Segmental prefabricated box girder mixed joint and construction method thereof

Abstract

The invention belongs to the technical field of bridge construction, and particularly provides a segmental prefabricated box girder mixed joint and a construction method thereof.The segmental prefabricated box girder mixed joint comprises a girder body, the outer side of the girder body is glued, a reinforced concrete structure is arranged and connected in the girder body, and the reinforced concrete structure adopts cast-in-place concrete. The environment endurance and durability are poor by adopting a dry joint, and the process is relatively complex and high in cost by adopting a glue joint; construction is carried out in the inner cavity of the beam body, an outer mold is not needed, the construction risk is low, high-altitude operation is little, the safety risk is low, temporary structures are few, and the construction cost is low; the reinforced concrete structure part does not occupy the construction period, the bridge construction speed is the same as that of full-glue joints and is higher than that of cast-in-place joints, and the joints are good in connection strength and durability.

Description

Technical Field

[0001] The present invention belongs to the technical field of bridge construction, and particularly relates to a segment precast box girder hybrid joint and a construction method thereof. Background Art

[0002] The common joint forms of segment precast box girders include wet joints, dry joints, and glue joints. Wet joints are divided into types such as plain concrete, reinforced concrete, and UHPC (ultra-high performance concrete). Among these joint forms, the reinforced concrete joint has the highest connection strength, and the construction process includes binding steel bars, installing templates, and pouring concrete, with the lowest construction efficiency. Dry joints have a fast construction speed, but poor environmental tolerance and durability. Glue joints have a fast construction speed, good sealing performance, relatively complex technology, and high cost.

[0003] The Chinese patent document with the publication number CN203977297U discloses a protection structure for the wet joint opening between bridge beams, which is arranged on precast box girders / precast T-beams with reserved steel bars for wet joints, and is used to protect the wet joint openings between two adjacent precast box girders / precast T-beams, and does not solve the technical problems existing in the above-mentioned common joint forms of existing segment precast box girders. Summary of the Invention

[0004] The segment precast box girder hybrid joint and the construction method provided by the present invention aim to overcome the problems that the wet joint construction efficiency of segment precast box girders in the prior art is low, the environmental tolerance and durability of dry joints are poor, and the glue joint process is relatively complex and costly.

[0005] To this end, the present invention provides a segment precast box girder hybrid joint, including a beam body. The outer side of the beam body is adhesively bonded, and a connecting reinforced concrete structure is arranged inside the beam body, and the reinforced concrete structure uses cast-in-place concrete.

[0006] Preferably, the beam body includes a top plate, wing plates, webs, and a bottom plate. One wing plate is connected to each of the left and right ends of the top plate. The upper ends of the webs are connected between the top plate and the wing plates, and the bottom plate is connected between the lower ends of the two webs. A plurality of concrete pouring ports are provided on the top plate.

[0007] Preferably, the hybrid joint is applied to pier top segment beams and mid-span segment beams. When the hybrid joint is applied to pier top segment beams and mid-span segment beams, a plurality of hybrid joints are connected in sequence. A glue joint is used between the pouring parts of two adjacent beam bodies, and a wet joint is used to connect the reinforced concrete structures inside two adjacent beam bodies.

[0008] Preferably, when the hybrid joint is applied to pier top segment beams, a manhole is provided in the reinforced concrete structure. The upper end of the manhole is not connected to the top plate, and the bottom plate is connected to the manhole.

[0009] Preferably, when the hybrid joint is applied to the mid-span segment beam, a through hole is transversely formed in the middle of the reinforced concrete structure.

[0010] Preferably, the transverse thickness of the reinforced concrete structure is the same.

[0011] Preferably, a plurality of temporary prestressed scale steps are connected and arranged on the upper surface of the top plate.

[0012] Preferably, the plurality of temporary prestressed scale steps are evenly distributed.

