Shear-resistant structure of segmental splicing box girder and construction method of shear-resistant structure

Abstract

The invention belongs to the technical field of segment splicing type bridges, and particularly relates to an anti-shearing structure of a segment splicing box girder and a construction method of the anti-shearing structure. The shear-resistant structure comprises a box girder body composed of a top plate, a web plate and a bottom plate, and further comprises two formwork units arranged at the two ends of the box girder body respectively in a pouring fixing mode, and a shell arranged on the formwork units and used for forming a concave key structure or a convex key structure of a shear key. The shear-resistant structure has the beneficial effects that the shear key formwork part of the shear-resistant structure at least comprises the formwork units and the shell, the shear key formwork part can effectively form the box girder body, does not need to be taken down during formwork removal and can also be used as a concave key structure and a convex key structure, and therefore the shear-resistant structure is simple and efficient during manufacturing and construction; and the precision is relatively high during splicing construction.

Description

Technical Field

[0001] The present application belongs to the technical field of segmental spliced ​​bridges, and in particular relates to a shear-resistant structure of a segmental spliced ​​box girder and a construction method thereof. Background Art

[0002] The general construction method of the segment-jointed bridge is as follows: prefabricated segments are produced in a factory, the segments are transported to a construction site, and the segments are joined together using shear keys at the construction site.

[0003] Among them, the common segment mentioned above refers to the segment spliced ​​box girder, whose structural components include the top plate, the web plate and the bottom plate. Generally, the top plate, the web plate and the bottom plate are provided with slots for shear keys, and the two ends of the steel shear keys are respectively inserted into the corresponding slots of the two adjacent box girders to complete the above splicing operation.

[0004] Correspondingly, the above-mentioned shear-resistant structure refers to the combination of shear keys and box beams.

[0005] For example, the Chinese utility model patent with authorization announcement number CN214219334U and authorization announcement date 2021.09.17 discloses a box girder segment with shear keys, whose structural components mainly include: web, top plate, bottom plate, web shear keys, top plate shear keys, bottom plate shear keys, top plate glue grooves, bottom plate glue grooves, joint area shear keys, joint area glue grooves, and shear recessed keys.

[0006] The advantages of the box girder segment in this utility model patent are mainly: improved shear resistance at the joints, and convenient alignment and splicing during segment bridge construction.

[0007] However, in the actual manufacturing and splicing construction process of the box girder segment, there are at least the following impractical and inefficient problems. Specifically, its shear key structure and shear recessed key structure need to be formed separately, which greatly reduces the efficiency and accuracy during manufacturing and construction. During the splicing construction, the convex keys and recessed keys at both ends of the box girder segment are relatively prone to position deviation, which increases the difficulty of splicing. Summary of the invention

[0008] The present application provides a shear-resistant structure of a segmental spliced ​​box girder, and the technical problem to be solved is: how to make the shear key structure of the segmental spliced ​​box girder simple and efficient during construction, and relatively high in precision during splicing.

[0009] On the other hand, the present application also provides a construction method of the shear-resistant structure.

[0010] The technical solution adopted by this application to solve the above problems is as follows: A shear-resistant structure for segmentally spliced box girders, including a box girder main body composed of a top plate, a web, and a bottom plate, further includes 2 formwork units respectively arranged at both ends of the box girder main body in a cast-in-place and fixed manner, and a housing arranged on the formwork unit and used to form a concave key structure or a convex key structure for the shear key.

[0011] A further preferred technical solution lies in that: the formwork unit includes an end formwork for casting and forming the box girder main body, and an opening for the concave key for inserting the housing of the adjacent formwork unit arranged on the end formwork.

[0012] A further preferred technical solution lies in that: the shape of the housing is a frustum or a frustum of a cone, and the larger end of the housing is arranged on the end formwork and covers the opening for the concave key.

[0013] A further preferred technical solution lies in that: the end formwork is used to correspondingly and synchronously form the housing and the opening for the concave key by the way of being jacked up and bent by itself.

[0014] A further preferred technical solution lies in that: the end formwork includes a top cross plate, an inclined plate, and a bottom cross plate all provided with the housing; the formwork unit further includes a tensioning opening arranged on the inclined plate and / or the bottom cross plate and used to pass through the prestressed steel strand.

[0015] A further preferred technical solution lies in that: it further includes a corrugated pipe arranged inside the box girder main body, with both ends respectively arranged on the tensioning openings of the two formwork units and used to pass through the prestressed steel strand.

