Double-thin-layer UHPC-NC laminated bridge deck slab

Abstract

The utility model relates to the technical field of bridge engineering, in particular to a double-thin-layer UHPC-NC laminated bridge deck slab. The problem that an existing common bridge deck is poor in cracking durability is solved, and meanwhile the problems that an existing UHPC bridge deck is high in price and difficult to popularize are solved. The structure comprises a prefabricated UHPC bottom plate, a common concrete cast-in-place layer and a UHPC-CA top plate. The prefabricated UHPC bottom plate is prefabricated in a factory, and the common concrete cast-in-place layer is formed on the prefabricated UHPC bottom plate; and the UHPC-CA top plate is formed on the common concrete cast-in-place layer. By the adoption of the double-thin-layer UHPC-NC composite bridge deck slab composite structure, the purposes of reducing the engineering production cost, being more convenient to construct and better in durability can be achieved, meanwhile, the problems that UHPC is high in price and difficult to popularize can be solved, and the application prospect is wide.

Description

Technical Field

[0001] The utility model relates to the technical field of bridge engineering, in particular to a double-thin-layer UHPC-NC composite bridge deck. Background Art

[0002] The bridge deck is located in the bridge's superstructure, directly laid atop the bridge's main beams, crossbeams, and other load-bearing components. Its primary function is to withstand various traffic loads from vehicles and pedestrians, transferring these loads to the substructure, and providing a smooth, stable driving surface for vehicles and pedestrians, ensuring traffic safety and comfort. Traditional steel-concrete composite beams are prone to cracking due to the poor tensile strength of concrete. Concrete decks that meet design requirements are thicker, and conventional concrete decks are susceptible to various defects such as cracking, corrosion, surface wear, water seepage, and spalling, which increase maintenance costs.

[0003] In recent years, ultra-high performance concrete (UHPC) has been introduced into bridge engineering as a new high-performance concrete material. Compared to traditional concrete bridge decks, UHPC decks are lighter and thinner, significantly reducing the overall weight of bridges, alleviating stress on the substructure and lowering foundation costs. The high durability of UHPC decks reduces the frequency and cost of maintenance required during bridge operation, improving the economic benefits of bridges. Although UHPC decks possess excellent mechanical properties and durability, their high price hinders their widespread application in practical engineering. Utility Model Content

[0004] The utility model provides a double-thin-layer UHPC-NC composite bridge deck, which aims to combine the advantages of ultra-high performance concrete (UHPC) and conventional concrete (NC) to meet the strict requirements of modern bridge engineering for bridge decks in terms of strength, durability and economy.

[0005] The technical solution of the utility model is as follows:

[0006] A double-thin-layer UHPC-NC composite bridge deck comprises a prefabricated UHPC bottom plate (1), a conventional concrete cast-in-place layer (2), and a UHPC-CA top plate (3);

[0007] The prefabricated UHPC base plate (1) comprises a UHPC casting layer (1-1), lower chord steel bars (1-2), upper chord steel bars (1-3), web steel bars (1-4), prefabricated UHPC base plate longitudinal steel bars (1-5) and prefabricated UHPC base plate transverse steel bars (1-6); the lower chord steel bars (1-2), upper chord steel bars (1-3) and web steel bars (1-4) together constitute a truss reinforcement structure; the prefabricated UHPC base plate longitudinal steel bars (1-5) and the prefabricated UHPC base plate transverse steel bars (1-6) are fixed in a transverse and longitudinal direction to form a first grid structure; the lower chord steel bars (1-2) are welded to the first grid structure; and UHPC is cast on the first grid structure to form a UHPC casting layer (1-1);

[0008] The prefabricated UHPC base plate (1) further comprises prestressed steel wires (1-7), which are tensioned on a prestressed long line platform using a pre-tensioning method before the UHPC casting layer (1-1) is cast, and the prestressed steel wires (1-7) are symmetrically released bundle by bundle after the strength reaches the designed strength.

