A double-lateral I-beam composite beam cable-stayed bridge body and side span pressure weight system

Abstract

The application relates to the technical field of bridge engineering, and provides a double-side I-steel composite beam cable-stayed bridge body and a side span weight pressing system. The double-side I-steel composite beam cable-stayed bridge body and the side span weight pressing system comprise a cable-stayed bridge body, a side span weight pressing system and a supporting system. The double-side I-steel composite beam cable-stayed bridge body and the side span weight pressing system can effectively offset the negative reaction force of the side span support caused by the main span live load, avoid the structure safety problem caused by the emptying of the support, do not need to set a tension-resistant support, simplify the design details of the bridge steel structure, reduce the workload of the later steel structure coating, do not need to transport the weight to the beam bottom for construction in the later period, reduce the on-site construction risk, can also reduce the lateral distance of the support, reduce the engineering cost of the lower structure, and have strong economic advantages.

Description

Technical Field

[0001] This application relates to the technical field of bridge engineering, and in particular to a double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system. Background Technology

[0002] In existing technologies, double-sided H-beam composite girder cable-stayed bridges use two H-beams as main girders, combined with precast concrete bridge decks, stay cables, and bridge towers to form a cable-stayed bridge structure, exhibiting good wind and flutter resistance in ultra-long span cable-stayed bridges. Conventional double-tower steel-concrete composite girder cable-stayed bridges use a short side span arrangement. When live loads are applied to the main span, the main girder will undergo warping deformation, generating negative reaction forces at the transition pier supports. If corresponding measures are not taken, this will adversely affect the structural safety.

[0003] To avoid negative reaction forces at the side span supports, existing technologies typically involve installing tensile support bearings at the transition pier supports, or adding counterweight structures, or a combination of both. Adding counterweight structures is mainly achieved by thickening the concrete bridge deck of the side span, or by using a steel box girder combined with counterweight blocks. In actual bridge designs, a combination of both methods is often used, with counterweight structures placed within a certain range near the transition pier supports.

[0004] Using tensile support bearings is costly and difficult to maintain. Using steel box lattice structures with counterweights increases the complexity of bridge design details, increases steel consumption and beam weight, leading to increased bridge construction costs and investment in hoisting equipment. The construction process is also more complex. In addition, the counterweights are heavy, making it inconvenient for workers to operate and increasing the risks of construction on the bridge. Summary of the Invention

[0005] In view of this, this application aims to propose a double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the technical solution of this application is implemented as follows: A double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system, comprising: The cable-stayed bridge body is a double-tower, double-cable-stayed composite beam structure, including bridge towers, cable stays, and double-sided I-beam steel-concrete composite beams. The double-sided I-beam steel-concrete composite beams include double-sided I-beam main beams, steel crossbeams, longitudinal beams, precast concrete bridge decks, asphalt pavement, and crash barriers. The double-sided I-beam main beams are fixedly connected to the steel crossbeams, and the steel crossbeams are fixedly connected to the longitudinal beams to form a steel beam grid frame. The precast concrete bridge decks are laid on top of the steel beam grid frame, the asphalt pavement is laid on top of the precast concrete bridge decks, and the crash barriers are symmetrically arranged on both sides of the bridge deck. The side span counterweight system is set in the side span tail cable area of ​​the cable-stayed bridge body. It consists of a thickened precast bridge deck, an end crossbeam counterweight part, an inter-crossbeam counterweight part and a counterweight transition part arranged sequentially along the longitudinal direction of the bridge. It is used to counteract the negative reaction force of the side span support caused by the live load of the main span. The support system includes bridge tower supports located below the double-sided I-beam side main beams, and transition pier supports located below the end crossbeams.

