Combined end plate and prefabricated pile

Abstract

The present invention relates to a combined end plate and precast pile, which can effectively save end plate consumables and ensure the firmness of the connection between the longitudinal main reinforcement of the precast pile and the end plate, and is easy to install. It includes an end plate, characterized in that: the end plate is provided with a plurality of evenly distributed mounting holes, the mounting holes are provided with internal threads or slots, and also includes a connecting piece, the connecting piece is provided with external threads or buckles, the connecting piece is screwed or slotted with the internal threads of the mounting holes through the external threads or buckles, and the connecting piece is provided with a connecting structure that can be connected to the longitudinal main reinforcement. The combined end plate is screwed or snapped with the end plate by the connecting piece with the internal anchor countersunk hole, so that the tensioning force during prestressing is not transmitted through the end plate, but is finally borne by the connecting piece and the threaded or snap-fitting part where the connecting piece is connected to the end plate, so that the thickness of the end plate can be effectively reduced and can be made the same as the cross-sectional size of the concrete pile.

Description

Technical Field

[0001] The invention relates to a combined end plate and a prefabricated pile. Background Art

[0002] Concrete piles are piles made of concrete, including ordinary reinforced concrete and prestressed concrete, and are commonly used in infrastructure projects. Concrete piles can be divided into end plate piles and non-end plate piles according to whether the two ends of the concrete piles include end plates, in which the two ends of the end plate piles are respectively provided with end plates.

[0003] Concrete piles are initially designed with end plate piles. The reason for using the end plate pile structure is that, on the one hand, the connection between the two concretes can be welded through the end plate, further ensuring the firmness of the connection between the two concrete piles. On the other hand, the internal structure of the concrete pile adopts the longitudinal steel bars and the end plates to be clamped through the anchor structure. The main reinforcement of the prestressed pile, PC prestressed main reinforcement, has a certain elasticity. The pre-tensioning process is adopted during production. After the concrete of the concrete pile is formed, the end plate can be driven to move closer to the middle by the contraction of the PC prestressed reinforcement to compact the concrete. We call this concrete compaction force the effective prestressing stress of concrete. The concrete piles that have been effectively prestressed are very strong and not easily damaged during transportation.

[0004] However, end plate piles also have disadvantages, because the effective precompression stress of concrete mainly comes from the firm connection between the PC prestressed main steel bars and the end plate, which in turn forms an effective pulling force of the PC prestressed main steel bars on the end plate. In order to ensure the firm connection between the PC prestressed main steel bars and the end plate, the thickness of the end plate must be guaranteed, otherwise the anchor structure of the end plate cannot form an effective connection with the PC prestressed main steel bars.

[0005] As disclosed in Chinese patent CN201520113072.7, a solid square pile end sheet pile joint requires that the thickness of the end plate be ensured for the effective connection between the anchor countersunk hole and the steel bar swage, otherwise the steel bar swage will easily deform or pull through the end plate anchor countersunk hole.

[0006] Because of this shortcoming, the current end plate piles must have certain requirements on the thickness of the end plate, but such thickness will make the cost of the end plate very high. Combined with such defects, end plate-free concrete piles are produced.

[0007] The end plate-less concrete pile eliminates the existence of the end plate from the root, but precisely because there is no end plate, the PC prestressed main reinforcement can only be tensioned by embedded nuts during the pre-tensioning method. After the concrete pile is cast and formed, the prestressed main reinforcement will have a tendency to shrink after the prestress is released. In the case of no end plates at both ends of the pile, its effective precompression stress will be lost. Such a structure will lead to a decrease in the bending resistance of the end plate-less concrete pile. If a collision occurs, concrete cracking is likely to occur. In addition, without the protection of the end plate, once the end of the end plate-less concrete pile is found to be bumped, the entire end plate-less concrete pile will be damaged or even unusable.

[0008] Therefore, the effective prestress of concrete piles is actually very necessary for the structural strength of concrete piles, but due to the high cost of end plates, the cost of concrete piles with end plates is relatively high.

[0009] To address this problem, Chinese patent CN201621311509.9 also discloses an integrated small end plate pile, including a square pile body with a square hole in the middle, a square small end plate connected to the square pile body as a whole structure is provided on the end face of the square pile body, a square through hole matching the square hole is provided in the middle of the square small end plate, the square small end plate is embedded in the end face of the square pile body and is reinforced and connected to the square pile body by a plurality of bolts, and the end face of the square small end plate is flush with the end face of the square pile body.

[0010] The above structural design adopts a small end plate structure, which will still cause partial loss of effective prestressing stress of concrete. At the same time, the area of ​​the square small end plate is smaller than the end face cross-sectional area of ​​the square pile, so the end face protection of the square pile is relatively small. In addition, the end plate connection between the two concrete piles generally requires welding, and the above technical solution does not reserve a position for welding rods on the end plate, resulting in welding failure. Therefore, the connection between the two end plates can only be performed by external welding at the gap at the edge. Such welding method will result in a loose connection between the two concrete piles.

