High-node stiffness self-adaptive prestressed fish-bellied beam structure and prestress applying method

Abstract

This invention discloses a high-nodal-stiffness adaptive prestressed fish-belly beam structure, including an upper chord beam, several support frame assemblies, and steel strands. Triangular connecting plates are provided at both ends of the upper chord beam. The steel strands are connected to the triangular connecting plates at both ends of the upper chord beam via the upper parts of each support frame. Each triangular connecting plate includes two steel frames and a reinforcing part. The two steel frames form a triangular connecting member with the upper chord beam. A steel strand inlet port is provided on one of the steel frames of the triangular connecting plate, located at 1 / 2 to 2 / 3 of the height of the steel frame. The steel strands are connected to the triangular connecting plate via the steel strand inlet port, and their ends are fixed to the upper chord beam. This invention also discloses a prestressing application method based on the above-mentioned fish-belly beam structure. This application solves the problem of large deformation caused by low stiffness at the connection between the steel strands and the triangular connecting plates, enabling adaptive adjustment of prestress, rapid and effective control of foundation pit deformation, and ensuring construction safety.

Description

Technical Field

[0001] This invention relates to the field of intelligent construction technology, and particularly to a high-nodal-stiffness adaptive prestressed fish-belly beam structure, suitable for the support of foundation pits during underground space development and construction, especially in soft soil areas and complex surrounding environments, such as deep foundation pits in coastal cities, foundation pits in complex environments with subway pipelines and high-rise buildings nearby, and construction environments such as foundation pits for highways, urban roads, and railway bridges. It also relates to a prestressing application method based on the high-nodal-stiffness adaptive prestressed fish-belly beam structure. Background Technology

[0002] With the rapid development of engineering technology, the methods of foundation pit support have also been updated and developed. Foundation pit support has evolved from traditional concrete internal support or steel support to a new type of green deep foundation pit support internal support structure system.

[0003] The novel foundation pit support system consists of fish-belly beams (composed of high-strength, low-relaxation steel strands as the upper chord, H-beams as the load-bearing beams, and H-beams of varying lengths for support), braces, corner braces, columns, beams, tie rods, triangular connectors, and prestressing devices, all combined with prestressing to form a planar prestressed support system and a three-dimensional structural system. Compared to traditional concrete internal supports and steel supports, this novel foundation pit support system requires fewer braces and covers a larger excavation area, facilitating the use of large machinery and improving construction efficiency. Prestressing effectively and precisely controls foundation pit displacement, significantly reducing the impact of foundation pit deformation on construction safety.

[0004] Although the new prestressed fish-belly type foundation pit support technology has made a breakthrough in deep foundation pit support technology compared with the traditional deep pit support method, it has been found in the specific construction process that its local structural design still has some operational inconveniences in specific construction applications.

[0005] like Figure 1 As shown in the standard "Technical Specification for Prestressed Fish-belly Type Steel Support for Foundation Pit" (T / CCES3-2017) published by the China Civil Engineering Society, the prestressed fish-belly beam structure and its detailed construction have a very small height at which the prestressing tendons extend into the triangular connecting plate. This results in low stiffness in the area near the connection point between the steel strands and the node plate, making it the area with the lowest stiffness in the entire fish-belly beam structure. In actual engineering projects, this location often experiences excessive deformation, which is extremely detrimental to the safety of the foundation pit support.

[0006] To facilitate the installation of the prestressing application device, a notch for the device is provided on the triangular connecting plate. However, due to the size of the triangular connecting plate, the notch design must consider its strength, resulting in a small operating area at the prestressing tendon tensioning end. This makes prestressing application inconvenient and difficult to adjust in real-time to control deformation based on potential pit deformation. Furthermore, the notch can cause localized deformation at that location, creating unnecessary safety risks.

[0007] Based on the problems existing in the current technology, the problem to be solved in this application is to design an adaptive prestressed fish belly beam structure that can improve the stiffness of the nodes. Summary of the Invention

[0008] The purpose of this invention is to provide a high-nodal-stiffness adaptive prestressed fish-belly beam structure, which solves the problem of large deformation caused by low stiffness at the connection between the steel strand and the triangular connecting plate. Simultaneously, this fish-belly beam structure can automatically adjust the prestress in real time according to the deformation of the foundation pit, quickly and effectively controlling the pit deformation and ensuring the safety of the foundation pit support.

