Pre-cast beam plate tension end anti-cracking rolling support device
By installing rolling support devices at the tensioning ends of precast beams and slabs, rolling friction is used instead of sliding friction to distribute the load and control lateral displacement, thus solving the problems of beam and slab end cracking and oil stain contamination and achieving stable and efficient construction results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HUNAN ROAD & BRIDGE CONSTR GROUP
- Filing Date
- 2025-08-07
- Publication Date
- 2026-07-21
AI Technical Summary
In the precast construction of post-tensioned prestressed beams and slabs, the arching of the middle section after tensioning causes slight displacement at both ends, which triggers horizontal tension due to sliding friction, leading to cracking or detachment of the concrete at the beam ends. Existing asphalt felt solutions have unstable friction coefficients and are prone to leakage, and the oil stains pollute the appearance of the bridge.
The system employs a detachable base, rolling components, and limiting components. Rolling friction replaces sliding friction, and the main and auxiliary rollers in the rolling components distribute the load. The limiting components control lateral displacement, thus preventing cracking at the ends of the beams and slabs.
It significantly reduced the horizontal tension during beam tensioning, prevented concrete cracking, improved the bridge's appearance quality, avoided oil stains, and enhanced construction stability and efficiency.
Smart Images
Figure CN224527568U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of precast beam and slab construction technology, specifically to a rolling support device for preventing cracking at the tensioning end of a precast beam and slab. Background Technology
[0002] During the precast construction of post-tensioned prestressed beams and slabs, the beams and slabs arch in the middle after tensioning, and the two ends will experience slight displacement towards the center. Since the middle of the continuous ends of the beams and slabs is a hollow structure with only a thin layer of concrete around the perimeter, the sliding friction between the beam ends and the abutment can easily induce horizontal tensile forces. At the same time, the conversion of the end surface load into a line load will lead to the concentration of vertical forces, ultimately causing the concrete at the beam ends to crack or fall off.
[0003] Currently, the commonly used protective measure is to lay multiple layers of asphalt felt (covering the beam end for 50-75cm) between the pedestal and the reinforcing cage, and apply lubricating grease between the asphalt felt and the pedestal steel plate. This method reduces the risk of cracking by replacing direct friction between the beam end and the pedestal with sliding friction between the asphalt felt and the pedestal. However, practice has shown that the asphalt felt method has the following drawbacks:
[0004] 1. The coefficient of friction is significantly affected by the evenness of the grease application. After long-term use, the grease is easily lost, which leads to an increase in the coefficient of friction. The beam end may still crack due to horizontal tension generated by sliding friction.
[0005] 2. Residual oil stains from the tar paper can seep into the bottom of the beam, forming stains that are difficult to remove, resulting in a bridge appearance qualification rate of only about 80%.
[0006] The purpose of this utility model is to provide a rolling support device for preventing cracking at the tensioning end of precast beams and slabs, so as to solve the problems mentioned in the background art. Utility Model Content
[0007] To achieve the above objectives, this utility model provides a precast beam tensioning end anti-cracking rolling support device, including a base detachably mounted on an enlarged foundation, a rolling assembly disposed on the base, and a sliding steel plate slidably connected to the rolling assembly. The base is located near the end of the beam-making platform, and the sliding steel plate is used to support the end of the beam. The base is also provided with a limiting assembly for limiting the lateral displacement of the end of the beam during rolling. Through the synergistic effect of the base, the rolling assembly, the sliding steel plate, and the limiting assembly, traditional sliding friction is transformed into rolling friction, significantly reducing the horizontal tension at the end of the beam during tensioning and effectively preventing concrete cracking.
[0008] As a further improvement of this utility model, the base includes symmetrically arranged upright plates and multiple angle steels for connecting the two upright plates. The multiple angle steels are symmetrically fixed between the two ends of the two upright plates, and the rolling assembly is installed between the two upright plates. This design provides stable support for the rolling assembly and ensures that it does not shift when subjected to force.
[0009] As a further improvement of this utility model, the thickness of the upright plate is 5 cm.
