Small-radius curve conjoined U-shaped beam for magnetic suspension

Abstract

The utility model discloses a small radius curve conjoined U-shaped beam for magnetic suspension, which comprises a beam body and a prestressing tendon arranged in the beam body, the beam body comprises a bottom plate, a middle web plate and side web plates, the middle web plate is arranged in the middle of the bottom plate, the side web plates are arranged on two transverse sides of the bottom plate, and the middle web plate is arranged in the middle of the bottom plate. The prestressing tendons comprise top plate tendons, web plate tendons and bottom plate tendons, the top plate tendons are located in the upper flanges of the side web plates and the middle web plates, the web plate tendons are located in the side web plates, and the bottom plate tendons are located in the bottom plate. According to the small-radius curve conjoined U-shaped beam, the number and indexes of adopted prestressing tendons are greatly reduced, prestress arrangement is reasonable, meanwhile, transverse prestress steel cables do not need to be arranged, the characteristic that loads are approximately evenly distributed on a magnetic suspension line is attached, the overall dead weight is small, the construction period is short, and the engineering cost is low.

Description

Technical Field

[0001] The utility model belongs to the field of magnetic levitation, and in particular relates to a magnetic levitation beam. Background Art

[0002] With the development of bridge construction, more and more elevated track forms have emerged. The structural forms of conventional elevated bridges mainly include box beams, T beams, plate beams, etc.

[0003] Due to their significant advantages in aesthetics, noise reduction, and low building height, U-shaped beams have become increasingly popular in urban rail transit projects (such as light rail and maglev). When used in maglev, two parallel U-beams are typically deployed to meet the requirements of both upstream and downstream lines. This often results in excessive prestressing tendons, which increases construction steps and project costs. Furthermore, due to the complex urban terrain and road conditions, U-shaped beams are often used in maglev applications. To leverage the maglev's advantages in curved and gradeable terrain, small-radius curves are required to navigate certain areas, leading to significant dynamic response issues for the maglev vehicle-track system. Furthermore, radial forces induced by prestressing can cause additional torque and bending moments in beams with small-radius curves. The extent of these torques and bending moments is influenced by factors such as the number, location, layout, and prestressing stress of the prestressing tendons, leading to bridge defects during maglev operations. Utility Model Content

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide a small-radius curved connected U-shaped beam for magnetic levitation with simple construction, low engineering cost and reasonable prestressed bundle arrangement.

[0005] In order to solve the above technical problems, the technical solutions proposed by the present invention are as follows:

[0006] A small-radius curved connected U-shaped beam for magnetic levitation includes a beam body and a prestressed beam arranged in the beam body. The beam body includes a bottom plate, a middle web and side webs. The middle web is arranged in the middle of the bottom plate, and the side webs are arranged on both lateral sides of the bottom plate. The prestressed beam includes a top plate beam, a web beam and a bottom plate beam. The top plate beam is located in the upper flanges of the side webs and the middle web, the web beam is located in the side webs, and the bottom plate beam is located in the bottom plate.

[0007] In the above-mentioned small-radius curved connected U-shaped beam, preferably, the top plate bundle is a top plate prestressed tendon, and a plurality of the top plate prestressed tendons are arranged in parallel in the upper flanges of the side webs and the middle webs.

[0008] In the above-mentioned small-radius curved connected U-shaped beam, preferably, the bottom plate bundle includes edge prestressed tendons arranged on both sides of the bottom plate and middle prestressed tendons arranged in the middle of the bottom, the edge prestressed tendons are arranged close to the side webs, and the middle prestressed tendons are located below the middle webs, and multiple edge prestressed tendons and middle prestressed tendons are arranged in parallel.

[0009] In the above-mentioned small-radius curved connected U-shaped beam, preferably, the number of the middle prestressed tendons is greater than the number of the edge prestressed tendons.

[0010] In the above-mentioned small-radius curved connected U-shaped beam, preferably, the web beam is a web prestressed tendon arranged in a broken line shape, with a high point and a low point, the high point is connected to the top plate beam, and the low point is connected to the edge prestressed tendon.