[0009] One aspect of this application provides a high-nodal-stiffness adaptive prestressed fish-belly beam structure, including an upper chord beam, several support frame assemblies disposed on the same side of the upper chord beam, and steel strands; triangular connecting plates are provided at both ends of the upper chord beam, and the steel strands are connected to the triangular connecting plates at both ends of the upper chord beam via bridges provided on the upper part of each support frame; the triangular connecting plate includes two steel frames and a reinforcing part disposed between the included angle of the two steel frames, the two steel frames are connected to the upper chord beam by welding or bolting to form a triangular connecting member, and a steel strand access port is provided on one of the steel frames of the triangular connecting plate, the steel strand access port being located at 1 / 2 to 2 / 3 of the height of the steel frame of the triangular connecting plate, the steel strands being connected to the triangular connecting plate via the steel strand access port, and their ends being connected and fixed to the upper chord beam.

[0010] In addition to the technical features described above, this application also makes improvements in the following aspects: In some embodiments, the steel strand access port is located at the steel frame at 1 / 2 the height of the triangular connecting plate.

[0011] In some embodiments, the reinforcing part includes a first reinforcing steel and a first reinforcing plate; at least two first reinforcing steels are provided, and every two first reinforcing steels are staggered and perpendicular to each other, wherein one of the first reinforcing steels passes through the first reinforcing steel perpendicular to it to form a cross-shaped structure.

[0012] In some embodiments, a first guide groove is provided on one side of the first reinforcing steel. One end of the first guide groove is connected to the steel strand access port, and the other end is connected to the guide groove provided on one side of the upper chord beam. The guide groove provided on one side of the upper chord beam, the first guide groove on one side of the first reinforcing steel, and the steel strand access port form a steel strand guide channel. The end of the steel strand passes through the steel strand guide channel and is fixed to the end of the upper chord beam by an anchor.

[0013] In some embodiments, a first stiffening rib is provided at the junction of the guide groove on one side of the upper chord beam and the first guide groove on the first reinforcing steel side. One side of the first stiffening rib is fixed to the upper chord beam, and the other side is fixed to the first reinforcing plate. The first stiffening rib distributes the concentrated force at the anchorage position of the upper chord beam to the upper chord beam, the first reinforcing plate, and the steel frame.

[0014] In some embodiments, the steel strand access port is located at the steel frame at 2 / 3 of the height of the triangular connecting plate.

[0015] In some embodiments, the reinforcing part includes a second reinforcing steel and a second reinforcing plate. At least three second reinforcing steels are provided, and the three second reinforcing steels are distributed in a radiating manner to both sides with a node on the upper chord beam as the base point. One of the second reinforcing steels is set perpendicular to the upper chord beam. One end of the vertically set second reinforcing steel is connected to the joint of the two steel frame pieces, and the other end is connected and fixed to the upper chord beam, serving as the central support of the triangular connecting plate. The other two second reinforcing steels are symmetrically distributed on both sides of the vertically set second reinforcing steel, with one end connected to the upper chord beam and the other end respectively connected to the two steel frame pieces.

[0016] In some embodiments, a second guide groove is provided on the side of one of the second reinforcing steels located on both sides of the central support. One end of the second guide groove is connected to the steel strand access port, and the other end is connected to the guide groove provided on one side of the upper chord beam. The guide groove on the upper chord beam side, the second guide groove on the second reinforcing steel side, and the steel strand access port form a steel strand guide channel. The end of the steel strand passes through the steel strand guide channel and is fixed to the end of the upper chord beam by an anchor.

[0017] In some embodiments, a second stiffening rib is provided at the location where the guide groove on one side of the upper chord beam combines with the second guide groove on the side of the second reinforcing steel perpendicular to the upper chord beam. One side of the second stiffening rib is fixed to the upper chord beam, and the other side is fixed to the second reinforcing steel perpendicular to the upper chord beam. The second stiffening rib concentrates the force at the anchoring position of the upper chord beam and distributes it to the second reinforcing plate, the second reinforcing steel, and the steel frame.

[0018] In some embodiments, the support frame assembly includes straight web members and diagonal web members, as well as a hydraulic lifting device disposed at the bottom of the straight web members; at least one set of diagonal web members is provided, which are arranged vertically along the height direction of the straight web members, and the diagonal web members and the straight web members are movably connected by a sliding sleeve, and the sliding sleeve and the straight web members are locked together by a locking bolt; a connecting beam is provided on the upper part of the set of diagonal web members, and the two ends of the connecting beam are respectively connected to the support frame assemblies disposed on both sides.