[0007] Furthermore, the steel crossbeam includes a standard section of I-beam crossbeam, a counterweight section of I-beam crossbeam, and an end crossbeam, with a standard spacing of 3.6m between the steel crossbeams; longitudinal / transverse stiffening ribs are provided on the steel crossbeam and the double-sided I-beam side main beams. The bottom plate of the standard section I-beam crossbeam adopts a zigzag-shaped variable beam height type, and its lower flange is welded to the horizontal stiffening rib of the web plate of the double-sided I-beam side main beam. The counterweight section I-beam and end beam are both horizontal straight lines, and their lower flanges are welded to the lower flanges of the double-sided I-beam side main beams. The end crossbeam is a single-box, double-cell box-type crossbeam.

[0008] Furthermore, adjacent precast concrete bridge decks are connected as a whole by cast-in-place micro-expansion concrete wet joints; the cast-in-place micro-expansion concrete wet joints are welded to the steel beams to form a composite beam structure system with the steel beams, so that the precast concrete bridge decks and steel beams share the load.

[0009] Furthermore, the thickened precast bridge deck covers the entire side span and has a thickness of 50cm; the precast concrete bridge deck of the standard section has a thickness of 28cm.

[0010] Furthermore, the end beam counterweight is made of iron sand concrete poured into the closed box of the single-box double-chamber end beam. The density of the iron sand concrete is 34kN / m³~40kN / m³, and it is poured to the designed height inside the box.

[0011] Furthermore, the counterweight between the beams is located between adjacent steel beams in the area near the top of the transition pier, and includes a counterweight longitudinal beam, a precast trough-shaped counterweight plate, and cast-in-place iron sand concrete counterweight. The counterweight longitudinal beams are arranged in pairs in the transverse direction of the bridge. A pair of counterweight longitudinal beams constitutes a single beam, which is installed on the lower flange of the adjacent steel crossbeam. The precast trough-shaped counterweight plate is a thin-walled cubic structure with an open top surface, and is reinforced with steel bars inside. It is precast as a whole with a small longitudinal counterweight beam. The cast-in-place iron sand concrete counterweight is poured into the precast trough-shaped counterweight plate to the design height marked inside the plate.

[0012] Furthermore, the height of the counterweight longitudinal beam is 500mm, and its web is connected to the stiffening ribs of the steel crossbeam by splicing plates and high-strength bolts. The precast trough-shaped counterweight plate has a side wall thickness of 12cm and a bottom plate thickness of 25cm. It is made of ordinary C40 concrete and is equipped with lifting rings for overall hoisting. The precast trough-shaped counterweight plate is connected to the counterweight longitudinal beam by upper flange shear studs.

[0013] Furthermore, the ballast transition section is a small longitudinal beam separately installed in a crossbeam section at the end of the ballast section, which is used to realize the stiffness transition between the ballast section and the standard section, while ensuring the out-of-plane stability of the steel crossbeam on the ballast side.

[0014] Furthermore, the length of the counterweight beam segment in the tail cable zone of the cable-stayed bridge body is 7.2 meters, and the length of the standard beam segment is 10.8 meters.

[0015] Furthermore, the transition pier support is a common spherical steel support; the transition pier support is arranged below the end crossbeam.

[0016] Compared with existing technologies, the double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system proposed in this application have the following advantages: Compared with existing technologies, the double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system proposed in this application have the following advantages: (1) This application sets up a side span counterweight system in the side span tail cable area of ​​the cable-stayed bridge body, which consists of a thickened precast bridge deck, an end crossbeam counterweight, an inter-crossbeam counterweight and a counterweight transition section arranged in sequence along the longitudinal direction of the bridge. This achieves the effect of effectively offsetting the negative reaction force of the side span support caused by the live load of the main span, avoiding the support detachment and the structural safety problems caused thereby. There is no need to set up tensile pull-out support, and ordinary spherical steel support can meet the usage requirements.

[0017] (2) This application achieves the effect of breaking down the weight into smaller parts by setting up a weight section between adjacent steel beams, consisting of a small longitudinal beam, a precast trough-shaped weight plate, and a cast-in-place iron sand concrete weight. This reduces the lifting weight of the steel beams in the weight section, eliminates the need for a larger bridge crane model, and eliminates the need to transport the weight to the bottom of the beam for construction later. This reduces the on-site construction risk, simplifies the design details of the bridge steel structure, reduces the amount of steel used, and reduces the workload of subsequent steel structure painting.

