A 0# block tower lifting method and structure when a variable system reinforces a continuous beam bridge

Abstract

The application belongs to the field of bridge reinforcement, and discloses a 0# block tower lifting method and structure for continuous beam bridge reinforcement in a variable system, which comprises bracket supports on the webs and bottom plates on both sides of a 0# block box girder, the bracket supports are connected and fixed with the 0# block box girder through prestressed steel strands, shear pins and fine rolled threaded steel bars and anchor cones, and the bracket supports support the bottom of a tower column, the application lifts the tower through fine rolled threaded steel bars and bracket supports, overcomes the shortcomings of traditional tower lifting methods, such as occupying bridge space, reducing the width of a driving lane, large material consumption, certain requirements for a pile cap and the like, and has the advantages of not changing the original support and constraint conditions of the continuous beam bridge, clear structure stress, simple construction, short construction period, small influence on traffic, flexible design, economic applicability and the like compared with the independent tower column structure newly added.

Description

Technical Field

[0001] This invention belongs to the field of bridge reinforcement, specifically relating to a method and structure for lifting the No. 0 block tower when reinforcing a continuous beam bridge with a variable system. Background Technology

[0002] Due to shortcomings and defects in past design, construction, and operation management, continuous beam bridges have largely developed varying degrees of cracking and deflection as operating time and traffic volume increase. The renovation of old and dangerous bridges is a key focus and hot topic for future industry development. Variable system reinforcement, as a method of actively controlling deformation and reducing internal forces, can significantly improve the load-bearing capacity of the structure and improve the stress and alignment of the beam. It has many advantages, including simple construction, clear stress distribution, and high reinforcement efficiency. Therefore, in recent years, variable system reinforcement has gradually gained attention and been practiced in the field of bridge reinforcement, becoming a major focus in this area.

[0003] Although the field of variable system reinforcement has developed in recent years, it has a relatively short development time and the technical system is not yet mature. There are still many problems to be solved in the design calculation and construction process.

[0004] When reinforcing old or damaged bridges using either a low-tower cable-stayed system or a self-anchored suspension system, the existing tower raising methods are as follows:

[0005] 1) The new bridge tower is placed in the center of the main beam section and fixed to the main beam. The disadvantage is that it occupies the bridge deck space and affects the layout of the driving lane.

[0006] 2) Add bridge towers on both sides of the mid-span pier on the original bridge abutment. The disadvantages are that it requires a large amount of material and requires sufficient space on the abutment. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a method and structure for lifting the No. 0 block of a continuous beam bridge using a variable system reinforcement method, thereby resolving the issues in the prior art. To achieve the aforementioned objective, the technical solution adopted by this invention is as follows:

[0008] A method for lifting the No. 0 block of a continuous beam bridge using variable system reinforcement includes the following steps:

[0009] Step 1: Survey the bridge to be reinforced to determine the required increase in load-bearing capacity. Based on the assessment results of the bridge to be reinforced and the reinforcement objectives, determine the required number, size, steel grade, and specific arrangement of each component.

[0010] Step 2: Prefabricate corbel supports;

[0011] Step 3: Erect the construction platform, treat the concrete surface to increase its roughness, and drill holes on the webs on both sides of the No. 0 block box girder and the side of the bottom plate.

[0012] Step 4: Pass the prestressed steel strands, shear pins, fine-rolled threaded steel bars, and anchor cones through the corresponding holes and connect the corbel supports. Tension and anchor the prestressed steel strands, fine-rolled threaded steel bars, anchor shear pins, and anchor cones to make the corbel supports anchored as one with the No. 0 block box girder. Corbel supports are installed on the web plates on both sides of the No. 0 block box girder.

[0013] Step 5: Set up formwork on the outside of the corbel support, pour concrete, and cure it. The tower column is placed on the platform formed by the concrete covering the corbel support.

[0014] Step 6: Follow the above steps to complete the construction of several bridge tower support platforms and then complete the tower raising.

[0015] A tower structure for the No. 0 block of a continuous beam bridge reinforced by a variable system includes corbel supports on the webs on both sides of the No. 0 block box girder. The corbel supports are connected and fixed to the No. 0 block box girder by prestressed steel strands, shear pins, finely rolled threaded steel bars and anchor cones. The corbel supports support the bottom of the tower column.