[0016] A further preferred technical solution lies in that: it further includes a positioning pipe inserted on the tensioning opening and used for screwing or clamping and connecting the corrugated pipe, and a lengthwise limiting ring arranged on the positioning pipe and used for clamping the exposed surface of the end formwork.

[0017] A further preferred technical solution lies in that: before splicing, an epoxy resin binder is added inside the housing used to form the concave key structure, and the lengthwise limiting ring is used to prevent the epoxy resin binder from entering and blocking the positioning pipe by blocking.

[0018] A further preferred technical solution lies in that: it further includes bolt holes respectively arranged at both ends of the web and used for installing connecting steel plates at the joints.

[0019] A construction method for a shear-resistant structure of segmentally spliced box girders successively includes the following steps: S1. Add the epoxy resin binder into the housing forming the concave key structure; S2. Interconnect the respective housings and concave keys on two adjacent template units with perforations; S3. Pass the prestressed steel strands through all the shear structures and tension and fasten them; S4. Screw and install the connecting steel plates at the joints on all adjacent shear structures.

[0020] The beneficial effects of this application include at least the following three points.

[0021] First, the template unit and the housing together form the shear key template part of the shear structure. This part can not only effectively form the main body of the box girder, but also does not need to be removed during form removal. It can also be used as the concave key structure and the convex key structure respectively, thus making the manufacturing and construction of the shear structure simple and efficient, and having relatively high precision during splicing construction.

[0022] Second, in this shear structure, the corrugated pipe is used to form the ducts required for the installation of the prestressed steel strands. During the entire construction process of this shear structure, the corrugated pipe has the dual advantages of stable position, not easy to fall off, and not easy to be blocked by the epoxy resin binder.

[0023] Third, the material of the above shear key template part is high-strength steel. Therefore, the joints are connected by steel structures and used together with the epoxy resin binder, ensuring that the joints have a relatively large structural strength connection effect, and it is not easy to occur harmful phenomena such as concrete structure damage and cracking at this place. Brief Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the splicing method of this application.

[0025] Figure 2 It is a schematic diagram of the structure of the shear key template in this application.

[0026] Figure 3 It is a schematic diagram of the position and shape of the positioning pipe in this application.

[0027] Figure 4 It is a schematic diagram of the position and shape of the lengthwise limiting ring in this application.

[0028] Figure 5 It is a schematic diagram of the usage method of the perforation for tensioning in this application.

[0029] Figure 6 It is a schematic diagram of the epoxy resin binder blocking effect of the lengthwise limiting ring in this application.

[0030] Figure 7 It is a schematic diagram of the position of the bolt holes in this application.

[0031] Figure 8 Schematic diagram of the casting and forming method of the box girder main body in this application.

[0032] Figure 9 Schematic diagram of the addition method of the epoxy resin binder in this application.

[0033] Figure 10 Schematic diagram of the insertion method of the shear key template in this application.

[0034] Figure 11 Schematic diagram of a shape of the connecting steel plate at the joint in this application.

[0035] Figure 12 Schematic diagram of the installation position of the corrugated pipe during the casting of the box girder main body in this application from a top view angle.

[0036] In the figure, the meanings of the respective markings are as follows.

[0037] Prestressed steel strand a, epoxy resin binder b, connecting steel plate c at the joint, concrete d under pouring, formwork e, bolt f; Top plate 11, web 12, bottom plate 13; Formwork unit 1, housing 2, corrugated pipe 3, positioning pipe 4, lengthwise limiting ring 5, bolt hole 6; End formwork 101, opening 102 for concave key, opening 103 for tensioning; Raised threaded section 401. Specific implementation manner

[0038] The following is only a preferred embodiment of this application, and does not limit the scope of this application.

[0039] As Figures 1 - 12 shown, a shear-resistant structure of a segment-spliced box girder includes a box girder main body composed of a top plate 11, a web 12, and a bottom plate 13, and is characterized in that: it further includes 2 formwork units 1 respectively arranged at both ends of the box girder main body in a casting and fixing manner, and a housing 2 arranged on the formwork unit 1 and used to form a concave key structure or a convex key structure for a shear key.

[0040] In this embodiment, the structural composition of this shear-resistant structure includes the following 2 parts: First, the shear key formwork part, including the formwork unit 1 and the housing 2; Second, the box girder main body part, including the top plate 11, the web 12, and the bottom plate 13.

[0041] So far, this shear-resistant structure has at least the following 4 advantages during the entire manufacturing and splicing construction.

[0042] 1. When the above shear key template part faces the concrete d being poured, it forms a concave key structure, and when it faces away from the concrete d being poured, it forms a convex key structure. Since the above concave key structure and convex key structure are formed by two shear key template parts of the same specification, the matching accuracy between the concave key structure and the convex key structure must be relatively high, ensuring the convenience and accuracy of construction operations.