[0018] (3) This application adopts a single-box double-cell box-type end beam and arranges the transition pier support below the end beam. At the same time, a ballast transition part is set at the end of the side span ballast, which reduces the lateral spacing of the support, thereby reducing the engineering cost of the substructure. At the same time, it realizes the stiffness transition between the ballast section and the standard section, ensuring the out-of-plane stability of the ballast side steel beam. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the overall elevation structure of the double-sided I-beam composite girder cable-stayed bridge body and the side span counterweight system as described in the embodiments of this application; Figure 2 This is a schematic diagram showing the cross-sectional comparison between the standard beam segment and the counterweight beam segment described in the embodiments of this application; Figure 3 This is a schematic diagram of the longitudinal bridge planar layout of the side span counterweight system described in the embodiments of this application; Figure 4 This is a schematic diagram of the cross-sectional structure of the end beam counterweight section described in the embodiment of this application; Figure 5 This is a schematic diagram of the transverse cross-sectional structure of the inter-beam counterweight section described in the embodiments of this application; Figure 6 This is a schematic diagram of the longitudinal cross-sectional structure of the crossbeam counterweight section described in the embodiment of this application.

[0020] Explanation of reference numerals in the attached figures: 1. Cable-stayed bridge body; 101. Bridge tower; 102. Cable stays; 103. Double-sided I-beam steel-concrete composite beam; 1031. Double-sided I-beam side main beam; 1032. Steel crossbeam; 1033. Small longitudinal beam; 1034. Precast concrete bridge deck; 1035. Asphalt pavement; 1036. Crash guardrail; 1037. Longitudinal / transverse stiffening ribs; 1038. Cast-in-place micro-expansion concrete wet joint; 2. Side span counterweight system; 201. Thickened precast bridge deck; 202. End crossbeam counterweight section; 203. Crossbeam inter-counter counterweight section; 2031. Counterweight small longitudinal beam; 2032. Precast trough-shaped counterweight plate; 2033. Cast-in-place iron sand concrete counterweight; 2034. Lifting ring; 204. Counterweight transition section; 3. Support system; 301. Bridge tower bearing; 302. Transition pier bearing. Detailed Implementation

[0021] To make the technical solution and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0023] Furthermore, it should be noted that in the description of this application, if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings and 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. In addition, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] Furthermore, in the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "joining," and "connector" 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 between two components. Those skilled in the art can understand the specific meaning of the above terms in this application in light of the specific circumstances.

[0025] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0026] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0027] The purpose of this invention is to overcome the shortcomings of the prior art and provide a double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system, which can effectively solve the problem of negative reaction force at the transition pier or auxiliary pier support of conventional cable-stayed bridges, while reducing the amount of steel used in the counterweight structure, reducing the lifting weight of the counterweight section steel beam, simplifying the construction process, and reducing construction risks and overall project costs.

[0028] Reference Figure 1 The cable-stayed bridge body and side span counterweight system provided by the present invention include a cable-stayed bridge body 1, a side span counterweight system 2 and a support system 3.

