Steel truss girder cable-stayed bridge vase-shaped concrete cable tower and construction method thereof

Abstract

The present application relates to the technical field of bridge tower construction, and particularly relates to a steel truss girder cable-stayed bridge vase-shaped concrete tower and a construction method thereof. The tower is vase-shaped in the transverse direction of the bridge and is composed of a lower tower column, a concrete bracket, a lower cross beam, a middle tower column, a tower closure section, an upper tower column and the like. The lower tower column is constructed by using a steel formwork turnover method, and the middle and upper tower columns are constructed by using a hydraulic climbing formwork method. A sliding guide rail support system is arranged on the outer upward angle side of the lower tower column to realize rapid installation, positioning and fixing of the formwork. An active counter-pulling system is arranged in the transverse direction of the lower tower column to control the line shape of the lower tower limb and the internal force at the root. The lower cross beam uses the concrete bracket to set up a support system and is simultaneously constructed with the corresponding sections of the tower column. An extended hoisting platform is used when the middle tower column is installed by using the hydraulic climbing formwork method. After the closure section is constructed, the hydraulic climbing formwork is used to complete the capping of the tower. The construction method effectively solves the problems of complex spatial modeling, low construction efficiency and great difficulty in line shape control of the vase-shaped concrete tower.

Description

Technical Field

[0001] This invention relates to the field of bridge pylon construction technology, specifically to a bottle-shaped concrete pylon for a steel truss cable-stayed bridge and its construction method. Background Technology

[0002] With the continuous development of cable-stayed bridge design and construction technology, the design of pylons has become bolder and more avant-garde, with more natural and beautiful outlines. Pylons have also seen the emergence of unique shapes such as sail-shaped, teardrop-shaped, square-shaped, and bronze phoenix-shaped, perfectly integrating modern bridge technology with natural landscapes and forming unique landmarks. When designing the pylon structure of a steel truss cable-stayed bridge, the relative positions of the steel truss and the pylon structure must be comprehensively considered. Because of the smooth and beautiful curves of the Guanyin jade vase, pylons with outlines inspired by it have also appeared. However, traditional pylon construction methods cannot meet the construction requirements for this shape. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a bottle-shaped concrete pylon for a steel truss cable-stayed bridge and its construction method.

[0004] This invention is achieved through the following technical solution: A bottle-shaped concrete pylon for a steel truss cable-stayed bridge includes a lower tower column, concrete corbels, a lower crossbeam, a middle tower column, a pylon closure section, and an upper tower column. The lower tower column gradually divides into two symmetrical tower limbs, both of which gradually incline outwards to the position of the lower crossbeam. Two concrete corbels are respectively located on the inner walls of the two tower limbs of the lower tower column, with the top surface of the corbels being horizontal and the inner surface being vertical. The lower crossbeam includes two independent crossbeams, each with a single-box, single-cell structure. The middle tower column includes two symmetrical tower limbs, both of which gradually incline inwards from the lower crossbeam, merging upwards to form the pylon closure section. The upper tower column is a single-limb structure, gradually tapering in the transverse direction, with the upper section being vertical.

[0005] This invention also includes a construction method for a bottle-shaped concrete pylon of a steel truss cable-stayed bridge, comprising the following steps: Step 1: Divide the cable tower construction into segments; Step Two: Design of Steel Formwork for Lower Tower Columns; Step 3: Install the sliding support system for the lower tower column steel formwork, and use the sliding support system to install the lower tower column steel formwork. The lower tower column and concrete corbel are constructed using the flip-form method. Step 4: Install the temporary tensioning prestressing system for the lower tower column and perform active tensioning; Step 5: Install the lower crossbeam support system using concrete corbels, and construct the lower crossbeam and corresponding tower segments; after the lower crossbeam construction is completed, tension the prestressed tendons and unload the temporary tension prestress. Step Six: Construction of the Central Tower Column; Step 7: Construction of the pylon closure section; Step 8: Hydraulic climbing formwork modification; Step Nine: Use the modified hydraulic climbing formwork from Step Eight to construct the upper tower column.

