A railway steel truss girder bridge with curved trusses

Abstract

The utility model discloses a railway steel truss girder bridge of curved truss curved making is used to improve the adaptability of bridge structure, accurate adaptation small curve radius scene, satisfy clearance control requirement and convenient construction. The bridge includes the upper chord structure and lower chord structure that are connected through web member, the bridge structure center line is identical with the average center line of railway line center line or multi-line railway, and the center line of upper chord structure and lower chord structure is the concentric circular arc line of bridge structure center line, and the lower chord is supported above the pier. The utility model provides a railway steel truss girder bridge of curved truss curved making, and the beam body line adaptability is strong, and the crossing ability is strong, and the landscape effect is good, and the vertical rigidity is big, and the comprehensive economy is good, is applicable to the special work spot such as curve crossing railway, highway or gorge, river etc.

Description

Technical Field

[0001] This utility model relates to bridge spanning structures for supporting railway tracks, and in particular to railway steel truss bridges with curved trusses. Background Technology

[0002] With the continuous development of the transportation construction industry, my country's railway network is becoming increasingly complete, and the construction of high-speed, intercity, and urban railways is booming. In this process, affected by multiple factors such as the optimization of connection schemes and constraints on land acquisition and demolition, the number of bridge construction sites with small curve radii and large spans crossing existing railways and highways has increased significantly. These construction sites often need to meet the dual requirements of crossing function and clearance control at the same time.

[0003] However, the challenges of adapting to small curve radii and the limitations of clearance control nodes have become core technical bottlenecks restricting the design and construction of such bridges. On the one hand, under small curve radius conditions, the bridge structure must adapt to the curvature of the track; otherwise, it is easy to cause poor driving comfort and unreasonable structural stress. On the other hand, clearance control requirements strictly limit the height of the substructure and the outline of the superstructure, further compressing the design space. The combination of these two major problems not only significantly increases the difficulty of route selection but also easily triggers a chain reaction such as the expansion of land acquisition and demolition areas and the increase in project investment, seriously affecting the economic efficiency and implementation efficiency of the project.

[0004] In existing bridge structures, straight truss bridges, due to their fixed structural form, require adjustments to the segment angles or the use of polygonal curve fitting under curved route conditions. This results in complex structural stress, high construction precision requirements, and difficulty in adapting to small curve radii. Some curve-adaptive bridges suffer from poor landscape coordination, cumbersome construction procedures, and excessive clearance occupation, failing to balance adaptability, convenience, and economy. For large-span bridges with small curve radii, existing technologies lack a bridge structure that can simultaneously address the core requirements of curve adaptation, clearance control, and convenient construction, making it difficult to meet the comprehensive demands of engineering projects for route optimization, reduced land acquisition and demolition, and cost savings.

[0005] Therefore, developing a bridge structure that is highly adaptable to railway conditions, can accurately adapt to small curve radius scenarios, meets clearance control requirements, and is easy to construct has become an urgent need in the current railway engineering construction field. It is of great significance for promoting the efficient implementation of special work sites such as railways, highways, rivers or canyons under curved lines.

[0006] It should be noted that the above technical information is the result of analysis and creative research. The detailed description of it in the background section is only intended to deepen the understanding of the overall background technology and non-obviousness of this utility model, and should not be regarded as an admission or implication in any form that the above technical information constitutes prior art known to those skilled in the art. Utility Model Content

[0007] To address the shortcomings in the aforementioned background technology, this utility model proposes a curved truss railway steel truss bridge. The technical problem to be solved is: how to improve the adaptability of the bridge structure, accurately adapt to small curve radius scenarios, meet clearance control requirements, and facilitate construction.

[0008] The technical solution of this utility model is as follows: A type of curved truss railway steel truss bridge includes an upper chord structure and a lower chord structure connected by web members. The centerline of the bridge structure coincides with the centerline of the railway line or the average centerline of a multi-track railway. The centerlines of the upper chord structure and the lower chord structure are concentric arcs with the centerline of the bridge structure. The lower chord is supported above the piers.

[0009] The beneficial effects of this technical solution are as follows: the center lines of the upper and lower chords are concentric arcs with the center line of the bridge structure, which can accurately adapt to small curve radius lines without the need for line fitting, thus avoiding problems such as poor ride smoothness and unreasonable structural stress; the structural outline is compact and does not occupy additional clearance, meeting strict clearance control requirements; the structural form is simple and construction does not require complex angle adjustments, reducing construction difficulty and precision requirements, and improving construction efficiency.