[0043] 2. When removing the formwork of this shear resistance structure, the above shear key template part does not need to be removed, which improves the manufacturing and construction efficiency.

[0044] 3. At the joint formed by this shear resistance structure, the directly abutting part is made of high-strength steel. Compared with the original concrete abutting method, the former is not prone to concrete cracking, enhancing the structural strength of the segmental spliced bridge.

[0045] 4. Whether the outer surface or the inner surface of the housing 2 contacts the concrete, it has a large contact surface and can obtain a sufficiently stable self-installation effect in the main part of the box girder.

[0046] Among them, the shape of the template unit 1 is consistent with the cross-sectional shape of the main body of the box girder. The template unit 1 and the housing 2 are integrally formed, and the forming method is: one-time forming after die casting, or obtaining by later extrusion deformation.

[0047] The template unit 1 includes an end template 101 for casting and forming the main body of the box girder, and an opening 102 for the concave key of the housing 2 which is arranged on the end template 101 and used for inserting the adjacent template unit 1.

[0048] In this embodiment, the opening 102 for the concave key is hermetically connected and smoothly transitioned with the housing 2, without gaps and holes.

[0049] The shape of the housing 2 is a frustum or a circular truncated cone. The larger end of the housing 2 is arranged on the end template 101 and covers the opening 102 for the concave key.

[0050] In this embodiment, when the shape of the housing 2 is a frustum, the shape of the opening 102 for the concave key is a rectangle matching it; when the shape of the housing 2 is a circular truncated cone, the shape of the opening 102 for the concave key is a circle matching it.

[0051] The smaller end of the housing 2 is its insertion end. When splicing this shear resistance structure, the above insertion end first passes through the corresponding opening 102 for the concave key on the adjacent template unit 1, and then is stuck on the inner side surface of the housing 2 corresponding to the opening 102 for the concave key. For details, please refer to the appendix Figure 10 .

[0052] If the two ends of the housing 2 have the same dimensions, for example, its shape is a cuboid or a cylinder, the accuracy requirements for its plugging operation are relatively high. On the contrary, this is one of the advantages of the above-mentioned housing 2.

[0053] The end template 101 is used to correspondingly and synchronously form the housing 2 and the opening 102 for the concave key by the way of being lifted and bent by itself.

[0054] In this embodiment, the wall thickness of the housing 2 is substantially the same as the thickness of the end template 101.

[0055] When the forming method of the shear key template part is extrusion deformation, the thickness of the steel plate part corresponding to the housing 2 and originally belonging to the end template 101 needs to be relatively large, so as to ensure that the thickness of the housing 2 will not be too small.

[0056] When the forming method of the shear key template part is casting, it is only necessary to control that the distance between the left and right plates of the forming die is equal everywhere.

[0057] The end template 101 includes a top cross plate, an inclined plate and a bottom cross plate where the housing 2 is provided; the template unit 1 further includes a tensioning opening 103 provided on the inclined plate and / or the bottom cross plate and used for passing through the prestressed steel strand a.

[0058] In this embodiment, the cross-sectional shape of the template unit 1 is the same as the shape of the end template 101, and their general shapes are both inverted isosceles trapezoids, which is also one of the common shapes of existing box girders.

[0059] On the other hand, when the segment spliced box girder is in normal use, the load on its upper surface will frequently, slightly and unevenly press down the entire box girder, resulting in: First, the end faces at the joints of the box girder main body collide with each other; Second, the end positions of the top plate 11, that is, the joints, incline downward and squeeze each other.

[0060] Based on the above first point, in order to avoid the end face of the box girder main body from cracking due to the above-mentioned impact problem, high-strength steel material is used to replace the original concrete material as the end face material of the box girder main body, which is one of the advantages of the above-mentioned shear key template part.

[0061] Based on the above second point, no prestressed steel strand a is provided at the top plate 11. Otherwise, the prestress tensioning effect will instead exacerbate the degree of the above-mentioned harmful phenomena of inclination and extrusion. This is the reason why the tensioning opening 103 is only provided on the inclined plate and / or the bottom cross plate.

[0062] Among them, the top horizontal plate corresponds to the top plate 11, the inclined plate corresponds to the web 12, and the bottom horizontal plate corresponds to the bottom plate 13. Consequently, the prestressed duct exists only at the web 12 and / or the bottom plate 13.

[0063] The shear-resistant structure further includes a corrugated pipe 3 disposed within the box girder body, with both ends respectively disposed on the tensioning openings 103 of the two formwork units 1 and adapted to pass through the prestressed steel strand a.