[0016] Furthermore, the corbel support includes a horizontally arranged upper chord, an inclined lower slant, and a vertically arranged connecting rod. The top of the connecting rod is fixedly connected to the lower surface of the upper chord, and together they form an "L" shape. The connecting rod is located on the side close to the web.

[0017] Furthermore, one end of one of the plurality of finely rolled threaded steel bars is connected to the connecting vertical rod by anchor bolts, and the other end passes through the web and is connected to the inner side of the web.

[0018] Furthermore, the bottom of the lower inclined rod is fixedly connected to a horizontally arranged lower crossbar, and the upper surface of the lower crossbar is fixedly connected to the bottom of the connecting vertical rod.

[0019] Furthermore, a lower pad is fixedly connected to the end of the lower crossbar, and the lower pad is connected to the bottom plate of the No. 0 block box girder by an anchor cone.

[0020] Furthermore, an upper pad is fixedly connected to the end of the upper chord, and a pressure plate is provided at intervals on the upper pad. The pressure plate is fixedly connected to the upper chord, and the pressure plate and the upper pad are fixedly connected by a stiffening plate. One end of the prestressed steel strand is anchored to the pressure plate, and the other end of the prestressed steel strand is anchored to the pressure plate of the corbel support on the other side. The prestressed steel strand passes through the upper pad and the webs on both sides of the No. 0 block box girder. Multiple prestressed steel strands are provided.

[0021] Furthermore, the shear pin passes through the upper pad and is inserted into the web plate, and multiple shear pins are provided.

[0022] Furthermore, the structure of the corbel support satisfies the following formula:

[0023]

[0024] Where L is the horizontal distance from the point where the vertical load N of the tower is applied to the connection node between the lower crossbar and the side of the base plate, H is the distance from the axis of the upper chord to the lower crossbar, and μ is the static friction coefficient between the steel plate and the concrete.

[0025] Furthermore, the structure of the prestressed steel strand satisfies the following formula:

[0026]

[0027] Where f pd A is the tensile design strength of the prestressed tendon. p denoted as the cross-sectional area of ​​a single prestressed tendon bundle, n as the number of prestressed tendons, G as the self-weight of the corbel support, and N as the vertical force transmitted by the tower column.

[0028] The present invention has the following advantages: by using high-strength threaded steel bars and corbel supports to lift the tower, it overcomes the disadvantages of traditional tower lifting methods, such as occupying bridge deck space, reducing the width of the driving lane, large material consumption, and certain requirements on the pier cap. Compared with adding independent tower column structures, it has the advantages of not changing the original support constraints of the continuous beam bridge, clear structural stress, simple construction, short construction period, small impact on traffic, flexible design, and economic applicability. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0030] Figure 2 This is a partially enlarged schematic diagram of the prestressed steel strand connection relationship;

[0031] Figure 3 This is a magnified view of the holes on the connecting vertical rod.

[0032] Figure 4 A schematic diagram of the implementation method when there is a single transverse partition;

[0033] Figure 5 This is a schematic diagram of the implementation method when there are two horizontal partitions;

[0034] Figure 6 This is a schematic diagram of the connection relationship of the upper pad;

[0035] Figure 7 This is an enlarged diagram of the cow leg support;

[0036] Figure 8 This is a schematic diagram of the calculation parameters for the corbel support. Detailed Implementation

[0037] The following will be based on embodiments of the present invention. Figures 1-8 The technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0038] A method for lifting the No. 0 block of a continuous beam bridge using variable system reinforcement includes the following steps:

[0039] Step 1: Review the design data and conduct on-site measurements to obtain the bridge structure and condition of defects. Survey the amount of load-bearing capacity that the bridge to be reinforced needs to be increased. Based on the assessment results of the bridge to be reinforced and the reinforcement objectives, obtain the stress conditions of the bridge towers, cables, composite steel sections, and connecting devices. In this way, determine the required number, size, steel grade, and specific layout of each component.

[0040] Step 2: Based on Step 1 and considering the mechanical operation capabilities of the construction site, if steel tower construction is selected, the bridge tower and corbel support 9 will be fabricated by the factory, and the size and number of holes will be determined by the dimensions of the connecting parts. If reinforced concrete bridge tower construction is selected, the corbel support 9 will be prefabricated by the factory.

