Socket type shear key used on segmental box girder

Abstract

The application belongs to the technical field of segmental precast beam, and particularly relates to a socketed shear key used on a segmental box beam. The structure of the socketed shear key comprises a male key block and a female key groove arranged at two end positions of a box beam body respectively, a steel column arranged on the male key block and inserted into the box beam body at one end and used for inserting the female key groove at the other end, and a circular groove arranged inside the female key groove and used for inserting the steel column. The socketed shear key has the advantages of the steel-concrete structure at the male key block, high compressive strength and tensile strength, and the male key block is not easy to break and fall off from the box beam body.

Description

Technical Field

[0001] This application belongs to the field of segmental precast beam technology, and particularly relates to a socket-type shear key used in segmental box girders. Background Technology

[0002] The main content of segmental precast beam technology is: dividing the bridge along the transverse direction to obtain multiple minimum units. The segmental box girder mentioned above is a common type of minimum unit. The segmental box girder is first prefabricated in the factory, then transported to the construction site, and finally connected at the joints of the segmental box girders to complete the entire construction operation of the segmental precast beam.

[0003] Compared with cast-in-place beam technology, the advantages of segmental precast beam technology are mainly controllable quality, short cycle time, less environmental impact, and high flexibility.

[0004] On the other hand, the common method for connecting the joints mentioned above is as follows: when the segmental box girder is prefabricated, shear keys and shear concave keys are left on the two end faces respectively through end templates of different shapes.

[0005] The shear key and shear key mentioned above together form a complete shear key structure. By interlocking the two, multiple segment box girders can be integrated into a whole, thereby providing sufficient vertical and lateral shear resistance at the joints of the segment box girders.

[0006] For example, Chinese utility model patent with authorization announcement number CN220619759U and authorization announcement date of March 19, 2024 discloses a shear key device applicable to both straight and curved segmental prefabricated box girders. Its structure mainly includes: segmental box girder, vertical shear key of web plate, radial shear key of top plate, and radial shear key of bottom plate.

[0007] The advantages of the shear key device in this utility model patent are mainly: shear keys are densely arranged on the web and top and bottom plates of the segment box girder splicing surface, which ensures the radial shear and torsional resistance of the segment box girder structure.

[0008] However, in the actual use of segmental precast beams, the shear key device still has at least the following problems with relatively low structural strength. Specifically, its vertical and radial shear key structures are essentially protruding concrete parts, which are relatively easy to break and fall off the main body of the segmental box girder when used for shear support, thus leading to the failure of shear resistance. Utility Model Content

[0009] This application provides a socket-type shear key for use on segmental box girders, and the technical problem to be solved is: how to make the shear key on the segmental box girder have relatively large structural strength.

[0010] The technical solution adopted by this application to solve the above problems is: a socket-type shear key used on segmental box girders, the structure of which includes a convex key block and a concave keyway respectively disposed at both ends of the main body of the box girder, a steel column disposed on the convex key block with one end inserted into the main body of the box girder and the other end used to insert into the concave keyway, and a circular groove disposed inside the concave keyway and used to insert the steel column.

[0011] A further preferred technical solution is that the shape of the convex key block is a frustum.

[0012] A further preferred technical solution is that: the circular groove is further provided with a steel pipe for fitting the steel column.

[0013] A further preferred technical solution is that: a semi-cylindrical block for reinforcing the steel column is provided on the end face of the convex key block, the steel column extends out of the arc surface of the semi-cylindrical block, and a semi-cylindrical groove for engaging the semi-cylindrical block is provided between the concave keyway and the circular groove.

[0014] A further preferred technical solution is that the diameter of the steel column is less than or equal to the diameter of the semi-cylindrical block.

[0015] A further preferred technical solution is that the steel column is also provided with a steel plate for connecting the box girder reinforcement cage.

[0016] A further preferred technical solution is that the steel plate is also provided with steel bar openings for passing through the box girder steel cage.

[0017] A further preferred technical solution is that the number of steel plates is two.

[0018] A further preferred technical solution is that the steel column is also provided with a vertical plate for installing the two steel plates and engaging the steel plates and the horizontal reinforcing bars.

[0019] A further preferred technical solution is that the vertical plate is also provided with concrete shear key forming holes.

