Asymmetric tension construction method for cable bent tower

Abstract

The invention provides an asymmetric tension construction method for a cable bent tower, and relates to the technical field of bridge erection. The method comprises the steps that part of steel beams are spliced in a splicing site; a cable bent tower is installed on the assembled part of the steel beams; two sets of inhaul cables are installed on the side, facing the pushing direction, of the cable bent tower, one set of inhaul cables is installed on the side, deviating from the pushing direction, of the cable bent tower, and the two ends of each set of inhaul cables are connected with the steel beam and the top end of the cable bent tower correspondingly; and after the part of the steel beams are moved by a certain distance in the pushing direction, the part of the steel beams are connected with the remaining steel beams assembled on the assembling site.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge erection, and in particular to a cable tower asymmetric tensioning construction method. Background Art

[0002] In bridge construction, top-pushing is a common method. However, due to the large spans of some bridges and the terrain's limitations, temporary supports are difficult to arrange. During top-pushing, the front end of the bridge remains suspended before being pushed onto the piers. Excessively long cantilevers can easily cause significant downward deflection, impacting construction quality. Cable towers are required to assist with top-pushing steel beams. However, due to the terrain constraints of the assembly site, the cables on both sides of the towers cannot be tensioned simultaneously during the early stages of construction, impacting construction efficiency. Summary of the Invention

[0003] The problem solved by the present invention is how to meet the pushing requirement under the condition of the terrain restriction of the assembly site.

[0004] In order to solve the above problems, the present invention provides a cable tower asymmetric tensioning construction method, comprising: Assembling some steel beams in the assembly yard; Installing the cable tower on the assembled portion of the steel beam; Two groups of cables are installed on the side of the cable tower facing the jacking direction, and one group of cables is installed on the side of the cable tower facing away from the jacking direction, with both ends of each group of cables being connected to the steel beam and the top of the cable tower respectively; After the partial steel beams are moved a certain distance in the pushing direction, they are connected with the remaining steel beams assembled on the assembly site.

[0005] Optionally, after the partial steel beam is connected to the remaining steel beam, another set of cables is installed between the remaining steel beam and the cable tower.

[0006] Optionally, a cable force feedback system is built on the cable tower, and the cable force feedback system is used to adjust the angle between the cable and the steel beam.

[0007] Optionally, an upper anchor box is provided at one end of the cable, and the upper anchor box is connected to the top of the cable tower through a pin; a lower anchor box is provided at the other end of the cable, and the lower anchor box is rotatably connected to the ear plate on the steel beam through a pin.

[0008] Optionally, a tensioning jack is provided inside the lower anchor box, a fixed end of the tensioning jack is connected to the lower anchor box, and a telescopic end of the tensioning jack is connected to the cable.

[0009] Optionally, the process of installing the cable tower on the assembled partial steel beam includes setting the straight-line distance between the cable tower and the end of the partial steel beam in the pushing direction to be greater than the maximum span between two adjacent bridge piers.

[0010] Optionally, the process of installing the cable tower on the assembled partial steel beam also includes connecting the bottom of the cable tower to the base on the partial steel beam through a pin shaft.

[0011] Optionally, the process of installing the cable tower on the assembled partial steel beam also includes: arranging a group of cable tower tensioning structures on both sides of the cable tower in the length direction of the partial steel beam, and each group of cable tower tensioning structures is obliquely connected between the cable tower and the partial steel beam.

[0012] Optionally, the process of installing the cable tower on the assembled partial steel beam also includes providing a cushion beam on the partial steel beam, and the cushion beam is used to level the partial steel beam.

[0013] Optionally, the process of moving the portion of steel beams a certain distance in the pushing direction also includes setting up a spare tensioning structure.

