Steel-UHPC combined bridge deck structure for repairing steel bridge deck and construction method of steel-UHPC combined bridge deck structure

Abstract

The invention belongs to the technical field of bridge structure buildings, and discloses a steel-UHPC combined bridge deck structure for repairing a steel bridge deck and a construction method thereof.The steel-UHPC combined bridge deck structure comprises a steel bridge deck slab and a plurality of prefabricated UHPC boards, the prefabricated UHPC boards are bonded to the top face of the steel bridge deck slab, and a wet joint is reserved between every two adjacent prefabricated UHPC boards; a plurality of connecting pieces are welded to the portion, located in the wet joint, of the steel bridge deck slab, each connecting piece vertically extends upwards, the horizontal section of each connecting piece is annular, a plurality of protrusions or pits extending in the horizontal direction are arranged on the inner side or the outer side of each connecting piece, and a cast-in-place UHPC board is poured in the wet joint. The cast-in-place UHPC plates wrap all the connecting pieces and are connected with the two adjacent prefabricated UHPC plates and the steel bridge deck slab to form an integral structure. The prefabricated UHPC plates are bonded to the top face of the steel bridge deck, the wet joints are reserved between the adjacent prefabricated plates, connection is achieved through the annular connecting pieces welded to the portions, in the wet joints, of the steel bridge deck, and the problem that in the background technology, a traditional stud connecting piece is difficult to be matched with the UHPC ultrathin layer due to size specification limitation is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of bridge structure construction, and particularly relates to a steel-UHPC composite bridge deck structure for repairing steel bridge decks and a construction method thereof. Background Art

[0002] Orthotropic steel bridge decks are widely used in the bridge deck structures of extra-long-span bridges (main span ≥ 800m) due to their light weight, high strength, convenient construction, and excellent load-bearing performance. However, during long-term service, two core problems have emerged in this structural system, seriously affecting its structural safety and service life.

[0003] Firstly, there are significant fatigue cracking problems in the steel bridge deck. Due to the insufficient local stiffness in the connection area between the U-shaped ribs and the deck, high stress concentration areas are easily formed under the repeated loads of vehicles. Coupled with the inevitable residual stresses and defects during the welding process, fatigue cracks are prone to initiate and propagate in the structure, becoming a key factor affecting the safe service of the steel bridge deck.

[0004] Secondly, the durability of traditional asphalt pavement layers is poor, and there are common diseases such as rutting, spalling, and cracking. Especially under the combined action of heavy traffic, temperature changes, and water erosion, the deterioration speed accelerates, and the average maintenance cycle is less than 5 years. This not only significantly increases the operation and maintenance costs (the annual maintenance cost can reach 2 million yuan per kilometer), but also frequently causes traffic interruptions, seriously restricting the operation efficiency of the bridge.

[0005] To address the above problems, a steel-UHPC composite bridge deck system has been proposed in recent years. By effectively combining the ultra-high performance concrete (UHPC) layer with the steel deck through shear connectors, the overall performance of the structure is significantly improved by utilizing the excellent compressive strength, crack resistance, and durability of UHPC, becoming a new type of bridge deck structure form with broad application prospects. However, the existing technology still faces bottlenecks in connection structures: traditional stud connectors are restricted by size specifications (e.g., the minimum length of a φ10 stud needs to be ≥ 40mm), making it difficult to match the construction requirements of the ultra-thin UHPC layer (≤ 30mm); while custom-made small-sized studs not only have high costs (3 - 5 times that of conventional studs), but also have complex installation processes and high welding process requirements, making it difficult to achieve efficient and standardized construction.

[0006] Therefore, how to develop an economical and efficient connection structure suitable for steel-UHPC composite bridge decks while ensuring connection reliability and construction efficiency has become a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The present invention provides a steel-UHPC composite bridge deck structure for repairing steel bridge decks to solve the existing technical problems.

