PBL shear key used on segmental box girder

Abstract

The utility model belongs to the technical field of bridge engineering, and particularly relates to a PBL shear key used on a segmental box girder. The PBL shear key structure is mounted at the joint of in-box web plates of two adjacent segments of box girders, and comprises a fixing plate of which the two sides are respectively connected with the in-box web plates of the two adjacent segments of box girders, and at least three positioning plates which are arranged on the fixing plate and are arranged along the splicing direction vertical to the segment box girders, and the connecting steel bars are perpendicular to the positioning plates and are used for connecting all the positioning plates. The structure at least comprises the fixing plates, the positioning plates and the connecting steel bars, so that the vertical shear stress at the splicing position of the segmental box girders can be quickly transmitted to the positioning plates through the fixing plates and dispersed, and the vertical shear resistance requirement of the splicing position of the segmental box girders is improved.

Description

Technical Field

[0001] This application belongs to the field of bridge engineering technology, and in particular relates to a PBL shear key used in segmental box girders. Background Technology

[0002] Prestressed concrete segmental precast box girder, also known as segmental box girder, is a type of concrete box girder that is longitudinally divided into multiple segments, precast in matching configurations, and then assembled into a complete bridge through prestressing tension. Segmental precast bridges offer advantages such as material savings, rapid construction, less on-site work, minimal traffic disruption, and a high degree of industrialization, making them an important form of modern industrialized bridge construction. They are currently widely used in railway, highway, and urban bridges in my country. PBL shear key structures are applied to the connection of segmental beams. Due to the excellent tensile strength of steel reinforcement and the compressive strength of concrete, PBL shear keys have been extensively researched and applied as a novel steel-concrete composite connection method.

[0003] However, for segmental box girders, the splice surfaces of the segments need to transfer significant vertical shear stress when the girder is subjected to vertical loads. Traditionally used PBL shear keys have low vertical shear resistance and cannot meet the shear requirements of segmental box girders.

[0004] For example, Chinese utility model patent application CN215368246U, published on April 12, 2021, discloses a PBL shear key capable of precisely positioning through-bar reinforcement. It mainly includes: an I-beam, a central perforated rib parallel to the web of the I-beam, two side perforated positioning ribs, and through-bar reinforcement. The central perforated rib has multiple holes, and the holes in the side perforated positioning ribs correspond one-to-one with the holes in the central perforated rib. Furthermore, the line connecting the centerlines of all the corresponding holes in the ribs is orthogonal to the plane containing the web of the I-beam, and finally, the through-bar reinforcement is inserted.

[0005] The advantages of the PBL shear key in this utility model patent application are: it provides a certain vertical shear stress and enables the through-bar reinforcement to be accurately positioned in the center of the hole, thus solving the positioning difficulties caused by traditional construction methods.

[0006] However, the PBL shear key still presents certain construction difficulties in actual use. The main reason is that the structure composed of I-beams, perforated ribs, and positioning ribs occupies too much space. Generally, at least two PBL shear keys need to be installed symmetrically at the joint of a box girder. Due to the limited space inside the box girder, after one PBL shear key on one side is installed, the space for the PBL shear key on the other side is compressed during installation, affecting construction efficiency. Utility Model Content

[0007] This application provides a PBL shear key for use on segmental box girders. The technical problem it aims to solve is: how to enable segmental assembled bridges to have a large vertical shear capacity at the joints, while reducing the construction difficulty of the PBL shear key and improving construction efficiency.

[0008] The technical solution adopted by this application to solve the above problems is: a PBL shear key used on segmental box girders, installed at the connection of the inner web of two adjacent segmental box girders, including a fixing plate on both sides connected to the inner web of the two adjacent segmental box girders respectively, at least three positioning plates arranged on the fixing plate along the splicing direction perpendicular to the segmental box girders, and connecting steel bars perpendicular to the positioning plates and used to connect all the positioning plates.

[0009] A further preferred technical solution is that the positioning plate is perpendicular to the fixing plate, and at least one of the positioning plates is disposed in the middle of the fixing plate.

[0010] A further preferred technical solution is that the fixing plate includes a base plate, at least two mounting holes provided on both sides of the base plate, and at least two fixing bolts that pass through the mounting holes and are connected to the inner web of the segmental box girder.