[0014] Compared with the related art, the cable tower asymmetric tensioning construction method of the present invention divides the steel beam into two parts: partial steel beam and remaining steel beam. According to the site of the assembly site, the partial steel beam is assembled preferentially in the limited assembly site. After the partial steel beam is assembled, the cable tower is installed on the partial steel beam, and two sets of cables are installed on the side of the cable tower facing the jacking direction, and one set of cables is installed on the side of the cable tower away from the jacking direction. The two ends of each set of cables are respectively connected to the top of the steel beam and the cable tower, so that there are three sets of asymmetric cables between the cable tower and the partial steel beam. The three sets of asymmetric cables can offset the downward disturbance deformation of the suspended part of the partial steel beam, so that after the partial steel beam is moved a certain distance in the jacking direction, the partial steel beam can be pushed away from the limited assembly site first, thereby freeing up the limited assembly site, making it convenient to assemble the remaining steel beam at the assembly site, and then the partial steel beam is connected to the remaining steel beam, so as to meet the jacking requirements of the steel beam under the conditions of the terrain restrictions of the assembly site. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 1 is a flowchart of the asymmetric tensioning construction method for a cable tower in an embodiment of the present invention; Figure 2 Schematic diagram of the structure of the steel beam in an embodiment of the present invention; Figure 3 A schematic structural diagram of a portion of steel beams in an embodiment of the present invention; Figure 4 A schematic diagram of installing a cable tower on a portion of a steel beam in an embodiment of the present invention; Figure 5 Schematic diagram of an asymmetric cable after installation of a cable tower in an embodiment of the present invention; Figure 6 Schematic diagram of the jacking of some steel beams in an embodiment of the present invention; Figure 7 This is a schematic diagram of a portion of the steel beams being connected to the remaining steel beams after being lifted out of a limited assembly area in an embodiment of the present invention; Figure 8 Schematic diagram of the structure of the anchor box in an embodiment of the present invention; Figure 9 Schematic diagram of the structure of the cable tower in an embodiment of the present invention.

[0016] Description of reference numerals: 1-steel beam; 1a-partial steel beam; 1b-remaining steel beam; 2-cable tower; 3-stay cable; 4-anchor box; 5-tensioning jack; 6-pin shaft; 7-cushion beam; 8-travel box; 9-disassembly cylinder. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0018] It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present invention described herein can be practiced in an order other than that illustrated or described herein.

[0019] Combine Figure 1 As shown, the embodiment of the present invention provides a method for asymmetric tensioning construction of a cable tower, comprising Assembling some steel beams 1a in a limited assembly area; Install the cable tower 2 on the assembled steel beam 1a; Two sets of cables 3 are installed on the side of the cable tower 2 facing the jacking direction, and one set of cables 3 is installed on the side of the cable tower 2 facing away from the jacking direction. Both ends of each set of cables 3 are connected between the steel beam and the top of the cable tower 2. After part of the steel beam 1a is moved a certain distance in the pushing direction, it is connected to the remaining steel beam 1b assembled on the assembly site.

[0020] Specifically, the assembly site can be a site with limited space, and the structure of the steel beam 1 is as follows: Figure 2As shown, the complete steel beam 1 is assembled in sections at a limited assembly site. According to the area of the assembly site, the steel beam 1 is divided into a partial steel beam 1a and a remaining steel beam 1b. The partial steel beam 1a includes sections ZL1 to ZL14, and the remaining steel beam 1b includes sections ZL15 to ZL20. Figure 3 As shown, the partial steel beam 1a is assembled first in the limited assembly site, and the leading beam is installed at the end of the segment ZL1 away from the segment ZL2. After the partial steel beam 1a is assembled, as shown in FIG. Figure 4 As shown, the cable tower 2 is installed on the segment ZL8 of the partial steel beam 1a, and then, as shown in FIG. Figure 5 As shown, after the tower 2 is installed, two groups of cables 3 are located on the side of the tower 2 facing the jacking direction, that is, the side of the tower 2 facing ZL1, and one group of cables 3 is installed on the side of the tower 2 away from the jacking direction. The three groups of cables 3 are asymmetrically distributed about the axis of the tower 2, as shown in FIG. Figure 6 As shown, after the three groups of cables 3 are installed, they are pushed to push the partial steel beam 1a onto Piers 18 and 19. Piers 18 and 19 support the partial steel beam 1a. The two groups of cables 3 located in the pushing direction tension the suspended part of the partial steel beam 1 upward, and the group of cables 3 away from the pushing direction tensions the remaining part of the partial steel beam 1 upward. During the pushing process of the partial steel beam 1a, the three groups of asymmetrically distributed cables 3 can overcome the offline bending caused by the suspended part of the steel beam 1a, so as to reduce the disturbance deformation of the partial steel beam 1a.