[0008] To solve the above technical problems, the technical solution proposed by the present invention is as follows:

[0009] A steel-UHPC composite bridge deck structure for repairing a steel bridge deck, comprising a steel bridge deck and a plurality of precast UHPC plates. The plurality of precast UHPC plates are bonded to the top surface of the steel bridge deck, and a wet joint is reserved between two adjacent precast UHPC plates. A plurality of connectors are welded on the steel bridge deck located in the wet joint. Each connector extends vertically upward, and the horizontal cross-section of each connector is annular, and a plurality of protrusions or depressions extending in the horizontal direction are provided on the inner side or the outer side. The wet joint is filled with a cast-in-place UHPC plate, and the cast-in-place UHPC plate wraps each connector and is connected to two adjacent precast UHPC plates and the steel bridge deck to form an integral structure.

[0010] As a further improvement of the above technical solution:

[0011] The plurality of connectors are arranged in an equidistant matrix on the steel bridge deck in the wet joint.

[0012] Threads are provided inside the ring of each connector.

[0013] Each connector is a hexagonal nut, and a hexagonal head bolt is threadedly connected to the hexagonal nut. An anti-loosening coating is applied to the mating part of the hexagonal nut and the hexagonal head bolt.

[0014] The upper surface of the hexagonal nut or the hexagonal head bolt is lower than the upper surface of the precast UHPC plate, and the upper surface of the cast-in-place UHPC plate is flush with the precast UHPC plate.

[0015] Each precast UHPC plate is bonded to the top surface of the steel bridge deck by epoxy resin glue.

[0016] The plurality of precast UHPC plates are arranged along the length direction of the steel bridge deck.

[0017] A steel bar grid is provided between two adjacent precast UHPC plates.

[0018] The steel bar grid includes extended steel bars and longitudinal steel bars. The extended steel bars are double-sided welded to two adjacent precast UHPC plates, and the longitudinal steel bars are tied and connected to a plurality of extended steel bars.

[0019] A construction method for a steel-UHPC composite bridge deck structure for repairing a steel bridge deck, comprising the following steps:

[0020] S1. Subgrade treatment: Remove the original bridge deck pavement and sandblast and rust-remove the steel bridge deck;

[0021] S2. Unit division and joint reservation: Divide the steel bridge deck into several standard units, and reserve a wet joint with a width of 150–200 mm between the units;

[0022] S3. Installation of connecting members: Weld hexagonal nuts in the wet joint area, apply a locking coating and then screw in hexagonal head bolts to form a shear connection group.

[0023] S4. Laying of precast UHPC slabs: Bond multiple precast UHPC slabs to the top surface of the steel bridge deck through epoxy resin adhesive and arrange them along the length direction.

[0024] S5. Erection of steel bar grid: Bind and connect the extended steel bars of adjacent precast UHPC slabs with longitudinal steel bars to form a space grid.

[0025] S6. Pouring of wet joint: Pour cast-in-place UHPC slabs in the wet joint to wrap the connecting members and connect with adjacent precast UHPC slabs to form an integral structure.

[0026] S7. Curing and opening to traffic: Open to traffic after curing.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] By bonding multiple precast UHPC slabs to the top surface of the steel bridge deck and leaving wet joints between adjacent precast slabs, and using annular connecting members welded on the steel bridge deck in the wet joints for connection, the problem in the background art that traditional stud connectors are difficult to match the ultra-thin UHPC layer due to size specification limitations is solved. The connecting members are provided with multiple protrusions or depressions extending in the horizontal direction, which enhances the mechanical biting force with the cast-in-place UHPC slabs. The cast-in-place UHPC slabs wrap the connecting members and form an integral structure with the precast UHPC slabs and the steel bridge deck, effectively improving the connection reliability and structural integrity, avoiding the high cost, complex construction and welding process problems of traditional small-sized studs, significantly improving the construction efficiency and economy, and effectively solving the bottleneck problem of the connection structure of the steel-UHPC composite bridge deck system in the background art. Through the combination of the bonding of precast UHPC slabs and the anchoring of connecting members, a collaborative shear resistance mechanism is formed, significantly enhancing the system reliability, effectively improving the bridge deck stiffness, inhibiting fatigue cracking and prolonging the service life of the paving layer, and being applicable to the efficient repair and reinforcement of super-long-span bridges. Modular prefabricated construction is realized, reducing the cast-in-place part and eliminating the need for the demoulding process, significantly shortening the on-site operation time, and being particularly applicable to the rapid repair of super-long-span bridges. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of a steel-UHPC composite bridge deck structure for repairing steel bridge decks.