[0064] In this embodiment, the corrugated pipe 3 is used to leave the above-mentioned prestressed duct in the concrete, and it has a relatively large deformable range in its length direction. Therefore, it does not affect or impede the tensioning operation of the prestressed steel strand a.

[0065] Correspondingly, the corrugated pipe 3 has sufficient support strength in its radial direction, making it difficult for the concrete d during pouring to flatten it. Otherwise, the prestressed duct will be blocked and the prestressed steel strand a will be difficult to completely pass through.

[0066] The shear-resistant structure further includes a positioning pipe 4 inserted into the tensioning opening 103 and adapted to be screwed or snap-connected to the corrugated pipe 3, and a longitudinal limiting ring 5 disposed on the positioning pipe 4 and adapted to snap onto the exposed surface of the end formwork 101.

[0067] In this embodiment, without the positioning pipe 4 and the longitudinal limiting ring 5, during the manufacturing and construction of the shear-resistant structure, both ends of the corrugated pipe 3 can only be relatively simply and weakly inserted or placed on the tensioning opening 103.

[0068] At this time, as the concrete d during pouring continuously pours, it will wash away the corrugated pipe 3, causing the corrugated pipe 3 to bend downward or even fall off, making it difficult for the prestressed duct to be effectively formed.

[0069] Conversely, this is one of the functions of the positioning pipe 4 and the longitudinal limiting ring 5. Among them, the positioning pipe 4 and the longitudinal limiting ring 5 are integrally formed. The outer diameter of the former is slightly smaller than the diameter of the tensioning opening 103. The inner ring surface of the former is screwed or snap-connected to the corrugated pipe 3. The outer diameter of the latter is larger than the diameter of the tensioning opening 103, thereby enabling the corrugated pipe 3 to be straightened and fixed and not easily washed away by the concrete.

[0070] In the prior art, the corrugation patterns of the corrugated pipe 3 are mainly the following two types: spiral and parallel circular. When the corrugated pipe 3 corresponds to a spiral corrugation, the positioning pipe 4 is screwed to it, and the inner ring surface of the positioning pipe 4 is provided with the raised thread section 401.

[0071] When the corrugated pipe 3 corresponds to parallel circular corrugations, the positioning pipe 4 is engaged and connected thereto. The inner circumferential surface of the positioning pipe 4 is also provided with raised corrugations in circles, which are stuck in the depressions of the corrugations of the corrugated pipe 3 and can also provide sufficient connection strength.

[0072] Before the shear-resistant structure is spliced, an epoxy resin binder b is added in the housing 2 for forming the concave key structure. The longitudinal limiting ring 5 is used to prevent the epoxy resin binder b from entering and blocking the positioning pipe 4 by a blocking method.

[0073] In this embodiment, the epoxy resin binder b is an existing product, which is relatively common in the construction operation of segmental spliced bridges. Its main function is to improve the splicing strength at the joint.

[0074] Among them, a relatively thin resin layer formed after the epoxy resin binder b is cured cannot completely avoid the above-mentioned problems of the impact of the end of the box girder and the mutual extrusion after the inclination of the end of the top plate 11.

[0075] On the other hand, when two adjacent box girders are fully inserted at the housing 2, the corresponding two longitudinal limiting rings 5 are completely abutted or relatively close. At this time, the second function of the longitudinal limiting ring 5 is that it can block the epoxy resin binder b that has not been completely cured and prevent the epoxy resin binder b from entering the positioning pipe 4. Otherwise, it will be difficult for the prestressed steel strand a to pass through the positioning pipe 4. For details, please refer to the appendix Figure 6 .

[0076] The shear-resistant structure further includes bolt holes 6 respectively arranged at both ends of the web 12 and used for installing the connecting steel plate c at the joint.

[0077] In this embodiment, the bolt holes 6 are used in combination with the connecting steel plate c and the bolt f at the joint, so that the connection strength between two adjacent box girders is greater.

[0078] At this time, the outer side edge of the inclined plate of the end template 101 abuts or is very close to the connecting steel plate c at the joint, but does not affect their respective connection functions, and both can significantly improve the shear strength at the joint.

[0079] Moreover, the connecting steel plate c at the joint can also provide the longitudinal connection strength that the shear key template part does not have. Correspondingly, the epoxy resin binder b can also appropriately provide this longitudinal connection strength.

[0080] Among them, the bolt f is used in combination with a fastening nut, and the fastening nut can be located inside or outside the web 12, that is, it can press on the connecting steel plate c at the joint or on the web 12.