[0011] In short, the above technical solution fails to effectively reduce costs, protect concrete piles, and the connection between adjacent concrete piles is not firm. Summary of the invention

[0012] The technical problem to be solved by the present invention overcomes the existing defects and provides a combined end plate and precast pile, which can effectively save end plate consumables and ensure the firmness of the connection between the longitudinal main reinforcement of the precast pile and the end plate. It is easy to install and effectively protects the end face of the concrete pile. Welding rod weld grooves are reserved to ensure cost reduction while making the connection between the concrete piles firm and stable. The whole design maximizes the retention of the advantages of the end plate piles and the characteristics of the precast piles and reduces costs while improving the pull-out and shear strengths.

[0013] In order to solve the above technical problems, the present invention provides the following technical solutions: a combined end plate, comprising an end plate, on which a plurality of evenly distributed mounting holes are provided, the mounting holes are provided with internal threads, and also comprising a connecting piece, on which an external thread is provided, the connecting piece is screwed to the internal thread of the mounting hole via the external thread, and the connecting piece is provided with a connecting structure that can be connected to a steel bar.

[0014] Preferably, the connection structure is an anchoring countersunk hole.

[0015] Preferably, the inner wall of the anchoring countersunk hole is a sloped surface.

[0016] Preferably, the anchoring countersunk hole is further provided with a second internal thread.

[0017] Preferably, a weld groove is provided on the edge of the end plate.

[0018] Preferably, the weld groove is provided on all edges of the end plate.

[0019] Preferably, the weld groove is arranged on a part of the edge of the end plate.

[0020] Beneficial effects of the present invention: the combined end plate of the present invention is screwed to the end plate through the connection piece with the built-in anchor countersunk hole, so that the tension of the PC prestressed steel bars on the end plate is finally borne by the connection piece and the threaded connection between the connection piece and the end plate, thereby making the thickness of the end plate thinner and the same as the cross-sectional size of the concrete pile, while reducing the cost of the end plate and ensuring effective protection of the end face of the concrete pile, and at the same time ensuring that the end plate will not be deformed due to the pulling of the PC prestressed main steel bars, and also ensuring the firmness of the connection between the connection piece and the PC prestressed steel bars.

[0021] In order to solve the above technical problems, the present invention provides the following technical solutions: a precast pile with a modular end plate, characterized in that it includes a plurality of longitudinal main reinforcements, the modular end plate and precast pile as described in claim 1, the longitudinal main reinforcement is arranged in the precast pile, there are two modular end plates and they are respectively located on both sides of the precast pile, and the two ends of the longitudinal main reinforcement are respectively connected to the connecting pieces in the modular end plates on both sides.

[0022] Preferably, a plurality of longitudinal grooves are provided on the side walls of the precast piles.

[0023] Beneficial effects of the present invention: The precast piles with combined end plates of the present invention have two ends of the longitudinal main reinforcement in the precast piles respectively connected to the connecting structure in the combined end plates. On the one hand, the longitudinal main reinforcement is anchored through the anchor countersunk holes when connected to the connecting pieces of the combined end plates, and on the other hand, it is screwed with the longitudinal main reinforcement through the internal threads provided on the inner walls of the anchor countersunk holes. When the longitudinal main reinforcement is cast to form the precast piles, the longitudinal main reinforcement will shrink. Since the longitudinal main reinforcement and the connecting piece are threadedly connected, the connection strength is extremely high. Furthermore, the connection between the connecting piece and the end plate is also threadedly connected, and the connection strength is also extremely high. Therefore, when the longitudinal main reinforcement shrinks, even if the end plate is very thin, it will not be broken or deformed at the connection between the connecting piece and the end plate. At the same time, the precast piles will ensure that the concrete generates sufficient effective prestressing stress due to the mutual approach and contraction of the end plates at both ends. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0025] Figure 1 It is a structural schematic diagram of the combined end plate of the present invention;

[0026] Figure 2 It is a structural schematic diagram of the back side of the combined end plate of the present invention;

[0027] Figure 3 It is a structural schematic diagram of the end plate of the combined end plate of the present invention;

[0028] Figure 4 It is a structural schematic diagram of a connector of a combined end plate of the present invention;

[0029] Figure 5 It is a schematic structural diagram of the combined end plate of the present invention when it is circular;

[0030] Figure 6 It is a schematic diagram of the end plate welding structure of the combined end plate of the present invention;

[0031] Figure 7 It is a structural schematic diagram of the prefabricated pile of the present invention.