[0011] In this utility model, our research shows that the dynamic response of the maglev vehicle-track system on small-radius curves is significantly affected. Furthermore, when the traditional prestressing method of U-beams is used for conjoined U-beams on small-radius curves, additional torque and bending moment will be generated. This utility model proposes a conjoined U-beam on a small-radius curve and optimizes the layout of the prestressed tendons, which can effectively control the overall bending and torsional deformation and vibration response increment of the bridge. By increasing the number of central prestressed tendons compared to the number of edge prestressed tendons, the larger number of central prestressed tendons can reduce the web overload effect and overcome the problem of the transverse component of force generated when tensioning the longitudinal tendons in conjoined U-beams on small-radius curves, which can easily cause cracks in the web concrete. This layout is more suitable for conjoined U-beams on small-radius curves. Furthermore, compared to traditional U-beams, the utility model appropriately thickens the web to meet the flat bending and anchoring requirements of the web tendons, and minimizes the web tendons, leaving sufficient clearance to prevent concrete crushing.

[0012] In the above-mentioned small radius curved conjoined U-shaped beam, preferably, the beam body is formed in one piece using high performance concrete, the number of spans of each unit of the small radius curved conjoined U-shaped beam is (2-4) × 25m, the curve radius R (inner curve radius R) is not less than 75m, and the top plate bundle, web plate bundle and bottom plate bundle all use low relaxation steel strands, and the index of low relaxation steel strands is 21.4kg / m 3 The top plate beam adopts 7 beams 9-φ s 15.2mm low relaxation steel strand, the web beam uses 6 bundles of 12-φ s 15.2mm low relaxation steel strand, the bottom plate bundle uses 15 bundles of 12-φ s 15.2mm low relaxation steel strand.

[0013] The small radius curved U-shaped beam of this utility model is considered as a fully prestressed component, and tensile stress is not allowed. The physical and chemical properties of the material will directly affect the performance of the U-shaped beam structure. Considering the bearing capacity and rigidity of the bridge, this utility model is made of high-performance concrete. The high-performance concrete is C50 concrete, and the beam concrete is mixed with polypropylene fiber at a dosage of 0.9kg / m 3 The main beam is made of high-performance concrete, and the beam concrete is mixed with polypropylene fiber, which significantly improves the performance and safety of the bridge. It is suitable for small-radius curve sections and also increases the life and reliability of the bridge.

[0014] The steel strands of the U-shaped beam of the utility model adopt φ s 15.2mm low relaxation steel strand, tensile strength standard value f pk =1860MPa, elastic modulus E P =1.95×10 5 MPa. For the case where the span number of each U-shaped beam with a small radius curve is (2-4) × 25m and the curve radius R is not less than 75m, a total of 28 bundles of low relaxation steel strands are used, and the index of low relaxation steel strands is 21.4kg / m 3 Compared with the conventional U-beam structure, the number and index of low relaxation steel strands are greatly reduced. Among them, the top plate beam adopts 7 bundles of 9-φ s 15.2mm low relaxation steel strand, web beams are 6 bundles of 12-φ s 15.2mm low relaxation steel strand, bottom plate bundle uses 15 bundles of 12-φ s 15.2mm low-relaxation steel strand. The layout principle of low-relaxation steel strand is to avoid embedded parts such as supports and anti-fall beam blocks.

[0015] In the above-mentioned small-radius curved connected U-shaped beam, preferably, a rail support platform is provided on the bottom plate between the side web and the middle web, and a drainage hole and an emergency drainage port are respectively provided on both sides of the rail support platform.

[0016] In the above-mentioned small-radius curved connected U-shaped beam, preferably, a waterproof layer is provided on the bottom plate, and a waterproof layer extending from the bottom plate to the side of the rail support platform is provided at the junction of the bottom plate and the rail support platform, and a concrete slope layer is provided below the waterproof layer. The waterproof layer includes a sealing paint layer, a waterproof primer layer and a waterproof topcoat layer from bottom to top; the total thickness of the waterproof layer is not less than 600μm and not more than 800μm, the dry film thickness of the waterproof primer layer is not less than 400μm, and the dry film thickness of the waterproof topcoat layer is not less than 200μm.