[0013] Preferably, the width of the reinforced concrete structure is smaller than the width of the cast-in-place part of the beam body connected by the reinforced concrete structure.

[0014] A construction method for a segment precast box girder hybrid joint includes the following steps:

[0015] S1. Apply glue on the outer side of the beam body to be constructed, and move the beam body to the target position;

[0016] S2. Apply temporary prestress to two adjacent glued beam bodies to complete the glue extrusion construction;

[0017] S3. First install the steel bars of the wet joint in the beam body after glue extrusion, then install the formwork of the wet joint, and finally pour concrete for the wet joint to complete the construction of the reinforced concrete structure;

[0018] S4. Carry out permanent prestress construction on the beam body, and the permanent prestress construction is carried out after step S2 or after step S3.

[0019] Advantages of the present invention:

[0020] The segment precast box girder hybrid joint and its construction method provided by the present invention are prefabricated integrally and hoisted integrally, which can ensure the integrity of the segment beam in the pier top area, and the segment beam can be divided into blocks, thus reducing the hoisting weight; a connecting reinforced concrete structure is arranged in the beam body, and the reinforced concrete structure part is constructed after the glue joint construction on the outer side of the beam body, and the construction is carried out in the inner cavity of the beam body, without the need for an external formwork, with low construction risk, less high-altitude operations, low safety risk, few temporary structures, and low construction cost; the reinforced concrete structure part does not occupy the construction period, and the bridge construction speed is the same as that of the full glue joint, faster than the cast-in-place joint, avoiding the problems of complex construction process, low efficiency, and low assembly rate of the pure cast-in-place pier top block construction process. Brief Description of the Drawings

[0021] The following will further describe the present invention in detail with reference to the drawings.

[0022] Figure 1 It is the cross-sectional structure diagram of the beam body;

[0023] Figure 2It is a cross-sectional view of the pier-top segment beam with a hybrid joint;

[0024] Figure 3 It is a three-dimensional structure diagram of the pier-top segment beam with a hybrid joint;

[0025] Figure 4 It is a three-dimensional structure diagram after the splicing of the pier-top segment beam with a hybrid joint;

[0026] Figure 5 It is a cross-sectional view of the mid-span segment beam joint with a hybrid joint;

[0027] Figure 6 It is an axonometric view of the mid-span segment beam joint with a hybrid joint;

[0028] Figure 7 It is an elevation view of the hybrid joint seam;

[0029] Figure 8 It is a seepage path diagram.

[0030] Explanation of reference numerals: 1. Beam body; 2. Manhole; 3. Through hole; 4. Temporary prestressed retaining wall; 5. Shear key; 6. Reinforced concrete structure; 1.1. Top plate; 1.2. Wing plate; 1.3. Web; 1.4. Bottom plate; 1.11. Concrete pouring port. Specific implementation mode

[0031] The principles and features of the present invention will be described below in conjunction with the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0032] Example 1:

[0033] As Figures 2 to 6 shown, a hybrid joint for a precast segment box girder includes a beam body 1, the outer sides of the beam body 1 are adhesively joined, and a connecting reinforced concrete structure 6 is provided inside the beam body 1. The reinforced concrete structure 6 is made of cast-in-place concrete.

[0034] Specifically, the beam body 1 adopts a glued joint and is constructed in a matching manner in the precast yard. An inner cavity is provided inside the beam body 1, and steel bar joints are reserved in the inner cavity. After connection on the bridge, concrete is poured, and after pouring, it becomes the reinforced concrete structure 6. Compared with the pier-top block of the full cast-in-place structure, which requires installing brackets and templates at the pier-top, hoisting and tying steel bars and pouring concrete on-site, the hybrid joint of the precast segment box girder of the present invention is integrally precast and integrally hoisted in the beam yard, using the precast concrete shell (beam body 1) as the external formwork, without the need to install templates and brackets, with less high-altitude operations and lower safety risks; fewer temporary structures and lower construction costs; the quality of the precast structure is better than that of the cast-in-place structure.

