Prestressed steel strand anchorage device
By using elastic-plastic support columns and self-locking mating anchors in prestressed steel strand anchors, the problems of tension loss and retraction in large prestressed structures are solved, and the stability and safety of the prestressed structure are improved.
Patent Information
- Application Number
- CN202422226244.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2025-07-22
- Estimated Expiration
- 2034-09-11
AI Technical Summary
Traditional prestressed anchors have problems such as large tension loss, large steel strand retraction and friction, and high maintenance costs in large prestressed structures, which affect the safety and stability of the prestressed structure.
The first and second anchors are arranged relatively, and connected by elastic-plastic support columns and anchor bolts, the destructive characteristics of the concrete columns are gradually converted into axial binding force during the tensioning process of the steel strand, reducing friction, and forming a self-locking fit with the conical inner cavity and the round table structure to achieve stable fixation of the steel strand.
It effectively reduces the damage risk of steel strands, improves the prestress transmission efficiency, ensures uniform distribution of prestresses, improves the long-term stability and safety of the structure, and reduces maintenance costs.
Smart Images
Figure CN223134968U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of prestressed anchors, and particularly relates to a prestressed steel strand anchor. Background Art
[0002] In modern construction projects, the prestress technology is an important technology widely used in large-span structures, high-rise buildings, bridges and other large building structures. The core of the prestress technology lies in improving the bearing capacity and stability of the structure through pre-applied stress. As a key material in the prestress structure, the fixing method of the steel strand directly affects the performance and safety of the prestress structure.
[0003] In the traditional prestressed anchor technology, the fixing of the steel strand usually relies on the clamping force of the anchor on the steel strand. However, with the enlargement and complexity of the prestress structure, the traditional anchor fixing method faces many challenges in terms of accuracy, reliability and construction efficiency. Especially in large prestress structures, the tension strength of the steel strand is often very high, which poses higher requirements for the fixing ability of the anchor.
[0004] The traditional prestressed anchor fixing method mainly relies on mechanical clamping fixation, and these methods have the following deficiencies in the operation process:
[0005] (1) Large loss of tensile force: Due to the large tensile force of the steel strand, it is difficult to accurately control the force value during the tensioning process by the traditional method, and the retraction of the steel strand will affect the tensile strength. (2) Large friction between the steel strand and the fixture: It may cause the prestressed steel strand to not reach the expected tensile strength, and even lead to structural safety accidents. (3) High maintenance cost: Due to the poor fixing effect, the prestress structure may need to be regularly inspected and maintained, increasing the long-term maintenance cost. Content of the Utility Model
[0006] The technical problem to be solved by the utility model is to provide a prestressed steel strand anchor that can effectively improve the safety and stability of the prestress structure.
[0007] The technical solution adopted by the utility model to solve its technical problems is as follows: A prestressed steel strand anchor, including a first anchor and a second anchor arranged oppositely. Taking the state where the second anchor is above the first anchor as the reference state, the first anchor has a plurality of first steel strand through holes. The lower surface of the second anchor is convexly provided with conical platforms corresponding to and coaxial with the first steel strand through holes one by one. The axial center position of the conical platform is provided with a second steel strand through hole penetrating the end face of the end of the conical platform far from the lower surface of the second anchor and the upper surface of the second anchor. The upper surface of the first anchor and the lower surface of the second anchor are butt-jointed through elastoplastic support columns. The first anchor and the second anchor are connected by a plurality of anchoring bolts. The axis of the anchoring bolts is parallel to the axis of the first steel strand through holes; a tapered inner cavity with an upper end diameter larger than the lower end diameter is coaxially arranged at the upper end of the first steel strand through hole. The shape and specification of the tapered inner cavity are adapted to the conical platform on the lower surface of the second anchor. A clamp coaxial with the first steel strand through hole is fixedly arranged at the connection part between the tapered inner cavity and the first steel strand through hole. The main body of the clamp is a conical cylinder structure with an upper end diameter smaller than the lower end diameter. The side wall of the clamp is provided with a deformation groove intersecting with the upper end face of the clamp and extending along the axis direction of the clamp; when the elastoplastic support column is in the natural state, there is a set distance between the inner wall of the second steel strand through hole and the outer peripheral surface of the clamp; the clamp has a first state of not clamping the steel strand and a second state of clamping the steel strand. When the second anchor moves towards the first anchor under the tensile force of the steel strand, the lower end inner wall of the second steel strand through hole can squeeze the outer peripheral wall of the clamp and generate deformation so that the clamp is converted from the first state to the second state. At this time, a self-locking fit can be formed between the outer peripheral surface of the conical platform and the tapered inner cavity.
