UHPC bridge deck and construction method therefor

Abstract

Disclosed in the present invention are a UHPC bridge deck and a construction method therefor. The UHPC bridge deck comprises a bridge deck body and several cavities, which are located inside the bridge deck body and are parallel to the direction of width of the bridge deck body and distributed spaced apart in the longitudinal direction of the bridge deck body, wherein sealing blocks used for sealing end openings are provided at two ends of each of the cavities; and the cavities comprise first cylindrical cavities in which external unbonded prestressing tendons are provided, and an anchoring block and an anchorage device which is used for anchoring an external unbonded prestressing tendon are provided at each end of each first cylindrical cavity. The construction method is used for constructing the UHPC bridge deck. In the present invention, the crack resistance of the UHPC bridge deck is improved by tensioning the external unbonded prestressing tendons in the first cylindrical cavities, and thus it is unnecessary to enhance the rigidity of the UHPC bridge deck by means of stiffening ribs or steel structures; the external unbonded prestressing tendons have a clear force-bearing mechanism and a simple structure, facilitating improvement in construction efficiency.

Description

UHPC bridge deck and construction method thereof Technical Field

[0001] The present invention relates to the technical field of bridges, and in particular to a UHPC bridge deck structure and a construction method thereof. Background Art

[0002] The bridge deck is a key load-bearing component of a concrete bridge. It not only directly bears the effects of wheel loads but also must withstand environmental factors such as sunlight and rain. Due to the low strength of ordinary concrete, bridge decks are often thick, typically exceeding 25 cm, resulting in a heavy bridge deck. Furthermore, due to concrete's weak crack resistance, transverse prestressed steel strands are required to offset the tensile stresses induced by wheel loads in the concrete deck. Internally bonded prestressing is commonly employed.

[0003] Ultra-high-performance concrete (UHPC) is a new cement-based composite material with ultra-high mechanical properties and excellent durability. Its use in bridge structures can not only significantly reduce the size of bridge panels, lowering the structure's deadweight, but also improving its durability. However, as the thickness of the bridge deck decreases, the flexural stiffness of the deck also decreases: the flexural stiffness of a solid slab is proportional to the cube of its thickness. If a UHPC deck is half the thickness of a concrete deck, its stiffness is only about one-eighth that of the latter. Therefore, increasing the stiffness of UHPC bridge decks is essential, especially for large-span and wide-span UHPC bridges.

[0004] In the existing technology, the stiffness of UHPC bridge decks is usually improved by setting unidirectional or bidirectional stiffening ribs at the bottom of the ribs, adding steel structures, etc., and its structure and construction are relatively complicated.

[0005] Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a UHPC bridge deck which has a simple structure and is easy to construct while basically ensuring its rigidity.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions: a UHPC bridge deck, comprising a bridge deck body and a plurality of cavities located inside the bridge deck body and parallel to the width direction of the bridge deck body and spaced apart along the longitudinal direction of the bridge deck body, each of the cavities being provided with a sealing block for closing the port at both ends; the cavity comprising a first cylindrical cavity with an external unbonded prestressed steel bundle arranged therein, and an anchor block and a pair of anchors for anchoring the external unbonded prestressed steel bundle at the end of the first cylindrical cavity.

[0008] As a further improvement of the above solution:

[0009] The cavity is located in the middle of the bridge deck body in the thickness direction.

[0010] The cavity further includes a second cylindrical cavity in which no external unbonded prestressed steel strand is arranged, and at least one second cylindrical cavity is arranged between two adjacent first cylindrical cavities.

[0011] The cross section of the cavity is a circular cross section.

[0012] The cavity is formed by arranging a bellows in the main body of the bridge deck.

[0013] The thickness of the bridge deck body is 20-26 cm, and the diameter of the cavity is 8-15 cm.

[0014] The distance between adjacent cavities is 18-35 cm.

[0015] The anchor block is formed by pouring UHPC concrete.

[0016] The anchor is arranged at the end of the in vitro unbonded prestressed steel bundle, and is a sealing block formed by UHPC casting after the in vitro unbonded prestressed steel bundle is completed.