[0041] Step 3: Erect a construction platform and use methods such as roughening the sides of the box girder or setting keyways to treat the concrete surface to increase the roughness of the concrete surface; according to the design drawings and on-site measurements, use machinery to drill holes on the sides of the web plate 4 on both sides of the No. 0 block box girder 2 and the sides of the bottom plate 5, avoiding the original steel bars inside the box.

[0042] Step 4: Hoist the prefabricated corbel support 9 symmetrically to the designated position on both sides, and pass the prestressed steel strands 23, shear pins 24, fine-rolled threaded steel bars 26, and anchor cones 29 through the corresponding holes. Tension and anchor the prestressed steel strands 23 and fine-rolled threaded steel bars 26, and anchor the shear pins 24 and anchor cones 29 to anchor the corbel support 9 to the No. 0 block box girder 2 as a whole, and perform a test load on the corbel support 9.

[0043] Step 5: After the test load is qualified, if a steel tower is used, use bolts to connect the lower section of the steel tower to the corbel support 9, set up formwork on the outside of the corbel support 9, pour concrete, cure, and remove the formwork; if a reinforced concrete bridge tower is used, pre-embed the bridge tower reinforcement on the corbel support 9, set up formwork on the outside of the corbel support 9, pour concrete, cure, and remove the formwork. The tower column 8 is arranged on the platform formed by the concrete covering the corbel support 9.

[0044] Step Six: Complete several bridge tower support platforms according to the above steps. After the concrete strength is qualified, if steel towers are used, install and weld the bridge tower segments one by one to complete the tower lifting. During construction, strictly control the assembly accuracy and welding quality. To reduce the adverse effects of temperature on the assembly and welding quality, construction should be carried out during a period of moderate temperature. If reinforced concrete bridge towers are used, set up formwork, arrange reinforcement, pour bridge tower concrete, cure, and remove formwork to complete the tower lifting.

[0045] A tower structure for the No. 0 block of a continuous beam bridge reinforced by a variable system, using the above-mentioned method, includes corbel supports 9 on the web plates 4 on both sides of the No. 0 block box girder 2. The corbel supports 9 are connected and fixed to the No. 0 block box girder 2 by prestressed steel strands 23, shear pins 24, finely rolled threaded steel bars 26 and anchor cones 29. The corbel supports 9 support the bottom of the tower column 8.

[0046] Before reinforcement, transverse diaphragms 3 were installed in the No. 0 block box girder 2 on the continuous box girder 1. The continuous box girder 1 was supported by the support 6 on the pier 7, the pier 7 was supported by the foundation, and the foundation was supported by the ground. The continuous box girder 1, the support 6, the pier 7, and the foundation formed a continuous box girder bridge. The tower columns 8 are the cable tower columns on both sides of the bridge tower.

[0047] The No. 0 box girder 2 includes web plates 4 on both sides, bottom plate 5 at the bottom, top plate at the top, and flange plates on both sides of the top plate, which together form a hollow structure.

[0048] In specific implementation, avoid the reinforcing bars in the transverse diaphragm 3 sections, web 4, and bottom slab 5. Drill holes on the sides of the web 4 and bottom slab 5, with symmetrical drilling on both sides of the web 4, so that the prestressed steel strands 23 pass through the No. 0 block box girder 2. The two ends of the prestressed steel strands 23 are connected to the two side corbel supports 9 respectively. At least two prestressed steel strands 23 are used so that the upper chord 10 of the left corbel support 9 is connected to the upper chord 10 of the right corbel support 9. At least two shear pins 24 are set between the upper chord 10 of the corbel support 9 and the web 4 of the box girder. Between the connecting vertical rod 11 of the corbel support 9 and the web 4 of the box girder. Several finely rolled threaded steel bars 26 are arranged in a matrix. Several anchor cones 29 are arranged between the lower crossbar 14 of the corbel support 9 and the bottom plate 5. The number of finely rolled threaded steel bars 26 and anchor cones 29 is determined by specific calculation results. The prestressed steel strands 23, shear pins 24, finely rolled threaded steel bars 26 and anchor cones 29 anchor the corbel and the box girder together. The prestressed steel strands 23 bear the tensile force generated by the self-weight of the corbel support 9 and the bridge tower load during the installation and use of the corbel support 9. The shear pins 24, finely rolled threaded steel bars 26 and anchor cones 29 are used to bear the shear force between the corbel support and the box girder.