[0008] A further preferred solution is that the elastoplastic support column is a concrete column.
[0009] A further preferred solution is that a plurality of elastoplastic support columns are arranged at uniform intervals.
[0010] A further preferred solution is that the upper surface of the first anchor has an annular sunk platform structure, and a first card slot corresponding to the lower end of the elastoplastic support column one by one is arranged on the upper surface of the annular sunk platform structure. The lower surface of the second anchor is provided with a second card slot corresponding to the lower end of the elastoplastic support column one by one.
[0011] A further preferred solution is that the outer diameter of the end face of the conical platform far from the lower surface of the second anchor is larger than the inner diameter of the bottom end of the tapered inner cavity.
[0012] A further preferred solution is that a plurality of first steel strand through holes are arranged at uniform intervals.
[0013] A further preferred solution is that a plurality of anchoring bolts are arranged at uniform intervals.
[0014] A further preferred solution is that a plurality of deformation grooves are arranged at equal intervals along the circumferential direction of the fixture.
[0015] A further preferred solution is that a pressing pad is attached to the upper surface of the second anchor, and the pressing pad is provided with nut through holes corresponding to the anchoring bolts one by one and third steel strand through holes corresponding to the second steel strand through holes one by one.
[0016] When the utility model is specifically implemented, the following steps are included:
[0017] Install the first anchor and the second anchor. First, pass the bolt part in the anchoring bolt through the first anchor correspondingly, and fix the first anchor on the anchor pad correspondingly. Then, pass the steel strand through the first steel strand through hole, the central hole of the fixture, and the second steel strand through hole in sequence, and the bolt part in the anchoring bolt passes through the second anchor correspondingly;
[0018] Estimate the initial distance between the upper surface of the first anchor and the lower surface of the second anchor according to the expected tensile strength of the steel strand and the material deformation characteristics of the elastoplastic support column, and correspondingly manufacture and install the elastoplastic support column;
[0019] If a pressing pad is provided, install the pressing pad correspondingly, pass the steel strand through the third steel strand through hole correspondingly, preliminarily connect the anchoring bolts in advance, and insert the nut - equipped section of the anchoring bolt into the nut through hole;
[0020] Connect the steel strand with the tensioning tool correspondingly;
[0021] Perform pre - tensioning: The tensioning force is 10% - 20% of the standard value of the expected tensile strength of the steel strand;
[0022] Increase the tensioning force in stages and gradually tension the steel strand;
[0023] When reaching 85% - 90% of the standard value of the expected tensile strength of the steel strand, maintain the load for a period of time. At this stage, the peak load at which the elastoplastic support column fails is reached, the elastoplastic support column gradually fails, the frustum gradually inserts into the conical inner cavity, so that the inner wall of the lower end of the second steel strand through hole gradually presses the outer peripheral wall of the fixture and deforms, and then the fixture gradually clamps the steel strand;
[0024] Continue to increase the tensioning force until the standard value of the expected tensile strength is reached, and maintain the load for a period of time to make the prestress transfer evenly. The tensile strength cannot be over - tensioned by 5%;
[0025] After the load - maintaining is completed, unload the tensioning tool;
[0026] Cut off the steel strand, and the exposed length of the steel strand is reserved for anchoring according to the design length;
[0027] Subsequently, remove the tensioning tool. If there is a top pressure pad, remove the top pressure pad simultaneously. Connect and fix the first and second anchorages using anchor bolts, and finally grout and seal the anchorages.