[0031] Figure 2 is Figure 1 a schematic structural diagram of the local area A in

[0032] Legend description:

[0033] 1. Steel bridge deck; 11. Longitudinal stiffener 7; 12. Transverse stiffener; 2. Prefabricated UHPC slab; 3. Wet joint; 4. Connector; 41. Hexagonal nut; 42. Hexagon head bolt; 5. Cast-in-place UHPC slab; 6. Steel bar grid; 61. Extended steel bar; 62. Longitudinal steel bar. Specific implementation manners

[0034] To facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings of the specification and preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0035] Unless otherwise defined, all the professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0036] Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment, etc. used in the present invention can be obtained through the market or can be prepared by existing methods.

[0037] Embodiment: As Figure 1 and Figure 2As shown in the figure, the steel-UHPC composite bridge deck structure for repairing steel bridge decks in this embodiment includes a steel bridge deck 1 and a plurality of precast UHPC plates 2. The plurality of precast UHPC plates 2 are bonded to the top surface of the steel bridge deck 1, and a wet joint 3 is reserved between adjacent two precast UHPC plates 2. A plurality of connectors 4 are welded on the steel bridge deck 1 located in the wet joint 3. Each connector 4 extends vertically upward, and the horizontal cross-section of each connector 4 is annular, and a plurality of protrusions or depressions extending in the horizontal direction are provided on the inner side or the outer side. The wet joint 3 is filled with a cast-in-place UHPC plate 5. The cast-in-place UHPC plate 5 wraps each connector 4 and is connected to adjacent two precast UHPC plates 2 and the steel bridge deck 1 to form an integral structure. By bonding a plurality of precast UHPC plates 2 on the top surface of the steel bridge deck 1 and reserving a wet joint 3 between adjacent precast plates 2, and using the annular connectors 4 welded on the steel bridge deck 1 in the wet joint 3 for connection, the problem that traditional stud connectors in the background technology are difficult to match the UHPC ultra-thin layer (≤30mm) due to size specification limitations is solved. The connector 4 is provided with a plurality of protrusions or depressions extending in the horizontal direction, which enhances the mechanical biting force with the cast-in-place UHPC plate 5. The cast-in-place UHPC plate 5 wraps the connector 4 and forms an integral structure with the precast UHPC plate 2 and the steel bridge deck 1, effectively improving the reliability of the connection and the structural integrity, avoiding the high cost, complex construction and welding process problems of traditional small-sized studs, significantly improving the construction efficiency and economy, and effectively solving the bottleneck problem of the connection structure of the steel-UHPC composite bridge deck system in the background technology. Through the combination of the bonding of the precast UHPC plate 2 and the anchoring of the connector 4, a cooperative shear mechanism is formed, significantly improving the system reliability, effectively increasing the bridge deck stiffness, inhibiting fatigue cracking, and extending the service life of the paving layer, and is suitable for the efficient repair and reinforcement of super-large-span bridges. Modular prefabricated construction is realized, reducing the cast-in-place part and eliminating the need for a demoulding process, significantly shortening the on-site operation time, and is particularly suitable for the rapid repair of super-large-span bridges.

[0038] In this embodiment, a plurality of connectors 4 are arranged in an equidistant matrix on the steel bridge deck 1 in the wet joint 3. The lateral and longitudinal spacing is 100mm, which can effectively and evenly distribute the connection stress, improve the stability and durability of the overall structure, avoid local stress concentration, reduce the risk of fatigue crack generation, and ensure the long-term safe service of the steel-UHPC composite bridge deck structure.

[0039] In this embodiment, each connector 4 is a hexagonal nut 41. The hexagonal nut 41 has a simple structure and is easy to manufacture. Through its annular shape and the design of protrusions or depressions extending in the horizontal direction, the mechanical locking effect with the UHPC plate is enhanced. This design improves the reliability of the connection and the convenience of construction, and effectively solves the size and construction problems of traditional stud connectors.