[0017] In this utility model, the waterproof layer consists of a sealer layer, a waterproof primer layer, and a waterproof topcoat layer. The sealer layer is formed with sealer, the waterproof primer layer is formed with a thin-coat polyurethane waterproof primer (PPU-M1), and the waterproof topcoat layer is formed with a thin-coat polyurethane waterproof topcoat (PPU-M2). The total thickness of the waterproof layer should be no less than 600μm and no more than 800μm. The dry film thickness of the primer layer should be no less than 400μm, and the dry film thickness of the topcoat layer should be no less than 200μm. The construction process is as follows: setting the drainage slope → base surface preparation → application of the sealer layer → application of the primer (PPU-M1) → application of the topcoat (PPU-M2). In addition to a 2% transverse drainage slope for the beam, when centralized drainage is required, beams located on the flat slope of the line should also have a longitudinal drainage slope of no less than 2‰, depending on the location of the centralized drainage pipe. The centralized drainage pipe should be located on the downslope side of the beam, with a total of eight centralized drainage pipes per U-beam. When a U-beam is located on the longitudinal slope of a line, drainage can be utilized. A centralized drainage pipe is installed at one end of the beam on the downslope side, with a total of four centralized drainage pipes per U-beam. The drainage slope is designed using structural sloping and is set during beam fabrication. After sloping, the bottom plate thickness must not be less than the original design structural dimensions. Four emergency drainage pipes are also installed near the centralized drainage pipe for emergency use.

[0018] The utility model can increase the height of the rail support platform, and the height from the rail surface to the bottom surface of the rail support platform is controlled to be above 1.1m, ensuring that the train pedal position is higher than the top of the upper flange of the small radius curved connected U-shaped beam.

[0019] The present invention also provides a construction method for the above-mentioned small-radius curved connected U-shaped beam. At the construction site of the small-radius curved connected U-shaped beam, the pre-tensioning method is adopted, and a tensioning process of single-beam initial adjustment, overall initial tensioning, and single-beam final tensioning is adopted. The over-tensioning coefficient is adjusted in combination with the upper arch value of the small-radius curved connected U-shaped beam after tensioning, and the tensioning force value of a single prestressed tendon is controlled individually.

[0020] This construction method utilizes a pre-tensioning method, employing a "single-beam initial adjustment, overall initial tensioning, and single-beam final tensioning" tensioning process. A "dual-control" control method and intelligent tensioning system ensure synchronized prestressing of the tendons. Combined with the over-tensioning coefficient adjusted for the camber value of the small-radius curved U-shaped beam after tensioning, this effectively controls the tension of individual tendons. A rational prestressing sequence minimizes prestress loss. Prestressed tendons and piping are adjusted based on slope, using the beam's symmetrical centerline as a baseline. When adjusting the tendons and piping at the beam end corners, first ensure that the dimensions from each bend starting point and anchorage point to the beam end boundary meet the designed prestressed tendon dimensions. Then, the horizontal sections of the tendons and piping are adjusted accordingly. The beam reinforcement is tied integrally, starting with the bottom plate and web reinforcement, followed by the top plate reinforcement. If the beam reinforcement collides with the prestressed tendons, the beam reinforcement can be appropriately moved or bent. The minimum protective layer for beam reinforcement is 35mm, and the tail end of the binding wire should not extend into the protective layer. Ring-shaped reinforcement is added to all pre-reserved holes in the beam. Reinforcement at drain holes can be appropriately moved and reinforced with spiral reinforcement and angled crisscross bars.

[0021] To ensure structural safety and stability, traditional large U-shaped beams require a high number of prestressed tendons and a high number of prestressed tendons. Beams with a wider transverse width generally require additional transverse prestressed tendons, increasing costs and construction time. However, the actively controlled levitation force of maglev lines is significantly different from the wheel-rail contact force, resulting in significant differences in the dynamic interaction mechanism and behavior between the maglev vehicle and the U-shaped beam compared to the wheel-rail system. This utility model proposes a new, one-piece U-shaped beam with an optimized prestressed tendon layout and tensioning method that aligns with the nearly uniformly distributed load characteristics of the maglev vehicle's suspended state. This eliminates the need for transverse prestressed tendons and allows for application on small-radius curves.