[0006] As a preferred option: In step two, the lower tower column steel formwork consists of standard formwork and customized formwork. The standard formwork is rectangular and its height is half the height of a standard segment. The irregular formwork is customized, including the formwork for the four sides of the tower limb, the rounded chamfered section, the corbel joint section, and the formwork at the joint section between the tower limb and the lower crossbeam.

[0007] In step four, two temporary prestressed tendons are set up. The two temporary prestressed tendons are located at the same elevation and are both located inside the tower wall. The tensioning end is set on the outer side of the tower leg.

[0008] In step five, the inner column of the lower crossbeam support system is located on the top surface of the concrete corbel. The inner column is fixedly connected to the top surface of the concrete corbel through embedded parts, and the bottom of the outer column is located on the inner wall of the tower leg.

[0009] In step six, an extended type of lifting platform is used.

[0010] In steps six and nine, the construction hoist adopts a relay form of straight ladder and curved ladder.

[0011] This invention discloses a bottle-shaped concrete pylon suitable for steel truss cable-stayed bridges and its construction method. The pylon is bottle-shaped in the transverse direction of the bridge and consists of a lower pylon column, concrete corbels, a lower crossbeam, a middle pylon column, a pylon closure section, and an upper pylon column. The lower pylon column is constructed using a steel formwork flipping method, with a standard segment height of 4m. The middle and upper pylon columns are constructed using hydraulic climbing formwork, with a standard segment height of 4.5m for the middle pylon column and 6m for the upper pylon column. The steel formwork for the lower tower column consists of standard and customized formwork, which can be reused frequently. A sliding support system is set on the outer angle side to achieve rapid installation, positioning, and fixation of the formwork. An active tie system is set in the transverse direction of the lower tower column to control the shape of the lower tower limb and the internal force at the root. The lower crossbeam uses a concrete corbel to build a support system for the lower crossbeam, which is constructed simultaneously with the corresponding segment of the tower column. When installing the hydraulic climbing formwork for the middle tower column, an extended hoisting platform is used, and 4.5m standard segments are used for construction up to the tower closure section. After the tower closure section is completed, the hydraulic climbing formwork is modified to 6.0m. The segments above the tower closure section are operated using the modified 6.0m hydraulic climbing formwork until the tower is capped.

[0012] The construction method of this invention effectively solves the difficulties of complex spatial shape, low construction efficiency, and high difficulty in controlling the alignment of bottle-shaped concrete cable towers. It also solves the technical problem that existing mature construction solutions are not applicable. This invention is safe and efficient in construction and provides a different construction solution for similar cable tower construction.

[0013] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the cross-sectional structure of the cable tower in this embodiment; Figure 2 This is a schematic diagram of the longitudinal section structure of the cable tower in this embodiment; Figure 3 This is a schematic diagram of the cross-sectional division of the cable tower segment in this embodiment; Figure 4 This is a schematic diagram of the longitudinal section of the cable tower segment in this embodiment; Figure 5 This is a cross-sectional view of the steel formwork design for the lower tower column in this embodiment. Figure 6 This is a longitudinal section view of the steel formwork design for the lower tower column in this embodiment; Figure 7 This is a schematic diagram of the steel formwork sliding rail support system for the lower tower column in this embodiment; Figure 8 This is a detailed drawing of the steel formwork sliding rail support system for the lower tower column in this embodiment; Figure 9 This is a cross-sectional view of the active tensioning system of the lower tower column in this embodiment; Figure 10 This is a longitudinal section view of the active tensioning system of the lower tower column in this embodiment; Figure 11 This is a design drawing of the crossbeam support system under the cable tower in this embodiment; Figure 12 This is a schematic diagram of the cross-sectional structure of the completed hydraulic climbing formwork installation of the tower column in this embodiment; Figure 13 This is a schematic diagram of the longitudinal section structure of the completed hydraulic climbing formwork installation of the tower column in this embodiment; Figure 14 This is a schematic diagram of the cross-sectional structure of the cable tower closure section before the hydraulic climbing formwork modification was completed. Figure 15 This is a schematic diagram of the longitudinal section structure before the hydraulic climbing formwork modification was completed during the construction of the cable tower closure section in this embodiment; Figure 16 This is a schematic diagram of the cross-sectional structure after the hydraulic climbing formwork modification was completed during the construction of the cable tower closure section in this embodiment; Figure 17 This is a schematic diagram of the longitudinal section structure after the hydraulic climbing formwork modification was completed during the construction of the cable tower closure section in this embodiment; Figure 18 This is a schematic diagram of the layout of the cable tower construction hoist in this embodiment.