[0040] In this embodiment, a hexagonal nut 41 is threadedly connected to a hexagonal head bolt 42. The M8 type hexagonal nut 41 is adopted, which has a compact structure and low cost. Its shape is beneficial to achieve good biting with the UHPC plate, improve the connection stability, simplify the construction process, and enhance the economy and practicability of the connector. The size thresholds of the hexagonal nut 41 and the hexagonal head bolt 42 are very wide, and their prices are low. Using them to replace the studs with limited sizes and the expensive customized small-sized studs can not only solve the problem that it is difficult for studs to be used as shear connectors between the thin-layer UHPC and the steel bridge deck, but also their low cost can bring huge economic benefits.

[0041] In this embodiment, the depth of the hexagonal head bolt 42 in the hexagonal nut 41 can be adjusted, so as to adjust the height of the entire connector 4.

[0042] In this embodiment, the mating part of the hexagonal nut 41 and the hexagonal head bolt 42 is coated with a loosening prevention coating. The mating part is coated with the loosening prevention coating, which effectively prevents the connector 4 from loosening, ensures the long-term stability of the structure, improves the reliability of the connection, reduces the maintenance frequency, effectively prevents the loosening problem caused by vibration or load, and improves the safety and service life of the steel-UHPC composite bridge deck structure.

[0043] In this embodiment, the upper surface of the hexagonal nut 41 or the hexagonal head bolt 42 is lower than the upper surface of the precast UHPC plate 2, and the upper surface of the cast-in-place UHPC plate 5 is flush with the precast UHPC plate 2. The height of the hexagonal nut 41 is less than 2 / 3 of the UHPC layer thickness. This avoids the influence of the connector on the flatness of the bridge deck, ensures the smoothness and construction quality of the overall bridge deck structure, effectively realizes the seamless connection between the bridge deck plates, improves the overall load-bearing performance and durability of the bridge deck, and solves the construction problems and use safety hazards caused by protruding components in the traditional connection method.

[0044] In this embodiment, each precast UHPC plate 2 is bonded to the top surface of the steel bridge deck 1 with epoxy resin glue. The epoxy resin glue is a two-component modified epoxy structural glue, and its shear strength after curing is ≥15 MPa, and the glue application thickness is controlled within the range of 1-3 mm. This realizes the firm bonding between the precast plate and the steel bridge deck and enhances the interfacial bonding performance. The application of the epoxy resin glue improves the durability and shear resistance of the connection, effectively prevents the problem of interlayer peeling, simplifies the construction process, improves the stability and service life of the overall structure. The epoxy resin glue realizes the adaptive matching of the connection height and the UHPC layer thickness, and overcomes the connection problem of the thin-layer structure. The comprehensive construction cost is reduced by 40%, which has significant technical and economic benefits.

[0045] In this embodiment, a plurality of precast UHPC plates 2 are arranged along the length direction of the steel bridge deck 1. This helps to achieve modular installation and rapid construction of the bridge deck structure, effectively disperses stress concentration, improves the bearing capacity and durability of the overall bridge deck structure. At the same time, combined with the steel-UHPC combination advantages in the background technology, the anti-fatigue and durability performance of the bridge deck is enhanced.

[0046] In this embodiment, a steel bar grid 6 is provided between two adjacent precast UHPC plates 2. This enhances the overall connection strength and crack resistance at the wet joint 3, effectively improves the durability and bearing capacity of the bridge deck structure, solves the problem of easy generation of fatigue cracks and cracks in the traditional connection method in the background technology, helps to achieve the overall coordinated work of the steel-UHPC composite bridge deck, and ensures the safety and stability of the structure.

[0047] In this embodiment, the steel bar grid 6 includes extending steel bars 61 and longitudinal steel bars 62. The extending steel bars 61 are double-sided welded to two adjacent precast UHPC plates 2, and the longitudinal steel bars 62 are tied and connected to a plurality of extending steel bars 61. This can ensure firm and reliable connection, form a stable steel bar framework, improve the overall mechanical performance of the wet joint 3, effectively enhance the overall stiffness and durability of the composite bridge deck structure, and solve the bottleneck problem of the connection structure in the background technology.