[0009] The ordinary concrete cast-in-place layer (2) is formed on the prefabricated UHPC base plate (1);

[0010] The UHPC-CA top plate (3) is formed on the ordinary concrete cast-in-place layer (2);

[0011] The UHPC-CA top plate (3) comprises a UHPC-CA cast-in-place layer (3-1), UHPC-CA top plate longitudinal steel bars (3-2) and UHPC-CA top plate transverse steel bars (3-3). The UHPC-CA top plate longitudinal steel bars (3-2) and the UHPC-CA top plate transverse steel bars (3-3) are fixed in a transverse and longitudinal direction to form a second grid structure. The second grid structure is welded to the upper chord steel bars (1-3) of the prefabricated UHPC bottom plate (1). UHPC-CA is cast on the second grid structure to form the UHPC-CA cast-in-place layer (3-1).

[0012] Furthermore, in the truss reinforcement structure, the lower chord reinforcement (1-2) and the upper chord reinforcement (1-3) are respectively located at the lower and upper ends of the truss reinforcement structure, and are welded together through the web reinforcement (1-4) to form a stable triangular structure.

[0013] Furthermore, the first grid structure fixes the prefabricated UHPC bottom plate longitudinal steel bars (1-5) and the prefabricated UHPC bottom plate transverse steel bars (1-6) together by welding or binding.

[0014] Furthermore, the UHPC-CA top plate (3) is connected to the ordinary concrete cast-in-place layer (2) through a second grid structure and chemical bonds during cement hydration, and is welded to the upper chord steel bars (1-3) of the prefabricated UHPC bottom plate (1) through the second grid structure and connected to the prefabricated UHPC bottom plate (1) through chemical bonds during cement hydration, thereby cooperating with the prefabricated UHPC bottom plate (1) and the ordinary concrete cast-in-place layer (2) to bear loads.

[0015] Furthermore, when the ordinary concrete cast-in-place layer (2) is connected to the prefabricated UHPC base plate (1), when the ordinary concrete cast-in-place layer (2) is poured on the prefabricated UHPC base plate (1), the truss reinforcement is embedded in the ordinary concrete, and chemical bonds are formed during the cement hydration process to strengthen the connection.

[0016] The beneficial effects of this utility model are as follows: The double-layer UHPC-NC composite bridge deck utilizes UHPC (CA) and UHPC at the top and bottom layers, respectively, fully leveraging the high strength, wear resistance, and durability of UHPC (CA) and the high toughness of UHPC. While maintaining the bridge deck's mechanical properties and durability, the use of ordinary concrete for the middle layer significantly reduces project costs. Furthermore, the use of composite slabs makes bridge deck construction more versatile, lightweight, and standardized. The use of a double-layer UHPC-NC composite bridge deck structure reduces project production costs, facilitates construction, and improves durability. It also addresses the high cost and limited promotion of UHPC, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 : Schematic diagram of the overall structure of the double-layer UHPC-NC composite bridge deck;

[0018] Figure 2 : Schematic diagram of the longitudinal section layout of the precast UHPC base plate of the double-thin-layer UHPC-NC composite bridge deck;

[0019] Figure 3 : Schematic diagram of the planar layout of the precast UHPC base plate of the double-thin-layer UHPC-NC composite bridge deck;

[0020] Figure 4 : Schematic diagram of the cross-sectional arrangement of the precast UHPC base plate of a double-thin-layer UHPC-NC composite bridge deck;

[0021] Figure 5 : Schematic diagram of the longitudinal section layout of the cast-in-place layer of the double-thin-layer UHPC-NC composite bridge deck;

[0022] Figure 6 : Schematic diagram of the cross-sectional arrangement of the cast-in-place layer of the double-thin-layer UHPC-NC composite bridge deck;

[0023] As shown in the figure: precast UHPC base plate 1; UHPC casting layer 1-1; lower chord reinforcement 1-2; upper chord reinforcement 1-3; web reinforcement 1-4; precast UHPC base plate longitudinal reinforcement 1-5; precast UHPC base plate transverse reinforcement 1-6; prestressed prestressed steel wire 1-7; ordinary concrete cast-in-place layer 2; UHPC-CA top plate 3; UHPC-CA cast-in-place layer 3-1; UHPC-CA top plate longitudinal reinforcement 3-2; UHPC-CA top plate transverse reinforcement 3-3. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific embodiments:

[0025] Example 1

[0026] The double-thin-layer UHPC-NC composite bridge deck involved in this utility model is an innovative structural design that aims to combine the advantages of ultra-high performance concrete (UHPC) and conventional concrete (NC) to meet the stringent requirements of modern bridge engineering for bridge decks in terms of strength, durability, and economy. Figure 1 The bridge deck shown is composed of a prefabricated UHPC bottom plate 1, a conventional concrete cast-in-place layer 2 and a UHPC-CA top plate 3.

[0027] As an important foundation of the bridge deck, the prefabricated UHPC base plate 1 plays a major role in force transmission and structural support. The prefabricated UHPC base plate 1 fully utilizes the high strength and excellent durability of UHPC materials.

[0028] The cast-in-place ordinary concrete layer 2 sits atop the precast UHPC baseplate 1, working in tandem with it to further enhance the overall performance of the bridge deck. This layer not only acts as a filler, filling irregularities on the surface of the precast UHPC baseplate 1, but also, through chemical bonding and mechanical connection to the truss reinforcement, forms a cohesive structure with the precast UHPC baseplate 1, sharing the load. This ensures that the bridge deck meets strength requirements while reducing material costs and improving the economic efficiency of the structure.

[0029] The UHPC-CA top plate 3 is the topmost structure of the bridge deck. It is primarily responsible for bearing direct loads from vehicles in motion, such as wheel pressure and friction. Its excellent wear resistance and impact resistance effectively protect the internal structure of the bridge deck from direct damage from external loads. Furthermore, the UHPC-CA top plate 3 is tightly connected to the underlying ordinary concrete cast-in-place layer 2 and precast UHPC bottom plate 1. The steel bar arrangement and connection ensure that loads are effectively transferred from the upper layer to the lower structure, achieving coordinated force bearing across the entire bridge deck structure.

[0030] Prefabricated UHPC base plate 1 Figure 2 、 3 , 4. The precast UHPC bottom plate 1 consists of a UHPC casting layer 1-1, a lower chord reinforcement 1-2, an upper chord reinforcement 1-3, a web reinforcement 1-4, a precast UHPC bottom plate longitudinal reinforcement 1-5, a precast UHPC bottom plate transverse reinforcement 1-6, and prestressed prestressed steel wires 1-7.

[0031] The lower chord steel bars 1-2, upper chord steel bars 1-3, and web bars 1-4 together constitute the truss bar structure in the precast UHPC base plate 1. The truss bar structure can effectively transfer and disperse the load, thereby improving the bearing capacity of the precast UHPC base plate 1. The lower chord steel bars 1-2 and the upper chord steel bars 1-3 are located at the lower and upper ends of the truss bar structure, respectively. The lower chord steel bars 1-2 and the upper chord steel bars 1-3 are welded together through the web bars 1-4 to form a stable triangular structure. The triangular structure has high mechanical stability and bearing capacity and can withstand large axial and bending forces. The precast UHPC base plate longitudinal steel bars 1-5 and the precast UHPC base plate transverse steel bars 1-6 are fixed in the horizontal and vertical directions to form a first grid structure. The first grid structure provides transverse and longitudinal reinforcement for the precast UHPC base plate 1, and can prevent cracks and deformation in the UHPC casting layer 1-1 during the stress process. Typically, the prefabricated UHPC bottom plate longitudinal reinforcements 1-5 and the prefabricated UHPC bottom plate transverse reinforcements 1-6 are fixed together by welding or tying to form a stable grid structure. UHPC is poured on the first grid structure to form a UHPC pouring layer 1-1.

[0032] The prestressed prestressed steel wires 1-7 are a special design in the prefabricated UHPC base plate 1. When the prefabricated base plate (1) is prefabricated, the prestressed tendons 1-7 are first tensioned on the prestressed long line platform using the prestressing method, and then UHPC is cast on the casting prestressed long line platform to form a UHPC cast-in-place layer (1). After the UHPC strength reaches more than 95% of the design strength and the curing age is not less than 7 days, the prestressed tendons are symmetrically tensioned one by one, and finally the prefabricated UHPC component is cured to 28 days.