[0029] The cable-stayed bridge body 1 is a double-tower, double-cable-stayed composite beam structure, including bridge towers 101, cable stays 102, and double-sided H-beam steel-concrete composite beams 103. Bridge towers 101 are reinforced concrete structures, H-shaped or diamond-shaped, symmetrically arranged along the bridge's centerline. Cable stays 102 are parallel wire cable stays, arranged in a fan shape, with their upper ends anchored to the tower anchorage zone of bridge tower 101 and their lower ends anchored to the side main beams of the double-sided H-beam steel-concrete composite beams 103. The double-sided H-beam steel-concrete composite beams 103 include double-sided H-beam side main beams 1031, steel crossbeams 1032, small longitudinal beams 1033, precast concrete bridge deck 1034, asphalt pavement 1035, and crash barriers 1036. The double-sided H-beam side main beams 1031 are welded H-beam sections, welded from the upper flange plate, web plate, and lower flange plate, arranged along the longitudinal direction of the bridge on both sides of the bridge deck. The double-sided I-beam main beams 1031 and steel crossbeams 1032 are fixedly connected by full penetration welding. The steel crossbeams 1032 and the small longitudinal beams 1033 are fixedly connected by friction-type high-strength bolts, together forming an integral steel beam grid frame. The precast concrete bridge deck 1034 is precast in sections, with each deck corresponding to one steel crossbeam segment, and is laid on top of the steel beam grid frame. Asphalt pavement 1035 is laid on top of the precast concrete bridge deck 1034, using a two-layer structure: a lower layer of coarse-grained asphalt concrete and an upper layer of fine-grained modified asphalt concrete. The crash barriers 1036 are reinforced concrete crash barriers, symmetrically arranged on both sides of the bridge deck, running longitudinally along the entire length of the bridge, and reliably connected to the precast concrete bridge deck 1034 by embedded steel bars.

[0030] The overall structure described above effectively solves the problem of negative reaction forces at the transition pier supports of conventional cable-stayed bridges. The side span counterweight system 2 adopts a multi-segment combination arrangement, allowing for flexible adjustment of the counterweight weight of each part according to actual calculation requirements, ensuring the counterweight effect while avoiding material waste caused by excessive counterweight. The support system 3 adopts a zoned arrangement, balancing the rationality of the overall bridge stress and the economy of the substructure.

[0031] The steel crossbeam 1032 includes a standard section of I-beam crossbeam, a counterweight section of I-beam crossbeam, and end crossbeams. The standard spacing of the steel crossbeams 1032 along the longitudinal direction of the bridge is 3.6 meters. Both the steel crossbeams 1032 and the double-sided I-beam side main beams 1031 are equipped with longitudinal and transverse stiffeners 1037. The longitudinal stiffeners are welded to the web surface along the length of the member, while the transverse stiffeners are arranged perpendicular to the longitudinal stiffeners. These stiffeners are used to improve the local stiffness and overall stability of the member, preventing local instability under load. (Refer to...) Figure 2The standard section of the I-beam crossbeam adopts a zigzag-shaped variable-height bottom plate, with its lower flange connected to the horizontal stiffening ribs of the web of the double-sided I-beam side main beam 1031 via full penetration welding. This design minimizes the amount of steel used in the crossbeams and reduces the overall self-weight of the bridge while meeting structural stress requirements. The counterweight section of the I-beam crossbeam and the end crossbeams both adopt a horizontal straight lower flange design, with their lower flanges connected to the lower flanges of the double-sided I-beam side main beam 1031 via full penetration welding. This provides a flat and continuous installation foundation for the counterweight components, ensuring that the counterweight load is evenly transferred to the double-sided I-beam side main beam 1031. The end crossbeams are single-box, double-cell box-type crossbeams, welded from a top plate, bottom plate, and three web plates, possessing high bending and torsional stiffness, and simultaneously meeting the dual functional requirements of counterweight bearing and support arrangement.

[0032] The standard section I-beam crossbeams adopt a zigzag-shaped variable-height base plate, which minimizes steel consumption while meeting structural stress requirements, thereby reducing the overall self-weight and construction cost of the bridge. The counterweight section I-beam crossbeams and end crossbeams use a horizontal, straight lower flange design, providing a flat installation foundation for the counterweight components and ensuring that the counterweight load is evenly distributed to the double-sided I-beam side main beams 1031. The longitudinal and transverse stiffening ribs 1037 effectively improve the local stiffness and overall stability of the steel crossbeams 1032 and the double-sided I-beam side main beams 1031, preventing local instability under load. The end crossbeams adopt a single-box, double-cell box-type structure, possessing high bending and torsional stiffness, simultaneously meeting the dual requirements of counterweight bearing capacity and support arrangement.

