An external prestressing device for box girders
By using the fastening, linkage, and locking devices of the external prestressing device for the box girder, the problem of small stress-bearing area of the anchor plate was solved, the compressive strength was improved, and the bending deformation and weld cracking of the steel box girder were avoided.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 哈尔滨市建筑工程研究设计院有限公司
- Filing Date
- 2025-08-05
- Publication Date
- 2026-06-30
AI Technical Summary
In the external prestressing construction of steel box girders, the existing anchoring structure has a small stress-bearing area and weak compressive strength, which leads to defects such as flexural deformation and cracking of plate welds.
It employs fastening devices, linkage devices, and locking devices, and increases the stress-bearing area through multi-point fixing and limiting structures to avoid flexural deformation and weld cracking. It includes the combined use of components such as trapezoidal cylinders, sliding cylinders, locking cylinders, and wedge blocks.
This effectively increases the stress-bearing area, avoids flexural deformation of the top plate of the steel box girder and cracking of the weld, and improves the compressive strength of the structure.
Smart Images
Figure CN224431265U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of bridge construction equipment, and in particular to an external prestressing device for box girders. Background Technology
[0002] Steel-concrete composite bridge decks utilize the tensile properties of steel structures and the compressive properties of concrete structures. Traditional prestressing of steel-concrete composite bridges employs internal tensioning technology within the concrete bridge deck. Due to the high compressive strength of concrete, it primarily relies on the concrete to resist the large compressive stress at the anchorage ends.
[0003] In recent years, with the continuous development of steel bridges and people's research on steel-concrete composite bridges, it has been found that the setting of external prestressing can greatly improve the various stress performance of steel-concrete composite bridges. However, in actual construction sites, it has been found that because the existing anchoring structure uses an anchor plate to fix the anchoring end of the prestressed steel strand, many steel box girders are prone to bending deformation and cracking of plate welds during the tensioning of external prestressing due to the small stress area and weak structural compressive strength of the prestressed anchor plate and the top plate of the steel box girder. Summary of the Invention
[0004] The purpose of this invention is to solve the above-mentioned problems existing in the prior art and to provide an external prestressing device for box girders.
[0005] An external prestressing device for box girders includes: a fastening device, a linkage device, and a locking device. The fastening device is internally slidably connected to the linkage device, and the locking device is slidably connected to the linkage device.
[0006] The fastening device includes: a fixing plate, a trapezoidal cylinder, a limiting protrusion, and a notch. The trapezoidal cylinder is fixed to one side of the fixing plate. Multiple limiting protrusions are provided on the outer surface of the trapezoidal cylinder along its circumference. Multiple notches are evenly distributed on the trapezoidal cylinder along its axial direction, and the multiple notches divide the trapezoidal cylinder into multiple arc-shaped plates.
[0007] The linkage device includes: a sliding cylinder, a raised edge, a sliding groove, and a limiting ring. One end of the sliding cylinder slides through the fixed plate, and a raised edge is provided at one end of the sliding cylinder. The raised edge slides against the inner wall of the trapezoidal cylinder. Sliding grooves are symmetrically arranged inside the sliding cylinder, and a limiting ring is fixed inside the sliding cylinder.
[0008] The locking device includes: a locking cylinder, wedge blocks, notches, sliders, screws, nuts, and U-shaped clamps. The diameter of one opening of the locking cylinder is smaller than that of the other opening. Wedge blocks are evenly distributed circumferentially along the inner wall of one side of the locking cylinder. Multiple notches are evenly distributed axially along one side of the locking cylinder, dividing one side of the locking cylinder into multiple arc-shaped plates. Slider blocks are symmetrically fixed on the outer wall of the locking cylinder. The locking cylinder passes into the sliding cylinder. A limiting ring passes through the side of the locking cylinder with the smaller diameter. Two sliders slide in the sliding grooves respectively. One end of the screw slides into the other side of the locking cylinder. A nut is screwed onto the screw. A U-shaped clamp is fixed to one end of the screw. The U-shaped clamp is located inside the locking cylinder. The screw, nut, and U-shaped clamp are set as a group, and there are two groups in total. The two groups of screws, nuts, and U-shaped clamps are symmetrically arranged.