[0010] As a further improvement of this utility model, the rolling assembly includes multiple main rollers, each with a pin at both ends. The upright plates on both sides have slots for the pins to be inserted. The multiple rollers are arranged parallel to each other at equal intervals to form a support plane. The multiple parallel main rollers form a continuous support plane, which makes the load distribution more uniform and avoids local stress concentration. The way the pins and slots are matched facilitates the installation and replacement of the main rollers and reduces maintenance costs.
[0011] As a further improvement of this utility model, the rolling assembly also includes a channel steel and several auxiliary rollers installed in the channel steel. The channel steel is fixedly installed on the top of both upright plates, and the array of several auxiliary rollers is rotatably installed in the groove of the channel steel. The tops of the auxiliary rollers and the main rollers are flush. The auxiliary rollers work together with the main rollers to expand the support area and improve the stability of the sliding steel plate. The flush top design ensures a smooth transition of load, further disperses pressure, and reduces the risk of cracking at the ends of the beam and plate.
[0012] As a further improvement of this utility model, a wear-resistant rubber sleeve is fitted on the outer surface of the main roller, and the surface of the wear-resistant rubber sleeve is also provided with anti-slip texture. The wear-resistant rubber sleeve improves the wear resistance of the main roller and extends its service life, while the anti-slip texture increases the friction with the sliding steel plate, prevents slippage, and ensures the reliability of the rolling process.
[0013] As a further improvement of this utility model, the limiting component includes two limiting plates, which are respectively vertically fixed on the outside of the upright plate. The height of the limiting plates is higher than the upper surface of the roller. The distance between the two limiting plates is adapted to the width of the beam end. The sliding steel plate slides between the two limiting plates. The limiting plates accurately control the lateral displacement range of the beam, avoiding beam displacement or tilting caused by lateral force during tensioning, thus ensuring construction safety and quality.
[0014] As a further improvement of this utility model, the ends of the two upright plates are also provided with detachable steel plates. The detachable steel plates overlap between the upright plates and the ends of the beam-making platform. The detachable steel plates are flush with the sliding steel plates and the top surface of the ends of the beam-making platform. This design facilitates the lifting of the beam plates away from the beam-making platform.
[0015] As a further improvement of this utility model, a rubber pad is provided on the side of the detachable steel plate near the sliding steel plate.
[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0017] 1. This utility model uses a rolling component to replace the traditional tar paper and grease, transforming the sliding friction between the beam end and the platform into rolling friction, which greatly reduces the friction coefficient and makes the friction coefficient stable and unaffected by external factors. This effectively avoids the problem of concrete cracking at the beam end caused by horizontal tension generated by sliding friction. The entire device does not use grease or other lubricating substances, and will not form oil stains or dirt on the bottom of the beam, which significantly improves the appearance quality of the bridge and greatly increases the appearance qualification rate.
[0018] 2. The outer surface of the roller in the rolling assembly of this utility model is fitted with a wear-resistant rubber sleeve, which can not only reduce the frictional damage between the roller and the end of the beam, but also play a certain buffering role and reduce the impact of vertical force concentration on the concrete at the beam end.
[0019] 3. The limiting component of this utility model can effectively limit the lateral displacement of the beam end during the rolling process, ensure the stability of the beam during the tensioning process, avoid additional stress caused by lateral displacement, and further prevent cracking of the concrete at the beam end. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the overall design of this utility model;
[0021] Figure 2 This is a diagram showing the sliding steel plate and base separated from the present invention.
[0022] Figure 3 This is a diagram showing the separation of the main roller and the base of this utility model;
[0023] Figure 4 This is a schematic diagram of the installation of the base and enlarged foundation of this utility model.
