Method for improving shear resistance of connection section of assembly type composite bridge structure

Abstract

The invention discloses a method for improving the shear resistance of a connection section of a fabricated composite bridge structure, the shear resistance is improved through optimal combination of core components and improvement of a connection structure, the related core components comprise a corrugated steel composite web, an upper flange composite plate and a lower flange composite plate, and the corrugated steel composite web, the upper flange composite plate and the lower flange composite plate are combined through optimal combination of the components and improvement of the connection structure. And the shear resistance of the connection section is improved in a targeted manner. The key structure is as follows: firstly, the upper and lower edges of the corrugated steel web and the edges of the upper and lower composite flange plate steel members are correspondingly welded through two continuous fillet welds to form an integral stress steel skeleton; secondly, a perforated steel plate connecting piece is welded to the upper side of the upper flange steel plate through two spaced fillet welds, and a transverse steel bar horizontally penetrates through a circular hole of the connecting piece; thirdly, concrete slabs are poured on the outer sides of the box-shaped section corrugated steel webs and the surfaces of the upper flange steel plate and the lower flange steel plate according to the designed thickness; fourthly, welding interfaces of the corrugated steel webs and the flange plates are arranged in a staggered mode in the longitudinal direction of the bridge deck relative to splicing welding seams of the flange plates.

Description

Technical Field

[0001] This invention relates to the field of structural engineering technology, specifically to a method for improving the shear resistance of the connection section of a prefabricated composite bridge structure. Background Technology

[0002] Bridge engineering places higher demands on construction efficiency, material economy, and structural durability. Bridge structures are widely used not only in urban overpasses, subways, light rail, and high-speed railways, but also in cross-river and cross-sea structures. In recent years, with the construction of mega-bridge projects such as the Hong Kong-Zhuhai-Macau Bridge and the Hangzhou Bay Bridge, bridge structures both domestically and internationally are facing unprecedented development opportunities. Currently, traditional concrete box girder bridges, widely used in bridge structures, employ reinforced concrete or prestressed concrete as the core material. They form a closed box section enclosed by top and bottom slabs, webs, and diaphragms. The top and bottom flanges serve as the main load-bearing components, bearing the bending moments and axial forces generated during bridge operation; the webs are vertical load-bearing components, connecting the top and bottom flanges and transmitting shear forces. The closed section of traditional concrete box girder bridge structures gives the structure excellent bending, shear, and torsional resistance, with uniform internal force distribution under load, effectively dispersing the impact of concentrated loads on local sections.

[0003] Traditional prestressed concrete box girder bridges suffer from excessive self-weight and a high proportion of concrete web in the structural load-bearing capacity, which is a significant disadvantage in long-span bridges. Furthermore, the shrinkage, creep, and temperature changes in concrete lead to stress concentration at the junction of the web and the top and bottom slabs, causing cracks that severely impact structural durability and safety, resulting in high maintenance costs. Concrete-corrugated steel composite web box girder bridges, by replacing the concrete web with corrugated steel plates, completely eliminate the cracking problems caused by shrinkage, creep, and temperature changes in the concrete web, improving structural durability and safety. The corrugated steel web does not bear bending moments, only shear forces, resulting in a more rational stress state and avoiding the cracking risk under the complex stress state of traditional concrete webs. It also significantly reduces the weight of the web, decreasing the amount of engineering work required for the substructure and foundation. Prestress can be fully applied to resist external loads, improving material utilization. Moreover, compared to flat steel plates, the corrugated steel plate structure can withstand more downward pressure as the web, thus meeting both load-bearing capacity and economic efficiency requirements.

[0004] The combination of the composite bridge structure with prefabricated construction technology amplifies the lightweight and high durability advantages of the bridge structure itself, while overcoming many limitations of traditional cast-in-place methods, demonstrating multiple core values ​​throughout the entire construction cycle. In terms of construction efficiency, core components such as corrugated steel webs and composite flanges can be precisely processed and pre-assembled in the factory, unaffected by on-site weather or geological conditions, ensuring strong controllability of the production process. On-site work only requires segmental splicing, weld treatment, and a small amount of protective layer construction.