[0028] The beneficial effects of the present utility model are as follows: During specific implementation, the present utility model controls the displacement of the second anchorage through the elastoplastic support column, such that the steel strand is hardly affected by the friction force of the fixture in the early stage of tensioning. In the preferred embodiment of the present utility model, when the steel strand is tensioned to 85%-90%, the steel strand is only axially restricted by the fixture, greatly reducing the losses during the tensioning process. This method not only reduces the risk of damage to the steel strand but also improves the efficiency of prestress transfer.
[0029] The anchorage method implemented using the present utility model effectively solves the problem of the retraction of the prestressed steel strand after tensioning, ensuring that the prestress can be persistently and evenly distributed in the structure, thereby improving the long-term stability and durability of the structure.
[0030] The anchorage method implemented using the present utility model ensures the axial restraint force of the anchorage: On the one hand, the present utility model provides an axial restraint force for the prestressed steel strand through the wedge mechanism between the frustum of the second anchorage and the conical inner cavity of the first anchorage. On the other hand, the first and second anchorages are connected using anchor bolts, improving the overall stability and load-bearing capacity of the structure. This dual fixing mechanism ensures that the axial restraint force of the anchorage on the prestressed steel strand can be effectively guaranteed even under extreme conditions.
[0031] The anchorage method implemented using the present utility model improves the safety of the prestressed structure: Since the present utility model can effectively reduce friction and retraction problems, improving the reliability of prestress fixation, the safety of the prestressed structure is significantly enhanced. At the same time, with high fixing precision, the wear and deformation of the prestressed structure during use are reduced, thereby reducing the long-term maintenance cost.
[0032] The anchorage method implemented using the present utility model has strong adaptability: The design of the present utility model is applicable to steel strands of different specifications and tensioning strengths, with good versatility and adaptability, and can be widely applied to various prestressed structure projects such as bridges and aqueducts. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 is the overall structural schematic diagram of the present utility model;
[0034] Figure 2 is the top view of the first anchorage in the present utility model;
[0035] Figure 3 is Figure 2 the A-A sectional view of
[0036] Figure 4Yes Figure 2 The B-B sectional view of
[0037] Figure 5 is the top view of the second anchor in the present utility model (with the frustum structure facing upwards);
[0038] Figure 6 Yes Figure 5 The C-C sectional view of
[0039] Figure 7 Yes Figure 5 The D-D sectional view of
[0040] Figure 8 is the top view of the top pressure pad in the present utility model;
[0041] Figure 9 is the front view of the top pressure pad in the present utility model;
[0042] Figure 10 is the flow chart of the cable anchoring method when the present utility model is implemented.
[0043] Figures 1 to 9 The component markings in are: the first anchor 10, the first steel strand through-hole 11, the conical inner cavity 12, the fixture 13, the first card slot 14, the first bolt through-hole 15;
[0044] The second anchor 20, the second steel strand through-hole 21, the frustum 22, the second card slot 23, the second bolt through-hole 24;
[0045] The elastoplastic support column 30; the anchoring bolt 40; the steel strand 50;
[0046] The top pressure pad 60, the nut through-hole 61, the third steel strand through-hole 62. Detailed implementation manners
[0047] The present utility model will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0048] Such as Figures 1 to 9As shown in the figure, the prestressed steel strand anchor of the present utility model includes a first anchor 10 and a second anchor 20 arranged oppositely. Taking the second anchor 20 being located above the first anchor 10 as the reference state, the first anchor 10 has a plurality of first steel strand through holes 11. The lower surface of the second anchor 20 is convexly provided with frustums 22 corresponding to and coaxial with the first steel strand through holes 11 one by one. At the axial center position of the frustum 22, there is a second steel strand through hole 21 that penetrates the end surface of the frustum 22 far from the lower surface of the second anchor 20 and the upper surface of the second anchor 20. The upper surface of the first anchor 10 and the lower surface of the second anchor 20 are butt-connected through an elastoplastic support column 30. The first anchor 10 and the second anchor 20 are connected by a plurality of anchor bolts 40 (that is, it is equivalent to the first anchor 10 and the second anchor 20 being respectively provided with bolt