[0022] This new prestressing arrangement for conjoined U-shaped beams significantly reduces or even eliminates the need for prestressing beams compared to traditional large U-shaped beams, thus reducing construction steps and project costs. Furthermore, this optimized prestressing arrangement significantly addresses the dynamic response issues of the maglev vehicle-track system, avoiding excessive torque and bending moments and minimizing bridge damage. The utility model optimizes the arrangement of prestressed tendons, matches the steel strands with the connected U-shaped beams, greatly reduces the number and indicators of the steel strands used, and reduces the construction cost; at the same time, excessive prestressing will have a significant impact on the vehicle-bridge coupled vibration of the maglev line. The utility model effectively reduces the incremental vertical vibration response of the vehicle-bridge coupled maglev line, including the acceleration of the bridge and the displacement of the maglev vehicle suspension frame, by independently controlling the final tensioning force value of each prestressed tendon; moreover, cracks in U-shaped beams usually occur at the junction of the bottom plate and the web. This transition area is prone to stress concentration and is subject to bending and torsion. The connected U-shaped beams of the utility model set prestressed tendons on both sides and the middle of the bottom plate below the web, and the prestressed tendons in the middle are more than those on both sides, which effectively improves the durability of the bridge.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] 1. The small-radius curved conjoined U-shaped beam of this utility model has a simple structure, smooth curves, and a good overall visual effect. The side webs on both sides of the U-shaped beam section can act like a sound barrier, which can reduce the impact of vehicle noise on the surrounding environment to a certain extent. The side webs on both sides of the U-shaped beam can prevent derailed vehicles from overturning and falling, providing a reliable guarantee for driving safety. The U-shaped beam has a small width and height, ensuring the clearance under the bridge and a low overall deadweight. The addition of a middle web in the middle of the U-shaped beam improves its overall load-bearing performance and is suitable for a larger span. Overall, the load-bearing performance of this U-shaped beam structure meets the design specification requirements and has good mechanical properties and landscape effects.

[0025] 2. The small-radius curved connected U-shaped beam of the utility model uses a greatly reduced number and index of prestressed bundles, and the prestressing arrangement is reasonable. At the same time, there is no need to set up transverse prestressed steel cables, which conforms to the characteristics of the nearly uniformly distributed load of the magnetic levitation line. The overall dead weight is small, the construction period is short, and the project cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1It is a three-dimensional diagram of the small-radius curved connected U-shaped beam of the present invention.

[0028] Figure 2 This is a structural schematic diagram of the small-radius curved connected U-shaped beam of the present invention.

[0029] Figure 3 This is the elevational layout of the prestressed tendons of the small-radius curved connected U-shaped beam of the utility model (pre-tensioning method).

[0030] Figure 4 This is a cross-sectional arrangement diagram of the prestressed tendons of the small-radius curved connected U-shaped beam of the utility model (pre-tensioning method).

[0031] Figure 5 This is a schematic diagram of the waterproof layer system of the small-radius curved connected U-shaped beam of the utility model.

[0032] Figure 6 This is a schematic diagram of the waterproof layer structure of the small-radius curved connected U-shaped beam of the utility model.

[0033] Legend

[0034] 1. Side web; 2. Middle web; 3. Bottom plate; 4. Upper flange; 6. Rail support; 7. Top plate bundle; 8. Web bundle; 9. Bottom plate bundle; 10. Web steel bundle variation curve; 12. Waterproof layer; 121. Waterproof topcoat layer; 122. Waterproof primer layer; 123. Sealing paint layer; 13. Drain hole; 14. Emergency drain outlet; 15. Concrete grade layer. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the present invention, the present invention will be described in more comprehensive and detailed manner below in conjunction with the accompanying drawings and preferred embodiments of the specification, but the protection scope of the present invention is not limited to the following specific embodiments.

[0036] It should be noted that when an element is described as being "fixed, fixed, connected or communicated with" another element, it can be directly fixed, fixed, connected or communicated with the other element, or it can be indirectly fixed, fixed, connected or communicated with the other element through other intermediate connectors.

[0037] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0038] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0039] Example:

[0040] like Figures 1-4 As shown, the small-radius curved connected U-shaped beam for magnetic levitation in this embodiment includes a beam body and a prestressed beam arranged in the beam body. The beam body includes a bottom plate 3, a middle web 2 and a side web 1. The middle web 2 is arranged in the middle of the bottom plate 3, and the side web 1 is arranged on both sides of the bottom plate 3. The prestressed beam includes a top plate beam 7, a web beam 8 and a bottom plate beam 9. The top plate beam 7 is located in the upper flange 4 of the side web 1 and the middle web 2, the web beam 8 is located in the side web 1, and the bottom plate beam 9 is located in the bottom plate 3.

