A pre-buried steel pull rod end structure of a foundation pit beam string and a steel pull rod
By improving the anchorage node design of the tensioned beam steel tie rod and adopting a separate stress distribution method of nuts, reinforcing ribs and bearing plates, the stress concentration of the bearing plate and construction difficulties were solved, and the protection of concrete and construction convenience were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENZHEN JUKUN TECH CO LTD
- Filing Date
- 2025-08-25
- Publication Date
- 2026-07-24
AI Technical Summary
In the existing technology, the anchoring nodes of the tensioned beam steel tie rods are in direct contact with the bearing plate when transmitting force, which leads to excessive local stress in the bearing plate, rapid local compression failure of the concrete, and prominent assembly and splicing problems during construction.
The separate design of nuts, reinforcing ribs, and bearing plates forms a clear force path: steel tie rod - nut - reinforcing rib - bearing plate - reinforced concrete. The nut ends are sealed, and the ribs are wedge-shaped, forming an integrated structure that avoids assembly and splicing. The sleeve design prevents the impact of concrete pouring.
It improves the stress concentration problem of the bearing plate, slows down local damage to the concrete, simplifies the construction process, and enhances the ease and aesthetics of removing the steel tie rod.
Smart Images
Figure CN224549141U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a pre-embedded steel tie rod end structure for a tensioned beam in a foundation pit and the steel tie rod itself, belonging to the field of civil engineering technology. Background Technology
[0002] Currently, tensioned steel truss support structures are widely used in deep foundation pit projects. As an important key structure, the tensioned beams require steel tie rods at both ends to be pre-embedded in the cap beam as anchoring nodes to form an integral whole with the concrete support.
[0003] During construction, sleeves are typically pre-embedded, and then steel tie rods are passed through these sleeves before the bearing plate and nuts are installed on the tie rods. Therefore, in most anchored joints, the force transmission method involves the high-strength steel tie rod transferring tension to the bearing plate via the nuts, creating localized pressure on the reinforced concrete. In this method, the nuts and bearing plate are in direct contact. When the nuts are designed to be too small, the stress on the bearing plate is concentrated in the nut's projection area, leading to excessive bending moment and localized stress, which in turn causes the concrete to fail under localized pressure more quickly.
[0004] In addition, during construction, this set of anchoring nodes needs to be assembled and spliced, and pre-embedded positioning is also a challenge.
[0005] Publicly available patent documents of the prior art:
[0006] Publication date: January 15, 2021, Publication number: CN112227386A, Subject: Pre-embedded steel tie rod structure of tensioned beam in foundation pit. Summary of the Invention
[0007] The purpose of this utility model is to provide a pre-embedded steel tie rod end structure for the tension beam of the foundation pit, which can improve the problem of excessive local bending moment and excessive local stress in the bearing plate, which leads to faster local compression failure of the concrete. Moreover, the integrated structure can be better pre-embedded and positioned during construction.
[0008] The present invention adopts the following technical solution:
[0009] An embedded steel tie rod end structure for a tensioned beam in a foundation pit includes a nut 101, a reinforcing rib 102, and a bearing plate 103. The nut 101 and the bearing plate 103 are coaxial and separate from each other. The reinforcing rib 103 is evenly distributed around the nut 101, with one end fixedly connected to the nut 101 and the other end fixedly connected to the end face of the bearing plate 103. The bearing plate 103 has a central hole 103a with a diameter not smaller than that of the threaded hole in the nut 101. The threaded inlet of the nut 101 is located at one end close to the bearing plate 103.
[0010] In existing anchorage joints, the high-strength steel tie rod transmits tension to the bearing plate via a nut, creating localized pressure on the reinforced concrete. This method involves direct contact between the nut and the bearing plate. When the nut is too small, the stress on the bearing plate is concentrated in the nut's projection area, leading to excessive bending moment and localized stress, ultimately causing faster localized compressive failure of the concrete. This new technical solution employs a clear, sequential force transmission: steel tie rod - nut - reinforcing rib - bearing plate - reinforced concrete. The improved anchorage joint addresses stress concentration in the bearing plate, reduces bending moment, and slows down the rate of localized compressive failure in the concrete.