connection holes matching the anchor bolts 40. In the illustrated embodiment, they are respectively the first bolt through hole 15 and the second bolt through hole 24). The axis of the anchor bolt 40 is parallel to the axis of the first steel strand through hole 11. At the upper end of the first steel strand through hole 11, a tapered inner cavity 12 with an upper diameter larger than the lower diameter is coaxially arranged. The shape and specification of the tapered inner cavity 12 are adapted to the frustum 22 on the lower surface of the second anchor 20. At the connection part between the tapered inner cavity 12 and the first steel strand through hole 11, a clamp 13 coaxial with the first steel strand through hole 11 is fixedly arranged. The main body of the clamp 13 is a conical cylinder structure with an upper diameter smaller than the lower diameter. The side wall of the clamp 13 is provided with a deformation groove that intersects with the upper end surface of the clamp 13 and extends along the axis direction of the clamp 13. When the elastoplastic support column 30 is in the natural state (that is, equivalent to the initial state before bearing the pressure of the anchor), there is a set distance between the inner wall of the second steel strand through hole 21 and the outer peripheral surface of the clamp 13 (that is, equivalent to the clamp 13 being in the initial state without deformation, and it is necessary for the elastoplastic support column 30 to deform to a certain extent to make the second anchor 20 move towards the direction close to the first anchor 10, so that the inner wall of the second steel strand through hole 21 can contact the outer peripheral surface of the clamp 13, and finally make the clamp 13 gradually transform into clamping the steel strand 50).
[0049] The clamp 13 has a first state of not clamping the steel strand 50 and a second state of clamping the steel strand 50. When the second anchor 20 moves towards the direction close to the first anchor 10 under the tensile force of the steel strand 50, the lower end inner wall of the second steel strand through hole 21 can squeeze the outer peripheral wall of the clamp 13 and cause deformation so that the clamp 13 is transformed from the first state to the second state. At this time, a self-locking fit can be formed between the outer peripheral surface of the frustum 22 and the tapered inner cavity 12.
[0050] Specifically, the "elastoplastic support column 30" refers to a columnar member that first undergoes elastic deformation, then plastic deformation, and finally is damaged as the axial pressure increases. To facilitate processing and adjusting the mechanical parameters of the "elastoplastic support column 30", the elastoplastic support column 30 is preferably a concrete column. The selection of concrete material for the "elastoplastic support column 30" in the present utility model is greatly related to its material deformation characteristics, with high strength, small deformation, easy availability, and no explosion during the failure process under displacement control. In the initial stage of loading, it enters the compaction and elastic stage, and the concrete column is used to transfer the pressure applied by the second anchor 20 to the first anchor 10. During this process, the clamp 13 does not deform, so that the steel strand 50 is not restricted by the axial binding force of the anchor at the initial stage of tensioning. Subsequently, it enters the plastic stage, and the concrete column gradually fails. The tensile force on the prestressed steel strand can be smoothly converted into the axial binding force of the frustum 22 structure on the second anchor 20 to the first anchor 10. The frustum 22 gradually inserts into the conical inner cavity 12 of the first anchor 10 until the inner wall of the lower end of the second steel strand through-hole 21 gradually presses against the outer peripheral wall of the clamp 13 and deforms, thereby causing the clamp 13 to gradually clamp the steel strand 50. The failure strength of the concrete column in the present utility model is 85%-90% of the designed strength of the set prestressed steel strand, which can be controlled by adjusting the concrete strength grade and cross-sectional area, facilitating operation.
[0051] For the reasons that the concrete failure strength in the present utility model is 85%-90% of the designed strength of the set prestressed steel strand, on the one hand, it can greatly reduce the wear of the anchor on the steel strand 50. On the other hand, after the pressure is smoothly converted, a relatively large pressure can still be applied, which can better make the frustum 22 structure insert into the conical inner cavity 12 of the first anchor 10, and the clamp 13 and the steel strand 50 are tightly pressed. If it is set between 95%-100%, the strength of the concrete column has a certain discreteness. When the concrete just fails and the pressure of the tensioning tool on the anchor is still in the conversion process, the pressure between the frustum 22 and the conical inner cavity 12 is insufficient to lock the wedge mechanism here to reliably fix the steel strand 50.