[0017] A UHPC bridge deck construction method, used for constructing the above-mentioned UHPC bridge deck, comprises the following steps:

[0018] S1: Corrugated pipes are laid out at intervals along the longitudinal direction of the bridge, anchors are embedded at both ends of the corrugated pipes, and ordinary steel bars in the UHPC bridge deck are laid out according to structural requirements;

[0019] S2: Casting of UHPC bridge deck, high temperature steam curing and demoulding of the UHPC bridge deck;

[0020] S3: tensioning an external unbonded prestressed steel tendon in the corrugated tube corresponding to the first cylindrical cavity according to a preset configuration;

[0021] S4: Use UHPC to cast the sealing blocks at both ends of the first cylindrical cavity and the second cylindrical cavity to complete the UHPC bridge deck construction.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] The present invention proposes a UHPC bridge deck having a plurality of first cylindrical cavities arranged at intervals. The crack resistance of the UHPC bridge deck is improved by tensioning external unbonded prestressed steel strands in the first cylindrical cavities, thereby eliminating the need to use stiffening ribs or steel structures to enhance the rigidity of the UHPC bridge deck. At the same time, the external unbonded prestressed steel strands have clear force and a simple structure, which helps to improve construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a schematic top view of the structure of a UHPC bridge deck in an embodiment.

[0025] FIG2 is a schematic cross-sectional view of the structure of the end portion of the external unbonded prestressed steel strand in the embodiment.

[0026] FIG3 is a structural perspective view of the UHPC bridge deck in the embodiment, where the arrow direction is the longitudinal direction of the bridge.

[0027] FIG4 is a schematic structural front view of a cross section of a UHPC bridge deck in an embodiment, wherein the arrow direction in the figure is the transverse direction of the bridge.

[0028] The numbers in the figure represent: 1. Bridge deck body; 2. Cavity; 21. First cylindrical cavity; 22. Second cylindrical cavity; 3. Sealing block; 4. Anchor; 5. Anchor block; 6. External unbonded prestressed steel strand. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Device Example:

[0031] Figures 1 to 4 illustrate an embodiment of a UHPC bridge deck according to the present invention. The deck comprises a main body 1 and several cavities 2 located within the main body 1, parallel to the width of the main body 1 and spaced longitudinally along the main body 1. Each cavity 2 is provided with a sealing block 3 at each end for sealing the end. The cavity 2 includes a first cylindrical cavity 21, within which an external unbonded prestressed steel strand 6 is located. The ends of the first cylindrical cavity 21 are provided with anchor blocks 5 and a pair of anchors 4 for anchoring the external unbonded prestressed steel strands 6. In this structure, the provision of the cavities 2 substantially maintains the stiffness of the bridge deck while reducing its deadweight. By tensioning the external unbonded prestressed steel strands 6 within the first cylindrical cavity 21, the crack resistance of the UHPC bridge deck is enhanced, effectively preventing cracking of the UHPC bridge deck under vehicle load, temperature, and other factors. Furthermore, no stiffening ribs or steel structures are required to enhance the flexural stiffness of the UHPC bridge deck. The external unbonded prestressed steel strands 6 are clearly stressed, have a simple structure, and are easy to construct, thereby improving construction efficiency.

[0032] In this embodiment, the cavity 2 is located in the middle position in the thickness direction of the bridge deck body 1. The cavity 2 also includes a second cylindrical cavity 22 in which no external unbonded prestressed steel strands 6 are arranged, and at least one first cylindrical cavity 21 is provided between two adjacent first cylindrical cavities 21. In this structure, by arranging the cavity 2 near the neutral axis position of the cross section of the bridge deck body 1, the negative impact of the cavity 2 on the bending stiffness of the bridge deck is minimized; in the first cylindrical cavity 21, only external unbonded prestressed steel strands 6 are arranged inside, the structure is simple, and the force is clear. Furthermore, the second cylindrical cavity 22 can be arranged at intervals between the first cylindrical cavities 21 according to the actual situation of the overall force of the bridge deck body 1, thereby further reducing the overall deadweight of the bridge deck and improving the convenience of construction.

[0033] In this embodiment, the cross-section of cavity 2 is preferably circular. Cavity 2 is formed by installing a corrugated tube within the main bridge deck 1. The standard thickness of the main bridge deck 1 is 20-26 cm; the axil section can be thickened appropriately based on the actual design. The diameter of cavity 2 is 8-15 cm. The spacing between adjacent cavities 2 is 18-35 cm. In this structure, the formation of cavity 2 by installing a corrugated tube simplifies construction and further reduces the structural deadweight of the UHPC bridge deck.