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

[0021] First, the shear key structure has the advantages of a steel-concrete structure at the key block, with both high compressive and tensile strength, making the key block less likely to break and fall off the box girder body.

[0022] Secondly, this shear key structure achieves a more precise interlocking relationship between the steel column and the steel pipe, reducing the degree of vertical and lateral misalignment at the joint.

[0023] Third, the shear key structure is connected to the box girder reinforcement cage, which further improves the structural strength and installation stability of the key block on the main body of the box girder. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of this application.

[0025] Figure 2 This is a schematic diagram showing the location of this application.

[0026] Figure 3 This is a schematic diagram showing the position and shape of the semi-cylindrical block in this application.

[0027] Figure 4 This is a schematic diagram showing the position and shape of the semi-cylindrical groove in this application.

[0028] Figure 5 This is a schematic diagram showing the location of the steel plate in this application.

[0029] Figure 6 This is a schematic diagram illustrating the method of using the rebar opening in this application.

[0030] Figure 7 This is a schematic diagram illustrating the principle of using a semi-cylindrical block to reinforce a steel column in this application.

[0031] Figure 8 This is a schematic diagram showing the location of the holes forming the concrete shear keys in this application.

[0032] The meanings of the markings in the diagram are as follows.

[0033] a) Box girder main body, b) Box girder reinforcement cage, b-1 transverse reinforcement strip, c) Arc-shaped support edge of semi-cylindrical block to steel column, d) Original straight support edge;

[0034] 1. Convex key block; 2. Concave keyway; 3. Steel column; 4. Circular groove; 5. Steel pipe; 6. Semi-cylindrical block; 7. Semi-cylindrical groove; 8. Steel plate; 9. Reinforcing bar opening; 10. Vertical plate; 11. Concrete shear key forming hole. Detailed Implementation

[0035] The following description is merely a preferred embodiment of this application and is not intended to limit the scope of this application.

[0036] like Figures 1-8 As shown, a socket-type shear key used on a segmental box girder includes a convex key block 1 and a concave keyway 2 respectively disposed at both ends of the main body a of the box girder, a steel column 3 disposed on the convex key block 1 with one end inserted into the main body a of the box girder and the other end used to insert into the concave keyway 2, and a circular groove 4 disposed inside the concave keyway 2 and used to insert the steel column 3.

[0037] In a narrow sense, socket connection refers to a type of pipe connection. In this connection method, the spigot end of one pipe is inserted into the socket end of another pipe, thereby achieving a connection and sealing effect. In this embodiment, the "pipe" refers to the steel column 3, and the "other pipe" refers to the circular groove 4. The two are interlocked to form a stable connection, ultimately providing a certain degree of shear resistance.

[0038] However, the shear resistance of the shear key is mainly provided at the convex key block 1 and the concave keyway 2. The main function of the steel column 3 is, firstly, to upgrade the original single concrete structure at the convex key block 1 to a reinforced concrete structure, thereby giving the convex key block 1 outstanding compressive and tensile strength, making it less prone to fracture on the main body a of the box girder.

[0039] The main body of the box girder a comprises a top plate, a web plate, and a bottom plate, and the socket-type shear key is distributed on all three. The convex key block 1 and the concave keyway 2 correspond in position, shape, and size.

[0040] However, the material of the convex key block 1 is concrete, which is more difficult to precisely control in terms of size compared to steel. Therefore, the second function of the steel column 3 is to precisely insert the circular groove 4, so that when the load on the segment box girder is relatively small, it is less likely to experience vertical or lateral misalignment at the joint.

[0041] In summary, the connection between the convex key block 1 and the concave keyway 2 is mainly used to provide shear resistance, while the connection between the steel column 3 and the circular groove 4 is mainly used to provide positioning. The former has a larger internal gap than the latter. The positioning effect of the latter is most obvious when no vehicles are passing on the segmental box girder, while it can still provide some shear resistance when vehicles are passing on the segmental box girder.

[0042] The convex key block 1 has a frustum shape.

[0043] In this embodiment, the shape of the convex key block 1 includes four inclined isosceles trapezoidal surfaces and two vertical rectangular surfaces of different sizes. The larger rectangular surface is disposed on the box girder body a, and the steel column 3 extends from the smaller rectangular surface. The box girder body a, the convex key block 1, and the steel column 3 are integrally formed during the prefabrication stage in the factory.