[0033] The connection between the ordinary concrete cast-in-place layer 2 and the precast UHPC base plate 1 is mainly achieved through truss bars and chemical bonds formed by cement hydration. As a mechanical connection method, the truss bars play a role in transferring load and strengthening the connection between the precast UHPC base plate 1 and the ordinary concrete cast-in-place layer 2. When the ordinary concrete cast-in-place layer 2 is poured on the precast UHPC base plate 1, the truss bars are embedded in the ordinary concrete, so that there is a direct mechanical connection between the ordinary concrete and the precast UHPC base plate 1. At the same time, during the cement hydration process of the ordinary concrete cast-in-place layer 2, the chemical components in the cement will chemically react with the substances on the surface of the precast UHPC base plate 1 to form chemical bonds, making the connection between the two tighter and stronger. This dual connection method not only ensures that the load can be smoothly transferred from the precast UHPC base plate 1 to the ordinary concrete cast-in-place layer 2, but also prevents the ordinary concrete cast-in-place layer 2 from separating from the precast UHPC base plate 1 during use.

[0034] like Figure 5 and 6 As shown, the UHPC-CA top plate 3 and the ordinary concrete cast-in-place layer 2 are connected via a second grid structure formed by the longitudinal reinforcement 3-2 and transverse reinforcement 3-3 of the UHPC-CA top plate 3, as well as chemical bonds generated during the cement hydration process. When the UHPC-CA top plate 3 is cast on the ordinary concrete cast-in-place layer 2, the second grid structure is embedded in the ordinary concrete cast-in-place layer 2, forming a mechanical connection. UHPC-CA is cast on the second grid structure to form the UHPC-CA cast-in-place layer 3-1. During the cement hydration process, the cement components in the UHPC-CA cast-in-place layer 3-1 chemically react with substances on the surface of the ordinary concrete cast-in-place layer 2, forming chemical bonds and strengthening the connection between the two. The connection between the UHPC-CA top plate 3 and the precast UHPC bottom plate 1 is achieved by welding the second grid structure to the upper chord reinforcement 1-3 of the precast UHPC bottom plate 1 and chemical bonds generated during the cement hydration process. This connection method ensures that the UHPC-CA top plate 3 can be tightly integrated with the underlying structure, and the load can be effectively transferred from the UHPC-CA top plate 3 to the ordinary concrete cast-in-place layer 2 and the precast UHPC bottom plate 1, thereby achieving coordinated stress bearing of the entire bridge deck structure.

[0035] The specific construction methods are as follows:

[0036] The prefabricated UHPC baseplate longitudinal reinforcements 1-5 and transverse reinforcements 1-6 are fixed in the horizontal and vertical directions according to the design requirements to form a first grid structure. The bottom chord reinforcements 1-2 are then welded to the first grid structure. Next, the bottom chord reinforcements 1-2 are welded to the top chord reinforcements 1-3 via the web reinforcements 1-4 to form truss reinforcement. UHPC is then cast on the first grid structure to form a UHPC casting layer 1-1, completing the fabrication of the prefabricated UHPC baseplate 1.

[0037] When prefabricating the prefabricated UHPC base plate 1, it is also necessary to use a pre-tensioning method to tension the prestressed steel wires 1-7 on the prestressed long line platform, and then cast UHPC on the casting prestressed long line platform to form a UHPC casting layer 1-1. After the UHPC strength reaches more than 95% of the design strength and the curing age is not less than 7 days, the prestressed steel wires 1-7 are symmetrically placed one by one. Finally, the prefabricated UHPC base plate 1 is cured to 28 days.

[0038] The prepared prefabricated UHPC base plate 1 is placed at a predetermined position and a cast-in-place layer 2 of ordinary concrete is poured on the prefabricated UHPC base plate 1.

