A vibration-reducing and noise-reducing U-shaped beam for urban rail transit elevated

Abstract

The present invention discloses a vibration-damping and noise-reducing U-shaped beam for elevated urban rail transit. The U-shaped beam is composed of a bottom plate, a first web located on one side of the bottom plate, a second web located on the other side of the bottom, a first web upper flange located on the top of the first web, and a second web upper flange located on the top of the second web, forming a U-shaped cross-sectional structure. The first webs of the two U-shaped beams are arranged adjacent to each other, and are characterized in that the first web and the second web are both thickened structures, and the thickness gradually increases from top to bottom. The inner side and outer side of the first web are non-concentric circular curves, the inner side and outer side of the second web are non-concentric circular curves, the first web upper flange is F-shaped, and the second web upper flange is T-shaped. The bottom plate and web form of the present invention can significantly reduce the vibration and noise of the U-shaped beam, improve the durability of the bolts of auxiliary components such as sound barriers and contact networks installed on the U-beam, and reduce the workload of operation and maintenance.

Description

Technical Field

[0001] The invention relates to a novel urban rail transit viaduct bridge for supporting a track structure and auxiliary facilities, in particular to a vibration-reducing and noise-reducing U-shaped beam for an urban rail transit viaduct. Background Art

[0002] Urban rail transit viaducts serve as supporting structures for rail lines and ancillary facilities. The cross-sections include box sections, T sections, and U sections. Among them, the box section and T section are top-bearing structures. The rail lines and ancillary facilities are located above the bridge section. The disadvantage is that the structure under the track is high, and the train is easy to run out of the bridge after derailment. The U-shaped beam is a bottom-bearing structure. The track structure is located on the bottom plate, and the bottom plate, the webs on both sides, and the top of the webs are all laid with ancillary facilities. The height of the elevated structure under the track is small, and the clearance requirements are low when crossing roads, rivers, and buildings; the webs on both sides can shield the wheel-rail noise, and the webs on both sides can prevent the train from falling after the train derails. The above advantages make the U-shaped beam have broad application prospects in urban rail transit viaducts.

[0003] The prior art generally has the following problems:

[0004] (1) The vibration characteristics of open thin-walled components have not been fully taken into account. The U-beams of existing projects are currently in operation, and the vibration effect of the beams is obvious, which makes the bolts of auxiliary components such as sound barriers and contact lines installed on the U-beams easy to fall off, increasing the workload of operation and maintenance. At the same time, the noise generated by the self-vibration of the beam structure is more obvious than that of general box beams.

[0005] (2) In order to facilitate the template production of the U-shaped beam and the arrangement of the prestressing of the bottom plate, the U-shaped beam is generally in the form of a straight line instead of a curve. The single-span track beam structure is a straight beam, and the track structure on the beam is laid according to the actual curve. In addition to being a load-bearing component, the inner upper flange of the U-shaped beam also serves as an emergency evacuation platform. The upper flanges of the known patents and the built U-shaped beams are all "T-shaped" or "7-shaped". In the curved section, the change in the elevation of the line plane curve makes the distance between the center of the line and the upper flange a variable value, and the minimum value must meet the limit requirements. At the maximum elevation, there is a large gap between the door and the evacuation platform when the train stops in an emergency, which exceeds the allowable value in the specification and affects the evacuation safety of passengers.

[0006] (3) The inner web of the patent with publication number CN 100585081C and the double-sided web of the patent with publication number CN 101120140A are of equal thickness and no armpit is provided on the inner side of the connection between the web and the bottom plate. The above-mentioned structural form is not conducive to the force transmission connection between the web and the bottom plate. Since the U-shaped beam is a spatial thin-walled structure, the connection between the bottom plate and the web is a key force-bearing part and should be strengthened.

[0007] (4) The U-shaped beams in the known patent and the existing ones are both ordinary reinforced concrete structures in the transverse direction without prestressing. As a result, the bottom plate is in a cracked working state in the transverse direction under the rail transit operation load, affecting the durability of the structure.

