A beam end displacement adjusting device for a railway simply supported beam

Abstract

The utility model relates to a kind of beam end displacement adjusting device for ballast shape position keeping, belong to railway bridge engineering technical field.The device is set on the beam joint above between movable end and fixed end or abutment of adjacent two span simply supported beam, including cover plate main body, fixed support component and movable support component.The cover plate main body has opposite first end and second end;Its first end is fixedly connected with fixed end or abutment by fixed support component;Its second end is connected with movable end by movable support component, and allow beam body longitudinal free expansion.The utility model provides a stable ballast bed support platform when beam body expansion, effectively prevent ballast subsidence and loss, ensure the smoothness of beam end line, significantly reduce maintenance cost.

Description

Technical Field

[0001] This utility model relates to the field of railway bridge engineering technology, and in particular to an adjustment device for preventing the settlement of the track bed at the end of a simply supported beam bridge with ballast track and the deterioration of the track geometry. Background Technology

[0002] Ballasted track, a common track structure in railway lines, consists of ballast particles in its track bed, playing a crucial role in transmitting train loads and maintaining track geometry. In the beam-end regions of simply supported beam bridges, the beam undergoes longitudinal expansion and contraction due to factors such as temperature changes and train loads. Traditional construction typically involves directly connecting the ballast retaining plate to the beam. This connection method allows the beam's expansion and contraction to be directly transmitted to the ballast retaining plate, thereby causing periodic displacement of the ballast layer above it.

[0003] This periodic displacement causes repeated compression, pulling, and friction between ballast particles, leading to ballast rearrangement, breakage, and wear. Over time, the ballast bed gradually develops uneven settlement, compaction, and ballast loss, severely impacting the smoothness and stability of the track. The track geometry in the beam-end area deteriorates rapidly, resulting in the so-called "bridge approach slab slab" phenomenon, which not only reduces train running smoothness and ride comfort but also poses a potential threat to traffic safety.

[0004] Furthermore, the maintenance cost of traditional beam-end structures is high, requiring frequent ballast replenishment and track adjustments, which increases the workload. Therefore, there is an urgent need in this field for a novel device that can effectively decouple the contradiction between beam expansion and contraction and track bed stability to solve the aforementioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a simple and reliable displacement adjustment device for the beam end of a simply supported ballast track beam. This device can effectively adapt to the longitudinal expansion and contraction deformation of the beam while ensuring the stability of the ballast layer covering it, preventing loosening, slippage, or subsidence, thereby maintaining the long-term smoothness and stability of the track in the beam end area.

[0006] To solve the above-mentioned technical problems, the technical solution proposed in this application is as follows:

[0007] This invention provides a beam end displacement adjustment device for simply supported railway beams, comprising: a cover plate body disposed above the beam joint between the movable end and the fixed end / abutment of two adjacent spans of simply supported beams, and below the ballast track bed; the cover plate body having a first end and a second end opposite to each other; a fixed support assembly disposed at the first end of the cover plate body for fixing the first end to the fixed end of the simply supported beam or the abutment; and a movable support assembly disposed at the second end of the cover plate body for connecting the second end to the movable end of the simply supported beam and allowing the movable end of the simply supported beam to slide telescopically relative to the cover plate body along the longitudinal axis of the bridge.

[0008] As a further improvement of this utility model, the fixed support assembly includes a fixing member pre-embedded in the fixed end of the simply supported beam or in the abutment, and a connecting part disposed below the first end of the cover plate body and fixedly connected with the fixing member.

[0009] As a further improvement of this utility model, the fixing component is a threaded anchor bolt pre-embedded in the fixed end of the simply supported beam or the top surface of the abutment; the first end of the cover plate body has a hole corresponding to the anchor bolt for it to pass through; the connecting part is a high-strength nut and washer that mate with the thread of the anchor bolt; by tightening the nut, the first end of the cover plate body is fixed to the fixed end of the simply supported beam or the abutment. This specific connection method provides reliable force transmission and is convenient to install.

[0010] As a further improvement of this utility model, the movable support assembly includes a support member disposed at the end of the beam body, and a sliding mechanism disposed between the support member and the second end of the cover plate body.

[0011] As a further improvement of this utility model, the sliding mechanism is a polytetrafluoroethylene (PTFE) sliding plate support, which includes a lower pad fixed to the supporting member by anchor bolts, and a PTFE sliding plate disposed at the bottom of the second end of the cover plate body, forming a sliding friction pair with the lower pad. This structure has low friction and can reliably adapt to the longitudinal displacement of the beam end.

[0012] As a further improvement of this utility model, the upper surface of the cover plate body is provided with an anti-slip texture or an anti-wear layer to increase the frictional resistance between it and the ballast and prevent the ballast from sliding.

[0013] As a further improvement of this utility model, the main body of the cover plate is made of high-strength steel or reinforced concrete, and has sufficient rigidity and strength to withstand the loads transmitted from the upper track bed and the train.

