A bridge beam based beam string system and method thereof

Abstract

The present application relates to the field of building construction, particularly relates to a kind of based on bridge beam's Zhang Xing system and method thereof;Including surrounding purlin 1, pull rod 2, cable 3, web 4, anchor base 5, and multi-hinged node 6, jointly constitute a parabolic open-web truss, between multiple described cable 3 can be set transverse tension device 7;Described transverse tension device is used for the transverse tension of intermediate section described cable 3;Strut 8 is set between two symmetrically arranged anchor base 5, is fixed by the connecting hole on described anchor base 5, is used to balance the tensile force of described pull rod 2, described cable 3 to described anchor base 5 along the axis direction of described strut 8, with described corbel 10 jointly acting can further improve the shear capacity between anchor base 5 and surrounding purlin 1, meet the engineering stress demand;Greatly increase the span of prestressed composite Zhang Xing truss, so that main support can be arranged according to large interval, earthwork construction is convenient and fast.

Description

Technical Field

[0001] This invention relates to the field of building engineering, specifically to a tensioned system and method based on bridge girder. Background Technology

[0002] In underground structure engineering, in order to meet the construction excavation conditions and control the deformation of the surrounding environment, special foundation pit retaining construction is required. Some foundation pit retaining projects adopt plate support systems, that is, retaining walls such as cast-in-place piles, steel piles, and underground continuous walls are set around the foundation pit. Inside the foundation pit, the top and middle of the retaining wall need to be equipped with an in-pit support system as the reaction support point of the retaining wall to balance the soil pressure on the outside of the retaining wall. The support system generally adopts steel supports or reinforced concrete supports.

[0003] Fish-belly beam technology is also used in foundation pit engineering. It adopts a large-span steel cable truss support system, combined with steel main bracing for foundation pit support. It uses a lot of post-tensioned prestressed cables to balance the pressure with the soil outside the pit. However, due to the large number of steel cables and the need to turn at each node, the prestress loss of the prestressed cables is too large, and the tension does not meet the design requirements, affecting the safety of the project.

[0004] Therefore, it is necessary to provide a tensioning system and method based on bridge girder to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a tensioning system and method based on bridge girder to solve the problems mentioned in the background art.

[0006] This invention relates to the field of building construction, and particularly to a tensioned truss system and method based on a bridge girder; it includes walers, tie rods, cables, web members, anchors, and multi-hinged nodes, which together form a parabolic hollow truss. A transverse tensioning device can be installed between the multiple cables; the transverse tensioning device is used for transverse tensioning of the intermediate cable segments; the tie rod is installed between two symmetrically arranged anchors and fixed through connecting holes on the anchors, used to balance the tension of the tie rods and cables on the anchors along the axis of the tie rod. Working together with the corbels, it further improves the shear bearing capacity between the anchors and the walers, meeting the engineering stress requirements; it greatly increases the span of the prestressed composite tensioned truss, allowing the main supports to be arranged at large intervals, facilitating convenient and rapid excavation construction.

[0007] Preferably, a tensioned truss system and method based on a bridge girder is characterized by comprising: walers, tie rods, cables, web members, and multi-hinged nodes; the prestressed composite tensioned truss has a parabolic shape with its opening facing downwards; multiple cables are provided, and a transverse tensioning device is provided between the multiple cables; the walers are placed horizontally and located at the bottom of the truss; the walers are made of reinforced concrete; the walers have a rectangular cross-section and are located on the top or side of the foundation pit retaining piles; the cables are composed of steel strands.

[0008] Preferably, the cable includes a cable body, a cable anchor head, and a threaded anchor rod, with a ball nut passing through one side of the threaded anchor rod; the multi-hinged node has a flared opening; the cable body bypasses the multi-hinged node and passes through the channel of the flared opening of the multi-hinged node; the cable body is composed of 7 high-strength steel strands, the cable body is covered with a PE sheath, and the cable body is slidable between itself and the inner wall of the flared opening channel of the multi-hinged node.

[0009] Preferably, the web member includes: a profile section, a jack, and a web member fork lug; the profile section is composed of a profile, a first end plate, and a second end plate, the profile is welded to the end plate, the outer edge of the end plate is provided with bolt holes, and the bolt holes are connected to the jack and the web member fork lug.