[0044] Correspondingly, the shape and size of the concave keyway 2 are adapted to the convex key block 1, and the gap width between the two is ≤5mm, while the gap width between the steel column 3 and the circular groove 4 is generally ≤3mm.

[0045] The circular groove 4 is also provided with a steel pipe 5 for fitting the steel column 3.

[0046] In this embodiment, the steel pipe 5, the main body a of the box girder, the key block 1, and the steel column 3 are also integrally formed. This can further improve the insertion accuracy at the steel column 3 and further improve the splicing and installation accuracy at the joint when it is not subjected to obvious load.

[0047] It should be noted that the circular groove 4 at this time is formed by the steel pipe 5, and the diameter of the circular groove is larger than that of the circular groove used alone above. The difference is caused by the wall thickness of the steel pipe 5.

[0048] Generally, the gap width between the annular surface of the steel column 3 and the inner annular surface of the steel pipe 5 is ≤1.5mm, because steel is easier to control in terms of dimensional accuracy compared to concrete.

[0049] At this time, the groove pattern at the concave keyway 2 is as follows: the outer part of the annular surface of the groove is exposed concrete, the inner part of the annular surface of the groove is the inner annular surface of the steel pipe 5, and the innermost end face of the groove is also exposed concrete.

[0050] The end face of the convex key block 1 is also provided with a semi-cylindrical block 6 for reinforcing the steel column 3. The steel column 3 extends out of the arc surface of the semi-cylindrical block 6. A semi-cylindrical groove 7 for engaging the semi-cylindrical block 6 is also provided between the concave keyway 2 and the circular groove 4.

[0051] In this embodiment, the main function of the semi-cylindrical block 6 is that when the steel column 3 is subjected to shear force, it can provide an arc-shaped support edge for the steel column 3, that is, the arc-shaped support edge c of the semi-cylindrical block for the steel column. If there is no semi-cylindrical block 6, the convex key block 1 can only provide a straight support edge for the steel column 3, that is, the original straight support edge d.

[0052] It is obvious that the former is larger than the latter, thus improving the installation stability and shear strength of the steel column 3.

[0053] Correspondingly, the semi-cylindrical groove 7 and the semi-cylindrical block 6 are also corresponding in position, shape and size, ensuring at least the same insertion accuracy as the convex key block 1 and the concave keyway 2.

[0054] The semi-cylindrical block 6 is also integrally formed with the convex key block 1.

[0055] The diameter of the steel column 3 is less than or equal to the diameter of the semi-cylindrical block 6.

[0056] In this embodiment, the mounting surface of the semi-cylindrical block 6 on the convex key block 1 is rectangular. This mounting surface corresponds to the smaller rectangular surface on the convex key block 1. The length and width of the former are less than or equal to the latter, and it does not protrude from the latter.

[0057] Furthermore, on the vertical plane, the steel column 3 does not protrude from the semi-cylindrical block 6, and the upper limit of the diameter of the steel column 3 is the smaller value between the length and the diameter of the semi-cylindrical block 6.

[0058] As attached Figure 3 As shown, the smaller value mentioned above is the length of the semi-cylindrical block 6. In this case, the diameter of the steel column 3 is less than or equal to the aforementioned length. The reason for this dimensional setting is to avoid small, relatively independent concrete portions on the key block 1 and the semi-cylindrical block 6, which are relatively easy to break and fall off.

[0059] The steel column 3 is also provided with a steel plate 8 for connecting the box girder reinforcement cage b.

[0060] In this embodiment, the steel plate 8 and part of the steel column 3 are located inside the main body a of the box girder. The steel plate 8 is then connected to the reinforcing cage b of the box girder. This allows the force at the socket shear key to be distributed to the reinforcing cage b of the box girder, significantly improving the shear strength of the socket shear key.

[0061] The steel plate 8 is also provided with a steel bar opening 9 for passing through the steel bar cage b of the box girder.