[0009] Compared with the prior art, the beneficial effects of this utility model are:
[0010] This utility model provides an external prestressing device for box girders, which can solve the problems mentioned in the background art: the existing anchoring structure uses an anchoring plate to fix the anchoring end of the prestressed steel strand. During the tensioning of external prestressing of many steel box girders, the prestressed anchoring plate and the top plate of the steel box girder are prone to bending deformation, cracking of plate welds and other defects due to the small stress area and weak structural compressive strength. Attached Figure Description
[0011] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0012] Figure 2 This is a schematic diagram of the linkage device structure;
[0013] Figure 3 This is the front view of the convex edge;
[0014] Figure 4 This is a schematic diagram of the locking device structure;
[0015] Figure 5 This is a rear view of the locking device;
[0016] Figure 6 This is a schematic diagram showing the fixing of the device to the box girder. Detailed Implementation
[0017] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the protection scope of this utility model.
[0018] An external prestressing device for box girders includes: a fastening device 1, a linkage device 2, and a locking device 3. The fastening device 1 is internally slidably connected to the linkage device 2, and the locking device 3 is slidably connected to the linkage device 2.
[0019] The fastening device 1 includes: a fixing plate 1-1, a trapezoidal cylinder 1-2, a limiting protrusion 1-3, and a notch 1-4. The trapezoidal cylinder 1-2 is fixed to one side of the fixing plate 1-1. Multiple limiting protrusions 1-3 are provided on the outer surface of the trapezoidal cylinder 1-2 along its circumference. Multiple notches 1-4 are evenly distributed on the trapezoidal cylinder 1-2 along its axial direction. The multiple notches 1-4 divide the trapezoidal cylinder 1-2 into multiple arc-shaped plates.
[0020] The linkage device 2 includes: a sliding cylinder 2-1, a raised edge 2-2, a sliding groove 2-3, and a limiting ring 2-4. One end of the sliding cylinder 2-1 slides through the fixed plate 1-1. A raised edge 2-2 is provided at one end of the sliding cylinder 2-1. The raised edge 2-2 slides against the inner wall of the trapezoidal cylinder 1-2. Sliding grooves 2-3 are symmetrically arranged inside the sliding cylinder 2-1. A limiting ring 2-4 is fixed inside the sliding cylinder 2-1.
[0021] The locking device 3 includes: a locking cylinder 3-1, wedge blocks 3-2, notches 3-3, sliders 3-4, screws 3-5, nuts 3-6, and U-shaped clamps 3-7. The diameter of one opening of the locking cylinder 3-1 is smaller than the diameter of the other opening. Wedge blocks 3-2 are evenly distributed circumferentially along the inner wall of one side of the locking cylinder 3-1. Multiple notches 3-3 are evenly distributed axially along one side of the locking cylinder 3-1, dividing one side of the locking cylinder 3-1 into multiple arc-shaped plates. Slider blocks 3-4 are symmetrically fixed on the outer wall of the locking cylinder 3-1. -1 is inserted into the sliding cylinder 2-1. The smaller diameter side of the locking cylinder 3-1 is inserted into the limiting ring 2-4. The two sliders 3-4 slide in the sliding groove 2-3 respectively. One end of the screw 3-5 slides into the other side of the locking cylinder 3-1. A nut 3-6 is screwed onto the screw 3-5. A U-shaped clamp 3-7 is fixed to one end of the screw 3-5. The U-shaped clamp 3-7 is set inside the locking cylinder 3-1. The screw 3-5, nut 3-6 and U-shaped clamp 3-7 are set as a group, and there are two groups in total. The two groups of screw 3-5, nut 3-6 and U-shaped clamp 3-7 are symmetrically arranged.