[0010] Preferably, a tensioned cable system and method based on a bridge girder further includes: anchor seats and steel plate embedded parts; the inner side of the anchor seats is provided with brackets, the threaded anchor rod is anchored to the anchor seats at both ends, the brackets are used to bear the component of the tension force of the tie rod and the cable on the anchor seats along the waler direction; steel plate embedded parts are provided at the intersection of the waler and the web member; the tie rod is made of steel, and the two ends of the tie rod are provided with ear plates and pin holes, the ear plates and the pin holes are respectively connected to the anchor seats and the multi-hinged nodes by pins to form rotatable hinged nodes.

[0011] Preferably, the jack is a prefabricated self-locking jack, the jack base is provided with bolt holes, and the jack is bolted to the first end plate of the profile; the top part of the jack is perpendicularly pressed against the side of the waler, and the top surface of the jack is provided with a ball joint washer; the web rod fork lug is welded from steel plate, and the web rod fork lug includes a double lug plate, a base plate and a web rod pin, the lug plate is provided with a pin hole, the pin hole and the multi-hinged node are connected by the web rod pin, and the connection between the web rod fork lug and the multi-hinged node is a hinge.

[0012] Preferably, the multi-hinge node includes a fork lug, a bottom plate of the duct, a middle plate of the duct, a cover plate of the duct, and a tie rod pin. The fork lug is formed by two thick steel plates, and is welded to the bottom plate of the duct. The fork lug has three pin holes, which are located in the middle and on both sides of the fork lug. The middle pin hole is connected to the web rod fork lug via the web rod pin. Tie rod pins are provided in the pin holes on both sides and are connected to the tie rod fork lug. The bottom plate of the duct, the middle plate of the duct, and the cover plate of the duct are formed by three layers of thick steel plates of the same length and width. The upper surface of the bottom plate of the channel has two semi-circular grooves, and the lower surface of the middle plate of the channel has two semi-circular grooves. The two ends of the channel are flared openings. The upper surface of the middle plate of the channel has two semi-circular grooves, and the lower surface of the cover plate of the channel has two semi-circular grooves. The two ends of the channel are flared openings. When the bottom plate, the middle plate, and the cover plate of the channel are all stacked and assembled, four flared opening channels are formed. The smallest diameter of the four channels is located in the middle, and its diameter is slightly larger than the outer diameter of the cable.

[0013] Preferably, the lateral tensioning device is used for lateral tensioning of the intermediate segment of the cable. The lateral tensioning device includes a jack cylinder, a jack piston rod, a pull plate, and a top plate. The pull plate is threaded to the opening of the jack cylinder. The pull plate has a central hole with an internal thread, and the opening of the jack cylinder has an external thread that matches the internal thread. The top plate is threaded to the head of the jack piston rod. The top plate has a central hole with an internal thread, and the head of the jack piston rod has an external thread that matches the internal thread. The pull plate and the top plate have arc-shaped grooves at positions corresponding to the cable, and the cable bends smoothly when it passes through the arc-shaped grooves.

[0014] Preferably, a tie rod is provided between the two anchors, and the tie rod is fixed through a connecting hole on the end plate of the anchor.

[0015] Preferably, the tensioning system and method based on a bridge girder further includes a fixed pulley; the fixed pulley is located on the side of the anchor seat; the cable changes direction via the fixed pulley.

[0016] Preferably, the waler has a first cavity and a slider in the middle; a first spring is provided in the first cavity; a rope hole is provided on the right side of the cavity; the cable passes through the rope hole; the right side of the slider is fixedly connected to the cable; the first spring is fixedly connected to the inside of the waler and the slider; the slider moves in the first cavity; the left side of the slider is fixedly connected to the first spring.

[0017] Preferably, the pull rod includes a sleeve rod and a connecting rod; the sleeve rod is sleeved onto the connecting rod; the sleeve rod has a second cavity on the side near the connecting rod; a second spring is provided in the second cavity; the second spring is used to connect the sleeve rod and the connecting rod.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. By setting the connection between the first cavity, the first spring, and the cable, the deformation range of the cable can be increased; by setting the sleeve rod and the connecting rod, the length of the rod can be extended or shortened according to the force.

[0020] 2. The length of the tensioned string can be increased or decreased by extending or shortening the tie rod and cable; this allows for the addition or reduction of the number of web members.