[0081] A construction method for the shear-resistant structure of segment spliced box girders successively includes the following steps: S1. Add the epoxy resin binder b into the housing 2 forming the concave key structure; S2. Interconnect the respective housings 2 and concave keys on two adjacent template units 1 through the openings 102; S3. Pass the prestressed steel strand a through all the shear-resistant structures and tension and fasten it; S4. Screw and install the connecting steel plate c at the joints on all adjacent shear-resistant structures.

[0082] In S1 of this embodiment, another function of the housing 2 is to make it easier to control the addition amount of the epoxy resin binder b. As shown in the Figure 2 accompanying drawings, at the initial design of this shear-resistant structure, it is determined that the addition amount of the epoxy resin binder b is to fill 3 out of all 12 housings 2, then this addition amount is relatively easy to control and it is not easy to have problems of too much or too little.

[0083] In S3 of this embodiment, the prestressed steel strand a is respectively provided with tensioning fixtures on 2 of the shear-resistant structures at the end positions to maintain its tensioned and clamped state. Among them, the length direction of the prestressed steel strand a is the longitudinal bridge direction.

[0084] The embodiments of the present application have been described in detail above in conjunction with the accompanying drawings. However, the present application is not limited to the above embodiments. Within the knowledge scope of those of ordinary skill in the art in the said technical field, various modifications can also be made without departing from the purpose of the present application. These are all non-creative modifications and are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. Shear resistance structure of segment spliced box girder, including a box girder main body composed of a top plate (11), a web (12) and a bottom plate (13), characterized in that: It further includes two formwork units (1) respectively arranged at both ends of the box girder main body in a cast-in-place and fixed manner, and a housing (2) arranged on the formwork unit (1) and used for forming a concave key structure or a convex key structure of the shear key.

2. The shear resistance structure of a segment spliced box girder according to claim 1, characterized in that: The formwork unit (1) includes an end formwork (101) for casting and forming the box girder main body, and a concave key opening (102) arranged on the end formwork (101) and used for inserting the housing (2) of the adjacent formwork unit (1).

3. The shear-resistant structure of a segmentally spliced box girder according to claim 2, characterized in that: The housing (2) is in the shape of a frustum of a pyramid or a frustum of a cone, and the larger end of the housing (2) is arranged on the end formwork (101) and covers the concave key opening (102).

4. The shear-resistant structure of a segmentally spliced box girder according to claim 2, characterized in that: The end formwork (101) forms the housing (2) and the concave key opening (102) correspondingly and synchronously by the way of being jacked up and bent by itself.

5. The shear-resistant structure of a segment-spliced box girder according to claim 2, characterized in that: The end formwork (101) includes a top cross plate, an inclined plate and a bottom cross plate all provided with the housing (2); the formwork unit (1) further includes a tensioning opening (103) arranged on the inclined plate and / or the bottom cross plate and used for passing through the prestressed steel strand (a).

6. The shear resistance structure of a segmentally spliced box girder according to claim 5, characterized in that: It further includes a corrugated pipe (3) arranged in the box girder main body, with both ends respectively arranged on the tensioning openings (103) of the two formwork units (1) and used for passing through the prestressed steel strand (a).

7. The shear resistance structure of a segmentally spliced box girder according to claim 6, characterized in that: It further includes a positioning pipe (4) inserted on the tensioning opening (103) and used for screwing or clamping and connecting the corrugated pipe (3), and a longitudinal limiting ring (5) arranged on the positioning pipe (4) and used for clamping the exposed surface of the end formwork (101).

8. The shear-resistant structure of a segmentally spliced box girder according to claim 7, characterized in that: Before splicing the shear structure, an epoxy resin binder (b) is added into the housing (2) for forming the concave key structure, and the longitudinal limiting ring (5) is used to prevent the epoxy resin binder (b) from entering and blocking the positioning pipe (4).

9. The shear-resistant structure of a segmentally spliced box girder according to claim 8, characterized in that: It further includes bolt holes (6) respectively arranged at both ends of the web (12) and used for installing a connecting steel plate (c) at the joint.

10. A construction method of the shear-resistant structure of the segment-spliced box girder as described in claim 9, characterized in that It successively includes the following steps: S1. Add the epoxy resin binder (b) into the housing (2) for forming the concave key structure; S2. The respective housings (2) and concave key openings (102) on two adjacent formwork units (1) are inserted into each other; S3. Pass the prestressed steel strand (a) through all the shear structures and tension and fasten it; S4. Screw and install the connecting steel plate (c) at the joint on all adjacent shear structures.

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