[0010] Based on the above technical solutions, as a preferred technical solution for a curved railway steel truss bridge, the bridge piers are supported by foundations.

[0011] Further beneficial effects of this technical solution are: by enhancing the load-bearing stability and anti-settlement capacity of the bridge piers through foundation enhancement, displacement of the bridge piers due to uneven stress or geological conditions is avoided; reliable support is provided for the overall bridge structure, ensuring structural safety in scenarios with small curve radii and large spans, and extending the service life of the bridge.

[0012] Based on the above technical solutions, the preferred technical solution for a curved railway steel truss bridge is a pile foundation, an enlarged foundation, or a caisson foundation.

[0013] Further benefits of this technical solution include: adaptability to different geological conditions, such as soft soil, hard rock, and shallow water areas, expanding the application range of bridges, eliminating the need for additional customized foundation design; and the use of mature construction techniques for pile foundations, spread foundations, and caisson foundations, which balance economic efficiency and ease of construction, reducing project investment and construction period costs.

[0014] Based on the above technical solutions, the preferred technical solution for curved truss railway steel truss bridges is a simply supported structure or a continuous structure.

[0015] Further beneficial effects of this technical solution are: the simply supported structure is suitable for medium and short span scenarios, the construction process is simple and the erection is convenient, which can shorten the on-site construction cycle; the continuous structure is suitable for large span scenarios, the structure has high rigidity and more uniform stress, reduces mid-span deflection, improves driving comfort, and achieves flexible adaptation to different span requirements.

[0016] Based on the above technical solutions, as a preferred technical solution for a curved truss railway steel truss bridge, when it is a simply supported structure, the piers are set below the lower chord end nodes at both ends of the lower chord structure; when it is a continuous structure, the piers are set below the lower chord end nodes and some lower chord middle nodes.

[0017] Further beneficial effects of this technical solution are as follows: the simply supported structure only requires piers at the end nodes, reducing the number of substructures, the scope of land acquisition and demolition, and the project investment; the continuous structure supplements the support at the mid-nodes, enhancing structural stability; the pier layout is precisely matched with the structural type, avoiding redundant or insufficient support, while reducing the space occupied by the substructure and further meeting the clearance control requirements.

[0018] Based on the above technical solutions, as a preferred technical solution for a curved railway steel truss bridge, the upper chord structure includes an inner upper chord and an outer upper chord whose centerlines are concentric arcs with the centerline of the bridge structure. The inner upper chord and the outer upper chord are connected by several upper chord horizontal braces and upper chord diagonal braces.

[0019] Further beneficial effects of this technical solution are: the horizontal bracing and the diagonal bracing form a stable upper chord force system, which enhances the upper chord structure's resistance to lateral displacement and overall stiffness, and prevents the upper chord from deforming due to centrifugal force under small curve radii; it ensures coordinated force distribution on the inner and outer sides of the upper chord structure, simplifies the force transmission path, and improves the structure's fatigue resistance.

[0020] Based on the above technical solutions, as a preferred technical solution for railway steel truss bridges with curved trusses, both the inner upper chord and the outer upper chord of the curve include several upper chord nodes and upper chord members.

[0021] Further benefits of this technical solution include: modular design of chords and nodes facilitates factory prefabrication and on-site assembly, shortens the construction cycle, and improves component processing accuracy; the split structure allows for flexible adjustment of chord length and node spacing according to curve radius, adapting to different small curve radius requirements and enhancing line adaptability.

[0022] Based on the above technical solutions, as a preferred technical solution for a curved railway steel truss bridge, the lower chord structure includes an inner lower chord and an outer lower chord of a curve whose centerline is a concentric arc with the centerline of the bridge structure. The inner lower chord and the outer lower chord are connected by end beams, node beams, inter-segment beams, and small longitudinal beams.

[0023] Further beneficial effects of this technical solution are: the crossbeams and longitudinal beams form a complete lower chord bearing surface, providing a stable foundation for track laying and ensuring smooth train operation. The various types of crossbeams have clearly defined functions: end crossbeams reinforce end fixation, node crossbeams connect nodes, and inter-segment crossbeams distribute stress, resulting in more balanced structural stress without increasing the lower chord profile height, thus meeting clearance requirements.