[0005] Although the prefabricated construction process is well-suited to the bridge structure, it still faces a series of technical and engineering challenges in its practical application. Regarding the performance assurance of the connection nodes, the load-bearing reliability of the prefabricated bridge is highly dependent on the splicing quality between the segments. The splicing nodes of the concrete-corrugated steel composite web structure involve complex force transmission mechanisms such as steel-steel welding and steel-concrete collaborative stress. The splicing welds between the corrugated steel web and the composite flange plate need to withstand shear force, axial force and temperature stress simultaneously, which is prone to stress concentration. Under long-term repeated vehicle loads, fatigue cracks may develop, affecting structural safety. Summary of the Invention

[0006] To address the problems existing in traditional prefabricated composite bridge structures, this invention proposes a method for improving the shear resistance of the connection section of prefabricated composite bridge structures. This method aims to solve the problems of weak shear resistance at the segment splicing points of prefabricated composite bridges, easy stress concentration in welds, easy slippage of the steel-concrete interface, and insufficient structural durability. It is applicable to the segment splicing parts of prefabricated composite bridges.

[0007] This invention improves shear resistance through optimized combination and improved connection structure of core components. The core components include a corrugated steel composite web, an upper flange composite plate, and a lower flange composite plate. Optimized combination and improved connection structure of these components specifically enhance the shear resistance of the connection sections. Key structures are as follows: First, the upper and lower edges of the corrugated steel web are welded to the edges of the upper and lower composite flange steel components via two continuous fillet welds, forming an integral load-bearing steel skeleton. Second, perforated steel plate connectors are welded to the upper side of the upper flange steel plate via two spaced fillet welds, with transverse reinforcing bars horizontally passing through the circular holes of the connectors. Third, a layer of concrete slab of the designed thickness is poured onto the outer side of the box-section corrugated steel web and the surfaces of the upper and lower flange steel plates. Fourth, the welding interface between the corrugated steel web and the flange plates is staggered longitudinally along the bridge deck relative to the flange plate's own splicing welds.

[0008] A method for improving the shear resistance of the connection section of a prefabricated composite bridge structure, comprising prefabricated composite bridge units, wherein the prefabricated composite bridge units include: The upper flange composite plate includes an upper flange steel plate and an upper flange concrete plate disposed on the upper flange steel plate; The lower flange composite plate includes a lower flange steel plate and a lower flange concrete plate disposed below the upper flange steel plate; A corrugated steel composite web is disposed between the upper flange composite plate and the lower flange composite plate, and the upper flange composite plate and the lower flange composite plate are parallel. The corrugated steel composite web includes a corrugated steel web and an outer concrete plate disposed on the corrugated steel web. One end of the corrugated steel web protrudes slightly from the upper flange steel plate and the lower flange steel plate, forming an inner connecting end; The other end of the corrugated steel web protrudes slightly from the upper flange steel plate and the lower flange steel plate, forming an external connection end; The method for improving the shear resistance of the connection section includes the following steps: S1: Insert the inner connection end of the next prefabricated composite bridge unit into the outer connection end of the previous prefabricated composite bridge unit, and weld the inner connection end and the outer connection end together. S2: Weld the upper flange steel plate of the previous prefabricated composite bridge unit to the upper flange steel plate of the next prefabricated composite bridge unit, and weld the lower flange steel plate of the previous prefabricated composite bridge unit to the lower flange steel plate of the next prefabricated composite bridge unit. S3: A concrete blank section is left at the connection between the previous prefabricated composite bridge unit and the next prefabricated composite bridge unit. Perforated steel plate connectors are welded to the concrete blank section, and transverse steel bars are passed through the perforated steel plate connectors. Finally, concrete is poured on the concrete blank section to form a prefabricated composite bridge structure.

[0009] In the prefabricated composite bridge unit, the length of the upper flange concrete slab is shorter than the length of the upper flange steel plate, so that after the upper flange steel plates of two adjacent prefabricated composite bridge units are welded, a concrete blank section will be left.

[0010] The edge of the corrugated steel web is welded to the upper flange steel plate and the lower flange steel plate to form a composite bridge structure steel skeleton that is subjected to overall stress.

[0011] The perforated steel plate connector is provided with multiple circular holes, the diameter of which is adapted to the diameter of the transverse reinforcing bar. The transverse reinforcing bar passes through the circular holes and through the perforated steel plate connector.

[0012] In step S3, the thickness of the concrete poured on the blank concrete section covers the perforated steel plate connector.

[0013] The method for improving the shear resistance of the connection section of the prefabricated composite bridge structure is applied to the segmental splicing part of the prefabricated composite bridge to improve the shear bearing capacity at the splicing part of the prefabricated composite bridge structure. The core components involved in the method include corrugated steel composite web, upper flange composite plate, and lower flange composite plate. Through optimized combination of components and improvement of connection structure, the shear resistance of the connection section is improved in a targeted manner.