[0035] Example 2:

[0036] On the basis of Example 1, asFigure 1 As shown, the beam body 1 includes a top plate 1.1, wing plates 1.2, webs 1.3 and a bottom plate 1.4. Wing plates 1.2 are connected to both the left and right ends of the top plate 1.1. The upper end of the web 1.3 is connected between the top plate 1.1 and the wing plates 1.2, and the bottom plate 1.4 is connected between the lower ends of the two webs 1.3. A plurality of concrete pouring ports 1.11 are provided on the top plate 1.1.

[0037] Specifically, through the concrete pouring ports 1.11, it is convenient to pour concrete into the beam body 1 as required. The plurality of concrete pouring ports 1.11 can feed materials simultaneously. Compared with a single concrete pouring port 1.11, the concrete pouring in the beam body 1 can be completed in a shorter time, effectively reducing the total duration of concrete pouring, accelerating the construction progress, and also being conducive to reducing the time interval during layered concrete pouring to prevent cold joints. When the concrete supply is sufficient, the plurality of concrete pouring ports 1.11 can ensure continuous and uninterrupted concrete pouring, reducing construction stagnation caused by waiting for concrete supply, and improving construction efficiency and continuity.

[0038] Preferably, the plurality of concrete pouring ports 1.11 are evenly distributed in the middle of the top plate 1.1.

[0039] Specifically, concrete hardening will generate shrinkage stress, etc. The plurality of evenly distributed concrete pouring ports 1.11 make the concrete distribution more uniform, and the stress can be more evenly dispersed, reducing the risk of beam cracking caused by stress concentration; it helps the beam body 1 structure to transfer and bear loads more evenly when stressed, enhancing the structural stability and bearing capacity, and meeting the design requirements for structural performance. The plurality of concrete pouring ports 1.11 can be flexibly arranged according to the structural characteristics to more precisely control the concrete pouring position and speed, ensuring that the concrete fills into each part. In projects that require segmented pouring, the plurality of concrete pouring ports 1.11 can be used to pour different areas or segments respectively, facilitating construction organization and management.

[0040] Embodiment 3:

[0041] Based on Embodiment 1, as Figure 5 、 Figure 7 and Figure 8 shown, the hybrid joint is applied to the pier top segment beam and the mid-span segment beam. When the hybrid joint is applied to the pier top segment beam and the mid-span segment beam, a plurality of hybrid joints are connected in sequence. A glue joint is used between the pouring parts of two adjacent beam bodies 1, and a wet joint is used to connect the reinforced concrete structures 6 in two adjacent beam bodies 1.

[0042] Specifically, the segmental girder bridges currently using fully bonded joints generally have the defect of water seepage at the bonded joints. The present invention uses a hybrid joint (a glue joint is used between the cast parts of two adjacent girders 1, and a wet joint is used to connect the reinforced concrete structures 6 within two adjacent girders 1), which changes the water seepage path at the bonded joint from a straight line to a broken line (as Figure 8 shown), lengthens the water seepage path, improves the waterproof performance of the bonded joint, protects the steel bars and steel strands inside the bonded joint, and extends the service life of the bridge.

[0043] Preferably, as Figures 2 to 4 shown, when the hybrid joint is applied to the pier top segmental girder, a manhole 2 is provided in the reinforced concrete structure 6. The upper end of the manhole 2 is not connected to the top plate 1.1, and the bottom plate 1.4 is connected to the manhole 2.

[0044] Specifically, the manhole 2 facilitates personnel operation, is conducive to material transportation, and is convenient for inspection and maintenance. During concrete pouring, construction workers can enter the structure through the manhole to assist in vibrating the concrete, ensuring that the concrete is vibrated densely, improving the integrity and strength of the structure; reducing the self-weight and avoiding stress concentration.