[0024] Based on the above technical solutions, as a preferred technical solution for railway steel truss bridges with curved trusses, the lower chord on the inner side of the curve includes several lower chord end nodes, lower chord middle nodes, and lower chord members.

[0025] Further beneficial effects of this technical solution are: the combined design of nodes and chords enables precise shaping of the lower chord curve, adapting to the arc trajectory of the bridge structure's centerline. End nodes and mid-nodes provide reliable stress points for pier support, ensuring uniform transmission of support force to the foundation and avoiding localized stress concentration.

[0026] Based on the above technical solutions, as a preferred technical solution for railway steel truss bridges with curved trusses, the upper chord on the inner side of the curve and the lower chord on the inner side of the curve, as well as the upper chord on the outer side of the curve and the lower chord on the outer side of the curve, are connected by end web members and middle web members.

[0027] Further benefits of this technical solution include: the end web members and the middle web members form a vertical force-bearing system, efficiently transferring the load between the upper and lower chords and ensuring the overall coordinated operation of the structure. The web member arrangement is simple, does not additionally increase the bridge profile, and facilitates construction, installation, and subsequent maintenance, reducing the total life-cycle cost.

[0028] This utility model of a curved truss railway steel truss bridge has strong adaptability to railway lines, strong spanning capacity, good landscape effect, high vertical stiffness, and good overall economic efficiency. It is suitable for curved crossings of railways, highways, or special construction sites such as canyons and rivers, and has broad application prospects.

[0029] The circuit is highly adaptable: the concentric arc-shaped upper and lower chord structure completely solves the problem of adapting to small curve radii, eliminating the need for line fitting and allowing for flexible adaptation to curves with different curvatures.

[0030] Clearance control meets standards: The structure has a compact outline, and the arrangement of components such as upper and lower chords, web members, and crossbeams does not occupy additional clearance, fully meeting the clearance restrictions when crossing existing railways and highways.

[0031] Convenient and efficient construction: Modular components, nodes, chords, web members, etc. are easy to prefabricate in the factory and assemble on site, simplifying construction procedures, reducing precision requirements, shortening the construction period and reducing on-site work.

[0032] Structural safety and reliability: Through reasonable support arrangement of piers, foundations, and horizontal bracing, diagonal bracing, and web members in the load-bearing system, the load is evenly transferred, stress concentration is avoided, and structural stability and fatigue resistance are improved.

[0033] Outstanding economic efficiency: Reduces the scope of land acquisition and demolition, minimizes the space occupied by the substructure, reduces construction difficulty and investment costs, while adapting to different spans and geological conditions, reducing customized design, and balancing short-term construction costs with long-term operation and maintenance costs.

[0034] Good landscape harmony: The curved structure is smooth and natural, and compared with the straight truss bridge with broken line fitting, it has a higher degree of integration with the surrounding environment and enhances the landscape effect of the crossing site. Attached Figure Description

[0035] To more clearly illustrate the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A side view of a railway steel truss bridge structure with curved trusses.

[0037] Figure 2 for Figure 1 Top view of the upper chord structure.

[0038] Figure 3 for Figure 1 Top view of the overall lower chord structure.

[0039] Figure 4 This is a schematic diagram of the cross-section of a steel truss bridge member. a is rectangular section one; b is rectangular section two; c is H-shaped section; d is ribbed rectangular section one; e is ribbed rectangular section two; f is ribbed H-shaped section; g is irregular polygonal section one; h is irregular polygonal section two.

[0040] Explanation of icon numbers: 1: Top chord node; 2: Top chord member; 3: End web member; 4: Middle web member; 5: Bottom chord end node; 6: Bottom chord member; 7: Bottom chord middle node; 8: Pier; 9: Foundation; 10: Inner curve top chord; 11: Outer curve top chord; 12: Top chord cross brace; 13: Top chord diagonal brace; 14: Inner curve bottom chord; 15: Outer curve top chord; 16: Node crossbeam; 17: End crossbeam; 18: Inter-segment crossbeam; 19: Bridge structural centerline; 20: Small longitudinal beam. Detailed Implementation

[0041] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the core concept of the present utility model and the following embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0042] These embodiments are provided to make the application thorough and complete, and to fully express the scope of the application to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​illustrated in these embodiments should be interpreted as merely exemplary and not as limiting.