[0014] As a further improvement of this utility model, the cover plate body is composed of two or more plates spliced ​​together by connectors to adapt to the width requirements of different bridges.

[0015] Compared with the prior art, this application achieves the following beneficial technical effects:

[0016] By utilizing the combined action of fixed and movable supports, one end of the cover plate is fixed while the other end is slidably connected. This ensures that the cover plate itself remains stable during beam expansion and contraction, providing an undisturbed and stable support platform for the ballast layer above it. This effectively decouples the conflict between beam expansion and contraction and track bed stability, significantly reducing the direct impact of beam expansion and contraction on the track bed, minimizing track bed settlement, compaction, and runoff, thus maintaining long-term track smoothness and greatly reducing maintenance costs. Furthermore, the device features a simple structure, clearly defined stress distribution, high reliability, and ease of manufacture, installation, and maintenance. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the working principle of the beam end displacement adjustment device of this utility model installed at the beam end of a simply supported beam in the longitudinal section of the bridge.

[0019] Figure 2 This is the main view of the cover plate of the beam end displacement adjustment device for simply supported railway beams according to this utility model;

[0020] Figure 3 This is the top view of the cover plate of the beam end displacement adjustment device for simply supported railway beams of this utility model;

[0021] Figure 4 This is the side view of the cover plate of the beam end displacement adjustment device for simply supported railway beams according to this utility model.

[0022] In the diagram: 1. Fixed end of simply supported beam, 2. Movable end of simply supported beam, 3. Rail, 4. Sleeper, 5. Ballast, 6. Ballast area on the upper layer of the cover plate, 7. Main body of the cover plate, 8. Fixed support, 9. Movable support. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] like Figure 1 As shown, a preferred embodiment of the beam end displacement adjustment device for simply supported railway beams of this utility model is applied to the beam end positions of two adjacent simply supported beams. Ballast 5 is laid on top of the simply supported beam body, and rails 3 and sleepers 4 are placed on the ballast 5. In this embodiment, the cover plate body 7 is made of a reinforced concrete slab with a length L of 5 meters and a thickness of 300mm to 400mm. The cover plate body is placed horizontally, covering the bottom of the ballast layer in the beam end area. The width of the cover plate body should be slightly wider than the width of the top surface of the track bed to ensure sufficient protection of the track bed. Preferably, the cover plate body 7 is evenly positioned on both sides at the middle of the beam joint between the movable end and the fixed end / abutment of the simply supported beam.

[0025] The fixed support 8 is located at one end of the cover plate body 7 near the fixed end 1 of the simply supported beam. Specifically, threaded anchor bolts are pre-embedded on the top surface of the fixed end 1 of the simply supported beam, and corresponding holes are drilled in the cover plate body 7. During installation, the cover plate is fitted onto the anchor bolts, and then tightly secured to the fixed end 1 of the simply supported beam using high-strength nuts and washers. In this way, this end of the cover plate body 7 is integrated with the fixed end 1 of the simply supported beam.

[0026] A movable support 9 is located at the other end of the cover plate body 7. A polytetrafluoroethylene (PTFE) sliding plate support is installed below this end. The lower pad of the sliding plate support is fixed to the movable end 2 of the simply supported beam using chemical anchors. The bottom of this end of the cover plate body 7 is connected to the upper sliding plate. When the movable end 2 of the simply supported beam elongates or shortens due to temperature changes, the fixed support 8 fixes the position of the cover plate, while the movable support 9 adapts to this displacement through relative sliding, ensuring that the position of the cover plate body 7 remains unchanged, while its top surface always provides a stable supporting plane.

[0027] The ballast in the upper ballast area 6 of the cover plate body 7 is not affected by the relative movement of the structure below, and can maintain a dense and stable state for a long time, thus ensuring the smoothness of the track in the beam end area. The upper surface of the cover plate body 7 can also be provided with anti-slip texture or wear-resistant layer to further increase the frictional resistance between it and the ballast and prevent the ballast from sliding.

[0028] The main body of the cover plate 7 is made of high-strength steel or reinforced concrete, possessing sufficient rigidity and strength to withstand the loads transmitted from the upper track bed and trains. In addition, the main body of the cover plate 7 can be assembled from two or more plates through connectors to adapt to the width requirements of different bridges.

[0029] Example 1

[0030] A preferred embodiment of this utility model is as follows: Figure 1As shown. In this embodiment, the cover plate body 7 is made of a 5-meter-long reinforced concrete slab, and the thickness is determined according to the following structural calculation formula, typically 300mm to 400mm.

[0031] The structural calculations for the cover plate body 7 are as follows:

[0032] q = q1 + q2

[0033] Where: q1 - dead load, q2 - live load

[0034] Depend on Can be launched

[0035]

[0036] Where: M u —Design bending moment, L—Beam length, α1—Partial factor, f c - Standard value of concrete compressive strength, b - beam width, h0 - effective height, x - height of concrete compression zone. Among them: A s -Reinforcement ratio, f y - Standard value of tensile strength of steel reinforcement, c - thickness of concrete cover, d - diameter of steel reinforcement.