[0033] To facilitate the casting of longitudinal joints in the concrete bridge deck and reduce the span of the precast bridge deck, a small longitudinal beam 1033 is installed at the centerline of each steel crossbeam 1032. The small longitudinal beam 1033 uses a welded I-beam section, and its web is connected to the corresponding vertical stiffening ribs on the steel crossbeam 1032 using friction-type high-strength bolts. Adjacent precast concrete bridge decks 1034 are connected as a whole by cast-in-place micro-expansion concrete wet joints 1038. These wet joints 1038, welded to the steel beams with shear studs, form a composite beam structure system, enabling the precast concrete bridge decks 1034 and the steel beams to jointly bear vertical and horizontal loads. Connecting reinforcing bars are installed within the wet joints, lapped with the protruding reinforcing bars within the adjacent precast concrete bridge decks 1034, further enhancing the overall integrity of the bridge deck structure.

[0034] The construction method of using precast concrete bridge deck 1034 combined with cast-in-place micro-expansion concrete wet joints 1038 can significantly accelerate the construction progress of the bridge superstructure and reduce the amount of on-site concrete pouring. By using shear studs to achieve synergy between the concrete and steel beams, the mechanical properties of both materials can be fully utilized, improving the overall stiffness and load-bearing capacity of the composite beam. The micro-expansion concrete can effectively compensate for shrinkage deformation during the concrete hardening process, preventing cracks at the wet joints and ensuring the integrity and durability of the structure.

[0035] Side span counterweight system 2 is installed in the tail cable area of ​​the side span of the cable-stayed bridge body 1 to counteract the negative reaction force at the side span supports caused by the live load of the main span. (Refer to...) Figure 3 The side span counterweight system 2 includes a thickened precast bridge deck 201, an end crossbeam counterweight part 202, an inter-crossbeam counterweight part 203, and a counterweight transition part 204, with the above parts arranged sequentially along the longitudinal direction of the bridge.

[0036] The thickened precast bridge deck 201 covers the entire side span and has a thickness of 50 cm. The standard section's precast concrete bridge deck 1034 has a thickness of 28 cm. (Refer to...) Figure 2 This allows for a direct comparison of the thickness difference between the thickened precast bridge deck 201 and the standard precast concrete bridge deck 1034. The reinforcing steel in the thickened precast bridge deck 201 is correspondingly strengthened to meet the bending and shear resistance requirements after the increase in thickness. By thickening the bridge deck across the entire side span, the dead load weight of the concrete itself can provide foundation counterweight, offsetting part of the uplift force on the side span caused by the live load of the main span.

[0037] By thickening the precast concrete bridge deck across the entire side span to 50 centimeters, the dead load weight of the concrete itself can provide foundation counterweight, offsetting some of the uplift forces on the side span caused by the live load of the main span. This method eliminates the need for additional complex counterweight components, simplifies the construction process, and ensures that the counterweight load is evenly distributed on the main beam of the side span, avoiding the adverse effects of localized load concentration on the main beam.

[0038] Reference Figure 3 and Figure 4 The end beam counterweight section 202 is made of iron sand concrete poured into the closed box of the single-box double-cell end beam. The iron sand concrete is composed of cement, sand, iron sand, water-reducing agent, and water mixed according to the design mix proportions, with a density controlled between 34 kN / m³ and 40 kN / m³. Before pouring, elevation marks are set inside the box of the end beam. During pouring, an immersion vibrator is used to ensure the concrete is compacted. After pouring to the design height marked inside the box, curing is carried out.

[0039] The dead load of the end beam counterweight 202 will directly act on the transition pier support 302 below it, maximizing the contribution efficiency of the counterweight and achieving the greatest pull-out resistance with the smallest counterweight volume. The iron sand concrete has a high density, providing sufficient counterweight weight within the limited end beam box. The method of filling the enclosed box with concrete effectively protects the counterweight material from external environmental erosion, improving the durability of the counterweight system.