[0015] In the diagram: 1. Foundation, 2. Tower base, 3. Lower tower column, 4. Concrete corbel, 5. Lower crossbeam, 6. Middle tower column, 7. Cable tower closure section, 8. Upper tower column, 9. Steel truss girder, 10. Steel pipe column, 11. Steel horizontal bracing, 12. Steel sliding rail, 13. Operating platform, 14. External steel formwork, 15. Installed steel formwork, 16. Segmental rigid frame and reinforcing bars, 17. Tower crane, 18. Tie rod, 19. Wedge-shaped pad, 20. Manual jack, 21. Standard formwork, 22. Customized formwork, 23. Steel strand, 24. Anchor plate, 25. Anchorage, 26. Corrugated pipe, 27. 28. Embedded parts, 29. Shear-resistant bracket, 30. Column, 31. Horizontal bracing, 32. Unloading block, 33. Distribution beam, 34. Bailey beam, 35. Steel truss, 36. 4.5m segment high hydraulic climbing formwork, 37. Hanging platform, 38. 12m long guide rail, 39. 4.5m high formwork system, 40. Relocation device A, 41. Top-level working platform, 42. 15m long guide rail, 43. 6.0m high formwork system, 44. Relocation device B, 45. Frame, 46. External protection system, 47. Cable tower closure section support system, 48. Curved ladder, 49. Transfer platform, 40. Straight ladder. Detailed Implementation

[0016] The following are specific embodiments of the present invention with reference to the accompanying drawings. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application are within the protection scope of the present invention.

[0017] As attached Figure 1 and 2 As shown, this invention provides a bottle-shaped concrete pylon suitable for steel truss cable-stayed bridges. The outer contour of the pylon structure adopts a streamlined design, widening and narrowing transversely from bottom to top, finally merging and rising vertically, forming an overall bottle shape. The pylon of this invention is a reinforced concrete structure, mainly comprising, from bottom to top: lower tower column 3, concrete corbel 4, lower crossbeam 5, middle tower column 6, pylon closure section 7, and upper tower column 8.

[0018] The lower tower column 3 is located on the tower base 2, and the tower base 2 is located on the pier 1. The first segment of the lower tower column 3 is an integral tower segment, which is divided into a symmetrical left tower segment and a right tower segment after rising to a certain height. Both tower segments gradually tilt outward to the position of the lower crossbeam 5, where the tower reaches its widest transverse width in the bridge direction.

[0019] Two concrete corbels 4 are respectively installed on the inner walls of the left and right tower legs of the lower tower column 3, forming two independent reinforced concrete structures. The top surface of each concrete corbel 4 is horizontal, and the inner surface is vertical. There is a certain distance between the two concrete corbels 4. The concrete corbels 4 are the main load-bearing components for the vertical load of the steel truss beam 9, transferring the vertical load to the lower tower column 3.

[0020] The lower crossbeam 5 includes two independent crossbeams. Each crossbeam is a single-box, single-cell structure. A steel truss 9 straight web member is placed in the space between the two crossbeams, and a steel truss 9 upper chord member and bridge deck components are placed on top of the crossbeam.

[0021] The middle tower column 6 also includes symmetrical left and right tower legs. Unlike the two tower legs of the lower tower column 3, the two tower legs of the middle tower column 6 gradually tilt inward from the lower crossbeam 5 upward, and then close together at a certain height to form the cable tower closure section 7.

[0022] The upper tower column 8 is a single-limb structure with a gradual tapering in the transverse direction. After the upper tower column 8 contracts upward to a certain height, it becomes a vertical section until the tower is capped.

[0023] This invention also provides a construction method for the above-mentioned steel truss cable-stayed bridge's bottle-shaped concrete pylon, comprising the following steps: Step 1: Divide the cable tower construction into segments.