[0011] A further preferred technical solution is that the positioning plate includes a rib plate, and a plurality of connecting holes are disposed on the rib plate and distributed at equal intervals.

[0012] A further preferred technical solution is that the connecting steel bar includes a threaded rod passing through the connecting hole, and fastening nuts screwed to at least both sides of the threaded rod and abutting against the rib plate.

[0013] A further preferred technical solution is that the fixing plate further includes a support plate disposed on one side of the box bottom plate near the segmental box girder and perpendicular to the positioning plate.

[0014] A further preferred technical solution is that the fixing plate further includes a limiting plate disposed on the side of the base plate away from the support plate and corresponding to the positioning plate for fixing the end of the positioning plate.

[0015] A further preferred technical solution is that the limiting plate includes at least two limiting bodies that are arranged opposite to each other and protrude from the surface of the fixing plate.

[0016] A further preferred technical solution is that the length of the support plate is greater than the maximum distance between the two positioning plates.

[0017] A further preferred technical solution is that the fixing plate further includes a positioning hole provided on the support plate; the diameter of the positioning hole matches the diameter of the fixing bolt.

[0018] The beneficial effects of this application include at least the following three points.

[0019] First, the overall structure consisting of the fixing plate, positioning plate, and connecting steel bars allows the vertical shear stress at the splice of the segmental box girder to be quickly transferred to the positioning plate and dispersed, thereby improving the vertical shear resistance requirements at the splice of the segmental box girder.

[0020] Secondly, the method of positioning and fixing plates being installed on-site not only achieves ideal shear resistance but also allows for the selection of positioning plates of appropriate height based on the site conditions, avoiding installation interference between the two PBL shear keys installed on the inner sides of the two webs of the same segment box girder.

[0021] Third, the fixing plate, positioning plate, and connecting steel bars all have the advantages of relatively simple and precise installation and operation. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the PBL shear key in this application.

[0023] Figure 2 This is a schematic diagram of the installation position of the PBL shear key in this application from the main view angle.

[0024] Figure 3 This is a structural schematic diagram of the PBL shear key in this application at an angle perpendicular to the inner web of the segmental box girder.

[0025] Figure 4 This is a three-dimensional structural diagram of the fixing plate in this application.

[0026] Figure 5 This is a schematic diagram showing the installation position of the base plate in this application.

[0027] The meanings of the markings in the diagram are as follows.

[0028] Segmental box girder a;

[0029] Fixing plate 1, positioning plate 2, connecting steel bars 3;

[0030] Base plate 101, fixing bolts 102, mounting holes 103, support plate 104, limiting plate 105, positioning holes 106;

[0031] Rib 201, connecting hole 202;

[0032] Threaded rod 301, fastening nut 302. Detailed Implementation

[0033] The following description is merely a preferred embodiment of this application and is not intended to limit the scope of this application.

[0034] like Figures 1-5 As shown, a PBL shear key for use on segmental box girders is installed at the connection of the inner web of two adjacent segmental box girders a. It includes a fixing plate 1 connected to the inner web of the two adjacent segmental box girders a on both sides, at least three positioning plates 2 arranged on the fixing plate 1 along the splicing direction perpendicular to the segmental box girders a, and connecting steel bars 3 perpendicular to the positioning plates 2 and used to connect all the positioning plates 2.

[0035] The segmental box girder a has an existing structure, mainly consisting of a top slab, web, and bottom slab, which are precast and cast in a factory. During the precasting process, several through-holes of prestressed ducts are formed at the bottom of the segmental box girder a. The main body of the segmental box girder a is an inverted isosceles trapezoid and is spliced ​​along the length of the bridge (or longitudinal direction). In this embodiment, there are multiple PBL shear keys, which are set at the connection between adjacent segments of the box girder a, and are therefore also longitudinally distributed. The "inner web" in "the inner web of the segmental box girder a" refers to the inner surface of the web of the segmental box girder a. Therefore, after the fixing plate 1 is connected to the inner web of the segmental box girder a, it is also inclined.

[0036] The positioning plate 2 is perpendicular to the fixing plate 1, and at least one of the positioning plates 2 is disposed in the middle of the fixing plate 1.