[0034] In this embodiment, the anchor blocks 5 at both ends of the first cylindrical cavity 21 are formed by casting UHPC. This structure facilitates the tensioning of the unbonded prestressed steel strands 6 in vitro.

[0035] In this embodiment, the sealing block 3 is formed by casting UHPC at both ends of the first cylindrical cavity 21 and the second cylindrical cavity 22. In this structure, the excellent mechanical properties and durability of UHPC are utilized to achieve a good sealing effect.

[0036] Method Example:

[0037] A UHPC bridge deck construction method, used for the UHPC bridge deck in the construction device embodiment, taking a UHPC box girder bridge as an example, comprises the following steps:

[0038] S1: Corrugated pipes are laid out at intervals along the longitudinal direction of the bridge. Anchors 4 are embedded at both ends of the corrugated pipes. At the same time, ordinary steel bars in the UHPC bridge deck are laid out according to the structural requirements.

[0039] S2: Cast UHPC bridge deck, perform high-temperature steam curing and demoulding on the UHPC bridge deck.

[0040] S3: tensioning the external unbonded prestressed steel strand 6 in the corrugated tube corresponding to the first cylindrical cavity 21 according to the preset conditions.

[0041] S4: Use UHPC to cast the sealing blocks 3 at both ends of the first cylindrical cavity 21 and the second cylindrical cavity 22 to complete the UHPC bridge deck construction.

[0042] Although the present invention has been disclosed above with reference to preferred embodiments, this is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, utilize the technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A UHPC bridge deck, characterized by: The invention comprises a bridge deck body (1) and a plurality of cavities (2) located inside the bridge deck body (1), parallel to the width direction of the bridge deck body (1) and spaced apart along the longitudinal direction of the bridge deck body (1), and each of the cavities (2) is provided with a sealing block (3) for closing the port at both ends; the cavity (2) comprises a first columnar cavity (21) inside which an external unbonded prestressed steel strand (6) is provided, and an anchor (4) and an anchor block (5) for anchoring the external unbonded prestressed steel strand (6) are provided at the end of the first columnar cavity (21).

2. The UHPC bridge deck according to claim 1, characterized in that: The cavity (2) is located in the middle of the bridge deck body (1) in the thickness direction.

3. The UHPC bridge deck according to claim 2, characterized in that: The cavity (2) further comprises a second cylindrical cavity (22) in which no external unbonded prestressed steel strand (6) is arranged, and at least one second cylindrical cavity (22) is arranged between two adjacent first cylindrical cavities (21).

4. The UHPC bridge deck according to claim 1, characterized in that: The cross section of the cavity (2) is a circular cross section.

5. The UHPC bridge deck according to claim 4, characterized in that: The cavity (2) is formed by arranging a corrugated tube in the bridge deck body (1).

6. The UHPC bridge deck according to claim 5, characterized in that: The standard section thickness of the bridge deck body (1) is 20-26 cm, and the diameter of the cavity (2) is 8-15 cm.

7. The UHPC bridge deck according to claim 6, characterized in that: The spacing between adjacent cavities (2) is 18-35 cm.

8. The UHPC bridge deck according to claim 1, characterized in that: The anchor block (5) is formed by casting UHPC.

9. The UHPC bridge deck according to claim 8, characterized in that: The anchor (4) is arranged at the end of the in vitro non-bonded prestressed steel bundle (6), and a sealing block (3) is formed by UHPC casting after the in vitro non-bonded prestressed steel bundle (6) is completed.

10. A UHPC bridge deck construction method, characterized in that: The method for constructing the UHPC bridge deck according to any one of claims 1 to 9 comprises the following steps: S1: Corrugated pipes are arranged at intervals along the longitudinal direction of the bridge, anchors (4) are embedded at both ends of the corrugated pipes, and ordinary steel bars in the UHPC bridge deck are arranged according to the structural requirements; S2: Casting of UHPC bridge deck, high temperature steam curing and demoulding of UHPC bridge deck; S3: tensioning an external unbonded prestressed steel strand (6) in a corrugated tube corresponding to the first cylindrical cavity (21) according to a preset method; S4: Using UHPC to cast the sealing blocks (3) at both ends of the first columnar cavity (21) and the second columnar cavity (22), completing the construction of the UHPC bridge deck.

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