[0021] Therefore, in this embodiment, the steel beam 1 is divided into two parts, a partial steel beam 1a and a remaining steel beam 1b. According to the site of the assembly site, the partial steel beam 1a is assembled first in the limited assembly site. After the partial steel beam 1a is assembled, the cable tower 2 is installed on the partial steel beam 1a, and two sets of cables 3 are installed on the side of the cable tower 2 facing the jacking direction, and a set of cables 3 is installed on the side of the cable tower 2 away from the jacking direction. The two ends of each set of cables 3 are connected to the top of the steel beam and the cable tower 2 respectively, so that the cable tower 2 and the partial steel beam 1a are connected. There are three groups of asymmetric cables 3 between the steel beams 1a. The three groups of asymmetric cables 3 can offset the downward disturbance deformation of the suspended part of the steel beam 1a, so that after the part of the steel beam 1a is moved a certain distance in the pushing direction, the part of the steel beam 1a can be pushed away from the limited assembly site first, thereby freeing up the limited assembly site, making it convenient to assemble the remaining steel beams 1b at the assembly site, and then connect the part of the steel beam 1a with the remaining steel beam 1b to meet the pushing requirements of the steel beam 1 under the conditions of the terrain restrictions of the assembly site.

[0022] Optionally, after the partial steel beam 1 a is connected to the remaining steel beam, another set of cables 3 is installed between the remaining steel beam and the cable tower 2 .

[0023] Specifically, when segment ZL14 is located at the boundary of the assembly site, Figure 7As shown in the figure, the remaining steel beam 1b is assembled within the limited assembly site. After connecting section ZL15 of the remaining steel beam 1b and section ZL14 of part of the steel beam 1a, a set of stay cables 3 is arranged. The stay cables 3 are obliquely pulled between the cable tower 2 and the remaining steel beam 1b. Then, the completed steel beam 1 is jacked. During the subsequent jacking process, the four sets of stay cables 3 can overcome the downward bending of the steel beam 1 in the air to reduce the deflection deformation of the steel beam 1. Among them, the connection position of the stay cable 3 and the steel beam 1 is prohibited from being set at the connection of two adjacent sections, that is, the connection position of the stay cable 3 and the steel beam 1 is only located on section ZL4 or section ZL5, rather than at the connection position of section ZL4 and section ZL5, so as to ensure the connection stability between section ZL4 and section ZL5.

[0024] Optionally, a cable force feedback system is built on the cable tower 2, and the cable force feedback system is used to adjust the included angle between the stay cable 3 and the steel beam 1.

[0025] Specifically, the cable force feedback system may include a tension sensor (such as a strain gauge, a displacement gauge, a strain gage), a control center, and an actuator. The tension sensor is communicatively connected to the control center, and the control center is communicatively connected to the actuator. During the jacking process, the tension sensor detects and feeds back the tension of the stay cable 3 in real time. The control center judges the tension. When the value fed back by the tension sensor reaches the first tension threshold and increases to the second tension threshold, it indicates that during the jacking process, the acting force exerted by the stay cable 3 on the steel beam 1 shows a gradually increasing trend, and further indicates that the suspended part of the steel beam 1 maintains a downward deformation trend. When the maximum tensile force is reached, at this time, it is necessary to increase the included angle between the stay cable 3 and the steel beam 1. The control center controls the actuator to operate, and the actuator drives the stay cable 3 to move upward, so that the component force of the stay cable 3 in the vertical direction increases to overcome the downward deformation trend of the steel beam 1. In this way, during the jacking process, the cable force feedback system can give feedback and dynamically adjust according to the tension of the stay cable 3 to improve the stability of the tensioning effect of the stay cable 3.

[0026] Optionally, an upper anchor box is provided at one end of the stay cable 3, and the upper anchor box is connected to the top of the cable tower 2 through a pin shaft ⑥; a lower anchor box 4 is provided at the other end of the stay cable 3, and the lower anchor box 4 is rotatably connected to the ear plate on the steel beam 1 through a pin shaft ⑥.

[0027] Specifically, the upper anchor box and the lower anchor box 4 have the same structure. The upper anchor box is installed at the top of the cable tower 2 through a pin shaft ⑥, and the lower anchor box 4 is installed on the ear plate of the steel beam 1 through a pin shaft ⑥ and can rotate relative to the ear plate around the pin shaft ⑥. During the installation of the stay cable 3, the upper anchor box and the lower anchor box 4 can be appropriately rotated to adjust the use angle, so as to ensure that the stay cable 3 can meet the use requirements of tensioning while improving the flexibility of the installation of the stay cable 3.

[0028] Based on the above embodiments, the actuator mentioned above may be an oil cylinder. When the oil cylinder drives the upper anchor box to deflect upward, the upper end of the cable 3 can be moved upward, thereby increasing the angle between the cable 3 and the steel beam 1.

[0029] Optionally, as shown in Figure 8 , a tension jack 5 is arranged inside the lower anchor box 4. The fixed end of the tension jack 5 is connected to the lower anchor box 4, and the telescopic end of the tension jack 5 is connected to the cable 3.