[0021] 3. By installing jacks at the bottom of the web members, the waler can achieve a balanced stress state when the cables are tightened and stretched, thus making the tensioning system more stable. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Figure 1 This is an exterior elevation view of the truss of the present invention;

[0024] Figure 2 This is a schematic diagram of the tie rod solution of the present invention;

[0025] Figure 3 This is a schematic diagram of the cable structure of the present invention;

[0026] Figure 4 This is a schematic diagram of the web member structure of the present invention;

[0027] Figure 5 This is a schematic diagram of the fork lug structure of the present invention;

[0028] Figure 6 This is a schematic diagram of the multi-hinge node structure of the present invention;

[0029] Figure 7 This is a side sectional view of the multi-hinge node of the present invention;

[0030] Figure 8 This is a cross-sectional view of the fork lug of the present invention;

[0031] Figure 9 This is a schematic diagram of the fork-ear connection method of the present invention;

[0032] Figure 10 This is a schematic diagram of the multi-piece fork lug connection method of the present invention;

[0033] Figure 11 This is a schematic diagram of the transverse tensioning device of the present invention;

[0034] Figure 12 This is a cross-sectional view of the tie rod of the present invention;

[0035] Figure 13 This is a cross-sectional view of the waler of the present invention;

[0036] Figure 14 This is a schematic diagram of the cable connection method of the present invention.

[0037] In the diagram: 1. Waler; 2. Tie rod; 201. Sleeve rod; 202. Connecting rod; 3. Cable; 31. Cable body; 32. Cable anchor head; 33. Threaded anchor rod; 34. Ball nut; 4. Web member; 41. Profile section; 411. Profile; 412. First end plate; 413. Second end plate; 42. Jack; 43. Web member fork lug; 431. Pin hole; 432. Base plate; 433. Web member pin; 5. Anchor seat; 6. Multi-hinged node; 61. Fork lug; 62. Bottom plate of the duct; 63. Middle plate of the duct; 64. Cover plate of the duct; 65. Tie rod pin; 7. Tensioning device; 71. Hydraulic cylinder of the jack; 72. Piston rod of the jack; 73. Pull plate; 74. Top plate; 8. Tie bar; 9. Main support; 10. Bracket; 11. Embedded steel plate; 12. First spring; 13. First cavity; 14. Second cavity; 15. Second spring; 16. Fixed pulley; 17. Sliding block. Detailed Implementation

[0038] This invention relates to the field of building construction, and particularly to a tensioned truss system and method based on a bridge girder; it includes walers 1, tie rods 2, cables 3, web members 4, anchors 5, and multi-hinged nodes 6, which together form a parabolic open-web truss. A transverse tensioning device 7 can be installed between the multiple cables 3; the transverse tensioning device 7 is used for transverse tensioning of the intermediate segments of the cables 3; a tie bar 8 is set between two symmetrically arranged anchors 5 and fixed through connecting holes on the anchors 5, used to balance the tension of the tie rods 2 and the cables 3 on the anchors 5 along the axis of the tie bar 8, and works together with the corbel 10 to further improve the shear bearing capacity between the anchors 5 and the walers 1, meeting the stress requirements of the project; it greatly increases the span of the prestressed composite tensioned truss, allowing the main supports 9 to be arranged in a concentrated manner at large intervals, making excavation construction convenient and quick.

[0039] Specifically, a tensioned truss system and method based on a bridge girder is characterized by comprising: walers 1, tie rods 2, cables 3, web members 4, and multi-hinged nodes 6; the prestressed composite tensioned truss has a parabolic shape with its opening facing downwards; multiple cables 3 are provided, and a transverse tensioning device 7 is provided between the multiple cables 3; the walers 1 are placed horizontally and located at the bottom of the truss; the walers 1 are made of reinforced concrete; the cross-section of the walers 1 is rectangular, and the walers 1 are set on the top or side of the foundation pit retaining piles; the cables 3 are composed of steel strands.

[0040] Specifically, the cable 3 includes a cable body 31, a cable anchor head 32, and a threaded anchor rod 33. A ball nut 34 is provided on one side of the threaded anchor rod 33 and passes through the threaded anchor rod 33. The multi-hinged node 6 has a flared opening. The cable body 31 passes around the multi-hinged node 6 and passes through the channel of the flared opening of the multi-hinged node 6. The cable body 31 is composed of 7 high-strength steel strands. The cable body 31 is covered with a PE sheath. The cable body 31 is slidable between itself and the inner wall of the flared opening channel of the multi-hinged node 6.