[0014] The method for improving the shear resistance of the connection section of the prefabricated composite bridge structure involves welding the upper and lower edges of the corrugated steel web to the edges of the steel components of the composite flange plate through two continuous fillet welds to form an integrally stressed composite bridge structure steel skeleton, which provides a stable initial shear foundation for the connection section of the prefabricated composite bridge structure.

[0015] The method for improving the shear resistance of the connection section of the prefabricated composite bridge structure involves welding a perforated steel plate connector with two fillet welds on the upper flange steel plate. The diameter of the circular hole on the perforated steel plate connector is adapted to the diameter of the transverse reinforcement. The transverse reinforcement passes horizontally through the circular hole and through the steel plate, thereby enhancing the shear resistance of the interface.

[0016] A layer of concrete slab is poured on the outer surface of the corrugated steel web of the box section and the outer surface of the flange steel plate. The thickness of the concrete slab on the upper flange plate should be higher than the height of the perforated steel plate connector, so as to cooperate with the steel components and transverse reinforcement to share the load and further improve the shear bearing capacity of the connection section.

[0017] The method for improving the shear resistance of the connection section of the prefabricated composite bridge structure involves staggering the welding interfaces of the corrugated steel web and the upper flange steel plate, and the welding interfaces of the corrugated steel web and the lower flange steel plate, relative to the splicing welding interfaces of the plates themselves, along the longitudinal direction of the bridge deck. The staggered distance is not less than the minimum spacing required by the design specifications. This is to avoid the concentrated superposition of welds, reduce stress concentration, and thus improve the overall shear resistance and stress stability of the connection section of the composite bridge structure after welding.

[0018] The method for improving the shear resistance of the connection section of the prefabricated composite bridge structure proposed in this invention is composed of a composite web, a composite flange, and a concrete slab. Furthermore, the welding interfaces between the corrugated steel web and the upper flange, and between the corrugated steel web and the lower flange, are staggered longitudinally along the bridge deck relative to the splicing welding interfaces of the upper and lower flanges themselves, respectively. This has the following advantages: (1) The method for improving the connection interface of the prefabricated composite bridge structure invented uses concrete slabs to wrap the internal steel frame, which can effectively block the steel from the external environment, prevent the steel from rusting, and improve the toughness, corrosion resistance and durability of the bridge deck structure.

[0019] (2) The method for improving the connection interface of the prefabricated composite bridge structure invented by welding two continuous fillet welds in a corresponding manner can accurately meet the shear resistance requirements of the connection section of the prefabricated composite bridge, significantly improve the shear bearing capacity, and make the force transmission path clear and reliable. The complete connection of the continuous welds makes the corrugated steel web and the upper and lower composite flanges form an inseparable integral steel skeleton, which effectively constrains the relative displacement of each component and avoids problems such as interface slippage and segment misalignment that may occur in the prefabricated splicing. (3) The prefabricated composite bridge structure connection interface improvement method invented adopts a construction method that combines perforated steel plate connectors with transverse reinforcing bars to ensure the shear connection effect between the steel frame and the concrete; the perforated steel plate connectors with two fillet welds are welded to the upper flange steel plate to play a pull-out resistance role and prevent the steel and concrete interface from separating; the system avoids the use of studs, significantly reduces construction complexity and costs, and significantly improves the fatigue performance of the structure.

[0020] (4) The prefabricated composite bridge structure connection interface improvement method invented uses perforated steel plate connectors as longitudinal reinforcement in the longitudinal direction of the bridge deck. Therefore, the use of longitudinal reinforcement can be avoided by appropriately adjusting the size of the steel plate, reducing the amount of steel used and avoiding the binding of steel mesh, thereby significantly improving construction efficiency and reducing costs.

[0021] (5) The method for improving the connection interface of the prefabricated composite bridge structure invented avoids the problems of dense stiffening ribs when using flat steel webs, requiring a large amount of welding work during factory processing, and complex node handling during on-site assembly; while the corrugated steel web structure is simple and can be continuously formed using an automated production line during factory prefabrication; at the same time, its characteristic of not requiring dense stiffening ribs reduces the amount of steel used, combined with the savings in foundation engineering brought about by lightweighting. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the connection of a prefabricated composite bridge structure using this method; Figure 2 This is a schematic diagram of a prefabricated composite bridge structure using this method; Figure 3 This is a side view of a prefabricated composite bridge structure using this method. Detailed Implementation