[0037] In this embodiment, there are three positioning plates 2 arranged longitudinally, with one plate located in the middle of the fixing plate 1 and the other two symmetrically distributed on both sides of the central positioning plate 2. The positioning plates 2 are all installed perpendicular to the fixing plate 1, and the length direction of the positioning plates 2 is parallel to the height extension direction of the inner web of the segmental box girder a.

[0038] Furthermore, both the fixing plate 1 and the positioning plate 2 are made of high-strength steel, allowing them to be connected on-site by welding. Therefore, the fixing plate 1 can be adjusted on-site so that its center aligns with the joint of the two segment box girder a, and the positioning plate 2, located in the center of the fixing plate 1, is also aligned with the joint. This allows the vertical shear stress at the joint of segment box girder a to be quickly transferred from the fixing plate 1 to the positioning plate 2, improving the vertical shear resistance requirements at the joint of segment box girder a.

[0039] On the other hand, the connecting steel bars 3 connect all the positioning plates 2 to form a whole, which not only improves the torsional resistance of the positioning plates 2, but also allows the shear stress transmitted to the positioning plates 2 to be quickly transmitted from the middle to both ends, thus improving the overall shear resistance of the positioning plates 2.

[0040] Finally, since the positioning plate 2 is positioned and installed on site, it can not only achieve the ideal shear resistance effect, but also select a positioning plate of appropriate height according to the site, so as to avoid installation interference between the two PBL shear keys installed on the inner side of the two webs of the same segment box girder a.

[0041] The fixing plate 1 includes a base plate 101, at least two mounting holes 103 on both sides of the base plate 101, and at least two fixing bolts 102 that pass through the mounting holes 103 and are connected to the inner web of the segment box girder a.

[0042] In this embodiment, the number of mounting holes 103 on one side of the base plate 101 is at least four, therefore the number of fixing bolts 102 on one side of the base plate 101 is also four, and the number of mounting holes on the inner web of a segment box girder a is also four. The fixing bolts 102 pass through the mounting holes 103 and connect with the inner web of the box girder. Therefore, the mounting holes 103 and the mounting holes on the inner web of the box girder should preferably be the same threaded holes, so that the fixing bolts 102 can complete the fixed connection between the base plate 101 and the web.

[0043] The positioning plate 2 includes a rib plate 201 and a plurality of connecting holes 202 disposed on the rib plate 201 and distributed at equal intervals.

[0044] In this embodiment, six connecting holes 202 are provided on the rib plate 201, arranged in two rows of three, and the spacing between any two adjacent connecting holes 202 is equal, both laterally and longitudinally. This ensures that the six connecting steel bars 3 are evenly distributed on a single positioning plate 2, ultimately strengthening the structure composed of all positioning plates 2 and connecting steel bars 3 so that the stress is evenly distributed, improving the stability and shear resistance of the structure.

[0045] The connecting steel bar 3 includes a threaded rod 301 passing through the connecting hole 202, and a fastening nut 302 screwed to at least both sides of the threaded rod 301 and abutting against the rib plate 201.

[0046] In this embodiment, each threaded rod 301 corresponds to two fastening nuts 302. The two fastening nuts 302 abut against the outer surfaces of the two ribs 201 respectively, thereby completing the pull-locking and forming an integral structure with sufficient strength.

[0047] The fixing plate 1 also includes a support plate 104 disposed on one side of the bottom plate of the bottom plate 101 near the box girder a and perpendicular to the positioning plate 2.

[0048] In this embodiment, the support plate 104 is parallel to the long side of the fixing plate 1 in the longitudinal direction, and the length of the support plate 104 is greater than the maximum distance between the two positioning plates 2. More preferably, the length of the support plate 104 is consistent with the long side, which helps to quickly locate and unify the position of the lower end of all positioning plates 2 when fixing the positioning plates 2 on site. At the same time, the protruding support plate 104 also has the function of supporting the positioning plates 2, which can keep the positioning plates 2 stably placed before installation.

[0049] In addition to positioning the positioning plate 2, as shown in the attached... Figure 3 As shown, the protruding support plate 104 can also serve as a platform for placing miscellaneous components such as fixing bolts 102, threaded rods 301, and fastening nuts 302, which helps to organize and store the components and improves the efficiency of on-site construction.