[0045] Example 4:

[0046] Based on Example 3, as Figure 5 and Figure 6 shown, when the hybrid joint is applied to the mid-span segmental girder, a through hole 3 is transversely provided in the middle of the reinforced concrete structure 6.

[0047] Specifically, providing the through hole 3 can reduce the self-weight of the structure, improve the material utilization rate, and the through hole 3 can be used as an operation passage during the construction process, facilitating the construction of construction workers.

[0048] Preferably, the transverse thickness of the reinforced concrete structure 6 is the same.

[0049] Specifically, when the structure bears the load, the same thickness enables the concrete and steel bars to work together evenly at each part, avoiding stress concentration caused by thickness differences, ensuring the pouring quality of the concrete, making the concrete evenly distributed inside the structure, and reducing quality defects caused by difficult operation.

[0050] Example 5:

[0051] Based on Example 4, a plurality of temporary prestressed scale steps 4 are provided and connected on the upper surface of the top plate 1.1.

[0052] Specifically, the temporary prestressed scale steps 4 can be used to apply prestress between the segmental girders, tightly connect each segmental girder together, complete the glue extrusion construction, form an integral structure, ensure the reliability of the connection of the segmental girders and the integrity of the structure, and at the same time facilitate the positioning and adjustment of the segmental girders.

[0053] Preferably, when the hybrid joint is applied to the mid-span segment beam, a plurality of temporary prestressed scale steps 4 are connected to the reinforced concrete structure 6 at the lower position of the through hole 3.

[0054] Specifically, it is convenient to tightly connect each segment beam together to complete the glue extrusion construction.

[0055] Preferably, the plurality of temporary prestressed scale steps 4 are evenly distributed.

[0056] Specifically, the uniform distribution of the plurality of temporary prestressed scale steps 4 ensures uniform pressure on the bonding surface.

[0057] Example 6:

[0058] Based on Example 5, the width of the reinforced concrete structure 6 is smaller than the width of the cast part of the beam body 1 connected to the reinforced concrete structure 6.

[0059] Specifically, this structure makes the outer surface of the reinforced concrete structure 6 form a concave surface with the outer surface of the beam body 1. When adjacent two segment beams are connected, the adjacent two beam bodies 1 are adhesively bonded, and the reinforced concrete structures 6 in the adjacent two beam bodies 1 are connected by a wet joint (cast-in-place wet joint), so that the wet joint is located inside the adjacent two beam bodies 1; it makes the water seepage path of the bonding surface change from the existing straight line to a broken line, the water seepage path becomes longer, improves the waterproof performance of the bonding surface, protects the steel bars and steel strands inside the bonding surface, and extends the service life of the bridge.

[0060] Preferably, as Figure 2 shown, the hybrid joint further includes a plurality of shear keys 5. The plurality of shear keys 5 are connected inside the beam body 1, and the ends of the plurality of shear keys 5 are connected to the reinforced concrete structure 6.

[0061] Specifically, there is shear force transfer between the beam body 1 and the reinforced concrete structure 6. The beam body 1 and the reinforced concrete structure 6 are connected by a plurality of shear keys 5, which can effectively transfer the shear force, improve the structural stability, and facilitate the construction and installation.

[0062] Example 7:

[0063] Based on Example 6, a construction method of a segment precast box girder hybrid joint is characterized in that it includes the following steps:

[0064] S1. Apply glue on the outer side of the beam body (1) to be constructed, and move the beam body (1) to the target position;

[0065] S2. Apply temporary prestress to the adjacent two glued beam bodies (1) to complete the glue extrusion construction;

[0066] S3. Install the reinforcement bars of the wet joint in the beam body (1) after squeezing the glue, then install the formwork of the wet joint, and finally pour concrete for the wet joint to complete the construction of the reinforced concrete structure (6);

[0067] S4. Carry out permanent prestressing construction on the beam body (1), and the permanent prestressing construction is carried out after step S2 or after step S3.