[0040] Reference Figure 3 , Figure 5 and Figure 6 The inter-beam counterweight 203 is located between adjacent steel crossbeams 1032 near the top of the transition pier, and includes counterweight longitudinal beams 2031, precast channel-shaped counterweight plates 2032, and cast-in-place iron sand concrete counterweights 2033. The counterweight longitudinal beams 2031 are arranged in pairs transversely, with each pair constituting one beam, installed above the lower flange of the adjacent steel crossbeam 1032. The counterweight longitudinal beams 2031 use welded I-beam sections with a height of 500 mm, and their webs are connected to the vertical stiffening ribs of the steel crossbeams 1032 via splice plates and friction-type high-strength bolts. The precast channel-shaped counterweight plate 2032 is a thin-walled cubic structure with an open top surface, internally reinforced with a two-way steel mesh, and is prefabricated integrally with one counterweight longitudinal beam 2031 in the factory. The precast trough-shaped counterweight plate 2032 has a side wall thickness of 12 cm and a bottom plate thickness of 25 cm, made of ordinary C40 concrete. During precasting, the upper flange of the counterweight longitudinal beam 2031 is embedded in the bottom plate of the precast trough-shaped counterweight plate 2032, and the two are reliably connected by shear studs welded to the upper flange of the counterweight longitudinal beam 2031. Lifting rings 2034, made of hot-rolled round steel, are installed at the top edge of the side plate of the precast trough-shaped counterweight plate 2032 and are embedded in the side plate concrete for overall lifting operations. Cast-in-place iron sand concrete counterweight 2033 is poured into the precast trough-shaped counterweight plate 2032. Before pouring, elevation marks are set inside the counterweight plate. After pouring to the design height marked inside the plate, vibration and curing are performed.

[0041] The inter-beam counterweight section 203 can provide supplementary counterweight as needed to further offset the negative reaction force of the side span support. Prefabricating the counterweight longitudinal beam 2031 and the precast trough-shaped counterweight plate 2032 as a whole enables factory prefabrication of the counterweight structure, ensuring component processing quality and reducing on-site construction workload. The counterweight load is transferred through the counterweight longitudinal beam 2031 to the steel crossbeam 1032, and then from the steel crossbeam 1032 to the double-sided I-beam side main beam 1031. The force transmission path is clear and well-defined, ensuring a uniform distribution of the counterweight load.

[0042] The counterweight longitudinal beam 2031 is connected to the steel crossbeam 1032 using high-strength bolts, ensuring convenient installation, high connection strength, and reliable connection between the counterweight structure and the main beam. The precast trough-shaped counterweight plate 2032 features a reasonable wall thickness design, reducing its own weight while meeting load-bearing requirements, facilitating overall hoisting operations. The lifting ring 2034 enables the overall hoisting of the combination of the counterweight longitudinal beam 2031 and the precast trough-shaped counterweight plate 2032 without requiring a larger bridge crane, reducing the investment cost of hoisting equipment. The reliable connection between the precast trough-shaped counterweight plate 2032 and the counterweight longitudinal beam 2031 is achieved through shear studs, ensuring that both share the load of the cast-in-place iron sand concrete counterweight 2033.

[0043] The counterweight transition section 204 is a small longitudinal counterweight beam separately installed in a crossbeam section at the end of the side span counterweight, as shown in the reference section. Figure 3 The location of the ballast transition section 204 at the end of the side span ballast system 2 is clearly visible. The structural form and connection method of the ballast longitudinal beam used in the ballast transition section 204 are exactly the same as those of the ballast longitudinal beam 2031 in the ballast section 203 between the crossbeams, but it does not have a precast trough-shaped ballast plate 2032 or a cast-in-place iron sand concrete ballast 2033. The ballast transition section 204 is used to achieve a stiffness transition between the ballast section and the standard section, and at the same time, it can provide lateral support for the steel crossbeam 1032 on the ballast side, ensuring the out-of-plane stability of the steel crossbeam 1032 on the ballast side.