[0030] Specifically, a cavity is arranged inside the lower anchor box 4. The tension jack 5 is installed in the cavity of the lower anchor box 4, and the tension jack 5 is connected to the cable 4 inside the lower anchor box 4.

[0031] In this way, by arranging the tension jack 5 inside the lower anchor box 4, with the fixed end of the tension jack 5 connected to the lower anchor box 4 and the telescopic end of the tension jack 5 connected to the cable 3, the use of the tension jack 5 inside the lower anchor box 4 can be satisfied, and the tension degree of the cable 3 can be adjusted by using the tension jack 5 to improve the flexibility of the cable 3 and enable the cable 3 to adapt to the jacking of steel beams 1 with different lengths.

[0032] Optionally, as shown in Figure 6 , during the process of installing the cable tower 2 on the partially assembled steel beam 1a, it includes that the linear distance between the cable tower 2 and the end of the partially assembled steel beam 1a in the jacking direction is greater than the maximum span between two adjacent piers.

[0033] Specifically, the maximum span is the distance between Pier No. 17 and Pier No. 18. The linear distance between the cable tower 2 and the end of the partially assembled steel beam 1a in the jacking direction being greater than the maximum span can ensure that when the partially assembled steel beam 1a is suspended at the maximum span, the cable tower 2 is not suspended, so as to avoid the situation where the cable tower 2 and the partially assembled steel beam 1a tilt downward simultaneously and ensure the stability of the cable tower 2.

[0034] Optionally, as shown in Figure 9 , during the process of installing the cable tower 2 on the partially assembled steel beam 1a, it also includes that the bottom of the cable tower 2 is connected to the base on the partially assembled steel beam 1a through a pin shaft 6.

[0035] Specifically, after the cable tower 2 is in the use position on the partially assembled steel beam 1a, the cable tower 2 is connected to the base on the partially assembled steel beam 1a through the pin shaft 6 to prevent the cable tower 2 from moving relative to the partially assembled steel beam 1a, so as to improve the use stability of the cable tower 2 and facilitate the disassembly and assembly of the cable tower 2.

[0036] Optionally, during the process of installing the cable tower 2 on the partially assembled steel beam 1a, it also includes: arranging a set of cable tower tension structures on both sides of the cable tower 2 in the length direction of the partially assembled steel beam 1a, and each set of cable tower tension structures is obliquely connected between the cable tower 2 and the partially assembled steel beam 1a.

[0037] Specifically, after the pylon 2 is connected to a part of the steel girder 1a through a pin shaft 6, a set of pylon tension structures are arranged on both sides of the pylon 2 in the length direction of the part of the steel girder 1a. Each set of pylon tension structures is obliquely connected between the pylon 2 and the part of the steel girder 1a. The two sets of pylon tension structures exert forces on the pylon 2 to ensure that the pylon 2 is vertical. In this way, by arranging a set of pylon tension structures on both sides of the pylon 2 in the length direction of the part of the steel girder 1a, each set of pylon tension structures is obliquely connected between the pylon 2 and the part of the steel girder 1a, and the two sets of pylon tension structures ensure that the pylon 2 is vertical, avoiding the inclination of the pylon 2, so as to improve the stability of the jacking process and ensure the tension reliability of the cable 3 at the same time.

[0038] Optionally, in combination with Figure 9 As shown, during the process of installing the pylon 2 on the assembled part of the steel girder 1a, a bearing beam 7 is provided on the part of the steel girder 1a, and the bearing beam 7 is used to level the part of the steel girder 1a.

[0039] Specifically, the whole steel girder 1 has a certain bending angle (bridge design). As a part of the steel girder 1, the part of the steel girder 1a also has a certain bending angle, that is, the alignment of the part of the steel girder 1a is a curve. During the process of installing the pylon 2 on the part of the steel girder 1a, the bearing beam 7 is used to level the part of the steel girder 1a to avoid the inclination of the pylon 2, so as to ensure the verticality of the pylon 2.

[0040] In this way, during the process of installing the pylon 2 on the assembled part of the steel girder 1a, the bearing beam 7 is arranged on the part of the steel girder 1a. The bearing beam 7 can level the part of the steel girder 1a, so that the pylon 2 is vertical after being connected to the part of the steel girder 1a, avoiding the inclination of the pylon 2, and further ensuring the stability of the pylon 2 during the jacking process.