[0041] Specifically, in this embodiment, the top plate bundle 7 is a top plate prestressed rib, and multiple top plate prestressed ribs are arranged in parallel in the upper flanges 4 of the side webs 1 and the middle webs 2. The bottom plate bundle 9 includes edge prestressed ribs arranged on both sides of the bottom plate 3 and middle prestressed ribs arranged in the middle of the bottom. The edge prestressed ribs are arranged close to the side webs 1, and the middle prestressed ribs are located below the middle webs 2. Multiple edge prestressed ribs and middle prestressed ribs are arranged in parallel. The number of middle prestressed ribs is greater than the number of edge prestressed ribs. The web bundle 8 is a web prestressed rib arranged in a broken line shape, with a high point and a low point. The high point is connected to the top plate bundle 7, and the low point is connected to the edge prestressed ribs. For details, please refer to Figure 3 Web steel tendon variation curve 10.

[0042] More specifically, Figure 4 As shown, in this embodiment, the number of spans of each U-shaped beam with a small radius curve × span is (2-4) × 25m, the inner curve radius R is 100m, and a total of 28 low-relaxation steel strands are used. The top plate strand 7, the web strand 8, and the bottom plate strand 9 all use low-relaxation steel strands. The index of the low-relaxation steel strand is 21.4kg / m 3 , the top plate beam 7 adopts 7 beams 9-φ s 15.2mm low relaxation steel strand, web bundle 8 uses 6 bundles of 12-φ s 15.2mm low relaxation steel strand, bottom plate bundle 9 uses 15 bundles of 12-φ s 15.2mm low relaxation steel strand.

[0043] In this embodiment, the beam body is formed in one piece using high-performance concrete. The high-performance concrete uses C50 concrete, and the beam body concrete is mixed with polypropylene fiber at a mixing rate of 0.9 kg / m 3 .

[0044] like Figure 5 、 Figure 6 As shown, in this embodiment, a rail support platform 6 is provided on the bottom plate 3 between the side web 1 and the middle web 2, and a drainage hole 13 and an emergency drainage port 14 are provided on both sides of the rail support platform 6 on the bottom plate 3.

[0045] In this embodiment, a waterproof layer 12 is provided on the base plate 3, and a waterproof layer 12 is provided at the junction of the base plate 3 and the rail support platform 6, extending from the base plate 3 to the side of the rail support platform 6. A concrete slope layer 15 is provided below the waterproof layer 12. The waterproof layer 12 includes a sealing paint layer 123, a waterproof primer layer 122 and a waterproof topcoat layer 121 from bottom to top; the total thickness of the waterproof layer 12 is not less than 600 μm and not more than 800 μm, the dry film thickness of the waterproof primer layer 122 is not less than 400 μm, and the dry film thickness of the waterproof topcoat layer 121 is not less than 200 μm.

[0046] This embodiment also provides a construction method for the above-mentioned small-radius curved connected U-shaped beam. At the construction site of the small-radius curved connected U-shaped beam, the pre-tensioning method is adopted, and the tensioning process of single-bundle initial adjustment, overall initial tensioning, and single-bundle final tensioning is adopted. The over-tensioning coefficient is adjusted in combination with the arch value of the small-radius curved connected U-shaped beam after tensioning, and the tensioning force value of a single prestressed tendon is controlled individually.

[0047] In a certain project in a certain area, a continuous beam bridge with a span of 3 × 25m is used. It has a small radius (the inner curve radius R is 100m, such as Figure 1 The continuous beam (shown in the figure) utilizes the aforementioned small-radius curved U-shaped beam. Each span of the U-beam has a total length of 24.9m, a calculated span of 24.1m, a standard section beam height of 1.8m, a top width of 10.2m, a bottom width of 8.78m, side web 1 thickness of 0.4m, and center web 2 thickness of 0.6m. The beam is arranged along the centerline of the right line of the work site design, and the corresponding beam outlines are all expanded dimensions along the centerline of the right line of the line. The arrangement of the prestressed tendons is as follows: Figure 4 As shown, a total of 28 low-relaxation steel strands are used. The top plate strand 7, web plate strand 8 and bottom plate strand 9 all use low-relaxation steel strands. The index of low-relaxation steel strands is 21.4 kg / m 3 , the top plate beam 7 adopts 7 beams 9-φ s 15.2mm low relaxation steel strand, web bundle 8 uses 6 bundles of 12-φ s 15.2mm low relaxation steel strand, bottom plate bundle 9 uses 15 bundles of 12-φ s The 15.2mm low-relaxation steel strands have a tensioning control stress of 72% of the standard value of the ultimate strength of the prestressed tendons, specifically 1339.2MPa. The number and indicators of the steel strands are significantly lower than those used in traditional U-beams.