[0011] Preferably, the end of the nut 101 has a sealed structure. This design prevents cast-in-place concrete from entering the nut and thus affecting the steel tie rod's disengagement from the threads.
[0012] Preferably, the reinforcing rib 103 is wedge-shaped. This design can increase the force transmission surface and reliability between the reinforcing rib and the bearing plate.
[0013] Preferably, the pressure plate 103 is circular.
[0014] Preferably, the nut 101, reinforcing rib 102, and bearing plate 103 are integrally cast structures; or, the reinforcing rib 102 is welded and fixed to the nut 101 and bearing plate 103 respectively. This design makes the pre-embedded end form an integral structure, avoiding the assembly and splicing work of the anchoring node, and the pre-embedded positioning is also more convenient.
[0015] Preferably, each of the reinforcing ribs 103 is arranged at 45° intervals, for a total of 8 ribs.
[0016] A steel tie rod includes the aforementioned pre-embedded steel tie rod end structure for a tensioned beam in a foundation pit; it also includes a steel tie rod 2, the head end of which is provided with a threaded portion, the threaded portion passing through the central hole 103a and being screwed into the nut 101 from the threaded inlet.
[0017] Preferably, the design also includes a pre-embedded sleeve 4, with the portion of the nut 101 near the threaded inlet inserted into the pre-embedded sleeve 4, the threaded sleeve extending to the outside of the poured concrete. This design prevents subsequent concrete pouring from causing difficulty in rotating and pulling out the steel tie rod.
[0018] Furthermore, the poured concrete is the cap beam 3 of the retaining structure.
[0019] Furthermore, after the cap beam 3 was poured, the exposed pre-embedded sleeve 4 was removed. This resulted in a better aesthetic appearance.
[0020] The beneficial effects of this utility model are as follows:
[0021] 1) Improve the problem of excessive local bending moment and excessive local stress in the bearing plate, which leads to faster local compressive failure of concrete.
[0022] 2) The steel tie rod end structure is an integral piece, which only needs to be inserted into the pre-fixed sleeve during pre-embedding; this set of anchoring nodes does not require assembly and splicing, and pre-embedding positioning is also more convenient;
[0023] 3) The integrated seal formed by the end and the pre-embedded sleeve makes it easier to rotate and pull out the steel tie rod. Attached Figure Description
[0024] Figure 1 This is a structural schematic diagram of the steel tie rod of this utility model.
[0025] Figure 2 This is a schematic diagram of the steel tie rod of this utility model being pre-embedded and fixed in the cap beam.
[0026] Figure 3 This is a schematic diagram of the pre-embedded steel tie rod end structure of the foundation pit tensioned beam of this utility model.
[0027] Figure 4 This is a top view of the pre-embedded steel tie rod end structure of the foundation pit tensioned beam of this utility model.
[0028] Figure 5 This is the front view of the pre-embedded steel tie rod end structure of the foundation pit tensioned beam of this utility model.
[0029] In the figure, 1. End, 2. Steel tie rod, 3. Crown beam, 4. Embedded sleeve, 101. Nut, 102. Reinforcing rib, 103. Bearing plate, 103a. Center hole. Detailed Implementation
[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0031] The tensioned beams inside the excavation pit are inverted at the pit opening. Through the combined action of "beam compression and cable tension," the load at the top of the pit is quickly transferred to the supports on both sides, forming a large-span, column-free temporary support system. The steel tie rods at both ends of the tensioned beam need to be pre-embedded in the capping beam as anchoring nodes to form an integral whole with the concrete support.