[0043] It should be noted that, in the description of this application, unless otherwise stated, "several" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "axial," "radial," etc., indicating orientation or positional relationships are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0044] Furthermore, the terms "first," "second," and similar words used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Words such as "including" or "contains" mean that the element preceding the word encompasses the element listed after the word, and do not exclude the possibility of encompassing other elements as well.

[0045] It should also be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances. 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.

[0046] All terms used in this application have the same meaning as understood by one of ordinary skill in the art to which this application pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0047] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0048] A type of railway steel truss bridge with curved trusses, the specific implementation of which is as follows: Figures 1 to 3 As shown, the railway steel truss bridge with curved truss structure consists of an inner upper chord 10, an outer upper chord 11, end web members 3, middle web members 4, an inner lower chord 14, an outer lower chord 15, an upper chord cross brace 12, an upper chord diagonal brace 13, an end crossbeam 17, a node crossbeam 16, a section crossbeam 18, a small longitudinal beam 20, and a substructure. The substructure consists of piers 8 and foundations 9, which can be pile foundations, spread foundations, caisson foundations, etc.

[0049] The skew arch bridge can be a simply supported structure or a continuous structure. When it is a simply supported structure, piers 8 and foundations 9 are only set at the lower part of the nodes 5 at the lower chord ends on both sides. When it is a continuous structure, in addition to setting piers 8 and foundations 9 at the lower part of the nodes 5 at the lower chord ends on both sides, piers 8 and foundations 9 can be set at the lower part of the nodes 7 in the middle of the lower chord at some or several locations according to the span requirements, forming a multi-span continuous structure.

[0050] The bridge track is curved. The centerline 19 of the bridge structure is consistent with the centerline of the railway line or the average centerline of the multi-track railway. The centerlines of the inner upper chord 10, the inner lower chord 14, the outer upper chord 11, the outer lower chord 15, and the small longitudinal beam 20 of the bridge structure are concentric circles with the centerline of the bridge structure.

[0051] The inner upper chord 10 of the curve consists of upper chord node 1 and upper chord member 2; the outer upper chord 11 of the curve consists of upper chord node 1 and upper chord member 2. The dimensions of the upper chord node 1 on the inner side of the curve and the upper chord node 1 on the outer side of the curve are different, and are determined according to the radius of the curve. The dimensions of the upper chord member 2 on the inner side of the curve and the upper chord node 2 on the outer side of the curve are different, and are determined according to the radius of the curve.

[0052] The inner lower chord 14 of the curve consists of the lower chord end node 5, the lower chord middle node 7, and the upper chord member 6; the outer upper chord 15 of the curve consists of the lower chord end node 5, the lower chord middle node 7, and the lower chord member 6. The dimensions of the lower chord end node 5 on the inner side of the curve are different from those on the outer side, and the dimensions of the lower chord middle node 7 on the inner side of the curve are also different from those on the outer side, determined by the radius of the curve. The dimensions of the lower chord member 6 on the inner side of the curve are also different from those on the outer side, determined by the radius of the curve.

[0053] The inner upper chord 10 and the outer upper chord 11 of the curve are connected by upper chord cross brace 12 and upper chord diagonal brace 13. The inner lower chord 14 and the outer lower chord 15 of the curve are connected by end crossbeam 17, node crossbeam 16, inter-section crossbeam 18, and small longitudinal beam 20.

[0054] The inner upper chord 10 and the inner lower chord 14 of the curve are connected by the end web member 3 and the middle web member 4. The outer upper chord 11 and the outer lower chord 15 of the curve are connected by the end web member 3 and the middle web member 4.

[0055] Preferably, such as Figure 4 As shown, the cross-section of each chord member can be rectangular, H-shaped, irregular polygonal, steel-concrete composite, or partially steel-concrete composite, and the connection method of each member can be bolted or welded.

[0056] Preferably, the centerline of the bridge structure is aligned with the centerline of the railway line (or the average centerline for multi-track railways), forming an overall arc curve. The main body of the bridge includes an upper chord structure, a lower chord structure, and web members. The web members are divided into end web members and middle web members, which connect the ends and middle areas of the upper and lower chords, respectively.