[0023] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] like Figure 1 and Figure 3As shown, a method for improving the shear resistance of the connection section of a prefabricated composite bridge structure includes the following components: an upper flange concrete slab 1, an upper flange steel plate 2, transverse reinforcing bars 3, perforated steel plate connectors 4, a corrugated steel web 5, a concrete web 6, a lower flange steel plate 7, and a lower flange concrete slab 8. Applied to the segmental splicing parts of prefabricated composite bridges, this method enhances the shear bearing capacity of the splice joints of the prefabricated composite bridge structure through optimized component combination and improved connection structure. The corrugated steel composite web includes a corrugated steel web 5 and an outer concrete slab 5; the upper flange composite slab includes an upper flange steel plate 2 and an upper flange concrete slab 1, as well as perforated steel plate connectors for steel-concrete interface connection; the lower flange composite slab includes a lower flange steel plate 7 and a lower flange concrete slab 8, as well as perforated steel plate connectors for steel-concrete interface connection.

[0025] like Figure 1 and Figure 2 As shown, the upper and lower edges of the corrugated steel web 5 are respectively welded to the steel component edges of the upper and lower composite flange plates through two continuous fillet welds. The welds must be full, continuous, and free of welding defects to form a composite bridge structure steel skeleton that bears the overall load, providing a stable initial shear foundation for the connection section.

[0026] like Figure 2 and Figure 3 As shown, this is a prefabricated composite bridge unit, which includes: an upper flange composite plate 2, comprising an upper flange steel plate 2 and an upper flange concrete plate 1 disposed on the upper flange steel plate 2; a lower flange composite plate, comprising a lower flange steel plate 7 and a lower flange concrete plate 8 disposed below the upper flange steel plate 7; a corrugated steel composite web, disposed between the upper flange composite plate and the lower flange composite plate, with the upper flange composite plate and the lower flange composite plate being parallel; the corrugated steel composite web includes a corrugated steel web 5 and an outer concrete plate disposed on the corrugated steel web 6; one end of the corrugated steel web protrudes slightly from the upper flange steel plate and the lower flange steel plate, forming an inner connecting end; the other end of the corrugated steel web protrudes slightly from the upper flange steel plate and the lower flange steel plate, forming an outer connecting end. Figure 2 and Figure 3 as well as Figure 1 Each prefabricated composite bridge unit has an inner connection end at one end and an outer connection end at the other end. Some of the structure at the connection end is not shown.

[0027] like Figure 1 As shown, two fillet welds are arranged at intervals along the length of the upper flange steel plate. A perforated steel plate connector is welded on the upper side of the upper flange steel plate. The diameter of the round hole on the perforated steel plate connector is matched with the diameter of the transverse reinforcement. The transverse reinforcement 3 passes horizontally through the round hole and passes through the steel plate to form a steel-concrete synergistic shear force transmission system, which enhances the shear resistance of the interface.

[0028] like Figure 1 , Figure 2 and Figure 3 As shown, a concrete slab of the designed thickness is poured on the outer surface of the corrugated steel web of the box section, the upper surface of the upper flange steel plate, and the lower surface of the lower flange steel plate. The thickness of the concrete slab should be higher than the height of the perforated steel plate connector. The concrete slab not only plays a protective role against corrosion and seepage, but also works together with the steel components and transverse reinforcement to share the load, further improving the shear bearing capacity of the connection section.

[0029] like Figure 1 and Figure 3 The welding interfaces of the corrugated steel web and the upper flange steel plate, and the welding interfaces of the corrugated steel web and the lower flange steel plate shown are staggered along the longitudinal direction of the bridge deck relative to the splicing welding interfaces of the upper and lower flange plates themselves. The staggered distance is not less than the minimum spacing required by the design specifications. By avoiding the concentrated superposition of welds, stress concentration is reduced, thereby improving the overall shear resistance and stress stability of the welded connection section of the composite bridge structure.

[0030] This invention addresses the problems of weak shear resistance, stress concentration in welds, slippage at the steel-concrete interface, and insufficient durability at the joints of prefabricated composite bridge segments. It proposes a method to improve the shear resistance of the joint sections. Through component combination optimization and structural innovation, it achieves a synergistic improvement in shear resistance, durability, and economy.

[0031] The core technology of this invention comprises four aspects: First, the upper and lower edges of the corrugated steel web and the edges of the upper and lower composite flange steel components are welded together by two continuous fillet welds to form an integral load-bearing steel skeleton, laying a stable initial shear-resistant foundation; Second, perforated steel plate connectors are welded to the upper side of the upper flange steel plate by two spaced fillet welds, with transverse reinforcing bars horizontally passing through the circular holes, forming a steel-concrete collaborative shear-resistant force transmission system, replacing traditional studs; Third, concrete slabs of the designed thickness are poured on the outer side of the box-section corrugated steel web and the surfaces of the upper and lower flange steel plates, taking into account both protection and collaborative load-bearing; Fourth, the welding interface between the corrugated steel web and the flange plate is staggered longitudinally relative to the splicing welds of the flange plate itself, with the staggered distance meeting the specification requirements and avoiding concentrated overlap of welds.