[0032] This embodiment focuses on the pre-embedded steel tie rod end structure of the tensioned beam in the foundation pit, as detailed below:
[0033] See Figures 3-5An end structure for a pre-embedded steel tie rod of a tensioned beam in a foundation pit includes a nut 101, a reinforcing rib 102, and a bearing plate 103. The nut 101 and the bearing plate 103 are coaxial and separate from each other. The reinforcing rib 103 is evenly distributed around the nut 101, with one end fixedly connected to the nut 101 and the other end fixedly connected to the end face of the bearing plate 103. The bearing plate 103 has a central hole 103a with a diameter not smaller than that of the threaded hole in the nut 101. The threaded entrance of the nut 101 is located at one end close to the bearing plate 103.
[0034] In the existing anchorage joint stress distribution method, the high-strength steel tie rod transmits the tensile force to the bearing plate through the nut, forming local pressure on the reinforced concrete. In this stress transmission method, the nut and the bearing plate are in direct contact. When the nut is designed to be too small, the stress on the bearing plate will be mainly concentrated in the nut projection area, resulting in excessive bending moment and excessive local stress, which in turn will cause the concrete to fail under local pressure more quickly.
[0035] In this technical solution, combined with Figure 1 , 3 5. Understandably, the force is transmitted in a clear, step-by-step manner: steel tie rod 2 - nut 101 - reinforcing rib 102 - bearing plate 103 - reinforced concrete. Therefore, the improved anchoring joint can improve the stress concentration problem of the bearing plate, reduce the bending moment of the bearing plate, and at the same time slow down the rate at which the concrete will experience localized compressive failure.
[0036] In this implementation, see Figure 5 The end of the nut 101 is a sealed structure. This design prevents cast-in-place concrete from entering the nut and thus affecting the steel tie rod's disengagement from the threads.
[0037] In this embodiment, see Figure 3 and Figure 5 The reinforcing rib 103 is wedge-shaped. This design increases the force transmission surface and reliability between the reinforcing rib and the bearing plate.
[0038] See also Figure 3 The pressure plate 103 is circular.
[0039] Preferably, the nut 101, reinforcing rib 102, and bearing plate 103 are integrally cast structures; or, the reinforcing rib 102 is welded and fixed to the nut 101 and bearing plate 103 respectively. This design makes the pre-embedded end form an integral structure, avoiding the assembly and splicing work of the anchoring node, and the pre-embedded positioning is also more convenient.
[0040] See Figure 4 Each of the reinforcing ribs 103 is arranged at 45° intervals, for a total of 8 ribs.
[0041] Combination Figure 1 and Figure 3 An embedded steel tie rod for a tensioned beam in a foundation pit includes the aforementioned end structure; it also includes a steel tie rod 2, the head end of which is provided with a threaded portion, the threaded portion passing through the central hole 103a and being screwed into the nut 101 from the threaded inlet.
[0042] See Figure 2 It also includes a pre-embedded sleeve 4, with the portion of the nut 101 near the threaded inlet inserted into the pre-embedded sleeve 4, the threaded sleeve extending to the outside of the poured concrete. This design prevents subsequent concrete pouring from causing difficulty in rotating and pulling out the steel tie rod. The connection point between the pre-embedded sleeve 4 and the nut can be found in the appendix. Figure 5 .
[0043] See also Figure 2 The poured concrete forms the capping beam 3 of the retaining structure. After the capping beam 3 is poured, the exposed embedded sleeve 4 is removed to improve aesthetics.
[0044] The pre-embedded steel tie rod end structure of the tensioned beam in this foundation pit can improve the problem of excessive local bending moment and excessive local stress in the bearing plate, which leads to faster local compressive failure of the concrete. Moreover, the integrated structure can be better pre-embedded and positioned during construction.
[0045] The construction method of this embodiment will be compared with the prior art below:
[0046] The existing construction method for anchoring nodes is as follows: pre-embedded sleeve - steel tie rod inserted into the sleeve - installation of bearing plate - installation of nut head; it can be seen that this anchoring node needs to be assembled and spliced, and the pre-embedded positioning is also a problem.