[0057] The upper chord structure consists of an inner upper chord and an outer upper chord, both of which have their centerlines concentric with the bridge structure's centerline. The inner and outer upper chords are fixedly connected by several horizontal upper chord braces and diagonal upper chord braces, forming a stable upper chord frame. Both the inner and outer upper chords are assembled from multiple upper chord nodes and upper chord members, with the length of the members precisely adapted to the curve radius.

[0058] The lower chord structure consists of the inner lower chord and the outer lower chord of the curve, with their centerlines concentric with the centerline of the bridge structure. The inner and outer lower chords are connected by end beams (arranged at the ends), node beams (arranged at the corresponding lower chord nodes), inter-segment beams (arranged between chord nodes), and small longitudinal beams (longitudinal connecting beams) to form a complete load-bearing surface. The inner lower chord includes the lower chord end nodes (both ends), the lower chord middle nodes (middle area), and the lower chord members. The nodes and chord members are spliced ​​together to form the lower chord curve.

[0059] The lower chord structure is supported above the piers, and foundations (pile foundations, spread foundations, or caisson foundations are selected based on geological conditions) are set below the piers. Bridges can be selected as simply supported or continuous structures depending on span requirements: in a simply supported structure, the piers are only located below the end nodes of the lower chord; in a continuous structure, the piers are located below the end nodes of the lower chord and some of the middle nodes of the lower chord to ensure stable support.

[0060] The track is laid on the bearing surface composed of the crossbeams and small longitudinal beams of the lower chord structure. The overall structure meets the comprehensive requirements of precise curve adaptation, clearance control, and convenient and efficient construction.

[0061] Preferably, the radius of the arc of the bridge structure centerline is set to 200-500m (small curve radius range). The centerlines of the upper and lower chord structures coincide with the center of the bridge structure centerline. The radius of the arc is precisely set according to the design spacing of the upper and lower chords to ensure that the upper and lower chords are concentric arcs without the need for additional adjustment of the inter-segment angle.

[0062] Preferably, a foundation is added below the pier in the general embodiment, and the top of the foundation is welded to the bottom of the pier by pre-embedded steel plates to ensure a rigid connection between the pier and the foundation and to avoid uneven settlement of the pier.

[0063] Preferably, when the geological conditions are soft soil, pile foundations (pile length 15-30m, pile diameter 1.2-1.5m) are selected; when the geological conditions are hard rock and the bearing capacity is sufficient, spread foundations are selected (bottom dimensions are determined according to the pier load calculation); when crossing shallow water areas, caisson foundations are selected (caisson depth to stable rock strata).

[0064] Preferably, when the span is 30-60m, a simply supported structure is adopted, and the main body of the bridge is a single-span steel truss girder; when the span is 60-100m, a continuous structure is adopted, and the main body of the bridge is a 2-3 span continuous steel truss girder with no pier support at mid-span.

[0065] Preferably, in the case of a simply supported structure, a pier is provided only at the bottom of the lower chord end node, with the center of the pier aligned with the center of the lower chord end node; in the case of a continuous structure, in addition to the lower chord end node, a pier is added at the bottom of the lower chord middle node at 1 / 3 of the span of each span to ensure the support stability of the continuous beam.

[0066] Preferably, the upper chord cross bracing is arranged every 4-6m along the longitudinal direction of the bridge, horizontally connecting the inner and outer upper chords; the upper chord diagonal bracing and the cross bracing form an angle of 45-60°, and are alternately arranged between the cross bracings to form a triangular stable structure, thereby enhancing the upper chord's resistance to lateral displacement.

[0067] Preferably, the upper chord nodes are made of cast steel, and the upper chord members are made of H-beams or box-section steel. The two ends of the chord members are connected to the nodes by high-strength bolts. The length and end face angle of each chord member are calculated based on the arc radius of the bridge structure centerline to ensure that a precise arc is formed after splicing.

[0068] Preferably, the end crossbeam is arranged at the end node of the lower chord and is rigidly connected to the inner and outer chord members of the lower chord; the node crossbeam is arranged corresponding to the middle node of the lower chord, and the inter-node crossbeam is arranged in the middle of the chord member between the two lower chord nodes; the small longitudinal beam connects the top of all the crossbeams along the longitudinal direction to form a flat track laying surface.