[0024] The construction segments of the cable tower are divided according to its structural form and main construction techniques, as shown in the attached figure. Figure 3 and 4 As shown, in this embodiment, the tower is divided into 33 construction segments, of which: the lower tower column 3 is divided into 7 segments (①~⑦), constructed using the all-steel formwork flipping method, with a standard segment height of 4m; the middle tower column 6 is divided into 12 segments (⑨~⑳), constructed using hydraulic climbing formwork, with a standard segment height of 4.5m; and the upper tower column 8 is divided into 11 segments (22~㉝), constructed using hydraulic climbing formwork, with a standard segment height of 6.0m.

[0025] Step 2: Design of steel formwork for the lower tower column 3.

[0026] Based on the structural form of the lower tower column 3, the steel formwork design for lower tower column 3 is carried out, including the steel formwork design for lower tower column 3, concrete corbel 4, and lower crossbeam 5, as shown in the attached document. Figure 5 and 6 As shown, the steel formwork for the lower tower column 3, concrete corbel 4, and lower crossbeam 5 of the cable tower is composed of reusable standard formwork 21 and customized formwork 22. The standard formwork 21 is rectangular and its height is half the height of the standard segment. The irregular formwork for the four sides of the tower limb, the rounded corner section, the joint section of the concrete corbel 4, and the joint section between the tower limb and the lower crossbeam 5 are all customized.

[0027] Step 3: Install the sliding support system for the steel formwork of the lower tower column 3. Use the sliding support system to install the steel formwork for the lower tower column 3. Use the flip-form method to construct the lower tower column 3 and the concrete corbel 4.

[0028] As attached Figure 7 and 8 As shown, the sliding support system structure includes steel pipe columns 10, steel horizontal bracing 11, steel sliding rails 12, operating platform 13, wedge-shaped pads 19, manual jacks 20, and hand-operated hoists. This sliding support system has two main functions: firstly, to provide a sliding track for the installation of the lower tower column 3 steel formwork; and secondly, to provide vertical support for the lower tower column 3 steel formwork. During the construction of the foundation 1 and tower base 2, pre-embedded connectors are installed on the steel pipe columns 10. The steel pipe columns 10 use flanges to connect the pre-embedded connectors. The steel horizontal bracing 11 and steel sliding rails 12 are welded on-site. The steel sliding rails 12 are set parallel to the outer contour line of the tower, with a distance of 30cm-40cm between the steel sliding rails 12 and the outer side of the tower. Before the construction of the lower tower column 3 segment, the sliding support system is inspected and accepted, ensuring that the sliding system is 4-6m higher than the construction segment. After the construction of the rigid frame and reinforcing bars 16 of the lower tower column 3 is completed, the outer steel formwork 14 of the lower tower column 3 is assembled into a whole on the ground and hoisted to the top of the segment using a tower crane 17. The posture of the outer steel formwork 14 is adjusted, and it is slid down to the bottom of the segment. Jacks and hand-operated hoists are used to adjust the spatial position of the outer steel formwork 14, and bolts are used to connect it to the already installed steel formwork 15. Tie rods 18 are used through the inner and outer formwork, and wedge-shaped pads 19 are used to firmly support the back ribs of the steel formwork and the steel slide rails 12 before the segment concrete is poured.

[0029] Step 4: Install the temporary tension prestressing system for the lower tower column 3 and perform active tensioning.

[0030] As attached Figure 9 and 10 As shown, before the construction of the tower segments, components such as anchor plates 24 and corrugated pipes 26 are pre-embedded. Before the construction of the lower crossbeam 5, according to the monitoring instructions, the steel strands 23 are cut, threaded, and anchors 25 are installed, and the temporary prestressing system is tensioned. In this embodiment, two temporary prestressing tendons are set up. The two temporary prestressing tendons are located at the same elevation and are both located inside the tower wall. The tensioning end is set on the outer side of the tower leg.

[0031] Step 5: Use concrete corbel 4 to install the lower crossbeam 5 support system, construct the lower crossbeam 5 and the corresponding sections of the cable tower, and after the lower crossbeam 5 is constructed, perform prestressed tendon tensioning to unload the temporary tension prestress.