[0047] The construction method of the anchoring node in this utility model is as follows: pre-embedded sleeve - installation end - steel tie rod inserted into the sleeve - tightening.
[0048] Meanwhile, in the existing anchorage joint stress distribution method, the high-strength steel tie rod transmits the tensile force to the bearing plate through the nut, forming local pressure acting on the reinforced concrete. In this stress transmission method, the nut and the bearing plate are in direct contact. When the nut is designed to be small, the stress on the bearing plate will be mainly concentrated in the nut projection area, resulting in excessive bending moment and excessive local stress, which in turn will cause the concrete to fail under local pressure more quickly.
[0049] In summary, this utility model improves the problem of excessive local bending moment and local stress in the bearing plate, which leads to faster local compressive failure of the concrete. The steel tie rod end structure is integrated, and it only needs to be inserted into the pre-fixed sleeve during pre-embedding. This anchoring node does not require assembly and splicing, and the pre-embedding positioning is also more convenient. The integrated sealing formed by the end and the pre-embedded sleeve makes it easier to rotate and pull out the steel tie rod.
[0050] The above are preferred embodiments of the present utility model. Those skilled in the art can make various changes or improvements based on this. Without departing from the overall concept of the present utility model, these changes or improvements should all fall within the scope of protection claimed by the present utility model.
Claims
1. A pre-embedded steel tie rod end structure for a tensioned beam in a foundation pit, characterized in that: Includes nuts (101), reinforcing ribs (102), and bearing plates (103); The nut (101) is coaxial with the pressure plate (103) and is separate from it; The reinforcing ribs (102) are evenly distributed around the nut (101), with one end fixedly connected to the nut (101) and the other end fixedly connected to the end face of the bearing plate (103). The pressure plate (103) has a center hole (103a) with a diameter not less than that of the threaded hole of the nut (101); The threaded inlet of the nut (101) is located at one end near the bearing plate (103).
2. The pre-embedded steel tie rod end structure for the tensioned beam in the foundation pit as described in claim 1, characterized in that: The end of the nut (101) is a sealed structure.
3. The pre-embedded steel tie rod end structure for the tensioned beam in the foundation pit as described in claim 1, characterized in that: The reinforcing rib (102) is wedge-shaped.
4. The pre-embedded steel tie rod end structure for the tensioned beam in the foundation pit as described in claim 1, characterized in that: The pressure plate (103) is circular.
5. The pre-embedded steel tie rod end structure for the tensioned beam in the foundation pit as described in claim 1, characterized in that: The nut (101), reinforcing rib (102), and bearing plate (103) are integrally cast structures; or, the reinforcing rib (102) is welded and fixed to the nut (101) and bearing plate (103) respectively.
6. The pre-embedded steel tie rod end structure for the tensioned beam in the foundation pit as described in claim 1, characterized in that: The reinforcing ribs (102) are arranged at 45° intervals, for a total of 8 ribs.
7. A steel tie rod, characterized in that: The structure includes the pre-embedded steel tie rod end structure of the foundation pit tension beam as described in any one of claims 1-6; it also includes a steel tie rod (2), the head end of which is provided with a threaded part, the threaded part passing through the central hole (103a) and screwed into the nut (101) from the threaded inlet.
8. The steel tie rod as described in claim 7, characterized in that: It also includes a pre-embedded sleeve (4), the nut (101) near the threaded inlet of which is inserted into the pre-embedded sleeve (4), the pre-embedded sleeve extending to the outside of the poured concrete.
9. The steel tie rod as described in claim 8, characterized in that: The poured concrete is the capping beam (3) of the enclosure structure.
10. The steel tie rod as described in claim 9, characterized in that: After the crown beam (3) is poured, the exposed pre-embedded sleeve (4) is cut off.