[0044] The design of the counterweight transition section 204 avoids abrupt changes in stiffness between the counterweight section and the standard section, reduces stress concentration under load, and improves the fatigue performance of the bridge structure. Simultaneously, the counterweight longitudinal beam provides lateral support to the steel crossbeam 1032 on the counterweight side, effectively limiting the out-of-plane deformation of the steel crossbeam 1032 and ensuring its overall stability.

[0045] The length of the counterweight beam segment in the tail cable zone of the cable-stayed bridge body 1 is 7.2 meters, and the standard beam segment length is 10.8 meters. This beam segment length design matches the standard spacing of 3.6 meters for the steel crossbeams 1032, facilitating the standardized design and production of steel beam components. The shorter length of the counterweight beam segment allows for concentrated distribution of the counterweight load, improving counterweight efficiency, and also facilitates the prefabrication and hoisting of the counterweight beam segment. The aforementioned beam segment length design matches the standard spacing of 3.6 meters for the steel crossbeams 1032, facilitating the standardized design and production of steel beam components. The shorter length of the counterweight beam segment allows for concentrated distribution of the counterweight load, improving counterweight efficiency, and also facilitates the prefabrication and hoisting of the counterweight beam segment.

[0046] The support system 3 includes a bridge tower support 301 located below the double-sided I-beam side main beams 1031, and a transition pier support 302 located below the end crossbeams. (Refer to...) Figure 1The bridge tower supports 301 are located above the bridge tower crossbeams, corresponding to the lower positions of the double-sided I-beam side main beams 1031. Each bridge tower has four bridge tower supports 301, supporting the left and right sides of the double-sided I-beam side main beams 1031 respectively. The transition pier supports 302 are ordinary spherical steel supports, capable of meeting the requirements for vertical bearing capacity, horizontal displacement, and rotation. The transition pier supports 302 are arranged below the end crossbeams, with two transition pier supports 302 for each transition pier, supporting the lower positions of the left and right box girders of the end crossbeam respectively.

[0047] Since the side span counterweight system 2 can completely offset the negative reaction force of the side span supports caused by the live load of the main span, there is no need to install high-cost and difficult-to-maintain tensile supports. Ordinary spherical steel supports can meet the requirements, which greatly saves the project cost. Arranging the transition pier support 302 below the end crossbeam can reduce the lateral spacing of the supports, thereby reducing the transverse dimensions of the transition pier and the cantilever dimensions of the cap beam, further reducing the construction cost of the substructure.

[0048] The above descriptions are merely some embodiments of this application and are not intended to limit this application. The technical features or structures in the foregoing different embodiments can be arbitrarily combined to form other specific technical solutions as needed. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system, characterized in that, include: The cable-stayed bridge body (1) is a double-tower, double-cable-stayed composite beam structure, including bridge towers (101), cable stays (102), and double-sided I-beam steel-concrete composite beams (103); the double-sided I-beam steel-concrete composite beams (103) include double-sided I-beam side main beams (1031), steel crossbeams (1032), small longitudinal beams (1033), precast concrete bridge deck (1034), asphalt pavement (1035), and crash barriers (1036); the double-sided I-beam steel-concrete composite beams (1033) include double-sided I-beam side main beams (1031), steel crossbeams (1032), small longitudinal beams (1033), precast concrete bridge deck (1034), asphalt pavement (1035), and crash barriers (1036); The side I-beam main beam (1031) is fixedly connected to the steel crossbeam (1032), the steel crossbeam (1032) is fixedly connected to the small longitudinal beam (1033) to form a steel beam grid frame, the precast concrete bridge deck (1034) is laid on the steel beam grid frame, the asphalt pavement (1035) is laid on the precast concrete bridge deck (1034), and the crash barriers (1036) are symmetrically arranged on both sides of the bridge deck; The side span counterweight system (2) is set in the side span tail cable area of ​​the cable-stayed bridge body (1). It consists of a thickened precast bridge deck (201), an end crossbeam counterweight part (202), a crossbeam inter-counter counterweight part (203), and a counterweight transition part (204) arranged sequentially along the longitudinal direction of the bridge. It is used to counteract the negative reaction force of the side span support caused by the live load of the main span. The support system (3) includes a bridge tower support (301) located below the double-sided I-beam side main beam (1031) and a transition pier support (302) located below the end crossbeam.