[0019] Another aspect of this application provides a prestressing application method based on a high-nodal-stiffness adaptive prestressed fish-belly beam structure, comprising the following steps: S1. Adjust the locking bolts between the sliding sleeve and the straight web rod to unlock the straight web rod from the sliding sleeve, allowing the straight web rod to move up and down along the sliding sleeve; S2. Start the hydraulic lifting device. The hydraulic lifting device drives the straight web bar to rise, apply force to the steel strand, open the prestressing tendons, and increase the prestress. S3. Continue to apply prestress, so that the prestress applied to the central support frame assembly is evenly distributed to the support frame assemblies on both sides through the steel strands, and reacts on the upper chord beam. S4. Adjust the prestress until the prestress design value is reached. After the adjustment is completed, tighten the locking bolts on both sides of the sliding sleeve to fix the straight web rod and lock it. S5. Repeat the above process to make multiple adaptive adjustments to the prestress under different working conditions.

[0020] The beneficial effects of this invention are: 1. In this application, the anchoring end of the prestressed steel strand is set inside the upper chord beam of the triangular connecting plate, and the steel strand access port is set at the steel frame at 1 / 2 to 2 / 3 of the height of the triangular connecting plate. Compared with the existing design, the height of the steel strand access end node is increased, which can significantly improve the stiffness of the steel strand connection area of ​​the triangular plate and reduce the deformation of the foundation pit at that location.

[0021] 2. In this application, the anchoring end of the prestressed steel strand is set inside the upper chord beam of the triangular connecting plate, and the steel strand access port is set at the steel frame at 1 / 2 to 2 / 3 of the height of the triangular connecting plate. Compared with the existing design, the height of the steel strand access end node is increased, which can better balance the axial force of the triangular connecting plate, the corner brace or figure-eight brace, and the steel strand. The additional shear force required for the triangular connecting plate is smaller, which improves the stability of the triangular connecting plate node connection.

[0022] 3. This application changes the traditional location for applying prestress by placing the hydraulic lifting device at the bottom of the straight web member. The prestressing strands are opened by lifting the straight web member to achieve the purpose of applying prestress. This design not only facilitates the installation of the hydraulic lifting device for applying prestress, but also allows for a wider range of prestress adjustment. Furthermore, it enables timely adjustment of prestress according to different working conditions, meeting the construction requirements under different working conditions and improving construction safety.

[0023] 4. In order to meet the requirement of timely adjustment of prestress, this application provides a sliding sleeve between the straight web members and the diagonal web members, and the straight web members and the diagonal web members are connected by a movable connection. The straight web members can move up and down along the sliding sleeve after passing through it. A hydraulic servo cylinder is provided at the lower end of the support rod to lift the straight web members to open the steel strands and apply prestress. After the prestress adjustment is completed, the locking bolts are tightened without affecting the stability of the entire structure. The adjustment is flexible and convenient. Attached Figure Description

[0024] The accompanying drawings, which are provided to further illustrate this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application.

[0025] Figure 1 This is a schematic diagram of the existing fish-belly beam structure; Figure 2 This is a schematic diagram of the overall structure of Embodiment 1 of this application; Figure 3 This is a schematic diagram of the structure of the triangular connecting plate and steel strand combined in Embodiment 1 of this application; Figure 4 This is a schematic diagram of the overall structure of Embodiment 2 of this application; Figure 5 This is a schematic diagram of the combined use of the triangular connecting plate and steel strand in Embodiment 2 of this application; Figure 6 This is a schematic diagram of the combined use of the hydraulic lifting device and the straight web bar in this application; Figure 7 This is a diagram showing the relationship between the unbalanced torques of the triangular connecting plate. Figure 8 A schematic diagram showing the change in the position of the steel strand connection node of the triangular connecting plate; Figure 9 Based on Figure 8 Simulation diagram A1 showing the change in the location of the foundation pit at the connection node of the China Steel strand; Figure 10 Based on Figure 8 Simulation diagram A2 showing the change in the location of the foundation pit at the connection node of the China Steel strand; The numbers in the diagram are as follows: 1. Top chord beam; 2. Support frame assembly; 21. Straight web member; 22. Diagonal web member; 23. Hydraulic lifting device; 3. Steel strand; 4. Triangular connecting plate; 41. Steel frame; 42. Reinforcing part; 421. First reinforcing steel; 4211. First guide groove; 422. First reinforcing plate; 423. Second reinforcing steel; 4231. Second guide groove; 424. Second reinforcing plate; 425. First stiffening rib; 426. Second stiffening rib; 5. Steel strand access port; 6. Anchorage; 7. Sliding sleeve; 8. Locking bolt; 9. Connecting beam. Detailed Implementation

