Large-span steel truss arch bridge arch ring chord member material-saving efficient combined structure

Abstract

The utility model relates to the field of bridges, in particular to a large-span steel truss arch bridge arch ring chord member material-saving efficient combined structure which comprises a main plate splice plate and a longitudinal rib plate splice plate. The longitudinal rib plate splice plates are used for connecting the longitudinal stiffening rib plates of the adjacent chord members; the main plate splicing plates are used for connecting main plates of adjacent chord members; the threshold value of the thickness of the main board is configured to be set according to the strength of a chord member material; when the thickness of the main plate is greater than a threshold value, the adjacent chord members are bolted by adopting the main plate splicing plates and the longitudinal rib plate splicing plates; and when the thickness of the main plate is smaller than or equal to a threshold value, the adjacent chord members are bolted only by adopting the main plate splicing plates. Through a dynamic combination mode of direct bolting and indirect bolting, the material economy and the splicing structure performance are obviously optimized on the premise of ensuring the feasibility of full-bridge construction.

Description

A material-saving and efficient composite structure for the arch ring chords of a long-span steel truss arch bridge Technical Field

[0001] This utility model relates to the field of bridge technology, and in particular to a material-saving and efficient combined structure for the arch ring chords of a large-span steel truss arch bridge. Background Technology

[0002] Steel truss arch bridges are an important bridge structure in the field of bridge engineering, with the arch chord as the key load-bearing component primarily transmitting axial forces. The chord typically consists of four main steel plates welded together to form a box-shaped cross-section, with internal longitudinal stiffeners. Chord joint design follows the principle of equal strength, and high-strength bolt connections are commonly used to ensure construction accuracy and quality stability.

[0003] Depending on the bridge span, the stress characteristics of the chord members vary significantly: For steel truss arch bridges with spans under 200 meters, the axial force level of the chord members is low, and the longitudinal stiffeners are only used as structural measures to enhance the stability of the main plate; therefore, splicing between adjacent longitudinal stiffener plates along the axial direction is unnecessary. In medium-span steel truss arch bridges of 200 to 500 meters, the longitudinal stiffeners begin to participate in the overall structural stress. At this time, an indirect bolting technique is used, where only the chord main plate is spliced, and the stress area of ​​the longitudinal stiffener plates is converted to the main plate splicing plate. During internal force transmission, the internal force borne by the longitudinal stiffener plates is first transmitted to the main plate through the T-weld at their root, and then the subsequent transmission process is completed with the help of the main plate splicing plate. Because the material strength of the chord members, the thickness of the main plate, and the size of the longitudinal stiffener plates are relatively moderate, the thickness of the main plate splicing plate and the number of bolt rows can be optimized and controlled.

[0004] However, in recent years, with the continuous increase in the span of steel truss arches, especially approaching the 600-meter mark, the surge in chord axial force has necessitated the use of high-strength steel of Q500 grade or higher and thicker main plates. Traditional splicing methods present three technical challenges: first, the increased thickness of the splice plates leads to material waste; second, the uneven force transmission path of the longitudinal stiffening ribs results in significant stress concentration at the splice joints; and third, an excessive number of bolt rows causes uneven stress distribution among the bolts (relevant specifications require that "the number of bolt rows arranged in the direction of stress should be minimized"), affecting connection reliability. These drawbacks severely restrict the economy and structural safety of large-span steel truss arch bridges. Summary of the Invention

[0005] The purpose of this utility model is to address the problems existing in the prior art, such as the surge in axial force of the chords of large-span steel truss arch bridges with spans exceeding 500 meters, the use of indirect bolted splicing between the longitudinal stiffening ribs of adjacent chords leading to a doubling of the thickness of the spliced ​​plates, significant stress concentration at the splicing points, and uneven stress on multiple rows of bolts. This invention provides a material-saving and efficient combined structure for the arch chords of large-span steel truss arch bridges.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A material-saving and efficient composite structure for the arch chords of a long-span steel truss arch bridge includes a main plate splicing plate and a longitudinal rib splicing plate. The longitudinal rib splicing plate is used to connect the longitudinal stiffening ribs of adjacent chords. The main plate splicing plate is used to connect the main plates of adjacent chords. The threshold thickness of the main plate is configured according to the strength of the chord material. When the main plate thickness is greater than the threshold, adjacent chords are bolted together using the main plate splicing plate and the longitudinal rib splicing plate. When the main plate thickness is less than or equal to the threshold, adjacent chords are bolted together using only the main plate splicing plate.