[0048] After calculation and analysis, under the static and live loads of the small-radius curve working condition of the magnetic levitation, the maximum vertical displacement of the U-shaped beam in the mid-span is 3.829mm, and the deflection-span ratio is 1 / 6294.1, which is less than 1 / 4600; the vertical rotation angle at the beam end is 0.457‰rad, which is less than 1‰rad; the first-order vertical bending natural frequency n0=5.053>64 / L=2.66Hz, and the load-bearing performance can meet the requirements of the design specifications while having good economic efficiency.

Claims

1. A small radius curved U-shaped beam for magnetic levitation, characterized in that: The invention comprises a beam body and a prestressed beam arranged in the beam body, wherein the beam body comprises a bottom plate (3), a middle web plate (2) and an edge web plate (1), wherein the middle web plate (2) is arranged in the middle of the bottom plate (3), and the edge web plates (1) are arranged on both lateral sides of the bottom plate (3), and the prestressed beam comprises a top plate beam (7), a web beam (8) and a bottom plate beam (9), wherein the top plate beam (7) is located in the upper flanges (4) of the edge web plates (1) and the middle web plates (2), the web beam (8) is located in the edge web plates (1), and the bottom plate beam (9) is located in the bottom plate (3).

2. The small radius curved conjoined U-shaped beam according to claim 1, characterized in that: The top plate bundle (7) is a top plate prestressed tendon, and a plurality of the top plate prestressed tendons are arranged in parallel in the upper flanges (4) of the side webs (1) and the middle webs (2).

3. The small radius curved conjoined U-shaped beam according to claim 1, characterized in that: The bottom plate bundle (9) includes edge prestressed tendons arranged on both sides of the bottom plate (3) and middle prestressed tendons arranged in the middle of the bottom, the edge prestressed tendons are arranged close to the side web (1), and the middle prestressed tendons are located below the middle web (2), and multiple edge prestressed tendons and multiple middle prestressed tendons are arranged in parallel.

4. The small radius curved conjoined U-shaped beam according to claim 3, characterized in that: The number of the middle prestressed tendons is greater than the number of the edge prestressed tendons.

5. The small radius curved connected U-shaped beam according to claim 3, characterized in that: The web bundle (8) is a web prestressed tendon arranged in a broken line shape, and is provided with a high point and a low point, wherein the high point is connected to the top plate bundle (7), and the low point is connected to the edge prestressed tendon.

6. The small radius curved connected U-shaped beam according to any one of claims 1 to 5, characterized in that: A rail support platform (6) is provided on the bottom plate (3) between the side web (1) and the middle web (2), and a drain hole (13) and an emergency drain port (14) are provided on both sides of the rail support platform (6) on the bottom plate (3).

7. The small radius curved conjoined U-shaped beam according to claim 6, characterized in that: A waterproof layer (12) is provided on the bottom plate (3), and a waterproof layer (12) is provided at the junction of the bottom plate (3) and the rail support platform (6), extending from the bottom plate (3) to the side of the rail support platform (6). A concrete slope leveling layer (15) is provided below the waterproof layer (12), and the waterproof layer (12) includes, from bottom to top, a sealing paint layer (123), a waterproof primer layer (122), and a waterproof topcoat layer (121).

8. The small radius curved connected U-shaped beam according to claim 7, characterized in that: The total thickness of the waterproof layer (12) is not less than 600 μm and not more than 800 μm, the dry film thickness of the waterproof primer layer (122) is not less than 400 μm, and the dry film thickness of the waterproof topcoat layer (121) is not less than 200 μm.

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