[0026] Various exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the scope of this application or its application or use. This application may be implemented in other different forms and is not limited to the embodiments described herein.

[0027] I. Explanation of descriptive terms in this application The embodiments provided in this application, in conjunction with the technical solutions, are intended to make this application more thorough and complete, and to fully express the scope of this application to those skilled in the art. It should be noted that, unless otherwise specifically stated in this application, the relative arrangements of components described in these embodiments should be interpreted as merely exemplary and not as a limitation on the technical solutions of this application.

[0028] In this application, the use of directional terms such as "up," "down," "left," "right," "bottom," and "top" is defined relative to the directions shown in the accompanying drawings and is used only to indicate relative positional relationships. These relative positional relationships may change accordingly when the absolute position of the described object changes. These or other directional terms should not be construed as restrictive.

[0029] In this application, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may not be directly connected to the other devices but may have an intermediary device.

[0030] Furthermore, this application does not discuss in detail the technologies and equipment known to those skilled in the art, but where appropriate, such technologies and equipment should be considered part of the specification.

[0031] The application scenarios of this application are mainly based on the technical field of foundation pit support in intelligent buildings. It can also be applied to other scenarios according to its functions, such as construction scenarios of highways, urban roads and railway bridges. Its application scenarios are not constrained or limited by the specific embodiments described in this application.

[0032] II. Explanation of the Key Technical Problems Addressed in This Application Currently, in the structural and detailed design of prestressed fish-belly beams, the height h of the prestressing tendons extending into the triangular connecting plate is very small. This results in low stiffness at the connection point between the steel strands and the node plate, making the triangular connecting plate prone to deformation and creating safety hazards. To overcome the above problems, the technical solution presented in this application is specifically provided.

[0033] In conjunction with the structural design of this application, such as Figure 7 As shown, the forces acting on the triangular connecting plate 4 are analyzed, and the formula for calculating the unbalanced torque on the triangular connecting plate 4 is as follows: M = Fangle brace * a + Fsteel strand * (3a - √2H) Where: M: unbalanced torque a: Distance of action, representing the size of the lever arm. H: The height of the steel strand entering the triangular connecting plate node relative to the bottom edge. As can be seen from the above formula, as H increases, the unbalanced moment M decreases, the additional shear force that needs to be applied to the triangular connecting plate 4 is smaller, and the stress on the triangular connecting plate 4 is more reasonable.

[0034] like Figure 8 As shown, to further verify the influence of the maximum displacement of the foundation pit on the node height of the steel strand 3 connected to the triangular connecting plate 4, the following verification numerical simulation experiment was conducted. The tension height H of the steel strand 3 was changed, and the height of the connection point was moved from H1 to H2. The maximum displacement of the foundation pit is as follows: like Figure 9 As shown, the height of the connection node for steel strand 3 is at height H1, and the maximum displacement of the foundation pit is 15.7 mm. like Figure 10 As shown, the height of the steel strand 3 connection node is at height H2 (1.5m higher than H1), and the maximum displacement of the foundation pit is reduced to 12.7mm.

[0035] In summary, the greater the height H of the connection point where the steel strand 3 connects to the triangular connecting plate 4, the smaller the deformation at the connection point of the triangular connecting plate. Furthermore, increasing the height H of the connection point can effectively reduce the deformation of the foundation pit. Based on the results of the numerical simulation experiment in this application and the limit recommendations for the angle of the steel strand in the "Technical Specification for Steel Support of Prestressed Fish-belly Type Foundation Pit" T / CCES3-2017, the connection point height H should preferably be between 1 / 2 and 2 / 3 of the edge of the triangular connecting plate.

[0036] III. Detailed Description of This Application in Conjunction with Specific Embodiments This invention describes a high-nodal-stiffness adaptive prestressed fish-belly beam structure, which is typically used in conjunction with bracing, corner bracing, and top chord beams for foundation pit support, in order to meet the needs of adaptive prestress adjustment under different working conditions.