[0008] This invention employs a material-saving and efficient composite structure for the arch chords of a large-span steel truss arch bridge. Different chord internal forces are matched with varying chord material strengths and main plate thicknesses. In high-stress areas, a novel direct bolted connection is used, where the main plate and longitudinal stiffening ribs work together to transmit force via dual paths. This direct and smooth force transmission reduces the thickness of the main plate splice and the specifications of the T-welds at the roots of the longitudinal stiffening ribs, while also reducing the number of bolt rows. This results in more uniform force transmission in the longitudinal bolt group and a shorter splice length, further saving splicing materials. In low-stress areas, an indirect bolted connection is used, where the force of the longitudinal stiffening ribs is equivalently transferred to the main plate. This effectively controls the splice thickness and the number of bolt rows within conventional standards, ensuring reliable force transmission without significantly increasing the amount of splicing materials used, and making construction more convenient. Through this dynamic combination of direct and indirect bolting, material economy and splice structure performance are significantly optimized while ensuring the overall feasibility of bridge construction.

[0009] As a preferred technical solution of this utility model, the motherboard and the motherboard splicing board are bolted together by a group of motherboard bolts.

[0010] As a further preferred technical solution of this utility model, the longitudinal stiffening rib and the longitudinal rib splicing plate are bolted together by a group of longitudinal stiffening rib bolts.

[0011] As a further preferred technical solution of this utility model, when adjacent chords are bolted together using the main board splicing plate and the longitudinal rib splicing plate, the main board bolt group and the corresponding longitudinal stiffening rib bolt group are staggered by 30mm-50mm along the chord axis.

[0012] As a preferred technical solution of this utility model, when adjacent chords are bolted together using only the main board splicing plate, the main board splicing plate is thickened based on calculation.

[0013] As a preferred technical solution of this utility model, when the chord is made of Q500 grade steel, the threshold is 45mm-55mm.

[0014] As a preferred technical solution of this utility model, when the chord is made of Q420 grade steel, the threshold is 55mm-65mm.

[0015] As a preferred technical solution of this utility model, the span of the steel truss arch bridge is greater than 500m.

[0016] As a further preferred technical solution of this utility model, the internal clearance of the chord is greater than or equal to 1.8m.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0018] This utility model describes a material-saving and efficient composite structure for the arch chords of a large-span steel truss arch bridge. Different chord internal forces are matched with varying chord material strengths and main plate thicknesses. In high-stress areas, a direct bolted connection is innovatively used, employing a dual-path collaborative force transmission between the main plate and the longitudinal stiffening ribs. This direct and smooth force transmission reduces the thickness of the main plate splice and the specifications of the T-welds at the roots of the longitudinal stiffening ribs, while also reducing the number of bolt rows. This results in more uniform longitudinal force transmission from the bolt group, and the splice length is also reduced, further saving splicing materials. In low-stress areas, an indirect bolted connection is used, where the force of the longitudinal stiffening ribs is equivalently transferred to the main plate. The splice thickness and the number of bolt rows can be effectively controlled within conventional standard ranges, ensuring reliable force transmission without significantly increasing the amount of splicing materials used, and making construction more convenient. Through a dynamic combination of direct and indirect bolting, material economy and splice structure performance are significantly optimized while ensuring the feasibility of overall bridge construction. Attached Figure Description

[0019] Figure 1 is a cross-sectional schematic diagram of the direct bolted connection of the chord members;

[0020] Figure 2 is a cross-sectional view of AA in Figure 1;

[0021] Figure 3 is a cross-sectional schematic diagram of the indirect bolted connection method of the chord members;

[0022] Figure 4 is a stress distribution cloud map of the longitudinal stiffening rib plate at the direct bolted splice of the chord member;

[0023] Figure 5 shows the stress distribution cloud map of the longitudinal stiffening rib plate at the indirect bolted splice of the chord members.

[0024] The markings in the diagram are: 1-Main board, 2-Main board splicing board, 3-Main board bolt group, 11-Longitudinal stiffening rib, 12-Longitudinal rib splicing board, 13-Longitudinal stiffening rib bolt group. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. All technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0026] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of this utility model is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the utility model solution or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on this utility model.

[0027] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0028] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0029] Furthermore, in the description of the embodiments of this utility model, "several", "multiple", and "several" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0030] Furthermore, in the description of the technical solution of this utility model, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "equipped with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0031] In related technologies, the axial force of the chords of large-span steel truss arch bridges with a span exceeding 500 meters surges. The longitudinal stiffening ribs of adjacent chords are spliced ​​using an indirect bolted connection method, resulting in a doubling of the splice plate thickness, significant stress concentration at the splice site, and uneven stress distribution on multiple rows of bolts. Therefore, the technical solution of this application was developed, and will be described below with reference to Figures 1 to 5.

[0032] Example 1

[0033] As shown in Figures 1 to 5, the material-saving and efficient combined structure of the arch chord of a large-span steel truss arch bridge according to this utility model includes a main board splicing plate 2 and a longitudinal rib splicing plate 12.