[0008] (5) The patent with publication number CN 100585081C requires that the track support platform and the beam body be cast in one go. There are three disadvantages: ① On the same line, due to different environmental protection requirements for each section, different types of track fasteners will be used, and the corresponding requirements for the size of the track support platform will also be different. The known U-shaped beam is not conducive to the unification of the template of the prefabricated beam. ② Casting the track support platform and the beam body in one go will result in a heavy prefabricated beam, which is not convenient for transportation and lifting. ③ In the one-time casting method, the manufacturing error of the track beam, the later shrinkage creep deformation and the installation error of the beam body will increase the difficulty of installing the track in the later stage.

[0009] The existing U-shaped beams have obvious disadvantages of vibration and noise, which limits the promotion and application of U-shaped beams. The present invention provides a vibration-reducing and noise-reducing U-shaped beam, which effectively solves the vibration and noise problems and improves evacuation safety and structural durability. Summary of the invention

[0010] The purpose of the present invention is to provide a vibration-reducing and noise-reducing U-shaped beam for elevated urban rail transit, which can effectively reduce the vibration and noise of the U-shaped beam, solve the problem of excessive gap between the evacuation platform and the door, ensure the safety of passenger evacuation in emergency situations, and at the same time increase the stiffness of the compressed upper flange to avoid the upper flange from being compressed and unstable and damaged. Improve the force transmission connection between the web and the bottom plate, solve the problem of cracking of the bottom plate of the U-shaped beam, and improve the durability of the structure. The beam body and the rail support platform are cast in two times, which simplifies the template varieties of prefabricated beams, reduces the weight of transportation and hoisting, and facilitates construction.

[0011] In order to achieve the above-mentioned purpose, the technical scheme of the present invention is as follows: A vibration-damping and noise-reducing U-shaped beam for urban rail transit elevated roads, comprising two U-shaped beams arranged side by side, the U-shaped beam consisting of a bottom plate, a first web located on one side of the bottom plate, a second web located on the other side of the bottom, a first web upper flange located on the top of the first web, and a second web upper flange located on the top of the second web to form a U-shaped cross-sectional structure, the first webs of the two U-shaped beams are adjacent to each other, and a post-cast rail supporting platform is arranged on the top of the bottom plate, characterized in that the first web and the second web are both thickened structures, and the thickness gradually increases from top to bottom, the inner side surface and the outer side surface of the first web are non-concentric circular curves, the inner side surface and the outer side surface of the second web are non-concentric circular curves, the upper flange of the first web is F-shaped, and the upper flange of the second web is T-shaped.

[0012] Furthermore, a first arm is provided at the junction of the inner side of the first web and the bottom plate, and a second arm is provided at the junction of the inner side of the second web and the bottom plate, so as to strengthen the boundary support conditions of the bottom plate and the web and improve the force transmission connection between the web and the bottom plate. The rigidity of the bottom plate can be further enhanced and the vibration and noise of the beam body can be reduced.

[0013] Furthermore, the thickness of the upper portion of the first web is 0.24-0.27 m, and the thickness of the lower portion is 0.26-0.32 m; the thickness of the upper portion of the second web is 0.24-0.27 m, and the thickness of the lower portion is 0.26-0.32 m.

[0014] Furthermore, the bottom plate adopts a uniform thickness plate with a thickness of 0.26~0.3m.

[0015] Furthermore, the top of the flange on the first web also serves as an evacuation platform, and a widened section is provided on the top of the evacuation platform. The width of the widened section in the straight section of the U-shaped beam is a fixed value, and the width in the curved section of the U-shaped beam is a variable value, so as to adapt to the change of the sagittal height of the flat curve and control the distance between the door edge and the evacuation platform within a safe value range when the train runs on the curve. The straight section of the U-shaped beam and the straight section and curved section of the U-shaped beam here refer to the straight section and curved section along the length direction of the U-shaped beam.