[0068] Technical advantages of the construction of the pier top segment beam with a hybrid joint:

[0069] Compared with the pier top segment beam of the full-cast-in-place structure, the pier top segment beam of the cast-in-place structure needs to install brackets and formwork at the pier top, hoist and bind reinforcement bars on-site, and pour concrete. In the present invention, it is integrally precast in the beam yard and integrally hoisted, and the precast concrete shell is used as the external formwork, without the need to install formwork and brackets. There is less high-altitude operation and lower safety risk; less temporary structures and lower construction cost; the quality of the precast structure is better than that of the cast-in-place structure. Using a hybrid joint can ensure the integrity of the pier top segment beam, the pier top segment beam can be divided into blocks, thereby reducing the hoisting weight, and at the same time, there is no need to install formwork, and the technical advantages are obvious. It avoids the problems of complex construction process, low efficiency and low assembly rate of the pure cast-in-place pier top segment beam construction process, and solves the problem that the pier top segment beam cannot be divided into blocks by glue joints due to high connection strength.

[0070] Example 8:

[0071] Based on Example 7, taking segment beam 1 and segment beam 2 as examples, a construction method for a hybrid joint of a precast box girder segment includes the following steps:

[0072] 1) Hoist segment beam 2. After approaching the installation position, apply glue to the glue-bonding area (beam body 1) between segment beam 1 and segment beam 2;

[0073] 2) Hoist segment beam 2 to the installation position, connect the temporary prestressed scale sill 4 between segment beam 1 and segment beam 2 with tie rods, and tension the temporary prestress to complete the glue-squeezing construction;

[0074] Specifically, the pressure construction specification for the glue-bonding surface requires 0.2 - 0.3 Mpa. Two high-strength deformed steel bars are installed for each temporary prestressed scale sill 4. The temporary prestressed scale sill 4 used for temporary prestress is evenly arranged in the cross-section to ensure uniform pressure on the glue-bonding surface. It is also possible to simulate and calculate through analysis software to adjust the position of the temporary prestressed scale sill 4 to ensure uniform pressure on the glue-bonding surface.

[0075] 3) Continue to complete the hoisting and glue-bonding construction of other segment beams; synchronously carry out the construction of steel bar connection, internal formwork installation and concrete pouring in the wet joint area (between the reinforced concrete structures 6 in two adjacent beam bodies 1);

[0076] 4) Performing permanent prestressing construction, which is performed after step 3) or after step 2). Performing permanent prestressing construction after step 3) is one construction method, while performing permanent prestressing construction after step 2) is another construction method.

[0077] Technical advantages of mid-span segmental beam construction using hybrid joints:

[0078] A. Compared with the fully adhesive joint, it has the following advantages

[0079] Currently, segmental beam bridges using fully bonded joints generally have the defect of water seepage on the bonded joints. By using the hybrid joint of the present invention, the water seepage path of the bonded joint is changed from a straight line to a broken line, the water seepage path becomes longer, the waterproof performance of the bonded joint is improved, the steel bars and steel strands inside the bonded joint are protected, and the service life of the bridge is extended.

[0080] The design of the adhesive joint is based on the compression condition of the entire bridge cross section. However, during the 80-100 years of operation of the bridge, it may encounter vehicle overloads, earthquakes and other situations not considered in the design stage, which may cause the adhesive joint to be subjected to tension conditions. The hybrid joint of the present invention has a strong tensile capacity and can cope with the tensile conditions of the adhesive joint, avoiding cracking and leakage of the adhesive joint.

[0081] B. Compared with cast-in-place wet joints, it has the following advantages

[0082] Cast-in-place wet joints need to be constructed after the segmental beams are hoisted to the installation location. Wet joints require connecting steel bars, installing formwork, and pouring concrete at high altitude, which results in a long construction period and high risks. The reinforced concrete portion of the hybrid joint of the present invention is arranged on the inside of the box section (inside the beam body 1). The reinforced concrete portion is constructed after the outer glue joint is completed. Construction is carried out within the inner cavity of the box beam, eliminating the need for external formwork. This reduces construction risks, reduces overhead work, and does not take up construction time for the reinforced concrete portion. The bridge construction speed is the same as that of a fully glued joint, which is faster than a cast-in-place joint.