2. The double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system according to claim 1, characterized in that, The steel crossbeam (1032) includes a standard section I-beam crossbeam, a counterweight section I-beam crossbeam, and an end crossbeam. The standard spacing of the steel crossbeam (1032) is 3.6m. Both the steel crossbeam (1032) and the double-sided I-beam side main beam (1031) are provided with longitudinal / transverse stiffening ribs (1037). The bottom plate of the standard section I-beam crossbeam adopts a zigzag-shaped variable beam height type, and its lower flange is welded to the horizontal stiffening rib of the web plate of the double-sided I-beam side main beam (1031). The counterweight section I-beam and end beam are both horizontal straight lines, and their lower flanges are welded to the lower flanges of the double-sided I-beam side main beam (1031). The end crossbeam is a single-box, double-cell box-type crossbeam.

3. The double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system according to claim 1, characterized in that, The adjacent precast concrete bridge decks (1034) are connected into a whole by cast-in-place micro-expansion concrete wet joints (1038); the cast-in-place micro-expansion concrete wet joints (1038) are connected to the steel beams by shear studs welded to the steel beams to form a composite beam structure system, so that the precast concrete bridge decks (1034) and the steel beams share the load.

4. The double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system according to claim 1, characterized in that, The thickened precast bridge deck (201) covers the entire side span and has a thickness of 50cm; the precast concrete bridge deck (1034) of the standard section has a thickness of 28cm.

5. The double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system according to claim 2, characterized in that, The end beam counterweight part (202) is iron sand concrete poured into the closed box of the single box double chamber end beam. The density of the iron sand concrete is 34kN / m³~40kN / m³, and it is poured to the designed height inside the box.

6. The double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system according to claim 1, characterized in that, The crossbeam counterweight (203) is located between adjacent steel crossbeams (1032) in the area near the top of the transition pier, and includes a counterweight small longitudinal beam (2031), a precast trough-shaped counterweight plate (2032), and a cast-in-place iron sand concrete counterweight (2033). The counterweight longitudinal beams (2031) are arranged in pairs in the transverse direction. A pair of counterweight longitudinal beams (2031) constitutes a frame and is installed on the lower flange of the adjacent steel crossbeam (1032). The prefabricated trough-shaped counterweight plate (2032) is a thin-walled cubic structure with an open top surface, and is reinforced with steel bars inside. It is prefabricated as a whole with a counterweight longitudinal beam (2031). The cast-in-place iron sand concrete weight (2033) is poured into the precast trough-shaped weight plate (2032) to the design height marked inside the plate.

7. The double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system according to claim 6, characterized in that, The height of the counterweight longitudinal beam (2031) is 500mm, and its web is connected to the stiffening rib of the steel crossbeam (1032) by splicing plates and high-strength bolts. The precast trough-shaped counterweight plate (2032) has a side plate wall thickness of 12cm and a bottom plate thickness of 25cm. It is made of ordinary C40 concrete and is equipped with lifting rings (2034) for overall hoisting. The precast trough-shaped counterweight plate (2032) and the counterweight longitudinal beam (2031) are connected by upper flange shear studs.

8. The double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system according to claim 1, characterized in that, The weight transition section (204) is a small longitudinal beam (2031) that is set separately in a crossbeam section at the end of the side span weight section. It is used to realize the stiffness transition between the weight section and the standard section, and at the same time ensure the out-of-plane stability of the weight side steel crossbeam (1032).

9. The double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system according to claim 1, characterized in that, The length of the counterweight beam segment in the tail cable zone of the cable-stayed bridge body (1) is 7.2 meters, and the length of the standard beam segment is 10.8 meters.

10. The double-sided I-beam composite girder cable-stayed bridge body and side span counterweight system according to claim 1, characterized in that, The transition pier support (302) is a common spherical steel support; the transition pier support (302) is arranged below the end crossbeam.

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