[0049] In specific implementation, for the box girder 2 of block 0# with a transverse diaphragm 3 inside, four corbel supports 9 are symmetrically arranged on both sides of the transverse diaphragm 3 in the longitudinal direction of the bridge, two on each side. After erection, the two corbel supports 9 are wrapped together with concrete to form a tower platform.

[0050] For the box girder 2 of block #0 with two transverse diaphragms 3, three corbel supports 9 are arranged at intervals in the longitudinal direction to avoid the transverse diaphragms 3. The corbel supports 9 are wrapped with concrete to form a tower platform. The tower column 8 is arranged on the platform formed by the concrete wrapped with the corbel supports 9. The number of corbel supports can be increased according to the calculation results.

[0051] Furthermore, the corbel support 9 includes a horizontally arranged upper chord 10, an inclined lower sloping rod 15, and a vertically arranged connecting rod 11. The top of the connecting rod 11 is fixedly connected to the lower surface of the upper chord 10, and together they form an "L" shape. The connecting rod 11 is located on the side close to the web plate 4.

[0052] Furthermore, one end of one of the several finely rolled threaded steel bars 26 is connected to the connecting vertical rod 11 by anchor bolts 27, and the other end passes through the web 4 and is connected to the inner side of the web 4.

[0053] Furthermore, the bottom of the lower inclined rod 15 is fixedly connected to the horizontally arranged lower crossbar 14, and the upper surface of the lower crossbar 14 is fixedly connected to the bottom of the connecting vertical rod 11.

[0054] Furthermore, the lower crossbar 14 is fixedly connected to the lower pad 22 at its end, and the lower pad 22 is connected to the bottom plate 5 at the bottom of the No. 0 block box girder 2 by an anchor cone 29.

[0055] In practice, holes are drilled in the connecting vertical rod 11 and the web plate 4. The finely rolled threaded steel bar 26 passes through the web plate 4 and is anchored at one end to the flange plate of the connecting vertical rod 11 and the other end to the web plate 4 using anchor bolts 27. Holes are drilled at the anchor cone locations in the web plate 4 and the bottom plate 5 and tapered anchors 28 are placed there. Anchor cones 29 pass through the connecting vertical rod 11 and are anchored to the web plate 4 with tapered anchors 28. A lower pad plate 22 is welded at the connection between the lower horizontal rod 14 and the bottom plate 5. A mechanical hole is drilled and a tapered anchor 28 is placed there. Anchor cones 29 pass through the anchor cone holes 32 on the lower pad plate 22 and are driven into the box girder.

[0056] Furthermore, the upper chord 10 is fixedly connected to an upper pad 21 at its end. The upper pad 21 is provided with bearing plates 20 at intervals. The bearing plates 20 are fixedly connected to the upper chord 10. The bearing plates 20 and the upper pad 21 are fixedly connected by stiffening plates 25. One end of the prestressed steel strand 23 is anchored to the bearing plate 20, and the other end of the prestressed steel strand 23 is anchored to the bearing plate 20 of the corbel support 9 on the other side. The prestressed steel strand 23 passes through the upper pad 21 and the web plates 4 on both sides of the No. 0 block box girder 2. Multiple prestressed steel strands 23 are provided.

[0057] Furthermore, the shear pin 24 passes through the upper pad 21 and is inserted into the web 4, and multiple shear pins 24 are provided.

[0058] In specific implementation, a bearing plate 20, an upper pad plate 21, and a stiffening plate 25 are welded directly above the connecting vertical rod 11 and onto the upper chord 10. The upper pad plate 21 is located at the contact surface between the rod and the web plate 4. Shear pins 24 are arranged through shear pin holes 31 on the upper pad plate 21. Prestressed steel strands 23 pass through prestressed steel strand holes 30 on the upper pad plate 21 and are anchored to the bearing plate 20. Several stiffening plates 25 are welded between the upper pad plate 21 and the bearing plate 20.