[0041] Based on the above embodiments, in combination with Figure 9 As shown, a traveling box 8 is also assembled on the pylon 2, and a disassembly oil cylinder 9 is also assembled on the part of the steel girder 1. Specifically, the two traveling boxes 8 are symmetrically distributed about the axis of the pylon 2 and are respectively connected to the pylon 2. The pylon 2 can move on the part of the steel girder 1a through the two traveling boxes 8 to facilitate the use of the pylon 2. After moving to the use position, the disassembly oil cylinder 9 jacks up the pylon 2. After placing the bearing beam 7 between the pylon 2 and the part of the steel girder 1a, the disassembly oil cylinder 9 retracts, and the pylon 2 and the part of the steel girder 1a are connected through the pin shaft 6. When disassembling the pylon 2, the disassembly oil cylinder 9 first jacks up the pylon 2, and after disassembling the bearing beam 7, the pylon 2 drives away from the steel girder 1 through the traveling box 8.

[0042] Optionally, during the process of moving the part of the steel girder 1a a certain distance along the jacking direction, a spare tension structure is also provided.

[0043] Specifically, the spare tensioning structure can be the same as the cable 3 structure mentioned above. The specific application situation is as follows: when it is found that the downward deflection is still large during the jacking process of some steel beams 1a (or steel beams 1), the jacking process is notified, and the spare tensioning structure is connected between the cable tower 2 and some steel beams 1a (or steel beams 1) to assist the already installed cable 3 through the spare tensioning structure to jointly overcome the downward deflection of some steel beams 1a (or steel beams 1).

[0044] In this way, during the process of moving some steel beams 1a a certain distance along the jacking direction, a spare tensioning structure is also set. The spare tensioning structure can assist the cable 3 to jointly overcome the downward deflection of some steel beams 1a (or steel beams 1), so as to further improve the positioning stability of some steel beams 1a (or steel beams 1).

[0045] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A construction method for asymmetric tensioning of a cable tower, characterized in that, include: Assembling some steel beams in the assembly yard; Installing the cable tower on the assembled portion of the steel beam; Two groups of cables are installed on the side of the cable tower facing the jacking direction, and one group of cables is installed on the side of the cable tower facing away from the jacking direction, with both ends of each group of cables being connected to the steel beam and the top of the cable tower respectively; After the partial steel beams are moved a certain distance in the pushing direction, they are connected with the remaining steel beams assembled on the assembly site.

2. The cable tower asymmetric tensioning construction method according to claim 1, characterized in that, After the partial steel beams are connected to the remaining steel beams, another set of cables is installed between the remaining steel beams and the cable tower.

3. The cable tower asymmetric tensioning construction method according to claim 1, characterized in that, A cable force feedback system is built on the cable tower, and the cable force feedback system is used to adjust the angle between the cable and the steel beam.

4. The cable tower asymmetric tensioning construction method according to claim 1, characterized in that, An upper anchor box is provided at one end of the cable, and the upper anchor box is connected to the top of the cable tower through a pin shaft; a lower anchor box is provided at the other end of the cable, and the lower anchor box is rotatably connected to the ear plate on the steel beam through a pin shaft.

5. The cable tower asymmetric tensioning construction method according to claim 4, characterized in that, A tensioning jack is provided inside the lower anchor box, a fixed end of the tensioning jack is connected to the lower anchor box, and a telescopic end of the tensioning jack is connected to the cable.

6. The cable tower asymmetric tensioning construction method according to claim 1, characterized in that, The process of installing the cable tower on the assembled partial steel beam includes setting the straight-line distance between the cable tower and the end of the partial steel beam in the pushing direction to be greater than the maximum span between two adjacent bridge piers.

7. The cable tower asymmetric tensioning construction method according to claim 1, characterized in that The process of installing the cable tower on the assembled partial steel beam also includes connecting the bottom of the cable tower with the base on the partial steel beam through a pin shaft.

8. The cable tower asymmetric tensioning construction method according to claim 1, characterized in that, The process of installing the cable tower on the assembled partial steel beam also includes: arranging a group of cable tower tensioning structures on both sides of the cable tower in the length direction of the partial steel beam, and each group of cable tower tensioning structures is obliquely connected between the cable tower and the partial steel beam.

9. The method for asymmetric tensioning construction of a pylon according to claim 7, characterized in that, The process of installing the cable tower on the assembled partial steel beam also includes arranging a pad beam on the partial steel beam, and the pad beam is used to level the partial steel beam.

10. The method for asymmetric tensioning construction of a pylon according to claim 1, wherein The process of moving the portion of steel beams a certain distance along the jacking direction includes setting up a spare tensioning structure.

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