[0062] In this embodiment, the steel plate 8 and the steel column 3 are integrally formed, and the box girder reinforcement cage b includes steel bars in three mutually tied and fixed and perpendicular to each other. One of the steel bars can be inserted into the steel bar opening 9, thereby increasing the connection strength between the steel plate 8 and the box girder reinforcement cage b, so that the overall structure of the steel plate 8 and the steel column 3 is not easily tilted or displaced when concrete is poured.

[0063] The number of steel plates 8 is 2.

[0064] In this embodiment, the two steel plates 8 are parallel to each other.

[0065] The steel column 3 is also provided with a vertical plate 10 for installing the two steel plates 8 and engaging the steel plates 8 and the transverse reinforcing bar b-1.

[0066] In this embodiment, the function of the vertical plate 10 is to make the distance between the two steel plates 8 no longer limited by the diameter of the steel column 3.

[0067] Generally, the distance between two adjacent transverse reinforcing bars b-1 is greater than the diameter of the steel column 3. Therefore, after setting the vertical plate 10, the two steel plates 8 can respectively abut against the two transverse reinforcing bars b-1, further improving the positional stability of the steel plates 8 during and after concrete pouring.

[0068] In addition, the aforementioned transverse reinforcing bar b-1 can also be a vertical reinforcing bar. The installation method of the steel column 3 is not limited in its circumferential direction. It is sufficient to ensure that the reinforcing bar that engages with the steel plate 8 and the reinforcing bar that is inserted into the reinforcing bar opening 9 include all the reinforcing bars in the above three directions.

[0069] The vertical plate 10 is also provided with concrete shear key forming holes 11.

[0070] In this embodiment, a section of concrete can be formed at the concrete shear key forming hole 11 of the box girder body a. At this time, the concrete section serves as the concrete shear key for fixing the vertical plate 10, which can also improve the installation stability of the steel column 3.

[0071] Of course, the concrete shear key forming holes 11 also have disadvantages, as they reduce the structural strength of the vertical plate 10 itself. Therefore, the total area of ​​the concrete shear key forming holes 11 should not be too large a proportion of the area of ​​the vertical plate 10.

[0072] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various modifications can be made without departing from the spirit of this application. These are non-inventive modifications and are protected by patent law as long as they are within the scope of the claims of this application.

Claims

1. A socket-type shear key for use in segmental box girders, characterized in that: The structure includes a convex key block (1) and a concave keyway (2) respectively located at both ends of the box girder body (a), a steel column (3) located on the convex key block (1) with one end inserted into the box girder body (a) and the other end used to insert into the concave keyway (2), and a circular groove (4) located inside the concave keyway (2) and used to insert the steel column (3).

2. A socket-type shear key for use in segmental box girders according to claim 1, characterized in that: The convex key block (1) is shaped like a frustum.

3. A socket-type shear key for use in segmental box girders according to claim 1, characterized in that: The circular groove (4) is also provided with a steel pipe (5) for connecting the steel column (3).

4. A socket-type shear key for use in segmental box girders according to claim 1, characterized in that: The end face of the convex key block (1) is also provided with a semi-cylindrical block (6) for reinforcing the steel column (3). The steel column (3) extends out of the arc surface of the semi-cylindrical block (6). A semi-cylindrical groove (7) for engaging the semi-cylindrical block (6) is also provided between the concave keyway (2) and the circular groove (4).

5. A socket-type shear key for use in segmental box girders according to claim 4, characterized in that: The diameter of the steel column (3) is less than or equal to the diameter of the semi-cylindrical block (6).

6. A socket-type shear key for use in segmental box girders according to claim 1, characterized in that: The steel column (3) is also provided with a steel plate (8) for connecting the box girder reinforcement cage (b).

7. A socket-type shear key for use in segmental box girders according to claim 6, characterized in that: The steel plate (8) is also provided with steel bar openings (9) for passing through the box girder steel cage (b).

8. A socket-type shear key for use in segmental box girders according to claim 6, characterized in that: The number of steel plates (8) is 2.

9. A socket-type shear key for use in segmental box girders according to claim 8, characterized in that: The steel column (3) is also provided with a vertical plate (10) for installing the two steel plates (8) and engaging the steel plates (8) and the transverse reinforcing bars (b-1).

10. A socket-type shear key for use in segmental box girders according to claim 9, characterized in that: The vertical plate (10) is also provided with concrete shear key forming holes (11).

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