[0041] Specifically, the web member 4 includes: a profile section 41, a jack 42, and a web member fork lug 43; the profile section 41 is composed of a profile 411, a first end plate 412, and a second end plate 413, the profile 411 is welded to the end plate, the outer edge of the end plate is provided with bolt holes, and the bolt holes are connected to the jack 42 and the web member fork lug 43.

[0042] Specifically, a tensioned cable system and method based on a bridge girder further includes: an anchor 5 and a steel plate embedded part 11; the inner side of the anchor 5 is provided with a bracket 10, the threaded anchor rod 33 is anchored to the anchor 5 at both ends, the bracket 10 is used to bear the component of the tension force of the tie rod 2 and the cable 3 on the anchor 5 along the direction of the waler 1; a steel plate embedded part 11 is provided at the intersection of the waler 1 and the web member 4; the tie rod 2 is made of steel, and the two ends of the tie rod 2 are provided with ear plates and pin holes 431, the ear plates and the pin holes 431 are respectively connected to the anchor 5 and the multi-hinged node 6 by pins to form a rotatable hinged node.

[0043] Specifically, the jack 42 is a pre-made self-locking jack. The base of the jack 42 is provided with bolt holes. The jack 42 is bolted to the first end plate 412 of the profile 411. The end of the jack 42 is perpendicularly pressed against the side of the waler 1. The end face of the jack 42 is provided with a ball joint washer. The web rod fork lug 43 is welded from steel plate. The web rod fork lug 43 includes a double lug plate, a base plate 432 and a web rod pin 433. The lug plate is provided with a pin hole 431. The pin hole 431 and the multi-hinged node 6 are connected by the web rod pin 433. The connection between the web rod fork lug 43 and the multi-hinged node 6 is a hinge.

[0044] Specifically, the multi-hinge node 6 includes a fork lug 61, a channel bottom plate 432, a channel middle plate 63, a channel cover plate 64, and a tie rod pin 65. The fork lug 61 is shaped like two thick steel plates and is welded to the channel bottom plate 432. The fork lug 61 has three pin holes 431, which are located in the middle and on both sides of the fork lug 61. The middle pin hole 431 is connected to the web rod fork lug 43 via the web rod pin 433. The two side pin holes 431 are provided with tie rod 2 pins that are connected to the tie rod 2 fork lug 61. The channel bottom plate 432, the channel middle plate 63, and the channel cover plate 64 are also included. The structure consists of three layers of thick steel plates of the same length and width. The upper surface of the bottom plate 432 has two semi-circular grooves, and the lower surface of the middle plate 63 has two semi-circular grooves. The two ends of the channel are funnel-shaped openings. When the bottom plate 432, the middle plate 63, and the cover plate 64 are all stacked together, they form four funnel-shaped openings. The smallest diameter of the four channels is located in the middle, and its diameter is slightly larger than the outer diameter of the cable 3.

[0045] Specifically, the transverse tensioning device 7 is used for transverse tensioning of the intermediate segment of the cable 3. The transverse tensioning device 7 includes a jack cylinder 71, a jack piston rod 72, a pull plate 73, and a top plate 74. The pull plate 73 is threadedly connected to the opening of the jack cylinder 71. The pull plate 73 has a central hole with an internal thread, and the opening of the jack cylinder 71 has an external thread that matches the internal thread. The top plate 74 is threadedly connected to the head of the jack piston rod 72. The top plate 74 has a central hole with an internal thread, and the head of the jack piston rod 72 has an external thread that matches the internal thread. The pull plate 73 and the top plate 74 have arc-shaped grooves at positions corresponding to the cable 3, and the cable 3 bends smoothly when it passes through the arc-shaped grooves.

[0046] Specifically, a tie rod 8 is provided between the two anchor seats 5, and the tie rod 8 is fixed through the connecting hole on the end plate of the anchor seat 5.

[0047] Specifically, the tensioning system and method based on bridge girder further includes a fixed pulley 16; the fixed pulley 16 is located on the side of the anchor 5; the cable 3 changes direction through the fixed pulley 16.

[0048] Specifically, the waler 1 has a first cavity 13 and a slider 17 in the middle; a first spring 12 is provided in the first cavity; a rope hole is provided on the right side of the first cavity 13; the cable 3 passes through the rope hole; the right side of the slider 17 is fixedly connected to the cable 3; the first spring 12 is fixedly connected to the inside of the waler 1 and the slider 17; the slider 17 moves in the first cavity 13; the left side of the slider 17 is fixedly connected to the first spring 12.