[0037] The cover plate is placed horizontally, covering the bottom of the ballast layer in the beam end area. The width of the cover plate should be slightly wider than the width of the top surface of the track bed to ensure adequate protection of the track bed. A fixed support 8 is located at the end of the cover plate body 7 near the simply supported beam fixed end 1. Specifically, threaded anchor bolts are pre-embedded on the top surface of the simply supported beam fixed end 1, and corresponding holes are drilled in the cover plate body 7. During installation, the cover plate is fitted onto the anchor bolts, and then tightly fixed to the simply supported beam fixed end 1 using high-strength nuts and washers. In this way, this end of the cover plate is integrated with the simply supported beam fixed end 1.

[0038] The movable support 9 is located at the other end of the cover plate body 7. A polytetrafluoroethylene (PTFE) sliding plate support is installed below this end. The lower pad of the sliding plate support is fixed to the movable end 2 of the simply supported beam by chemical anchors. The bottom of this end of the cover plate body 7 is connected to the upper sliding plate. When the movable end 2 of the simply supported beam elongates or shortens due to temperature changes, the fixed support 8 fixes the position of the cover plate, while the movable support 9 adapts to this displacement by relative sliding, ensuring that the position of the cover plate body 7 remains unchanged. At the same time, its top surface always provides a stable support plane. The ballast in the upper ballast area 4 of the cover plate can maintain a dense and stable state for a long time because it is not affected by the relative movement of the structure below, thereby ensuring the smoothness of the track in the beam end area.

[0039] In other embodiments of this utility model, the fixed end 1 of the simply supported beam can be a bridge abutment. In this case, the first end of the cover plate body 7 is fixedly connected to the bridge abutment through the fixed support assembly 8, or the first end of the cover plate body 7 is directly embedded in the concrete of the bridge abutment. The cover plate body 7 can also be made of high-strength steel, or it can be composed of two or more plates spliced ​​together. The sliding mechanism in the movable support assembly 9 can also be in the form of a roller or the like.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A beam end displacement adjustment device for simply supported railway beams, characterized in that, include: The cover plate body (7) is located above the beam joint between the movable end (2) and the fixed end (1) / abutment of the simply supported beam of two adjacent spans of simply supported beams and below the ballast (5). The cover plate body (7) has a first end and a second end opposite to each other. A fixed support assembly (8) is disposed at the first end of the cover plate body (7) for fixing the first end to the simply supported beam fixed end (1) or the bridge abutment. The movable support assembly (9) is disposed at the second end of the cover plate body (7) for connecting the second end to the movable end (2) of the simply supported beam and allowing the movable end (2) of the simply supported beam to slide telescopically relative to the cover plate body (7) along the longitudinal axis of the bridge.

2. The beam end displacement adjustment device for a simply supported railway beam according to claim 1, characterized in that: The fixed support assembly (8) includes a fastener embedded in the fixed end (1) of the simply supported beam or in the abutment, and a connecting part located below the first end of the cover plate body (7) and fixedly connected with the fastener.

3. The beam end displacement adjustment device for a simply supported railway beam according to claim 2, characterized in that: The fastener is a threaded anchor bolt pre-embedded in the fixed end (1) of the simply supported beam or the top surface of the abutment; the first end of the cover plate body (7) is provided with a hole for the anchor bolt to pass through; the connecting part includes a high-strength nut and a washer that are threadedly engaged with the anchor bolt; by tightening the nut, the first end of the cover plate body (7) is fixed to the fixed end (1) of the simply supported beam or the abutment.

4. The beam end displacement adjustment device for a simply supported railway beam according to claim 1, characterized in that: The movable support assembly (9) includes a support member disposed at the movable end (2) of the simply supported beam, and a sliding mechanism disposed between the support member and the second end of the cover plate body (7).

5. A beam end displacement adjustment device for simply supported railway beams according to claim 4, characterized in that: The supporting component includes chemical anchors, and the sliding mechanism includes a polytetrafluoroethylene (PTFE) sliding plate support. The lower pad of the PTFE sliding plate support is fixed to the fixed end (1) of the simply supported beam or the bridge abutment by means of chemical anchors.

6. The beam end displacement adjustment device for a simply supported railway beam according to claim 1, characterized in that: The upper surface of the cover plate body (7) is provided with an anti-slip texture or wear-resistant layer to increase the frictional resistance between the cover plate body and the ballast (5).

7. A beam end displacement adjustment device for simply supported railway beams according to claim 1, characterized in that: The cover plate body (7) is made of high-strength steel or reinforced concrete.

8. A beam end displacement adjustment device for simply supported railway beams according to claim 1, characterized in that: The cover plate body (7) is composed of two or more plates spliced ​​together by connectors.

9. A beam end displacement adjustment device for a simply supported railway beam according to any one of claims 1 to 8, characterized in that: The length L of the main body of the cover plate (7) is 4 to 6 meters, the thickness is 300 to 400 millimeters, and the width is greater than the top surface width of the track bed.

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