[0052] To simplify the calculation process and make the structure simple and reliable, multiple elastoplastic support columns 30 are arranged at equal intervals. In the embodiment shown in the figure, two elastoplastic support columns 30 are symmetrically arranged.
[0053] To ensure an appropriate initial spacing between the first anchor 10 and the second anchor 20, so as to match an elastoplastic support column 30 of a suitable length and facilitate the positioning and installation of the elastoplastic support column 30, the upper surface of the first anchor 10 has an annular sunk structure, and a first card slot 14 corresponding to the lower end of the elastoplastic support column 30 one by one is arranged on the upper surface of the annular sunk structure. A second card slot 23 corresponding to the lower end of the elastoplastic support column 30 one by one is arranged on the lower surface of the second anchor 20. That is, the center of the upper end of the first anchor 10 is a cylindrical boss structure, and the first steel strand through-hole 11, the tapered inner cavity 12, the clamp 13, and the first bolt through-hole 15 are all arranged in the area where the cylindrical boss is located.
[0054] To make the structure more reliable, the outer diameter of the end face of the frustum 22 away from the lower surface of the second anchor 20 is larger than the inner diameter of the bottom end of the tapered inner cavity 12. The specific dimensional difference can be reasonably designed according to the actual situation. In this embodiment, the outer diameter of the end face of the frustum 22 away from the lower surface of the second anchor 20 is 4 mm larger than the inner diameter of the bottom end of the tapered inner cavity 12.
[0055] To make the force more uniform, preferably, the first steel strand through-holes 11 are multiple and arranged at uniform intervals. The anchoring bolts 40 are multiple and arranged at uniform intervals. The deformation grooves are arranged at uniform intervals along the circumference of the clamp 13. The number of structures such as the steel strand through-holes, the anchoring bolts 40, and the deformation grooves can be flexibly designed according to the actual situation. In this embodiment, the number of the first steel strand through-holes 11, the second steel strand through-holes 21, the anchoring bolts 40, and the deformation grooves is three. The number of the deformation grooves is three, that is, the clamp 13 is composed of three separated clip combinations.
[0056] To facilitate converting the tensile force of the tensioning tool into the pressure on the second anchor 20, preferably, a top pressure pad 60 is attached to the upper surface of the second anchor 20. The top pressure pad 60 is provided with nut through-holes 61 corresponding to the anchoring bolts 40 one by one and third steel strand through-holes 62 corresponding to the second steel strand through-holes 21 one by one.
[0057] It can be understood that the dimensions of each component of the anchor can be reasonably designed according to the actual situation. In this embodiment, the thickness of the barrel of the clamp 13 is 2 mm, the diameter of the concrete column is 50 mm, and the diameters of the first card slot 14 and the second card slot 23 are 52 mm.
[0058] Further referring to Figure 10 , when the specific implementation of the present invention is carried out, it includes the following steps:
[0059] Install the first anchor 10 and the second anchor 20. First, pass the bolt part of the anchor bolt 40 through the first anchor 10, and fix the first anchor 10 correspondingly on the anchor cushion block. Then, pass the steel strand 50 through the first steel strand through-hole 11, the central hole of the clamp 13, and the second steel strand through-hole 21 in sequence, and pass the bolt part of the anchor bolt 40 through the second anchor 20; estimate the initial distance between the upper surface of the first anchor 10 and the lower surface of the second anchor 20 according to the expected tensile strength of the steel strand 50 and the material properties of the elastoplastic support column 30, and correspondingly manufacture and install the elastoplastic support column 30; according to the specific subsequent tensioning steps, in this step of this embodiment, the specific parameters of the elastoplastic support column 30 should be designed on the principle that when the tensile force reaches 85%-90% of the expected tensile strength standard value of the steel strand 50, the elastoplastic support column 30 will gradually fail;
[0060] If a top pressure cushion block 60 is provided, install the top pressure cushion block 60 correspondingly, and the steel strand 50 passes through the third steel strand through-hole 62 correspondingly. Generally, the anchor bolt 40 can also be preliminarily connected, and the threaded nut section of the anchor bolt 40 is inserted into the nut through-hole 61; then connect the steel strand 50 with the tensioning tool correspondingly; the tensioning tool can adopt existing mature equipment, usually composed of a system host, an oil pump, a jack, etc.;