[0016] Furthermore, a space for arranging pipelines is reserved below the upper flange of the first web.

[0017] Furthermore, the width of the upper flange on the second web is 0.65~0.8m, which meets the size requirements for setting up sound barriers or contact network columns. The width of the upper flange on the first web is 0.5~0.65m to reduce the total width of the structure when two lines are parallel.

[0018] Furthermore, small-radius annular post-tensioned prestressed steel strands are arranged in the transverse direction of the web and the bottom plate, and the steel strands are evenly arranged along the length of the beam.

[0019] Furthermore, a low-voltage cable bracket is installed on the inner side of the first web, a high-voltage cable bracket is installed on the inner side of the second web, a sound barrier or contact network column, a power maintenance box and a distribution box are installed on the upper flange of the second web, and a public security leakage cable is installed below the flange of the first web.

[0020] The U-shaped beam of the present invention has the following technical characteristics:

[0021] 1) The use of the bottom plate and web form of the present invention can significantly reduce the vibration and noise of the U-beam, improve the durability of the bolts of the auxiliary components such as the sound barrier and contact network installed on the U-beam, and reduce the workload of operation and maintenance. The non-concentric circular curves are used on both sides of the web, which facilitates the template production while realizing the gradual thickening of the web from top to bottom. The addition of the haunches at the junction of the inner side of the web and the bottom plate has a significant effect on improving the force transmission connection between the web and the bottom plate of the U-beam. The bottom plate adopts a plate of equal thickness, which can give full play to the bending resistance of the bottom plate concrete and facilitate the template production.

[0022] 2) The first web adopts an F-shaped upper flange. The widened platform at the top of the F-shape controls the gap between the door and the evacuation platform after the train stops in an emergency. Space for pipeline layout is reserved below. Ensure that the gap between the door and the evacuation platform is controlled within a safe range in both straight and curved sections to ensure the safety of passenger evacuation. The widened platform also increases the stiffness of the compressed upper flange to avoid instability under compression.

[0023] 3) Post-tensioned annular prestressed steel bars are installed inside the U-shaped beam, so that no cracks appear in the transverse direction of the bottom plate under the limit state of normal use, the durability of the bottom plate is significantly improved, and the web plate is longitudinally shear-resistant and transversely resistant to bending. The transverse bending bearing capacity of the bottom plate is greatly improved compared with the existing technology.

[0024] 4) After the beam of the prefabricated U-shaped beam is erected in place, the rail bearing platform is cast. Simplify the types of prefabricated beam templates, reduce the transportation and lifting weight of prefabricated beams, reduce the difficulty of track installation, and facilitate construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the U-shaped beam structure of the present invention.

[0026] Figure 2 Schematic diagram of the U-beam bridge deck layout when a sound barrier is installed.

[0027] Figure 3 Schematic diagram of U-beam bridge deck layout when contact network columns are erected.

[0028] Figure 4 Schematic diagram of the relationship between the arc radius and center of the U-shaped beam web.

[0029] The figure includes: the upper flange 1 of the first web, the first web 2, the upper flange 3 of the second web, the second web 4, the bottom plate 5, the rail support 6, the prestressed steel strand 7, the widened section of the evacuation platform 8, the weak-current cable support 9, the sound barrier 10, the public security leakage cable 11, the power maintenance box and the distribution box 12, the contact network column 13, the strong-current cable support 14, the first axil 15, and the second axil 16. DETAILED DESCRIPTION

[0030] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0031] The main contents of the present invention are as follows Figures 1 to 3As shown, a vibration-damping and noise-reducing U-shaped beam for elevated urban rail transit comprises two U-shaped beams arranged side by side, the U-shaped beam body comprising a U-shaped cross-section structure consisting of a bottom plate (bottom plate 5), webs on both sides (first web 2, second web 4) and upper flanges on the top of the webs (upper flange 1 on the first web, upper flange 3 on the second web) and an evacuation platform widening section 8, the first webs of the two U-shaped beams are arranged adjacent to each other, a circumferential prestressed steel bundle 7 is arranged inside the U-shaped beam, and a rail support platform 6 is arranged on the top of the bottom plate.