[0039] On top of the conventional cast-in-place concrete layer 2, the UHPC-CA top slab longitudinal reinforcement 3-2 and transverse reinforcement 3-3 are fixed in a horizontal and vertical arrangement to form a second grid structure. This grid structure is then welded to the upper chord reinforcement 1-3 of the prefabricated UHPC bottom slab 1. Finally, UHPC-CA is poured onto this second grid structure to form the UHPC-CA cast-in-place layer 3-1, ultimately forming the UHPC-CA top slab 3.

[0040] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced within the present invention.

[0041] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A double-layer UHPC-NC composite bridge deck, characterized in that: It includes a prefabricated UHPC bottom plate (1), a conventional cast-in-place concrete layer (2), and a UHPC-CA top plate (3); The prefabricated UHPC base plate (1) comprises a UHPC casting layer (1-1), lower chord steel bars (1-2), upper chord steel bars (1-3), web steel bars (1-4), prefabricated UHPC base plate longitudinal steel bars (1-5) and prefabricated UHPC base plate transverse steel bars (1-6); the lower chord steel bars (1-2), upper chord steel bars (1-3) and web steel bars (1-4) together constitute a truss reinforcement structure; the prefabricated UHPC base plate longitudinal steel bars (1-5) and the prefabricated UHPC base plate transverse steel bars (1-6) are fixed in a transverse and longitudinal direction to form a first grid structure; the lower chord steel bars (1-2) are welded to the first grid structure; and UHPC is cast on the first grid structure to form a UHPC casting layer (1-1); The prefabricated UHPC base plate (1) further comprises prestressed steel wires (1-7), which are tensioned on a prestressed long line platform using a pre-tensioning method before the UHPC casting layer (1-1) is cast, and the prestressed steel wires (1-7) are symmetrically released bundle by bundle after the strength reaches the designed strength. The ordinary concrete cast-in-place layer (2) is formed on the prefabricated UHPC base plate (1); The UHPC-CA top plate (3) is formed on the ordinary concrete cast-in-place layer (2); The UHPC-CA top plate (3) comprises a UHPC-CA cast-in-place layer (3-1), UHPC-CA top plate longitudinal steel bars (3-2) and UHPC-CA top plate transverse steel bars (3-3). The UHPC-CA top plate longitudinal steel bars (3-2) and the UHPC-CA top plate transverse steel bars (3-3) are fixed in a transverse and longitudinal direction to form a second grid structure. The second grid structure is welded to the upper chord steel bars (1-3) of the prefabricated UHPC bottom plate (1). UHPC-CA is cast on the second grid structure to form the UHPC-CA cast-in-place layer (3-1).

2. The double-thin-layer UHPC-NC composite bridge deck according to claim 1, characterized in that: In the truss reinforcement structure, the lower chord steel bars (1-2) and the upper chord steel bars (1-3) are respectively located at the lower and upper ends of the truss reinforcement structure and are welded together through the web reinforcement bars (1-4) to form a stable triangular structure.

3. The double-thin-layer UHPC-NC composite bridge deck according to claim 1, characterized in that: The first grid structure fixes the prefabricated UHPC bottom plate longitudinal steel bars (1-5) and the prefabricated UHPC bottom plate transverse steel bars (1-6) together by welding or binding.

4. The double-thin-layer UHPC-NC composite bridge deck according to claim 1, characterized in that: The UHPC-CA top plate (3) is connected to the ordinary concrete cast-in-place layer (2) via a second grid structure and chemical bonds during cement hydration, and is welded to the upper chord steel bars (1-3) of the prefabricated UHPC bottom plate (1) via the second grid structure and chemical bonds during cement hydration to connect to the prefabricated UHPC bottom plate (1), thereby cooperating with the prefabricated UHPC bottom plate (1) and the ordinary concrete cast-in-place layer (2) to bear loads.

5. The double-thin-layer UHPC-NC composite bridge deck according to claim 4, characterized in that: When the ordinary concrete cast-in-place layer (2) is connected to the prefabricated UHPC base plate (1), when the ordinary concrete cast-in-place layer (2) is poured on the prefabricated UHPC base plate (1), the truss reinforcement is embedded in the ordinary concrete, and chemical bonds are formed during the cement hydration process to strengthen the connection.

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