[0032] Numbers in the figure: 1. end plate, 11. mounting hole, 12. internal thread, 13. weld, 14. internal hole, 2. connector, 21. external thread, 22. anchor countersunk hole, 23. internal thread II, 3. longitudinal main reinforcement, 4. precast pile, 41. groove, 5. welding rod. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0034] like Figures 1 to 4 As shown, a combined end plate includes an end plate 1, wherein the edge of the end plate 1 is provided with a plurality of evenly distributed mounting holes 11, wherein the mounting holes 11 are provided with internal threads 12, and further includes a plurality of connecting members 2, wherein the connecting members 2 can be bolts, wherein one end of each bolt 2 is provided with an external thread 21, wherein the bolt 2 is screwed with the internal thread 12 of the mounting hole 11 through the external thread 21, and the bolt 2 is provided with an anchoring countersunk hole 22 and an internal thread 23, and during installation, the PC can be firstly The steel bar head of the prestressed main steel bar passes through the anchor countersunk hole 22 of the bolt 2. At the same time, the inner wall of the anchor countersunk hole 22 is a slope, which can further ensure the connection firmness between the steel bar head and the anchor countersunk hole 22. Moreover, it can offset a part of the pulling force when the PC prestressed main steel bar shrinks. Then, the end of the PC prestressed main steel bar is screwed with the second internal thread 23, and the bolt 2 is screwed with the internal thread 12 of the end plate 1 through the external thread 21. When the PC prestressed main steel bar shrinks, its pulling force will be mainly offset by the second internal thread 23 on the connecting piece 2 and the external thread 21 of the connecting piece 2 and the internal thread 12 of the mounting hole 11. Due to the connection point and the shrinkage stress point of the PC prestressed main steel bar, the thickness of the end plate 1 is greatly reduced. Figure 5 As shown, in order to match the shapes of different concrete piles, the end plate 1 can be designed to be round or square, and each end plate 1 is provided with an inner hole 14, which can further reduce the material consumption of the end plate.

[0035] The thickness of the conventional end plate 1 is at least 20 mm, while the end plate of the present invention generally only needs 10 mm to fully realize the pressure requirement of all concrete piles when realizing effective prestressing stress. At the same time, when encountering a situation where the pull-out resistance requirement is high, it is often necessary to firmly connect the concrete piles. Therefore, a weld 13 is provided at the edge of the end plate 1. The weld 13 can be provided at the entire edge of the end plate 1 or at a part of the edge of the end plate 1. Specifically, Figure 2 and 5 As shown, the welding rod 3 is embedded in the weld formed between the adjacent end plates 1 for one welding pass, and then the welding rod 3 is embedded in the weld for two more welding passes, thereby ensuring the welding firmness between the adjacent end plates.

[0036] When installing the combined end plate with precast piles, Figure 7As shown, the longitudinal main reinforcement 3 is first kept in a tensioned state. Taking one end of the longitudinal main reinforcement 3 as an example, the connecting piece 2 is first passed through the longitudinal main reinforcement 3 and connected with the anchor countersunk hole 22 of the connecting piece 2. The connecting piece 2 is then rotated on the longitudinal main reinforcement 3 so that the internal thread 23 of the connecting piece 2 is embedded in the longitudinal main reinforcement 3 so that the connecting piece 2 and the end of the longitudinal main reinforcement 3 are screwed together. The connecting piece 2 is then screwed together with the internal thread 12 on the mounting hole 11 of the end plate 1 through the external thread 21. After casting to form the precast pile 4 while keeping the longitudinal main reinforcement 3 in a tensioned state, the longitudinal main reinforcement 3 is allowed to shrink after being steamed and dried to form. The longitudinal main reinforcement 3 will drive the two end plates 1 to move inward, thereby continuously squeezing the precast pile 4, thereby greatly improving the effective prestress of the precast pile. Such a design can reduce the material consumption of the end plate while retaining the prestressed strength of the traditional end plate pile.

[0037] The above are preferred implementation modes of the present invention. Those skilled in the art to which the present invention belongs can also change and modify the above implementation modes. Therefore, the present invention is not limited to the above specific implementation modes. Any obvious improvements, substitutions or modifications made by those skilled in the art on the basis of the present invention belong to the protection scope of the present invention.

Claims

1. A combined end plate, comprising an end plate (1), characterized in that: The end plate (1) is provided with a plurality of evenly distributed mounting holes (11), the mounting holes (11) are provided with internal threads (12), and further comprises a connecting piece (2), the connecting piece (2) is provided with external threads (21), the connecting piece (2) is screwed to the internal threads (12) of the mounting holes (11) via the external threads (21), and the connecting piece (2) is provided with a connecting structure that can be connected to a steel bar; the connecting structure is an anchoring countersunk hole (22); the inner wall of the anchoring countersunk hole (22) is a slope surface; the anchoring countersunk hole (22) is also provided with an internal thread (23); the edge of the end plate (1) is provided with a weld groove (13); the weld groove (13) is provided on all or part of the edge of the end plate (1).

2. A prefabricated pile with a combined end plate, characterized in that: The modular end plate as claimed in claim 1 comprises a plurality of longitudinal main reinforcements (3), and further comprises precast piles (4), wherein the longitudinal main reinforcements (3) are arranged in the precast piles (4), and there are two modular end plates, which are respectively located on both sides of the precast piles (4), and the two ends of the longitudinal main reinforcements (3) are respectively connected to the connecting pieces (2) in the modular end plates on both sides; and a plurality of longitudinal grooves (41) are arranged on the side walls of the precast piles (4).

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