[0032] After the beam is erected in place, the rail support platform 6 is cast. The weak current cable bracket 9 is installed on the inner side of the inner web 2, the strong current cable bracket 14 is installed on the inner side of the outer web 4, the sound barrier 10, the power maintenance box and the distribution box 12, the contact network column 13 are installed on the flange 3 of the outer web, and the public security leaky cable 11 is installed under the extended platform 8.

[0033] The specific features of the present invention are as follows:

[0034] 1) The form of the bottom plate and the web is the key to vibration reduction and noise reduction. Through the research and analysis of vibration reduction and noise reduction of U-shaped beams, a new design method of U-shaped beams is proposed: improve the stiffness of the bottom plate, strengthen the support of the bottom plate boundary, and strengthen the stiffness of the bottom of the web. The specific features are as follows: ① The web layout abandons the conventional equal thickness form, and the curves on both sides of the web adopt non-concentric circle forms. They are all thickening structures, and the thickness gradually increases from top to bottom. The first curve Q1 and the second curve Q2 are non-concentric circular curves, and the third curve Q3 and the fourth curve Q4 are non-concentric circular curves. The curve elements of the inner web and the outer web are shown in the figure below. Figure 4As shown, for the convenience of construction and arc template processing, preferably, the radius R1 of the first curve Q1 is taken as the radius R3 of the third curve Q3 = 1.5m~1.8m, the radius R2 of the second curve Q2 is taken as the radius R4 of the fourth curve Q4 = R1+0.5m=R3+0.5m. By adjusting the relative positions of the center O1 of the first curve Q1 and the center O2 of the second curve Q2, the center O3 of the third curve Q3 and the center O4 of the fourth curve Q4, the thickness B of the upper part of the first web is 0.24~0.27m, and the thickness C of the lower part is 0.26~0.32m; the thickness D of the upper part of the second web is 0.24~0.27m, and the thickness E of the lower part is 0.26~0.32m. Thereby, the thickness of the web is uniformly changed along the height direction, and the vibration and noise of the U-beam are significantly reduced while increasing the strength of the web. ② In order to improve the rigidity of the bottom plate, give full play to the bending resistance of the bottom plate concrete and facilitate the production of formwork, the bottom plate adopts equal thickness plate with thickness F=0.26~0.3m. ③ Strengthen the boundary support conditions of the bottom plate and the web plate, improve the force transmission connection between the web plate and the bottom plate, and set the first armpit 15 and the second armpit 16 at the junction of the inner side of the web plate and the bottom plate. Under the condition of the same amount of concrete, the above method can significantly improve the rigidity of open thin-walled components, reduce the vibration and noise of U-beams, improve the durability of bolts of auxiliary components such as sound barriers and contact networks installed on U-beams, and reduce the workload of operation and maintenance. This feature is crucial for the promotion and application of U-beams.

[0035] 2) In order to avoid transverse cracks in the bottom plate and improve the shear bearing capacity of the web plate, a small radius annular post-tensioning prestressed steel strand 7 is set in the transverse direction of the web plate and the bottom plate. The steel strands are evenly arranged along the length of the beam to apply uniform transverse prestress to the bottom plate and the web plate. By reasonably setting the prestress, the bottom plate 5 will not have transverse cracks under the normal use limit state, the durability of the bottom plate is significantly improved, and the web plate is longitudinally shear-resistant and transversely resistant to bending. The transverse bending bearing capacity of the bottom plate is greatly improved compared with the existing U-shaped beam.