[0034] The longitudinal rib splicing plate 12 is used to connect the longitudinal stiffening ribs 11 of adjacent chords; the main board splicing plate 2 is used to connect the main board 1 of adjacent chords.

[0035] The threshold for the thickness of the mainboard 1 is configured to be set according to the strength of the chord material; for example, when the chord is made of Q500 grade steel, the threshold is 45mm-55mm, and 50mm can be used; when the chord is made of Q420 grade steel, the threshold is 55mm-65mm, and 60mm can be used.

[0036] As shown in Figures 1 and 2, when the thickness of the main plate 1 is greater than the threshold, adjacent chord members are bolted together using the main plate splicing plate 2 and the longitudinal rib splicing plate 12. The main plate splicing plate 2 and the longitudinal rib splicing plate 12 are independently configured according to the principle of equal strength to ensure that the axial force is transmitted synchronously along the two sets of force transmission paths, thus forming a direct bolted connection. The main plate 1 and the main plate splicing plate 2 are bolted together by the main plate bolt group 3, and the longitudinal stiffening rib 11 and the longitudinal rib splicing plate 12 are bolted together by the longitudinal stiffening rib bolt group 13. The main plate bolt group 3 and the corresponding longitudinal stiffening rib bolt group 13 are staggered by 30mm-50mm along the chord axis. The spatial misalignment design eliminates interference of bolt hole positions at corners, ensuring construction operability.

[0037] As shown in Figure 3, when the thickness of the main board 1 is less than or equal to the threshold, adjacent chords are only bolted together using the main board splicing plate 2, and the internal force of the chord is transmitted based on the calculated thickening of the main board splicing plate 2, so as to form an indirect bolted connection; the main board 1 and the main board splicing plate 2 are bolted together by the main board bolt group 3.

[0038] In a large-span steel truss arch structure, the stress level of the chord members varies significantly at different locations along the axis. Based on the different internal forces of the chord members, the strength of the chord material and the thickness of the main plate 1 are matched. Based on this difference, a suitable bolting method (i.e., direct bolting or indirect bolting) is adopted.

[0039] In high-stress areas, the chord members are directly bolted together. These chord members are typically made of high-strength steel, characterized by their large thickness and cross-sectional dimensions. Direct bolting in these areas offers several advantages: First, compared to indirect bolting, it effectively reduces the number of bolt rows, decreasing the thickness and length of the main board splicing plate 2, thus significantly saving splicing plate material. Second, when the chord member's internal force is high, the internal forces of the main board 1 and the longitudinal stiffening rib 11 are transmitted through their respective splicing plates, resulting in a smoother force transmission process and effectively reducing stress concentration at the point where the forces converge. Third, the larger internal space facilitates personnel operation within the enclosure.

[0040] In the low-stress region, the chord members are indirectly bolted. In this region, the steel used is relatively low-strength, and the thickness of the main plate 1 and the dimensions of the longitudinal stiffening ribs 11 are moderate. Using indirect bolting in this area offers several advantages: First, it keeps the number of bolt rows, the thickness and length of the main plate splicing plate 2 within standard limits, preventing a significant increase in splicing material usage. Second, the low internal stress level of the chord members means that stress concentration caused by the indirect force transmission through the longitudinal stiffening ribs 11 is not a significant issue. Third, only the main plate 1 of the chord members needs to be spliced, providing more construction space and higher construction efficiency.

[0041] In one optional embodiment, the steel truss arch bridge has a span greater than 500m, a large chord section size, and an internal clearance greater than or equal to 1.8m, which meets the needs of workers to enter the box girder and complete the bolt tightening construction of the longitudinal rib splice plate 12.

[0042] A comparative verification was conducted on a 580-meter main span parallel steel truss arch bridge in a mountainous area. This bridge uses a double-layered variable-height steel truss arch ring with a rise-to-span ratio of 1 / 5. The center height of the arch truss at the top is 13.5 meters, and the center height of the arch foot truss is 16 meters. The entire bridge has 42 sections. The arch ring chords use a box-section, with two longitudinal stiffening ribs 11 arranged on each main plate within the box. The chords are made of Q500 grade steel, and the thickness of the main plate 1 ranges from 32 to 68 mm. A typical box-section chord in the high internal force zone at the arch foot was selected as a specific analysis example. Its cross-sectional parameters are: top and bottom plate dimensions 2300×60 mm, web dimensions 2480×60 mm, and the longitudinal stiffening ribs 11 dimensions 380×44 mm. Based on the principle of equal strength design, M30 high-strength bolts were used for splicing.

[0043] Table 1. Example chord section, direct bolted joint, splice plate weight.