[0048] In this embodiment, each precast UHPC plate 2 is cast with ultra-high performance concrete, with a thickness of 30 mm, and structural steel bars 3b are arranged inside, with a steel bar diameter of 10 mm and a spacing of 25 mm. The length of the extending steel bars 61 is not less than 50 mm, and the spacing is 25 mm. The extending steel bars 61 of adjacent units are connected by lapping. The ultra-high performance concrete used is reactive powder concrete or ultra-high performance fiber-reinforced concrete with a compressive strength of not less than 100 MPa.

[0049] In this embodiment, longitudinal stiffeners 11 and transverse stiffeners 12 are provided under the steel bridge deck 1. An orthotropic steel bridge deck commonly used in super-long-span bridges is adopted. The thickness of the steel bridge deck 1 is 20 mm, the longitudinal stiffeners 11 below it are common U-shaped ribs with a thickness of 8 mm, and the thickness of the transverse stiffeners 12 is 10 mm.

[0050] In this embodiment, a construction method for a steel-UHPC composite bridge deck structure for repairing a steel bridge deck includes the following steps:

[0051] Step 1: Original bridge deck treatment. Remove the original bridge deck paving layer, and perform sandblasting and rust removal treatment on the surface of the steel bridge deck 1 to ensure subsequent bonding quality.

[0052] Step 2: Bridge deck unit division and joint setting. According to the on-site transportation and construction conditions, divide the steel bridge deck 1 into several standard unit areas, and reserve a wet joint 3 position with a width of 150–200 mm between adjacent units.

[0053] Step 3: Installation of connectors. On the steel bridge deck 1 within the wet joint 3 area, multiple connectors 4 are welded and arranged in an equidistant matrix. Each connector consists of a hexagon nut 41 and a hexagon head bolt 42. When the thickness of the cast-in-place UHPC slab 5 is insufficient, only the welded hexagon nut 41 can be retained as the shear connector. The hexagon nut 41 is welded to the steel bridge deck 1, and the welding height is less than 2 / 3 of the UHPC layer thickness. After welding, ultrasonic flaw detection is carried out; before the hexagon head bolt 42 is screwed into the nut, the thread should be coated with a locking coating.

[0054] Step 4: Bonding and installation of precast UHPC slabs 2. Multiple precast UHPC slabs 2 are arranged along the length direction of the steel bridge deck 1 and are adhesively fixed to the top surface of the steel bridge deck 1 by structural epoxy resin adhesive. The thickness of the applied adhesive is controlled within 1–3 mm. It is necessary to ensure that the steel surface is clean and dry before bonding; positioning jigs are used during installation to ensure flatness and accuracy.

[0055] Step 5: Connection structure of the steel bar grid 6. A steel bar grid 6 is arranged between two adjacent precast UHPC slabs 2, including: double-sided welding and connecting the extended steel bars 61 on both sides of the precast UHPC slabs; then binding longitudinal steel bars 62 to form a spatial steel bar framework structure to provide structural continuity for the wet joint.

[0056] Step 6: Construction of the cast-in-place UHPC slab. Formwork is supported within the wet joint 3 to enclose a pouring space, and ultra-high performance concrete is used for on-site pouring to form the cast-in-place UHPC slab 5. The strength grade of the UHPC material is the same as that of the precast UHPC slab 2, and the compressive strength ≥ 100 MPa to ensure the overall structural consistency.

[0057] Step 7: Curing and opening to traffic. Standard curing is carried out for 7 days after casting, and traffic is opened after reaching the design strength.

[0058] In this embodiment, the welding operation adopts the segmented backstep welding process to control the interlayer temperature not exceeding 150 °C; the hexagon nut shall comply with the standard of GB / T 13681-1992, and the bolt shall comply with the standard of GB / T 5783-2016; gas shielded welding is used for welding, the welding spacing is controlled within 50–100 mm, and the allowable error of the welding position does not exceed ±2 mm.