[0069] Preferably, both the lower chord end nodes and the middle nodes are made of cast steel. The lower chord members have the same cross-sectional shape as the upper chord members. The chord members and nodes are spliced ​​together by high-strength bolts. The node spacing of the inner lower chord is set to 4-5m according to the curve radius to ensure the smoothness of the lower chord curve.

[0070] Preferably, the end web members are arranged at both ends of the bridge, connecting the end nodes of the upper chord and the end nodes of the lower chord, and are arranged vertically or slightly obliquely; the middle web members are arranged in the middle area of ​​the bridge, connecting the middle nodes of the upper chord and the middle nodes of the lower chord, forming a uniformly distributed vertical force system with the end web members. The web members are made of I-beams and are bolted to the nodes at both ends.

[0071] This utility model discloses a steel truss bridge with curved trusses that can be applied to curved railway engineering conditions, especially suitable for conditions with small curve radii. The main trusses on both sides of the bridge in the direction of traffic are arranged to adapt to the curve, so as to accommodate the bridge crossing railways, highways or rivers under curved conditions.

[0072] The curved truss railway steel truss bridge of this utility model has strong adaptability to line conditions, good landscape effect, and convenient construction. It is suitable for special bridge construction sites such as railways, highways, rivers, and canyons under curved line conditions.

[0073] Any aspects of this utility model that are not detailed herein are conventional technical means known to those skilled in the art.

[0074] The above content shows and describes the basic principles, main features, and beneficial effects of this utility model. The above description is merely a preferred embodiment of this utility model and is not intended to limit it. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A railway steel truss bridge with curved trusses, characterized in that: The structure includes an upper chord structure and a lower chord structure connected by web members. The center line of the bridge structure (19) is consistent with the center line of the railway line or the average center line of a multi-line railway. The center lines of the upper chord structure and the lower chord structure are concentric arcs with the center line of the bridge structure (19). The lower chord is supported above the pier (8).

2. The railway steel truss bridge with curved trusses according to claim 1, characterized in that: The pier (8) is supported by a foundation (9).

3. The railway steel truss bridge with curved trusses according to claim 2, characterized in that: The foundation (9) is a pile foundation, an enlarged foundation, or a caisson foundation.

4. The railway steel truss bridge constructed with curved trusses according to any one of claims 1-3, characterized in that: It can be a simply supported structure or a continuous structure.

5. The railway steel truss bridge constructed with curved trusses according to claim 4, characterized in that: When it is a simply supported structure, the piers (8) are set below the lower chord end nodes (5) at both ends of the lower chord structure; when it is a continuous structure, the piers (8) are set below the lower chord end nodes (5) and some lower chord middle nodes (7).

6. The railway steel truss bridge constructed with curved trusses according to any one of claims 1-3 and 5, characterized in that: The upper chord structure includes an inner upper chord (10) and an outer upper chord (11) whose center line is a concentric arc with the center line (19) of the bridge structure. The inner upper chord (10) and the outer upper chord (11) are connected by several upper chord cross braces (12) and upper chord diagonal braces (13).

7. The railway steel truss bridge with curved trusses according to claim 6, characterized in that: The inner upper chord (10) and the outer upper chord (11) of the curve both include several upper chord nodes (1) and upper chord bars (2).

8. The railway steel truss bridge with curved trusses according to claim 7, characterized in that: The lower chord structure includes an inner lower chord (14) and an outer lower chord (15) of a curve whose center line is a concentric arc with the center line (19) of the bridge structure. The inner lower chord (14) and the outer lower chord (15) are connected by an end crossbeam (17), a node crossbeam (16), a section crossbeam (18), and a small longitudinal beam (20).

9. The railway steel truss bridge constructed with curved trusses according to claim 8, characterized in that: The inner lower chord (14) of the curve includes several lower chord end nodes (5), lower chord middle nodes (7), and lower chord chords (6).

10. The railway steel truss bridge constructed with curved trusses according to claim 8 or 9, characterized in that: The inner upper chord (10) and inner lower chord (14) of the curve, and the outer upper chord (11) and outer lower chord (15) of the curve are connected by the end web rod (3) and the middle web rod (4).

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