[0032] The lower crossbeam 5 support system includes embedded parts 27, columns 29, horizontal bracing 30, shear-resistant corbel brackets 28, unloading blocks 31, distribution beams 32, Bailey beams 33, and steel truss panels 34, etc. (See attached diagram) Figure 11As shown, during the construction of the concrete corbel 4 and the lower tower column 3 in step three, embedded parts 27 are installed at corresponding positions on the top surface of the concrete corbel 4, and pre-drilled holes for shear corbel brackets 28 are installed at corresponding positions on the inner wall of the lower tower column 3. In this step, columns 29 are welded directly onto the embedded parts 27 on the top surface of the concrete corbel 4. Shear corbel brackets 28 are first installed on the inner wall of the lower tower column 3, and then columns 29 are installed on them. The horizontal bracing 30, unloading block 31, distribution beam 32, Bailey beam 33, and steel truss 34 are installed in sequence. After the support system of the lower crossbeam 5 is inspected, the reinforcement construction and concrete construction of the lower crossbeam 5 are carried out in sequence to complete the construction of the lower crossbeam 5.

[0033] After the concrete construction of the lower crossbeam 5 is completed, the prestressed tendons of the lower crossbeam 5 are tensioned. After the prestressed tendons of the lower crossbeam 5 are tensioned, the temporary prestress is unloaded, the steel strands 23 are removed, and the corrugated pipes 26 and the reserved holes at the anchor heads are sealed.

[0034] Step Six: Construction of the central tower column 6.

[0035] As attached Figure 12 and 13 As shown, during the construction of the 12 segments of the central tower column 6, a 4.5m high hydraulic climbing formwork 35 was installed in advance. The hoisting platform 36 was an extended type that met the needs of the later 6.0m climbing formwork construction. This hoisting platform 36 was 1.5m longer than the 4.5m hydraulic climbing formwork hoisting platform for the construction of the central tower column 6. The construction hoisting system adopted a relay form of straight ladder 49 and curved ladder 47. The straight ladder 49 and curved ladder 47 of the construction hoisting system relayed each other at a certain height of the central tower column 6. The straight ladder 49 was located on the transverse side of the bridge, and the curved ladder 47 was on the same side of the tower leg and on the longitudinal side of the bridge. The curved elevator guide rail was consistent with the outer contour of the tower, and the distance between the curved ladder 47 car and the hydraulic climbing formwork was always consistent.

[0036] Step 7: Construction of the 7th section of the cable tower closure.

[0037] Using tower crane 17, the hydraulic climbing formwork on the inner surface of the middle tower column 6 was dismantled, and the support system 46 for the closure section of the cable tower was constructed. The steel bars of the closure section 7 of the cable tower were tied, the formwork was installed and reinforced, and the concrete pouring of the closure section 7 of the cable tower was completed.

[0038] Step 8: Hydraulic climbing formwork modification.

[0039] The hydraulic climbing formwork was modified by replacing the guide rails, extending the formwork system, extending the platform, and the external protection system (45), enabling it to meet the construction requirements for 6.0m standard segments. (See attached document.) Figure 14-17As shown, before the hydraulic climbing formwork modification, the 4.5m high hydraulic climbing formwork 35 used a 12m long guide rail 37, a 4.5m high formwork system 38, and a formwork repositioning device A39 matching the 4.5m high formwork system 38. During the modification, the original guide rail was replaced with a 15m long guide rail 41, the formwork system was extended to a 6.0m high formwork system 42, the repositioning device B43 matching the 6.0m high formwork system 42 was replaced, the hydraulic climbing formwork frame 44 was extended, the top working platform 40 was adjusted upwards by 1.5m, and the outer protective system 45 was extended. The modified hydraulic climbing formwork now meets the construction requirements for 6.0m segments.

[0040] Step 9: Use the modified hydraulic climbing formwork from Step 8 to construct the upper tower column 8.

[0041] The modified hydraulic climbing formwork from step eight was used to continue construction of the remaining segments of the upper tower column 8 until the tower was topped out. (See attached...) Figure 18 As shown, the cable tower construction hoist adopts a relay form of straight ladder 49 and curved ladder 47, and a conversion platform 48 is set in the middle tower column 6 of the cable tower.