[0061] Perform pre-tensioning: The tensile force is 10%-20% of the expected tensile strength standard value of the steel strand 50; the purpose of pre-tensioning is to eliminate the relaxation of the steel strand 50 in the duct; since the concrete material is elastoplastic, at a lower pressure, the deformation is elastic deformation, which has little effect on the material strength;
[0062] Subsequently, perform formal tensioning, control the oil speed, gradually increase the tensile force, and increase the tensile force in stages to gradually tension the steel strand 50; the specific tensioning parameters can be flexibly designed according to the actual situation. Preferably, set the tensile forces to 20%, 40%, 65%, and 90% of the expected tensile strength standard value of the steel strand 50 respectively, and the holding time is 3 min to 5 min (specifically preferably 4 min);
[0063] When reaching 85%-90% of the expected tensile strength standard value of the steel strand 50, maintain the load for a period of time (preferably 4 min to 6 min, and can be further preferably 5 min). At this stage, the peak load at which the elastoplastic support column 30 fails is reached, and the elastoplastic support column 30 gradually fails. The frustum 22 gradually inserts into the conical inner cavity 12, so that the inner wall of the lower end of the second steel strand through-hole 21 gradually presses against the outer peripheral wall of the clamp 13 and deforms, and then the clamp 13 gradually clamps the steel strand 50;
[0064] Continue to increase the tensile force until the expected tensile strength standard value is reached. The tensile strength cannot be over-tensioned by 5%, and maintain the load for a period of time to make the prestress transfer evenly;
[0065] After the holding load is completed, unload the tensioning tool; that is, slowly return the oil to unload the jack.
[0066] Cut the steel strand 50, and the exposed length of the steel strand 50 is reserved as the design length for anchoring; specifically, make marks on the steel strand 50 exposed outside the anchor, and use a cutting tool to cut the steel strand 50, and reserve a length of 50 mm for anchoring.
[0067] Subsequently, remove the tensioning tool. If there is a jacking pad 60, remove the jacking pad 60 correspondingly at the same time; use the anchoring bolt 40 to connect and fix the first anchor 10 and the second anchor 20 (that is, lock it with the nut in the anchoring bolt 40), and finally seal the anchor. Specifically, apply anti-corrosion grease around the anchor, and then grout to seal the anchor to protect the anchor and the prestressed steel strand.
[0068] In the present utility model, the failure strength of the concrete column is about 85%-90% of the expected tensioning strength of the steel strand. When it is lower than this tensioning strength, the prestressed steel strand is not subject to the axial binding force of the anchor, greatly reducing the wear of the anchor on the steel strand. On the other hand, after the pressure is smoothly converted, a large pressure can still be applied, so that the wedge mechanism corresponding to the frustum 22 can be better inserted into the conical inner cavity 12 of the first anchor 10, and the clamp 13 is tightly pressed against the steel strand 50. In the present utility model, when the prestressed steel strand reaches the expected tensioning strength, due to the connection and fixation of the clamp 13 and the first anchor 10, it will not cause the retraction of the clamp 13, affecting the change of the tensioning value of the prestressed steel strand.
[0069] In the present utility model, the distance between the first anchor 10 and the second anchor 20 is estimated according to the material properties of the concrete material, so that during the failure process, a part of the tension is converted into the pressure of the jacking pad 60 on the second anchor 20, and it is gradually converted into the axial binding force of the prestressed steel strand.
[0070] In the present utility model, the function of the anchoring bolt 40 is to fix the first anchor 10 and the second anchor 20 together, forming a double guarantee mechanism with the axial binding force of the clamp 13 on the prestressed steel strand, greatly improving the anchoring effect of the anchor on the prestressed steel strand.
[0071] In the present utility model, two anchors are used to fix the prestressed steel strand. Among them, only the inner hole of the clamp 13 of the first anchor 10 provides axial binding force for the prestressed steel strand, and the main function of the second anchor 20 is to insert its frustum 22 structure into the conical inner cavity 12 of the first anchor 10 to form a wedge mechanism and then lock it, so that the clamp 13 provides axial binding force for the prestressed steel strand.