[0059] In addition, the outer contour of the corbel support 9 is formed by welding the upper chord 10, the force transmission vertical bar 12, the lower diagonal bar 15, the lower horizontal bar 14 and the connecting vertical bar 11 together. The upper diagonal bar 13 can also be welded between the lower surface of the upper chord 10 and the upper surface of the lower diagonal bar 15. All members are I-beams or double I-beams. The specific steel type can also be selected according to the calculation results. The bearing plate 20, the upper pad plate 21, the lower pad plate 22, the stiffening plate 25 and the second stiffening plate 19 are located in the side groove of its I-beam structure.

[0060] The upper chord 10 and the force-transmitting vertical member 12 bear the pressure transmitted by the main tower at the node. Therefore, several second stiffening plates 19 are arranged on the upper chord 10 in this section. The lower node plate 16 is set at the connection between the lower horizontal member 14 and the lower diagonal member 15 for node reinforcement. The upper node plate 17 is set at the connection between the force-transmitting vertical member 12 and the lower diagonal member 15 for node reinforcement. The anti-slip steel plate 18 is set at the connection between the upper diagonal member 13 and the lower diagonal member 15 to prevent the weld from cracking and causing slippage, and to strengthen the node connection.

[0061] Furthermore, the structure of the corbel support 9 satisfies the following formula:

[0062]

[0063] The parameters can be referenced here. Figure 8 L is the horizontal distance from the point where the vertical load N of the cable tower is applied to the connection node between the lower horizontal bar 14 and the side of the base plate 5, which is... Figure 7The horizontal distance between the lower pad 22 at the left end of the middle and lower crossbar 14, which is connected to the base plate 5, and the point at the right end of the upper chord 10 that bears the vertical load N of the tower, is H, which is the distance from the axis of the upper chord to the lower crossbar, and μ is the static friction coefficient between the steel plate and the concrete.

[0064] Furthermore, the structure of the prestressed steel strand 23 satisfies the following formula:

[0065]

[0066] Where f pd A is the tensile design strength of the prestressed tendon. p denoted as the cross-sectional area of ​​a single prestressed tendon bundle, n as the number of prestressed tendons, G as the self-weight of the corbel support, and N as the vertical force transmitted by the tower column.

[0067] The reinforcement principle of this invention is as follows:

[0068] The stay cables share part of the beam load and transfer it to the bridge tower. Tower column 8 is arranged on a platform formed by concrete covering the corbel support 9. The self-weight of the bridge tower and the load it bears are transferred to the corbel support 9 through the concrete. The corbel members transmit the force to the web 4 and bottom plate 5 of the No. 0 block box girder 2. The web 4 transmits the force to the bottom plate 5. Finally, the force is transferred to the foundation through the support 6, pier 7, and foundation.

[0069] The downward vertical force transmitted by the bridge tower column to the corbel support 9 is balanced by the upward friction generated by the lower horizontal bar 14 pressing against the side of the No. 0 box girder 2. The tension of the upper diagonal bar 13 under the prestressed steel strand 23 is balanced by the pressure from the side of the box girder when the lower horizontal bar 14 is pressed against it. The shear pin 24, the fine-rolled threaded steel bar 26, and the anchor cone 29 assist in bearing the self-weight of the corbel support and the vertical forces that may be generated during the installation and use process.

[0070] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, alterations, substitutions, or variations made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for lifting the No. 0 block tower in a variable-system reinforcement continuous beam bridge, characterized in that: Includes the following steps: Step 1: Survey the bridge to be reinforced to determine the required increase in load-bearing capacity. Based on the assessment results of the bridge to be reinforced and the reinforcement objectives, determine the required number, size, steel grade, and specific arrangement of each component. Step 2, prefabricate corbel supports (9); Step 3: Erect a construction platform, treat the concrete surface, increase the roughness of the concrete surface, and drill holes on the sides of the web (4) on both sides of the No. 0 block box girder (2) and the bottom plate (5). Step 4: Pass the prestressed steel strands (23), shear pins (24), fine-rolled threaded steel bars (26), and anchor cones (29) through the corresponding holes and connect the corbel supports (9). Tension and anchor the prestressed steel strands (23), fine-rolled threaded steel bars (26), anchor the shear pins (24), and anchor cones (29) so that the corbel supports (9) are anchored to the No. 0 block box girder (2) as a whole. Corbel supports (9) are installed on the web plates (4) on both sides of the No. 0 block box girder (2). Step 5: Formwork is erected on the outside of the corbel support (9), concrete is poured and cured, and the tower column (8) is placed on the platform formed by the concrete covering the corbel support (9). Step 6: Follow the above steps to complete the construction of several bridge tower support platforms and then lift the tower.