[0044]

[0045] Table 2 Example of chord section indirect bolted connection splice plate weight

[0046]

[0047] Combining Tables 1 and 2, the example calculation results show that, compared to the traditional indirect bolting method, the direct bolting method can save approximately 5.2 tons of material in a single joint splice plate, reduce the number of longitudinal rows of bolts on one side by 3 rows, and shorten the main bolt shank length by 26 mm, thereby reducing the risk of delayed fracture. Figures 4 and 5 show that, after adopting the direct bolting method, the stress flow distribution of the longitudinal stiffening rib 11 at the connection is more uniform and smooth, and the stress peak value is reduced by approximately 15%, further demonstrating the superior mechanical performance of the direct bolting method. In the splice joints of the entire bridge chord members, approximately 40% adopt the direct bolting method. Practical application has shown that this method can save hundreds of tons of steel in the splice plate.

[0048] This embodiment describes a material-saving and efficient composite structure for the arch chords of a large-span steel truss arch bridge. Different internal forces in the chords are matched with varying chord material strengths and the thickness of the main plate 1. In high-stress areas, a direct bolted connection is innovatively used, employing a dual-path collaborative force transmission between the main plate 1 and the longitudinal stiffening ribs 11. This direct and smooth force transmission reduces the thickness of the main plate splice plate 2 and the specifications of the T-shaped weld at the root of the longitudinal stiffening ribs 11, and also reduces the number of rows of bolts arranged longitudinally. This results in more uniform force transmission in the bolt group and a reduction in the splice plate length, further saving splicing materials. In low-stress areas, an indirect bolted connection is used, where the force of the longitudinal stiffening ribs 11 is equivalently converted to that of the main plate 1. The splice plate thickness and the number of bolt rows can be effectively controlled within conventional standard ranges, ensuring reliable internal force transmission without a significant increase in splicing material consumption, and making construction more convenient. Through a dynamic combination of direct and indirect bolting, material economy and splice structure performance are significantly optimized while ensuring the feasibility of overall bridge construction.

[0049] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A material-saving and efficient composite structure for the arch ring chords of a long-span steel truss arch bridge, characterized in that: It includes a main board splicing plate (2) and a longitudinal rib splicing plate (12); the longitudinal rib splicing plate (12) is used to connect the longitudinal stiffening ribs (11) of adjacent chords; the main board splicing plate (2) is used to connect the main board (1) of adjacent chords; the threshold of the thickness of the main board (1) is configured to be set according to the strength of the chord material; when the thickness of the main board (1) is greater than the threshold, adjacent chords are bolted together using the main board splicing plate (2) and the longitudinal rib splicing plate (12); when the thickness of the main board (1) is less than or equal to the threshold, adjacent chords are bolted together using only the main board splicing plate (2).

2. The material-saving and efficient composite structure of the arch ring chord of the large-span steel truss arch bridge according to claim 1, characterized in that, The mainboard (1) and the mainboard splicing board (2) are bolted together by a group of mainboard bolts (3).

3. The material-saving and efficient composite structure of the arch ring chord of the large-span steel truss arch bridge according to claim 2, is characterized in that... The longitudinal stiffening rib (11) and the longitudinal rib splicing plate (12) are bolted together by a group of longitudinal stiffening rib bolts (13).

4. The material-saving and efficient composite structure of the arch ring chord of the large-span steel truss arch bridge according to claim 3, is characterized in that... When adjacent chords are bolted together using the main board splicing plate (2) and the longitudinal stiffening rib splicing plate (12), the main board bolt group (3) and the corresponding longitudinal stiffening rib bolt group (13) are staggered by 30mm-50mm along the chord axis.

5. The material-saving and efficient composite structure of the arch ring chord of the large-span steel truss arch bridge according to claim 1, characterized in that, When adjacent chords are bolted together using only the main board splicing plate (2), the main board splicing plate (2) is thickened based on the calculation.

6. The material-saving and efficient composite structure of the arch ring chord of the long-span steel truss arch bridge according to claim 1, characterized in that, When the chord is made of Q500 grade steel, the threshold is 45mm-55mm.

7. The material-saving and efficient composite structure of the arch ring chord of the large-span steel truss arch bridge according to claim 1, characterized in that, When the chord is made of Q420 grade steel, the threshold is 55mm-65mm.

8. The material-saving and efficient composite structure for the arch ring chords of a large-span steel truss arch bridge according to any one of claims 1-7, characterized in that, The span of the steel truss arch bridge is greater than 500m.

9. The material-saving and efficient composite structure of the arch ring chord of a large-span steel truss arch bridge according to claim 8, characterized in that, The internal clearance of the chord is greater than or equal to 1.8m.

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