[0024] In the diagram: 1. Base; 101. Angle steel; 102. Vertical plate; 2. Rolling assembly; 201. Main roller; 202. Shaft pin; 203. Channel steel; 204. Secondary roller; 205. Wear-resistant rubber sleeve; 3. Sliding steel plate; 4. Limiting plate; 5. Slot; 6. Removable steel plate; 7. Rubber pad; 8. Beam-making platform; 9. Enlarged foundation. Detailed Implementation
[0025] To facilitate understanding of this utility model, a more comprehensive description of it will be given below with reference to the accompanying drawings, which show several embodiments of the utility model. However, the utility model can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the disclosure of this utility model more thorough and comprehensive.
[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0027] The present invention will be further described in detail below with reference to the accompanying drawings.
[0028] Example 1:
[0029] Please see Figure 1-4 This utility model provides a rolling support device for preventing cracking at the tensioning end of a precast beam slab, including a base 1 detachably installed on an enlarged foundation 9, a rolling component 2 set on the base 1, and a sliding steel plate 3 slidably connected to the rolling component 2. The base 1 is located near the end of the beam-making platform 8, and the sliding steel plate 3 is used to support the end of the beam slab. The base 1 is also provided with a limiting component for limiting the lateral displacement of the end of the beam slab during rolling. Through the synergistic effect of the base 1, the rolling component 2, the sliding steel plate 3, and the limiting component, the traditional sliding friction is transformed into rolling friction, which significantly reduces the horizontal tension at the end of the beam slab during tensioning and effectively prevents concrete cracking.
[0030] The base 1 includes symmetrically arranged upright plates 102 and multiple angle steels 101 for connecting the two upright plates 102. The multiple angle steels 101 are symmetrically fixed between the two ends of the two upright plates 102, and the rolling assembly 2 is installed between the two upright plates 102.
[0031] The thickness of the upright plate 102 is 5 cm.
[0032] The rolling assembly 2 includes multiple main rollers 201, each with a pin 202 at both ends. The upright plates 102 on both sides have slots 5 for the pins 202 to be inserted. The multiple rollers are arranged parallel to each other at equal intervals to form a support plane. The multiple parallel main rollers 201 form a continuous support plane, which makes the load distribution more uniform and avoids local stress concentration. The way the pins 202 and slots 5 are matched facilitates the installation and replacement of the main rollers 201 and reduces maintenance costs. The distance between adjacent main rollers 201 is 50cm to 60cm. The outer diameter of the main roller 201 is between 15cm and 25cm, the inner diameter is between 8cm and 12cm, and the pin diameter is 3cm.
[0033] The outer surface of the main roller 201 is fitted with a wear-resistant rubber sleeve 205. The surface of the wear-resistant rubber sleeve 205 is also provided with anti-slip texture. The wear-resistant rubber sleeve 205 improves the wear resistance of the main roller 201 and extends its service life. The anti-slip texture increases the friction with the sliding steel plate 3, prevents slippage, and ensures the reliability of the rolling process.
[0034] The two upright plates 102 are also provided with detachable steel plates 6 at their ends. The detachable steel plates 6 overlap between the upright plates 102 and the ends of the beam-making platform 8. The detachable steel plates 6 are flush with the sliding steel plates 3 and the top surfaces of the ends of the beam-making platform 8.
[0035] A rubber pad 7 is provided on the side of the detachable steel plate 6 near the sliding steel plate 3. The rubber pad 7 achieves flexible buffering of the displacement of the sliding steel plate 3 through elastic deformation, which can reduce rigid impact to reduce the risk of beam end cracking, protect device components and enhance structural stability, and also has the auxiliary functions of noise reduction and adaptation to installation deviation, thus comprehensively improving the performance of the device.