[0022] Working principle:
[0023] When using this device, the steel strand 5 is passed through the pre-drilled hole in the box girder 4, then through the trapezoidal cylinder 1-2, into the sliding cylinder 2-1, and out through the locking cylinder 3-1. Then, the two nuts 3-6 are rotated to move the two screws 3-5 relative to each other, thereby clamping and fixing the steel strand 5 with the two U-shaped clamps 3-7. Next, the trapezoidal cylinder 1-2 is inserted into the pre-drilled hole in the box girder 4, and the fixing plate 1-1 rests against the side wall of the box girder. Then, the steel strand 5 is tightened on the other side. As the steel strand 5 is tightened and moves, the locking cylinder 3-1 is moved along the slide groove 2-3 via the slider 3-4 through the limiting U-shaped clamp 3-7. The slide groove 2-3 and the slider 3-4 provide limiting support for the locking cylinder 3-1. The movement of the locking cylinder 3-1, limited by the limiting ring 2-4, causes the steel strand 5 of the multiple arc-shaped plates to move in two directions. The steel strand 5 is clamped and fixed for a second time. At the same time, the wedge block 3-2 is set on the steel strand 5 to further limit and fix the steel strand 5 to prevent loosening. When the locking cylinder 3-1 moves to fix the steel strand 5, the locking cylinder 3-1 moves to push the limiting ring 2-4 and then drive the sliding cylinder 2-1 to move along the fixing plate 1-1. The sliding cylinder 2-1 moves and drives multiple arc plates to unfold outward through the convex edge 2-2. The limiting protrusion 1-3 is inserted into the inner wall of the box girder 4 hole for limiting and fixing. The arc plates increase the contact area with the box girder 4 hole, which can effectively reduce the stress on the fixing plate 1-1, thereby avoiding the problems of bending deformation of the fixing plate 1-1 and cracking of the plate weld. After the steel strand 5 is tightened, the fixing plate 1-1 and the side wall of the box girder 4 are fixed with bolts to complete the installation.
[0024] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. An external prestressing device for box girders, characterized in that: include: The fastening device (1), the linkage device (2) and the locking device (3) are provided. The fastening device (1) is internally connected to the linkage device (2), and the locking device (3) is slidably connected to the linkage device (2).
2. The external prestressing device for box girders according to claim 1, characterized in that: The fastening device (1) includes: a fixing plate (1-1), a trapezoidal cylinder (1-2), a limiting protrusion (1-3), and a notch (1-4). The trapezoidal cylinder (1-2) is fixed on one side of the fixing plate (1-1). Multiple limiting protrusions (1-3) are provided on the outer surface of the trapezoidal cylinder (1-2) along its circumferential direction. Multiple notches (1-4) are evenly distributed on the trapezoidal cylinder (1-2) along its axial direction. The multiple notches (1-4) divide the trapezoidal cylinder (1-2) into multiple arc-shaped plates.
3. The external prestressing device for box girders according to claim 2, characterized in that: The linkage device (2) includes: a sliding cylinder (2-1), a raised edge (2-2), a sliding groove (2-3), and a limiting ring (2-4). One end of the sliding cylinder (2-1) slides through the fixed plate (1-1). One end of the sliding cylinder (2-1) is provided with a raised edge (2-2). The raised edge (2-2) slides against the inner wall of the trapezoidal cylinder (1-2). The sliding groove (2-3) is symmetrically arranged inside the sliding cylinder (2-1). The limiting ring (2-4) is fixed inside the sliding cylinder (2-1).
4. The external prestressing device for box girders according to claim 3, characterized in that: The locking device (3) includes: a locking cylinder (3-1), a wedge block (3-2), a notch two (3-3), a slider (3-4), a screw (3-5), a nut (3-6), and a U-shaped clamp (3-7). The diameter of the opening on one side of the locking cylinder (3-1) is smaller than the diameter of the opening on the other side. Wedge blocks (3-2) are evenly distributed along the circumference of the inner wall of one side of the locking cylinder (3-1). Multiple notches two (3-3) are evenly distributed along the axial direction of one side of the locking cylinder (3-1). The multiple notches two (3-3) divide one side of the locking cylinder (3-1) into multiple arc-shaped plates. Slider blocks (3-4) are symmetrically fixed on the outer wall of the locking cylinder (3-1). The locking cylinder (3-1) is inserted into the sliding cylinder (2-1). The smaller diameter side of the locking cylinder (3-1) is inserted into the limiting ring (2-4). The two sliders (3-4) slide in the sliding groove (2-3) respectively. One end of the screw (3-5) slides into the other side of the locking cylinder (3-1). A nut (3-6) is screwed onto the screw (3-5). A U-shaped clamp (3-7) is fixed to one end of the screw (3-5). The U-shaped clamp (3-7) is set inside the locking cylinder (3-1). The screw (3-5), nut (3-6) and U-shaped clamp (3-7) are set as a group, and there are two groups in total. The two groups of screw (3-5), nut (3-6) and U-shaped clamp (3-7) are symmetrically arranged.