 40%.

3. The method of Claim 1, wherein the method is characterized in that: In the step S4, after the R2 region sling (42) is tensioned, the suspension bridge is evenly counterweighted along the longitudinal bridge direction, and the counterweight includes the sidewalk board and the guardrail.

4. The method of Claim 1, wherein the method is characterized in that: In the steps S3-S6, the length of the lengthening rod used in the process of tensioning the R1 region sling (41), the R2 region sling (42), the R3 region sling (43) and the R4 region sling (44) is less than 2.5 m, and the number of the lengthening rods is less than or equal to 8.

5. The method of Claim 1, wherein the method is characterized in that: In the steps S3-S6, the strength safety factor of the R1 region sling (41), the R2 region sling (42), the R3 region sling (43) and the R4 region sling (44) should be greater than 2.5 in any working condition, and the maximum tension control range is less than or equal to 2500 kN.

6. The method of Claim 1, wherein the method is characterized in that: In the steps S3-S5, the R1 region sling (41), the R2 region sling (42) and the R3 region sling (43) are tensioned according to the tensioning sequence of the two sides to the bridge tower (1).

7. The method of Claim 1, wherein the method is characterized in that: In the step S6, when the R4 region sling (44) is tensioned, the longer sling is tensioned first and then the shorter sling is tensioned.

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