[0042] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A construction method for a bottle-shaped concrete pylon of a steel truss cable-stayed bridge, characterized in that: The steel truss cable-stayed bridge's bottle-shaped concrete tower includes a lower tower column, concrete corbels, a lower crossbeam, a middle tower column, a closure section, and an upper tower column. The lower tower column gradually divides upwards into two symmetrical tower legs, both of which gradually incline outwards to the lower crossbeam. Two concrete corbels are respectively located on the inner walls of the two lower tower legs, with the top surface of the corbels being horizontal and the inner surface being vertical. The lower crossbeam includes two independent crossbeams, each with a single-box, single-cell structure. The middle tower column includes two symmetrical tower legs, both of which gradually incline inwards from the lower crossbeam, merging upwards to form the closure section. The upper tower column is a single-leg structure, gradually tapering transversely, with the upper section being vertical. The construction method includes the following steps: Step 1: Divide the cable tower construction into segments; Step 2: Design of steel formwork for lower tower column; The steel formwork for lower tower column consists of standard formwork and customized formwork. The standard formwork is rectangular and its height is half the height of a standard segment. The irregular formwork is all customized, including the formwork for the four sides of the tower leg, the rounded chamfered section, the corbel joint section, and the formwork at the joint section between the tower leg and the lower crossbeam. Step 3: Install the sliding support system for the lower tower column steel formwork. Use this system to install the lower tower column steel formwork, employing the formwork flipping method to construct the lower tower column and concrete corbels. The sliding support system includes steel pipe columns, steel horizontal bracing, steel sliding rails, an operating platform, wedge-shaped pads, manual jacks, and hand-operated hoists. During the construction of the pier cap and tower base, pre-embedded connectors are installed on the steel pipe columns. Flanges are used to connect the pre-embedded connectors to the steel pipe columns. The steel horizontal bracing and steel sliding rails are welded on-site. The steel sliding rails are set parallel to the outer contour line of the tower. The distance between the rail and the outer side of the tower is 30cm-40cm. After the construction of the stiffening frame and reinforcement of the lower tower column segment is completed, the outer steel formwork of the lower tower column is assembled into a whole on the ground and hoisted to the top of the segment by a tower crane. The posture of the outer steel formwork is adjusted and it slides down to the bottom of the segment. The spatial position of the outer steel formwork is adjusted by manual jacks and hand hoists and bolted to the installed steel formwork. Tie rods are passed through the inner and outer formwork. Wedge-shaped pads are used to support the back rib of the steel formwork and the steel slide rail firmly before the segment concrete is poured. Step 4: Install the temporary tensioning prestressing system for the lower tower column and perform active tensioning; Step 5: Install the lower crossbeam support system using concrete corbels, and construct the lower crossbeam and corresponding tower segments; after the lower crossbeam construction is completed, tension the prestressed tendons and unload the temporary tension prestress. Step Six: Construction of the Central Tower Column; Step 7: Construction of the pylon closure section; Step 8: Hydraulic climbing formwork modification; Step Nine: Use the modified hydraulic climbing formwork from Step Eight to construct the upper tower column.

2. The construction method for the bottle-shaped concrete pylon of a steel truss cable-stayed bridge according to claim 1, characterized in that: In step four, two temporary prestressed tendons are set up. The two temporary prestressed tendons are located at the same elevation and are both located inside the tower wall. The tensioning end is set on the outer side of the tower leg.

3. The construction method for the bottle-shaped concrete pylon of a steel truss cable-stayed bridge according to claim 1, characterized in that: In step five, the inner column of the lower crossbeam support system is located on the top surface of the concrete corbel. The inner column is fixedly connected to the top surface of the concrete corbel through embedded parts, and the bottom of the outer column is located on the inner wall of the tower leg.

4. The construction method for the bottle-shaped concrete pylon of a steel truss cable-stayed bridge according to claim 1, characterized in that: In step six, an extended type of lifting platform is used.

5. The construction method for the bottle-shaped concrete pylon of a steel truss cable-stayed bridge according to claim 1, characterized in that: In steps six and nine, the construction hoist adopts a relay form of straight ladder and curved ladder.

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