[0049] Specifically, the pull rod 2 includes a sleeve rod 201 and a connecting rod 202; the sleeve rod 201 is sleeved onto the connecting rod 202; the sleeve rod 201 is provided with a second cavity 14 on the side near the connecting rod 202; a second spring 15 is provided in the second cavity 14; the second spring 15 is used to connect the sleeve rod 201 and the connecting rod 202.

[0050] Specifically, the tie rod 8 is disposed between two symmetrically arranged anchor seats 5 and fixed through the connecting holes on the anchor seats 5. It is used to balance the tension of the tie rod 2 and the cable 3 on the anchor seats 5 along the tie rod axis. Together with the corbel 10, it can further improve the shear bearing capacity between the anchor seats 5 and the waler 1, and meet the stress requirements of the project.

[0051] Based on the above technical characteristics: when the jacks 42 of multiple web members 4 are simultaneously supported in a certain proportion, due to the tight connection between the anchor and the waler 1, the tie rod 2 and the steel strand will shift inward toward the pit, and at the same time, the waler 1 will tend to shift outward toward the pit. The deformation of each node is larger at the middle node and smaller at the edge node.

[0052] When the soil in the foundation pit is excavated downwards, the soil pressure inside the foundation pit is released, and the soil pressure outside the foundation pit is transmitted to the waler 1 through the retaining piles, pushing the waler 1 towards the inside of the pit. When the jack 42 is set with an appropriate elongation, the deformation of the waler 1 towards the outside of the pit can be balanced with the amount of displacement of the waler 1 towards the inside of the pit caused by the soil pressure, thereby achieving no displacement or slight displacement of the waler 1. At the same time, each multi-hinged node is offset towards the inside of the pit, and its displacement is the same as the elongation of the jack 42.

[0053] When the intersection of the broken line formed by each tie rod 2, cable 3, and multi-hinged node with the waler 1 and the main support is located on the same parabola, the soil pressure on the outside of each segment of the waler 1 is balanced with the axial pressure of the web member 4 at the corresponding position. The entire waler 1 reaches the most ideal mechanical equilibrium state, that is, the force on the waler 1 is transformed into a continuous beam supported by each web member 4. Its span is greatly reduced, so the maximum bending moment and shear force are also greatly reduced, and the overall deformation is a wave shape close to 0.

[0054] In contrast, if a conventional foundation pit uses a non-prestressed truss as a support beam, its deformation is too large, making it difficult to meet the needs of controlling the deformation of the foundation pit.

[0055] When tie rod 2 reaches its design strength, cable 3 has not yet reached its allowable strength and still has a large strength redundancy. If the project encounters extremely unfavorable conditions, and when there is a safety risk in the foundation pit, a transverse tensioning device can be used to further tension cable 3. The secondary tensioning construction in this case is simple and convenient, and the stress control is accurate. By making full use of the allowable strength of cable 3, most of the engineering problems caused by foundation pit deformation can be solved.

Claims

1. A tensioned cable system based on a bridge girder, characterized in that, include: Rafters; Pull rod; Cable; Spine; Anchor; Multi-hinge node; The walers, tie rods, cables, web members, anchors, and multi-hinged nodes together form a parabolic hollow truss with an opening facing downwards; the walers are placed horizontally and located at the bottom of the truss; the web members are spaced apart along the length of the walers, with one end of each web member contacting the waler and the other end connected to the multi-hinged node; the tie rods are located between adjacent multi-hinged nodes and between the multi-hinged nodes at the ends and the anchors; The cable has multiple strands, which bypass the multi-hinged node and are anchored to the anchor. A transverse tensioning device is provided between the multiple cables. The anchor is located at both ends of the truss and connected to the waler. The waler is made of reinforced concrete. The waler has a rectangular cross-section and is located on the top or side of the foundation pit retaining piles. The cable is composed of steel strands. It also includes a fixed pulley; the fixed pulley is located on the side of the anchor seat; the cable changes direction through the fixed pulley; a tie rod is also provided between the two anchor seats, and the tie rod is fixed through the connecting hole on the end plate of the anchor seat; The waler has a first cavity and a slider in the middle; a first spring is provided in the first cavity; a rope hole is provided on the right side of the first cavity; the cable passes through the rope hole; the right side of the slider is fixedly connected to the cable; the first spring is fixedly connected to the inside of the waler and the slider; the slider moves in the first cavity; the left side of the slider is fixedly connected to the first spring. The pull rod includes a sleeve rod and a connecting rod; the sleeve rod is sleeved onto the connecting rod; the sleeve rod has a second cavity on the side near the connecting rod; a second spring is provided in the second cavity; the second spring is used to connect the sleeve rod and the connecting rod.