[0037] Example 1 like Figure 2 As shown, the high nodal stiffness adaptive prestressed fish belly beam structure includes an upper chord beam 1, a support assembly, steel strands 3, and triangular connectors set at both ends of the upper chord beam 1.

[0038] The upper chord beam 1 is continuously installed along the perimeter of the foundation pit to bear the pressure from both sides. In this embodiment, the upper chord beam 1 is made of H-beam.

[0039] like Figure 6 As shown, the support frame assembly 2 is configured as five groups, which are spaced apart on the same side of the upper chord beam 1 and perpendicular to it. Each of the five support frame assemblies 2 consists of straight web members 21 and diagonal web members 22. The straight web members 21 of the support assembly located in the middle position are equipped with a hydraulic lifting device 23 at the bottom, which can adjust the relative height of the straight web members 21 to adjust the applied prestress.

[0040] In this support frame assembly 2, located in the middle position, two sets of diagonal web members 22 are mounted on the straight web member 21. The two sets of diagonal web members 22 are arranged vertically along the height direction of the straight web member 21. The two sets of diagonal web members 22 are movably connected to the straight web member 21 via sliding sleeves 7. Locking bolts 8 are used to lock the sliding sleeves 7 and the straight web member 21. The locking and unlocking of the two sets of diagonal web members 22 and the straight web member 21 can be achieved by adjusting the locking bolts 8.

[0041] To further improve the stability of the fish-belly beam during the prestressing process, a connecting beam is provided on the upper part of the inclined web member 22 of a set of support components located in the middle position. The two ends of the connecting beam are respectively connected to the support frame components 2 set on both sides.

[0042] When the fish-belly beam is used in combination with corner braces or parallel braces, triangular connecting plates 4 are provided at both ends of the upper chord beam 1 to facilitate connection with the corner braces or parallel braces. The steel strands 3 are connected to the triangular connecting plates 4 at both ends of the upper chord beam 1 via the bridges provided on the upper part of each support frame.

[0043] like Figure 3 As shown, the triangular connecting plate 4 includes two steel frame frames 41 and a reinforcing part 42 disposed between the included angle of the two steel frame frames 41. The two steel frame frames 41 and the upper chord beam 1 form a triangular connecting member.

[0044] A steel strand access port 5 is provided on one of the steel frame 41 of the triangular connecting plate 4. Preferably, in this embodiment, the steel strand access port 5 is located at the steel frame 41 at 1 / 2 height of the triangular connecting plate, and the steel strand 3 is connected to the triangular connecting plate 4 via the steel strand access port 5.

[0045] In this embodiment, the reinforcing part 42 of the triangular connecting plate includes a first reinforcing steel 421 and a first reinforcing plate 422. Two first reinforcing steels 421 are provided, staggered and perpendicular to each other. One of the first reinforcing steels 421 passes through the first reinforcing steel perpendicular to it, forming a cross-shaped structure. This cross-shaped structure, combined with the triangular structure design formed by the two steel frame frames 41 and the upper chord beam 1, further enhances the stability of the triangular connecting plate.

[0046] To facilitate the guidance of the steel strand 3, a guide groove is provided on one side of the first reinforcing steel 421 of the triangular connecting plate 4.

[0047] One end of the guide groove is connected to the steel strand access port 5, and the other end is connected to the guide groove set on one side of the upper chord beam 1. The guide groove on one side of the upper chord beam 1, the guide groove on one side of the first reinforcing steel 421, and the steel strand access port 5 form a steel strand guide channel. The end of the steel strand 3 passes through the steel strand guide channel and is fixed to the end of the upper chord beam 1 by the anchor 6.

[0048] To disperse the concentrated force at the anchorage position of the upper chord beam 1, a first stiffening rib 425 is provided at the junction of the guide groove on one side of the upper chord beam 1 and the guide groove on the other side of the first reinforcing steel 421. One side of the first stiffening rib 425 is fixed to the upper chord beam 1, and the other side is fixed to the first reinforcing plate 422. The first stiffening rib 425 disperses the concentrated force at the anchorage position of the upper chord beam 1 to the first reinforcing plate 422, the first reinforcing steel 421, and the steel frame 41, effectively solving the problem of concentrated force at the anchorage end.