[0032] This method possesses multiple core advantages: First, the outer concrete slab can block external environmental erosion, prevent steel corrosion, and significantly improve structural toughness, corrosion resistance, and durability. The concrete slab can also work in synergy with steel components and transverse reinforcement to further enhance structural load-bearing capacity. Second, the integral steel skeleton formed by two continuous fillet welds constrains the relative displacement of components, preventing interface slippage and segment misalignment. Combined with the staggered design of the welded interfaces, stress concentration is reduced, significantly improving the shear bearing capacity and stress stability of the connection section. Third, the combination of perforated steel plate connectors and transverse reinforcement can achieve a complete shear connection effect, effectively replacing traditional studs and eliminating the material and construction costs of studs, as well as the negative impact of welding on fatigue performance. Furthermore, the perforated steel plate can replace longitudinal reinforcement, eliminating the need for reinforcement tying, reducing material costs, and shortening the construction period. Fourth, the corrugated steel web structure is simple, requiring no dense stiffening ribs, and is suitable for automated prefabrication in factories, reducing on-site welding and wet work, lowering construction complexity. At the same time, its lightweight characteristics save on foundation engineering costs, meeting the core requirements of prefabricated construction.

Claims

1. A method for improving the shear resistance of the connection section of a prefabricated composite bridge structure, characterized in that, The bridge employs prefabricated composite bridge units, which include: The upper flange composite plate includes an upper flange steel plate and an upper flange concrete plate disposed on the upper flange steel plate; The lower flange composite plate includes a lower flange steel plate and a lower flange concrete plate disposed below the upper flange steel plate; A corrugated steel composite web is disposed between the upper flange composite plate and the lower flange composite plate, and the upper flange composite plate and the lower flange composite plate are parallel. The corrugated steel composite web includes a corrugated steel web and an outer concrete plate disposed on the corrugated steel web. One end of the corrugated steel web protrudes slightly from the upper flange steel plate and the lower flange steel plate, forming an inner connecting end; The other end of the corrugated steel web protrudes slightly from the upper flange steel plate and the lower flange steel plate, forming an external connection end; The method for improving the shear resistance of the connection section includes the following steps: S1: Insert the inner connection end of the next prefabricated composite bridge unit into the outer connection end of the previous prefabricated composite bridge unit, and weld the inner connection end and the outer connection end together. S2: Weld the upper flange steel plate of the previous prefabricated composite bridge unit to the upper flange steel plate of the next prefabricated composite bridge unit, and weld the lower flange steel plate of the previous prefabricated composite bridge unit to the lower flange steel plate of the next prefabricated composite bridge unit. S3: A concrete blank section is left at the connection between the previous prefabricated composite bridge unit and the next prefabricated composite bridge unit. Perforated steel plate connectors are welded to the concrete blank section, and transverse steel bars are passed through the perforated steel plate connectors. Finally, concrete is poured on the concrete blank section to form a prefabricated composite bridge structure.

2. The method for improving the shear resistance of the connection section of the prefabricated composite bridge structure according to claim 1, characterized in that, In the prefabricated composite bridge unit, the length of the upper flange concrete slab is shorter than the length of the upper flange steel plate, so that after the upper flange steel plates of two adjacent prefabricated composite bridge units are welded, a concrete blank section will be left.

3. The method for improving the shear resistance of the connection section of the prefabricated composite bridge structure according to claim 1, characterized in that, The edge of the corrugated steel web is welded to the upper flange steel plate and the lower flange steel plate to form a composite bridge structure steel skeleton that is subjected to overall stress.

4. The method for improving the shear resistance of the connection section of the prefabricated composite bridge structure according to claim 1, characterized in that, The perforated steel plate connector is provided with multiple circular holes, the diameter of which is adapted to the diameter of the transverse reinforcing bar. The transverse reinforcing bar passes through the circular holes and through the perforated steel plate connector.

5. The method for improving the shear resistance of the connection section of the prefabricated composite bridge structure according to claim 1, characterized in that, In step S3, the thickness of the concrete poured on the blank concrete section covers the perforated steel plate connector.

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