[0036] 3) The flange 1 on the first web adopts an F-shaped structure, and the top also serves as an evacuation platform. A widened section 8 of the evacuation platform is set on the top of the evacuation platform. The width of the straight section is a fixed value, and the width of the curved section is a variable value to adapt to the change of the sagittal height of the flat curve, and control the distance between the door edge and the evacuation platform within the safe value range when the train runs on the curve, so as to ensure the safety of passenger evacuation. The widened platform also plays a role in increasing the stiffness of the compressed upper flange to avoid instability under compression.

[0037] 4) Upper flanges are provided on the upper parts of the first web and the second web. The upper flange 3 on the second web is wider (width 0.65~0.8m), which meets the size requirements for setting up sound barriers or contact network columns. The upper flange 1 on the first web is narrower (width 0.5~0.65m) to reduce the total width of the structure when double lines are parallel.

[0038] 5) After the beam body of the prefabricated U-shaped beam is erected in place, the rail support platform 6 is cast.

Claims

1. A vibration-reducing and noise-reducing U-shaped beam for elevated urban rail transit, comprising two U-shaped beams arranged side by side, wherein the U-shaped beam is composed of a bottom plate, a first web plate located on one side of the bottom plate, a second web plate located on the other side of the bottom plate, a first web plate upper flange located on the top of the first web plate, and a second web plate upper flange located on the top of the second web plate to form a U-shaped cross-section structure, wherein the first web plates of the two U-shaped beams are arranged adjacent to each other, and a post-cast rail bearing platform is arranged on the top of the bottom plate, characterized in that The first web and the second web are both thickened structures, with the thickness gradually increasing from top to bottom. The inner side surface and the outer side surface of the first web are non-concentric circular curves, the inner side surface and the outer side surface of the second web are non-concentric circular curves, the upper flange of the first web is F-shaped, and the upper flange of the second web is T-shaped.

2. The vibration and noise reduction U-shaped beam according to claim 1 is characterized in that A first arm is provided at the junction of the inner side of the first web and the bottom plate, and a second arm is provided at the junction of the inner side of the second web and the bottom plate, so as to strengthen the boundary support conditions of the bottom plate and the web and improve the force transmission connection between the web and the bottom plate.

3. The vibration and noise reduction U-shaped beam according to claim 1, characterized in that The thickness of the upper part of the first web is 0.24~0.27m, and the thickness of the lower part is 0.26~0.32m; the thickness of the upper part of the second web is 0.24~0.27m, and the thickness of the lower part is 0.26~0.32m.

4. The vibration-reducing and noise-reducing U-shaped beam according to claim 1, characterized in that The bottom plate is made of uniform thickness plate with a thickness of 0.26~0.3m.

5. The vibration and noise reduction U-shaped beam according to claim 1, characterized in that: The top of the upper flange of the first web also serves as an evacuation platform. A widened section is arranged on the top of the evacuation platform. The width of the widened section in the straight section of the U-shaped beam is a fixed value, and the width in the curved section of the U-shaped beam is a variable value to adapt to the change of the sagittal height of the flat curve and control the distance between the edge of the door and the evacuation platform to be within a safe value range when the train runs on the curve.

6. The vibration-reducing and noise-reducing U-shaped beam according to claim 1, characterized in that: Space for arranging pipelines is reserved below the flange on the first web.

7. The vibration-reducing and noise-reducing U-shaped beam according to claim 1, characterized in that: The width of the upper flange on the second web is 0.65~0.8m, and the width of the upper flange on the first web is 0.5~0.65m.

8. The vibration-reducing and noise-reducing U-shaped beam according to claim 1, characterized in that: Small radius annular post-tensioned prestressed steel strands are set in the transverse direction of the web and bottom plate, and the steel strands are evenly arranged along the length of the beam.

9. The vibration-reducing and noise-reducing U-shaped beam according to claim 1, characterized in that: A weak-current cable bracket is installed on the inner side of the first web, a strong-current cable bracket is installed on the inner side of the second web, a sound barrier or contact network column, a power maintenance box and a distribution box are installed on the upper flange of the second web, and a public security leaky cable is installed below the flange of the first web.

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