[0083] In the description of the present invention, it should be understood that if there are terms such as "front", "inside", "right", etc. indicating an orientation or positional relationship, these are based on the orientation or positional relationship shown in the drawings, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention.

[0084] The above examples are merely illustrative of the present invention and do not limit the scope of protection of the present invention. Any design that is identical or similar to the present invention falls within the scope of protection of the present invention.

Claims

1. A segmental prefabricated box beam hybrid joint, comprising a beam body (1), characterized in that: The outer side of the beam body (1) is glued, and a connecting reinforced concrete structure (6) is provided inside the beam body (1), and the reinforced concrete structure (6) adopts cast-in-situ concrete.

2. The segmental prefabricated box girder hybrid joint according to claim 1, characterized in that: The beam body (1) comprises a top plate (1.1), a wing plate (1.2), a web plate (1.3) and a bottom plate (1.4); the left and right ends of the top plate (1.1) are each connected to a wing plate (1.2); the top plate (1.1) and the wing plate (1.2) are connected below to the upper end of the web plate (1.3); the lower ends of the two web plates (1.3) are connected to the bottom plate (1.4); and a plurality of concrete pouring openings (1.11) are provided on the top plate (1.1).

3. The segmental prefabricated box girder hybrid joint according to claim 1, characterized in that: The hybrid joint is applied to pier top segment beams and mid-span segment beams. When the hybrid joint is applied to the pier top segment beams and mid-span segment beams, multiple hybrid joints are connected in sequence, and the cast parts of two adjacent beam bodies (1) are connected by adhesive joints, and the reinforced concrete structures (6) in two adjacent beam bodies (1) are connected by wet joints.

4. The segmental prefabricated box girder hybrid joint according to claim 3, characterized in that: When the hybrid joint is applied to a pier top segment beam, a manhole (2) is provided in the reinforced concrete structure (6), the upper end of the manhole (2) is not connected to the top plate (1.1), and the bottom plate (1.4) is connected to the manhole (2).

5. The segmental prefabricated box girder hybrid joint according to claim 3, characterized in that: When the hybrid joint is applied to a mid-span segment beam, a through hole (3) is transversely opened in the middle of the reinforced concrete structure (6).

6. The segmental prefabricated box girder hybrid joint according to claim 5, characterized in that: The reinforced concrete structure (6) has the same transverse thickness.

7. The segmental prefabricated box girder hybrid joint according to claim 2, characterized in that: A plurality of temporary prestressed steps (4) are arranged and connected on the top of the top plate (1.1).

8. The segmental prefabricated box girder hybrid joint according to claim 7, characterized in that: The multiple temporary prestressed steps (4) are evenly distributed.

9. The segmental prefabricated box girder hybrid joint according to claim 1, characterized in that: The width of the reinforced concrete structure (6) is smaller than the width of the cast portion of the beam body (1) to which the reinforced concrete structure (6) is connected.

10. A construction method for a mixed joint of a segmental prefabricated box girder, characterized by: The steps include: S1, applying glue on the outside of the beam body (1) to be constructed, and moving the beam body (1) to the target position; S2, applying temporary prestress to two adjacent glued beams (1) to complete the glue extrusion construction; S3, first installing the steel bars of the wet joints in the beam body (1) after the glue is squeezed, then installing the formwork of the wet joints, and finally pouring concrete in the wet joints to complete the construction of the reinforced concrete structure (6); S4, performing permanent prestressing construction on the beam body (1), wherein the permanent prestressing construction is performed after the completion of step S2 or after the completion of step S3.

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