[0049] Example 2 like Figure 4 As shown, the difference between this embodiment 2 and embodiment 1 is that in this embodiment, the steel strand access port 5 is set at the steel frame 41 at 2 / 3 height of the triangular connecting plate.

[0050] In this embodiment, the height of the access point of the steel strand 3 changes, and the corresponding structural design also changes. In this embodiment, three second reinforcing steels 423 are provided on the triangular connecting plate 4.

[0051] like Figure 5As shown, three second reinforcing steel sections 423 are distributed radially outward from a base point on the upper chord beam 1. One of the reinforcing steel sections is perpendicular to the upper chord beam 1. One end of the vertically positioned second reinforcing steel section is connected to the junction of the two steel frame sections 41, and the other end is fixed to the upper chord beam 1. The vertically positioned second reinforcing steel section serves as the central support of the triangular connecting plate 4. The other two second reinforcing steel sections are symmetrically distributed on both sides of the vertically positioned second reinforcing steel section. One end of each section is connected to the upper chord beam 1, and the other end is connected to the two steel frame sections 41 respectively.

[0052] A guide groove is provided on the side of the second reinforcing steel 423 near the support frame assembly 2 of the triangular connecting plate 4. One end of the guide groove is connected to the steel strand inlet port 5, and the other end is connected to the guide groove provided on one side of the upper chord beam 1. The guide groove on the upper chord beam 1 side, the guide groove on the second reinforcing steel side, and the steel strand inlet port 5 form a guide channel for the steel strand 3. The end of the steel strand 3 passes through the guide channel and is fixed to the end of the upper chord beam 1 by the anchor 6.

[0053] To disperse the concentrated force at the anchorage position of the upper chord beam 1, a second stiffening rib 426 is provided at the junction of the guide groove on one side of the upper chord beam 1 and the guide groove on one side of the second reinforcing steel 423 perpendicular to the upper chord beam 1. One side of the second stiffening rib 426 is fixed to the upper chord beam 1, and the other side is fixed to the second reinforcing steel 423 perpendicular to the upper chord beam 1, so as to disperse the concentrated force at the anchorage position of the upper chord beam 1 to the second reinforcing plate 424, the second reinforcing steel 423 and the steel frame 41.

[0054] This invention also describes a prestressing application method for a high-nodal-stiffness adaptive prestressed fish-belly beam structure, comprising the following steps: S1. Adjust the locking bolts between the sliding sleeve and the straight web rod to unlock the straight web rod from the sliding sleeve, allowing the straight web rod to move up and down along the sliding sleeve; S2. Start the hydraulic lifting device. The hydraulic lifting device drives the straight web bar to rise, apply force to the steel strand, open the prestressing tendons, and increase the prestress. S3. Continue to apply prestress, so that the prestress applied to the central support frame assembly is evenly distributed to the support frame assemblies on both sides through the steel strands, and reacts on the upper chord beam. S4. Adjust the prestress until the prestress design value is reached. After the adjustment is completed, tighten the locking bolts on both sides of the sliding sleeve to fix the straight web rod and lock it. S5. Repeat the above process to make multiple adaptive adjustments to the prestress under different working conditions.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0056] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

Claims

1. A high-nodal-stiffness adaptive prestressed fish-belly beam structure, comprising an upper chord beam (1), several support frame assemblies (2) disposed on the same side of the upper chord beam (1), and steel strands (3); triangular connecting plates (4) are provided at both ends of the upper chord beam (1), and the steel strands (3) are connected to the triangular connecting plates (4) at both ends of the upper chord beam (1) via the upper part of each support frame; characterized in that, The triangular connecting plate (4) includes two steel frame frames (41) and a reinforcing part (42) set between the included angle of the two steel frame frames (41). The two steel frame frames (41) and the upper chord beam (1) form a triangular connecting member. A steel strand access port (5) is provided on one of the steel frame frames (41) of the triangular connecting plate (4). The steel strand access port (5) is set at the steel frame frame (41) at 1 / 2 to 2 / 3 of the height of the triangular connecting plate. The steel strand (3) is connected to the triangular connecting plate (4) through the steel strand access port (5), and its end is connected and fixed to the upper chord beam (1). The strengthening part (42) includes a first strengthening steel (421) and a first strengthening plate (422). The first strengthening steel (421) has a first guide groove (4211) on one side. One end of the first guide groove (4211) is connected to the steel strand access port (5), and the other end is connected to the guide groove provided on one side of the upper chord beam (1). The guide groove provided on one side of the upper chord beam (1), the first guide groove (4211) on one side of the first strengthening steel (421), and the steel strand access port (5) form a steel strand guide channel. The end of the steel strand (3) passes through the steel strand guide channel and is fixed inside the upper chord beam (1) by the anchor (6).