[0050] The fixing plate 1 further includes a limiting plate 105 disposed on the side of the base plate 101 away from the support plate 104 and corresponding to the positioning plate 2 for fixing the end of the positioning plate 2.

[0051] The limiting plate 105 includes at least two limiting bodies that are arranged opposite to each other and protrude from the surface of the fixing plate 1.

[0052] In this embodiment, the number of limiting plates 105 is the same as the number of positioning plates 2, and they are evenly distributed. Two limiting bodies form a group and are arranged in parallel, with the distance between the two limiting bodies matching the thickness of the positioning plate 2. This ensures that before the positioning plate 2 is fixedly installed on the fixing plate 1, the limiting plates 105 provide longitudinal restriction, and the support plate 104 provides height restriction. Together, they temporarily fix the two ends of the positioning plate 2, which helps improve welding efficiency. At the same time, the limiting plates 105 define the installation position of the positioning plate 2, reducing the difficulty of positioning during on-site installation and optimizing the construction process.

[0053] The fixing plate 1 also includes a positioning hole 106 provided on the support plate 104; the diameter of the positioning hole 106 matches the diameter of the fixing bolt 102.

[0054] In this embodiment, the positioning holes 106 can additionally serve as temporary fixing bolts 102, which helps to improve the storage capacity of the support plate 104. Furthermore, the equidistant distribution of the positioning holes 106 can help calculate the distance along the length direction of the support plate 104, which has good practicality.

[0055] 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 PBL shear key for use on segmental box girders, installed at the connection of the inner web of two adjacent segmental box girders (a), characterized in that: It includes a fixing plate (1) that is connected to the inner web of the two adjacent segments of the box girder (a) on both sides, at least three positioning plates (2) that are set on the fixing plate (1) and arranged in a direction perpendicular to the splicing direction of the segment box girder (a), and connecting steel bars (3) that are perpendicular to the positioning plates (2) and are used to connect all the positioning plates (2).

2. The PBL shear key for use in segmental box girders according to claim 1, characterized in that: The positioning plate (2) is perpendicular to the fixing plate (1), and at least one of the positioning plates (2) is located in the middle of the fixing plate (1).

3. The PBL shear key for use in segmental box girders according to claim 1, characterized in that: The fixing plate (1) includes a base plate (101), at least two mounting holes (103) provided on both sides of the base plate (101), and at least two fixing bolts (102) that pass through the mounting holes (103) and are connected to the inner web of the segment box girder (a).

4. A PBL shear key for use in segmental box girders according to claim 1, characterized in that: The positioning plate (2) includes a rib plate (201) and a plurality of connecting holes (202) disposed on the rib plate (201) and distributed at equal intervals.

5. A PBL shear key for use in segmental box girders according to claim 4, characterized in that: The connecting steel bar (3) includes a threaded rod (301) passing through the connecting hole (202) and a fastening nut (302) screwed at least on both sides of the threaded rod (301) and abutting against the rib plate (201).

6. A PBL shear key for use in segmental box girders according to claim 3, characterized in that: The fixing plate (1) also includes a support plate (104) disposed on one side of the bottom plate of the bottom plate (101) near the segment box girder (a) and perpendicular to the positioning plate (2).

7. A PBL shear key for use in segmental box girders according to claim 6, characterized in that: The fixing plate (1) further includes a limiting plate (105) disposed on the side of the base plate (101) away from the support plate (104) and corresponding to the positioning plate (2) for fixing the end of the positioning plate (2).

8. A PBL shear key for use in segmental box girders according to claim 7, characterized in that: The limiting plate (105) includes at least two limiting bodies that are arranged opposite to each other and protrude from the surface of the fixing plate (1).

9. A PBL shear key for use in segmental box girders according to claim 6, characterized in that: The length of the support plate (104) is greater than the maximum distance between the two positioning plates (2).

10. A PBL shear key for use in segmental box girders according to claim 6, characterized in that: The fixing plate (1) also includes a positioning hole (106) provided on the support plate (104); the diameter of the positioning hole (106) matches the diameter of the fixing bolt (102).

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