[0036] In use, during the pouring of the enlarged foundation 9, a 10cm thick pedestal concrete base adapted to the base 1 is simultaneously poured on top. Then, the base 1 is fitted onto the pedestal concrete, completing the installation between the device and the enlarged foundation 9. Next, the precast beam is tensioned. During the tensioning process, the ends of the precast beam are placed on the sliding steel plate 3, which contacts the main roller 201 in the rolling assembly 2. When the precast beam arches in the middle due to tensioning and its ends shift towards the center, the sliding steel plate 3 moves towards the main roller 201. The main roller 201 rotates within the slot 5 of the vertical plate 102 via the pin 202, converting sliding friction into rolling friction, significantly reducing frictional resistance and horizontal tension. The wear-resistant rubber sleeve 205 and anti-slip texture on the outside of the main roller 201 enhance wear resistance and prevent slippage between the sliding steel plate 3 and the main roller 201, ensuring smooth force transmission. The support plane formed by multiple equidistant parallel main rollers 201 can evenly distribute the load at the end of the beam, avoiding vertical force concentration. This facilitates the lifting of the beam from the pre-fabricated section. During the fabrication of the support platform, steel wire ropes are used to wrap around the detachable steel plate 6 and bind the precast beam slab before hoisting it away. The detachable steel plate 6 provides a temporary support point for the hoisting of the precast beam slab, avoiding direct contact between the steel wire rope and the beam slab, thus preventing damage. It also ensures hoisting safety through stable binding. Furthermore, it can be removed and unloaded along with the steel wire rope, improving construction efficiency and reducing wear on the support platform and support device. In this embodiment, rolling friction replaces sliding friction, effectively reducing the horizontal tension at the beam end during tensioning and minimizing the risk of concrete cracking at the beam end. The wear-resistant rubber sleeve 205 of the main roller 201 extends the device's service life, and the anti-slip texture ensures stability during sliding. The anti-slip pad enhances the reliability of the connection between the device and the support platform, preventing device displacement from affecting the support effect. The overall structure evenly distributes the load, alleviating the problem of vertical force concentration and further reducing the probability of beam end cracking. Simultaneously, it eliminates the need for tar paper and grease, avoiding oil stains on the bottom of the beam, significantly improving the bridge's appearance quality and greatly increasing the appearance qualification rate.
[0037] Example 2:
[0038] This embodiment is based on Embodiment 1. Please refer to... Figure 2-3 The rolling assembly 2 also includes a channel steel 203 and several auxiliary rollers 204 installed in the channel steel 203. The channel steel 203 is fixedly installed on the top of both upright plates 102. Several auxiliary rollers 204 are rotatably installed in the groove of the channel steel 203. The tops of the auxiliary rollers 204 and the main rollers 201 are flush. The auxiliary rollers 204 work together with the main rollers 201 to expand the support area and improve the stability of the sliding steel plate 3. The flush top design ensures a smooth load transition, further disperses the pressure, and reduces the risk of cracking at the ends of the beam and plate. The diameter of the auxiliary rollers 204 is 4cm to 6cm.
[0039] During beam tensioning, the sliding steel plate 3 not only contacts the main roller 201 but also the auxiliary roller 204 inside the channel steel 203 at the top of the vertical plate 102. Since the auxiliary roller 204 and the main roller 201 are flush, the main roller 201 and the auxiliary roller 204 work together during the movement of the sliding steel plate 3. The auxiliary roller 204 expands the range of rolling support. When the beam end is displaced, the sliding steel plate 3 drives the main roller 201 and the auxiliary roller 204 to rotate simultaneously, so that the load at the beam end can be distributed over a larger area, avoiding large stress in local areas due to excessive load concentration. In this embodiment, the addition of the auxiliary roller 204 increases the contact area of the rolling support, further dispersing the load at the beam end, effectively reducing local stress and reducing beam end cracking. The main roller 201 and the auxiliary roller 204 work together to make the sliding of the sliding steel plate 3 smoother, avoiding beam end swaying caused by uneven support and ensuring the stability of the tensioning process.
[0040] Example 3:
[0041] This embodiment is based on Embodiment 1. Please refer to... Figure 2-3 The limiting component includes two limiting plates 4, which are vertically fixed to the outside of the upright plate 102. The height of the limiting plates 4 is higher than the upper surface of the roller. The distance between the two limiting plates 4 is adapted to the width of the beam end. The sliding steel plate 3 slides between the two limiting plates 4. The limiting plates 4 precisely control the lateral displacement range of the beam, avoiding beam displacement or tilting due to lateral force during tensioning, thus ensuring construction safety and quality.