2. The tensioning system based on a bridge girder according to claim 1, characterized in that, The cable includes a cable body, a cable anchor head, and a threaded anchor rod. A ball nut is provided on one side of the threaded anchor rod and passes through it. The multi-hinged node has a flared opening. The cable body bypasses the multi-hinged node and passes through the channel of the flared opening of the multi-hinged node. The cable body is composed of 7 high-strength steel strands and is covered with a PE sheath. The cable body is slidable between itself and the inner wall of the flared opening channel of the multi-hinged node.

3. The tensioning system based on a bridge girder according to claim 1, characterized in that, The web member includes: a profile section, a jack, and a web member fork lug; the profile section is composed of a profile, a first end plate, and a second end plate, the profile is welded to the end plate, the outer edge of the end plate is provided with bolt holes, and the bolt holes are connected to the jack and the web member fork lug.

4. A tensioning system based on a bridge girder according to claim 2, characterized in that, Also includes: Anchor seats and steel plate embedded parts; the inner side of the anchor seats is provided with brackets, the threaded anchor rod is anchored to the anchor seats at both ends, the brackets are used to bear the component of the tension force of the tie rod and the cable on the anchor seats along the waler direction; steel plate embedded parts are provided at the intersection of the waler and the web member; the tie rod is made of steel, and the tie rod is provided with ear plates and pin holes at both ends, the ear plates and the pin holes are respectively connected to the anchor seats and the multi-hinged nodes by pins to form rotatable hinged nodes.

5. A tensioning system based on a bridge girder according to claim 3, characterized in that, The jack is a prefabricated self-locking jack. The jack base is provided with bolt holes, and the jack is bolted to the first end plate of the profile. The top part of the jack is perpendicularly pressed against the side of the waler, and the top surface of the jack is provided with a ball joint washer. The web rod fork lug is made of welded steel plate. The web rod fork lug includes a double lug plate, a base plate, and a web rod pin. The double lug plate is provided with a pin hole. The pin hole and the multi-hinged node are connected by the web rod pin. The connection between the web rod fork lug and the multi-hinged node is a hinge.

6. A tensioning system based on a bridge girder according to claim 5, characterized in that, The multi-hinge node includes a fork lug, a bottom plate of the duct, a middle plate of the duct, a cover plate of the duct, and a tie rod pin. The fork lug is formed by two thick steel plates and is welded to the bottom plate of the duct. The fork lug has three pin holes, located in the middle and on both sides of the fork lug. The middle pin hole is connected to the web rod fork lug via a web rod pin. Tie rod pins are installed in the pin holes on both sides and connected to the tie rod. The bottom plate of the duct, the middle plate of the duct, and the cover plate of the duct are three identical layers. The cable has a length and width of thick steel plate; the upper surface of the bottom plate of the channel has two semi-circular grooves, the lower surface of the middle plate of the channel has two semi-circular grooves, the upper surface of the middle plate of the channel has two semi-circular grooves, and the lower surface of the cover plate of the channel has two semi-circular grooves; when the bottom plate of the channel, the middle plate of the channel, and the cover plate of the channel are all stacked and assembled, four funnel-shaped openings are formed, and the smallest diameter of the four channels is located in the middle, and its diameter is slightly larger than the outer diameter of the cable.

7. A tensioning system based on a bridge girder according to claim 1, characterized in that, The lateral tensioning device is used for lateral tensioning of the intermediate segment of the cable. The lateral tensioning device includes a jack cylinder, a jack piston rod, a pull plate, and a top plate. The pull plate is threaded to the opening of the jack cylinder. The pull plate has a central hole with an internal thread, and the opening of the jack cylinder has an external thread that matches the internal thread. The top plate is threaded to the head of the jack piston rod. The top plate has a central hole with an internal thread, and the head of the jack piston rod has an external thread that matches the internal thread. The pull plate and the top plate have arc-shaped grooves at positions corresponding to the cable, and the cable bends smoothly when it passes through the arc-shaped grooves.

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