[0072] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present utility model.
Claims
1. A prestressed steel strand anchor, characterized in that: It includes a first anchor (10) and a second anchor (20) arranged relatively. Taking the state where the second anchor (20) is above the first anchor (10) as the reference state, the first anchor (10) has a number of first steel strand through-holes (11). The lower surface of the second anchor (20) is convexly provided with a frustum (22) corresponding to and coaxial with the first steel strand through-holes (11) one by one. The axial center position of the frustum (22) is provided with a second steel strand through-hole (21) that penetrates the end surface of the end of the frustum (22) away from the lower surface of the second anchor (20) and the upper surface of the second anchor (20). The upper surface of the first anchor (10) and the lower surface of the second anchor (20) are butt-jointed through an elastoplastic support column (30). The first anchor (10) and the second anchor (20) are connected by a number of anchoring bolts (40). The axis of the anchoring bolt (40) is parallel to the axis of the first steel strand through-hole (11). The upper end of the first steel strand through-hole (11) is coaxially provided with a tapered inner cavity (12) with an upper diameter larger than the lower diameter. The shape and specification of the tapered inner cavity (12) are adapted to the frustum (22) on the lower surface of the second anchor (20). A clamp (13) coaxial with the first steel strand through-hole (11) is fixedly arranged at the connection part of the tapered inner cavity (12) and the first steel strand through-hole (11). The main body of the clamp (13) is a conical cylinder structure with an upper diameter smaller than the lower diameter. The side wall of the clamp (13) is provided with a deformation groove that intersects with the upper end surface of the clamp (13) and extends along the axis direction of the clamp (13). When the elastoplastic support column (30) is in the natural state, there is a set distance between the inner wall of the second steel strand through-hole (21) and the outer peripheral surface of the clamp (13). The clamp (13) has a first state of not clamping the steel strand (50) and a second state of clamping the steel strand (50). When the second anchor (20) moves towards the direction close to the first anchor (10) under the tensile force of the steel strand (50), the inner wall of the lower end of the second steel strand through-hole (21) can squeeze the outer peripheral wall of the clamp (13) and cause deformation so that the clamp (13) is converted from the first state to the second state. At this time, a self-locking fit can be formed between the outer peripheral surface of the frustum (22) and the tapered inner cavity (12).
2. The prestressed steel strand anchor as claimed in claim 1, wherein: The elastoplastic support column (30) is a concrete column.
3. A prestressed steel strand anchor as claimed in claim 1, wherein: The elastoplastic support columns (30) are arranged at equal intervals.
4. A prestressed steel strand anchor as claimed in claim 1, wherein: The upper surface of the first anchor (10) has an annular sunk platform structure, and a first card slot (14) corresponding to the lower end of the elastoplastic support column (30) one by one is arranged on the upper surface of the annular sunk platform structure. The lower surface of the second anchor (20) is provided with a second card slot (23) corresponding to the lower end of the elastoplastic support column (30) one by one.
5. A prestressed steel strand anchor as claimed in claim 1, wherein: The outer diameter of the end surface of the frustum (22) away from the lower surface of the second anchor (20) is larger than the inner diameter of the bottom end of the tapered inner cavity (12).
6. A prestressed steel strand anchor as claimed in claim 1, characterized in that: The first steel strand through-holes (11) are arranged at equal intervals.
7. A prestressed steel strand anchor as claimed in claim 1, wherein: The anchoring bolts (40) are arranged at equal intervals.
8. A prestressed steel strand anchor as claimed in claim 1, wherein: The deformation grooves are arranged at equal intervals along the circumferential direction of the clamp (13).
9. A prestressed steel strand anchor as claimed in any one of claims 1 to 8, characterized in that: The upper surface of the second anchor (20) is fitted with a top pressure cushion block (60). The top pressure cushion block (60) is provided with nut through holes (61) corresponding to the anchoring bolts (40) one by one and third steel strand through holes (62) corresponding to the second steel strand through holes (21) one by one.