[0042] During beam tensioning, to prevent lateral displacement of the sliding steel plate 3 and the beam end, two limiting plates 4 form a lateral constraint space. Because the distance between the two limiting plates 4 is adapted to the width of the beam end, and the sliding steel plate 3 slides between the two limiting plates 4, when the beam end has a tendency to lateral displacement, it will be blocked by the limiting plates 4. This ensures that the beam end can only move within a limited lateral range, ensuring that the beam is always in the preset stress position during tensioning. This avoids uneven stress on both sides of the beam end caused by lateral offset, and prevents cracking caused by excessive local stress. The limiting components effectively restrict the lateral displacement of the beam end, ensuring the stability and uniform stress of the beam during tensioning, reducing the risk of beam end cracking caused by lateral offset; improving construction accuracy, ensuring that the beam completes the tensioning process according to design requirements, and reducing the workload of subsequent adjustments.
[0043] The present invention has been described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvement made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, shall be within the protection scope of the present invention.
Claims
1. A rolling support device for preventing cracking at the tensioning end of a precast beam slab, characterized in that: It includes a base (1) that can be detachably installed on an enlarged foundation (9), a rolling assembly (2) set on the base (1), and a sliding steel plate (3) that is slidably connected to the rolling assembly (2). The base (1) is located near the end of the beam-making platform (8). The sliding steel plate (3) is used to support the end of the beam plate. The base (1) is also provided with a limiting assembly for limiting the lateral displacement of the end of the beam plate during rolling.
2. The precast beam tensioning end anti-cracking rolling support device according to claim 1, characterized in that: The base (1) includes symmetrically arranged upright plates (102) and multiple angle steels (101) for connecting the two upright plates (102). The multiple angle steels (101) are symmetrically fixed between the two ends of the two upright plates (102), and the rolling assembly (2) is installed between the two upright plates (102).
3. The precast beam tensioning end anti-cracking rolling support device according to claim 2, characterized in that: The thickness of the upright plate (102) is 5 cm.
4. The precast beam tensioning end anti-cracking rolling support device according to claim 2, characterized in that: The rolling assembly (2) includes multiple main rollers (201), each of which has a pin (202) at both ends. The upright plates (102) on both sides have slots (5) for the pins (202) to be inserted. The multiple rollers are arranged parallel to each other at equal intervals to form a support plane.
5. The precast beam tensioning end anti-cracking rolling support device according to claim 4, characterized in that: The rolling assembly (2) also includes a channel steel (203) and several auxiliary rollers (204) installed in the channel steel (203). The channel steel (203) is fixedly installed on the top of both upright plates (102). Several auxiliary rollers (204) are rotatably installed in the groove of the channel steel (203). The tops of the auxiliary rollers (204) and the main rollers (201) are flush.
6. The precast beam tensioning end anti-cracking rolling support device according to claim 4, characterized in that: The outer surface of the main roller (201) is fitted with a wear-resistant rubber sleeve (205), and the surface of the wear-resistant rubber sleeve (205) is also provided with anti-slip texture.
7. A precast beam tensioning end anti-cracking rolling support device according to claim 2, characterized in that: The limiting assembly includes two limiting plates (4), which are vertically fixed to the outside of the upright plate (102). The height of the limiting plates (4) is higher than the upper surface of the roller. The distance between the two limiting plates (4) is adapted to the width of the beam end. The sliding steel plate (3) slides between the two limiting plates (4).
8. A precast beam tensioning end anti-cracking rolling support device according to claim 2, characterized in that: The two upright plates (102) are also provided with a detachable steel plate (6) at the end. The detachable steel plate (6) overlaps between the upright plate (102) and the end of the beam-making platform (8). The detachable steel plate (6) is flush with the sliding steel plate (3) and the top surface of the end of the beam-making platform (8).
9. A precast beam tensioning end anti-cracking rolling support device according to claim 8, characterized in that: A rubber pad (7) is provided on the side of the detachable steel plate (6) near the sliding steel plate (3).