2. A lifting tower structure for block #0 of a continuous beam bridge reinforced by a variable system, employing the method described in claim 1, characterized in that: The bracket supports (9) are located on the web plates (4) on both sides of the No. 0 block box girder (2). The bracket supports (9) are connected and fixed to the No. 0 block box girder (2) through prestressed steel strands (23), shear pins (24), finely rolled threaded steel bars (26) and anchor cones (29). The bracket supports (9) support the bottom of the tower column (8).

3. The No. 0 block lifting tower structure for variable system reinforcement of continuous beam bridge according to claim 2, characterized in that: The corbel support (9) includes a horizontally arranged upper chord (10), an inclined lower sloping bar (15), and a vertically arranged connecting rod (11). The top of the connecting rod (11) is fixedly connected to the lower surface of the upper chord (10) and together they form an "L" shape. The connecting rod (11) is located on the side close to the web plate (4).

4. The No. 0 block lifting tower structure for variable system reinforcement of continuous beam bridge according to claim 3, characterized in that: One end of several of the finely rolled threaded steel bars (26) is connected to the connecting vertical rod (11) by anchor bolts (27), and the other end passes through the web (4) and is connected to the inside of the web (4).

5. The No. 0 block lifting tower structure for variable system reinforcement of continuous beam bridge according to claim 3, characterized in that: The bottom of the lower inclined rod (15) is fixedly connected to the horizontally arranged lower horizontal rod (14), and the upper surface of the lower horizontal rod (14) is fixedly connected to the bottom of the connecting vertical rod (11).

6. The No. 0 block lifting tower structure for variable system reinforcement of continuous beam bridge according to claim 5, characterized in that: The lower crossbar (14) is fixedly connected to the lower pad plate (22) at its end, and the lower pad plate (22) is connected to the bottom plate (5) of the No. 0 block box girder (2) by an anchor cone (29).

7. The No. 0 block lifting tower structure for variable system reinforcement of continuous beam bridge according to claim 3, characterized in that: The upper chord (10) is fixedly connected to the upper pad (21) at its end. The upper pad (21) is provided with bearing plates (20) at intervals. The bearing plates (20) are fixedly connected to the upper chord (10). The bearing plates (20) and the upper pad (21) are fixedly connected by stiffening plates (25). One end of the prestressed steel strand (23) is anchored on the bearing plate (20), and the other end of the prestressed steel strand (23) is anchored on the bearing plate (20) of the corbel support (9) on the other side. The prestressed steel strand (23) passes through the upper pad (21) and the web plates (4) on both sides of the No. 0 block box girder (2). Multiple prestressed steel strands (23) are provided.

8. The No. 0 block lifting tower structure for variable system reinforcement of continuous beam bridge according to claim 7, characterized in that: The shear pin (24) passes through the upper pad (21) and is inserted into the web plate (4). Multiple shear pins (24) are provided.

9. The No. 0 block lifting tower structure for variable system reinforcement of continuous beam bridge according to any one of claims 2-8, characterized in that: The structure of the corbel support (9) satisfies the following formula: Where L is the horizontal distance from the point where the vertical load N of the tower is applied to the connection node between the lower crossbar (14) and the side of the base plate (5), H is the distance from the axis of the upper chord (10) to the lower crossbar (14), and μ is the static friction coefficient between the steel plate and the concrete.

10. The No. 0 block lifting tower structure for variable system reinforcement of continuous beam bridge according to any one of claims 2-8, characterized in that: The structure of the prestressed steel strand (23) satisfies the following formula: Where f pd A is the tensile design strength of the prestressed tendon. p denoted as the cross-sectional area of ​​a single prestressed tendon bundle, n as the number of prestressed steel bundles, G as the self-weight of the corbel support (9), and N as the vertical force transmitted by the tower column.

Images