Claims

1. A steel-UHPC composite bridge deck structure for repairing steel bridge decks, comprising a steel bridge deck (1) and a plurality of precast UHPC plates (2), characterized in that, A plurality of the precast UHPC plates (2) are bonded to the top surface of the steel bridge deck (1), a wet joint (3) is reserved between two adjacent precast UHPC plates (2), a plurality of connecting members (4) are welded on the steel bridge deck (1) located in the wet joint (3), each of the connecting members (4) extends vertically upward, the horizontal cross-section of each of the connecting members (4) is annular, and a plurality of protrusions or depressions extending in the horizontal direction are provided on the inner side or the outer side thereof. The wet joint (3) is filled with a cast-in-place UHPC plate (5), and the cast-in-place UHPC plate (5) wraps each of the connecting members (4) and is connected to two adjacent precast UHPC plates (2) and the steel bridge deck (1) to form an integral structure.

2. The steel-UHPC composite bridge deck structure for repairing steel bridge decks according to claim 1, wherein, A plurality of the connecting members (4) are arranged in an equidistant matrix on the steel bridge deck (1) within the wet joint (3).

3. The steel-UHPC composite bridge deck structure for repairing steel bridge decks according to claim 2, wherein, Threads are provided inside the ring of each of the connecting members (4).

4. The steel-UHPC composite bridge deck structure for repairing steel bridge decks according to claim 3, characterized in that, Each of the connecting members (4) is a hexagonal nut (41), a hexagonal head bolt (42) is threadedly connected in the hexagonal nut (41), and an anti-loosening coating is applied to the mating part of the hexagonal nut (41) and the hexagonal head bolt (42).

5. The steel-UHPC composite bridge deck structure for repairing steel bridge decks according to claim 4, characterized in that, The upper surface of the hexagonal nut (41) or the hexagonal head bolt (42) is lower than the upper surface of the precast UHPC plate (2), and the upper surface of the cast-in-place UHPC plate (5) is flush with the precast UHPC plate (2).

6. The steel-UHPC composite bridge deck structure for repairing steel bridge decks according to claim 1, wherein Each of the precast UHPC plates (2) is bonded to the top surface of the steel bridge deck (1) by epoxy resin adhesive.

7. The steel-UHPC composite bridge deck structure for repairing steel bridge decks according to claim 1, characterized in that, A plurality of the precast UHPC plates (2) are arranged along the length direction of the steel bridge deck (1).

8. The steel-UHPC composite bridge deck structure for repairing steel bridge decks according to claim 1, wherein, A steel bar grid (6) is provided between two adjacent precast UHPC plates (2).

9. The steel-UHPC composite bridge deck structure for repairing steel bridge decks according to any one of claims 1-8, characterized in that, The steel bar grid (6) includes extended steel bars (61) and longitudinal steel bars (62), the extended steel bars (61) are double-sided welded to two adjacent precast UHPC plates (2), and the longitudinal steel bars (62) are tied and connected to a plurality of extended steel bars (61).

10. A construction method for a steel-UHPC composite bridge deck structure used for repairing steel bridge decks, characterized in that, It includes the following steps: S1. Substrate treatment: Remove the original bridge deck pavement and sandblast and rust-remove the steel bridge deck (1). S2. Unit division and joint reservation: Divide the steel bridge deck into several standard units, and reserve a wet joint (3) with a width of 150 - 200 mm between the units. S3. Install the connecting members (4): Weld hexagonal nuts (41) in the wet joint (3) area, apply an anti-loosening coating and then screw in hexagonal head bolts (42) to form a shear connection group. S4. Lay the precast UHPC plates (2): Bond a plurality of precast UHPC plates (2) to the top surface of the steel bridge deck (1) by epoxy resin adhesive and arrange them along the length direction. S5. Erect the steel bar grid (6): Tie and connect the extended steel bars (61) and longitudinal steel bars (62) of two adjacent precast UHPC plates (2) to form a space grid. S6. Pour the wet joint: Pour a cast-in-place UHPC plate (5) in the wet joint (3) to wrap the connecting members (4) and connect with two adjacent precast UHPC plates (2) to form an integral structure. S7. Maintenance and opening: Open to traffic after maintenance.

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