2. The high nodal stiffness self-adapting pre-stressed fish-bellied beam structure according to claim 1, characterized in that, The support frame assembly (2) includes a straight web member (21) and a diagonal web member (22), as well as a hydraulic lifting device (23) disposed at the bottom of the straight web member (21); the diagonal web member (22) is configured as at least one set, and the diagonal web member (22) and the straight web member (21) are movably connected by a sliding sleeve (7); a connecting beam is provided on the upper part of the set of diagonal web members (22) disposed at the upper part, and the two ends of the connecting beam are respectively connected to the support frame assembly (2) disposed on both sides.

3. The high nodal stiffness adaptive prestressed fish-belly beam structure according to claim 2, characterized in that, The steel strand access port (5) is located at the steel frame (41) at 1 / 2 height of the triangular connecting plate.

4. The high nodal stiffness adaptive prestressed fish-belly beam structure according to claim 3, characterized in that, A first stiffening rib is provided at the junction of the guide groove on one side of the upper chord beam (1) and the first guide groove (4211) on one side of the first reinforcing steel (421). The first stiffening rib (425) is fixed on one side of the upper chord beam (1) and on the other side of the first reinforcing plate (422). The first stiffening rib (425) distributes the concentrated force at the anchoring position of the upper chord beam (1) to the upper chord beam (1), the first reinforcing plate (422) and the steel frame (41).

5. The high nodal stiffness adaptive prestressed fish-belly beam structure according to claim 2, characterized in that, The steel strand access port (5) is located at the steel frame (41) at 2 / 3 height of the triangular connecting plate.

6. The high nodal stiffness adaptive prestressed fish-belly beam structure according to claim 2, characterized in that, The strengthening part (42) includes a second strengthening steel (423) and a second strengthening plate (424). A second guide groove (4231) is provided on the side of the second strengthening steel (423). One end of the second guide groove (4231) is connected to the steel strand access port (5), and the other end is connected to the guide groove provided on one side of the upper chord beam (1). The guide groove on one side of the upper chord beam (1), the second guide groove (4231) on one side of the second strengthening steel (423), and the steel strand access port (5) form a steel strand (3) guide channel. The end of the steel strand (3) passes through the steel strand (3) guide channel and is fixed inside the upper chord beam (1) by an anchor (6).

7. The high nodal stiffness adaptive prestressed fish-belly beam structure according to claim 6, characterized in that, A second stiffening rib (426) is provided at the junction of the guide groove on one side of the upper chord beam (1) and the second guide groove (4231) on the side of the second reinforcing steel (423) perpendicular to the upper chord beam (1). One side of the second stiffening rib (426) is fixed on the upper chord beam (1), and the other side is fixed on the second reinforcing steel (423) perpendicular to the upper chord beam (1). The second stiffening rib (426) concentrates the force at the anchoring position of the upper chord beam (1) and distributes it to the second reinforcing plate (424), the second reinforcing steel (423) and the steel frame (41).

8. A method for applying prestress based on a high-nodal-stiffness adaptive prestressed fish-belly beam structure, using the high-nodal-stiffness adaptive prestressed fish-belly beam structure according to any one of claims 2 to 7, comprising the following steps: S1. First, adjust the locking bolts between the sliding sleeve and the straight web rod to unlock the straight web rod from the sliding sleeve, allowing the straight web rod to move up and down along the sliding sleeve. S2. Start the hydraulic lifting device. The hydraulic lifting device drives the straight web bar to rise, apply force to the steel strand, open the prestressing tendons, and increase the prestress to reach the prestress design value. S3. The prestress applied to the central support frame assembly is transferred to the support frame assemblies on both sides through the steel strands, and is evenly distributed to the support frame assemblies on both sides. S4. Each set of support frame components reacts to the upper chord beam to adjust the prestress. After the adjustment is completed, tighten the locking bolts on both sides of the sliding sleeve to fix the straight web member. S5. Repeat the above process to achieve the adjustment of prestress adaptability under different working conditions.

Images