Assembly for two-stage transverse tensioning method prestress tensioning

Abstract

The utility model relates to the technical field of civil engineering, in particular to an assembly used for two-stage transverse tensioning method prestress tensioning, which comprises two anchoring parts respectively arranged at two ends of two prestress tendons arranged along the main extension direction of a fixed beam, and one sides, close to the fixed beam, of the two anchoring parts are abutted against the side surface of the fixed beam; the two steering parts are arranged between the fixed beam and the two prestressed tendons and are configured to change the extension directions of the two prestressed tendons; and the tensioning pieces are arranged on the two prestressed tendons and are configured to fix the positions of the two prestressed tendons on the fixed beam. Based on the idea of a traditional transverse tensioning method, the two-stage transverse tensioning method technology is provided, the corresponding tensioning device is designed, the problem that the traditional transverse tensioning method is low in tensioning efficiency is solved, and a new idea is provided for application of the external prestressing technology.

Description

Technical Field

[0001] This utility model relates to the field of civil engineering technology, and more specifically, to a combination component for two-stage transverse tensioning of prestressed concrete. Background Technology

[0002] While traditional external prestressing eliminates the need for grouting in the ducts, greatly improving construction convenience, this process requires tensioning equipment to be installed at both ends of the beam. However, in reality, conditions for installing tensioning equipment are often lacking, thus limiting the application of traditional external prestressing technology. Utility Model Content

[0003] Based on the traditional transverse tensioning method, this invention proposes a two-stage transverse tensioning technique and designs a corresponding tensioning device, which solves the problem of low tensioning efficiency in the traditional transverse tensioning method and provides a new approach for the application of external prestressing technology.

[0004] To achieve the above objectives, this utility model is implemented through the following solution:

[0005] An assembly for two-stage transverse prestressing tensioning includes:

[0006] Two anchors are respectively installed at both ends of two prestressed tendons arranged along the main extension direction of the fixed beam, and the two anchors abut against the side of the fixed beam on the side closest to the fixed beam.

[0007] Two steering components, disposed between the fixed beam and the two prestressing tendons, are configured to change the extension direction of the two prestressing tendons;

[0008] Tensioning members, disposed on the two prestressing tendons, are configured to fix the positions of the two prestressing tendons on the fixed beam.

[0009] In a preferred embodiment, the steering component includes a first steel plate, the upper surface of which has a raised steel column, the steel column being semi-circular.

[0010] In a preferred embodiment, the steel column is welded to the first steel plate or is integral with the first steel plate.

[0011] In a preferred embodiment, the anchor includes a second steel plate, on which two wedge-type anchors are mounted, and the second steel plate has through holes communicating with the wedge-type anchors.

[0012] In the preferred embodiment, each of the clamp-type anchors is equipped with a through-hole sensor.

[0013] In a preferred embodiment, the tensioning member includes two external tensioning bolt assemblies and an internal shrinking bolt assembly. The external tensioning bolt assembly includes two first perforated plates, each with two first bolts vertically inserted through it. The two first perforated plates are arranged opposite each other, with the tails of the first bolts on different first perforated plates facing each other. The two pairs of first bolts with their tails facing each other are connected by a first threaded connector. Each first bolt has a first nut installed on the side of the two first perforated plates that is close to each other. The internal shrinking bolt assembly includes two second perforated plates, each with two second bolts vertically inserted through it. The two second perforated plates are arranged opposite each other, with the tails of the second bolts on different second perforated plates facing each other. The two pairs of second bolts with their tails facing each other are connected by a second threaded connector. Each second bolt has a second nut installed on the side of the two second perforated plates that is far apart from each other. The internal shrinking bolt assembly is positioned between the two external tensioning bolt assemblies. Each first perforated plate is located between two prestressing tendons and abuts against the prestressing tendons. Each second perforated plate abuts against the prestressing tendons on the side of the prestressing tendons that is far apart from each other.

[0014] In the preferred embodiment, the first and second perforated plates are steel plates, the first and second bolts are M10 bolts, and the first and second threaded joints are M10 internal thread joints.

[0015] In the preferred embodiment, the thickness of the second steel plate is ≥15mm, the thickness of the first steel plate is ≥10mm, the thickness of the first perforated plate is ≥6mm, and the thickness of the second perforated plate is ≥6mm.

[0016] In a preferred embodiment, the spacing between the two external tension bolt assemblies is 200–400 mm.

[0017] The beneficial effects of this utility model are:

[0018] The tensioning of the assembly provided by this utility model does not require mechanical jacks or other equipment; tensioning can be completed by manpower alone, making construction convenient and cost-effective.

[0019] This invention can effectively improve the ultimate bearing capacity of reinforced beams, and experimental studies have shown that the reinforced beams retain good ductility, making it an effective reinforcement method.

[0020] This invention provides reasonable structural requirements for reinforcement through experiments, offering theoretical support for practical applications. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the prestressed structure rotation mechanism and anchor before reinforcement of this utility model;

[0022] Figure 2 This is a schematic diagram showing the prestressed structure anchor reaching the set position of this utility model;

[0023] Figure 3 This is a schematic diagram of the final state of the prestressed structure after reinforcement according to this utility model;

[0024] Figure 4 This is a schematic diagram of the anchor of this utility model;

[0025] Figure 5 This is a schematic diagram of the external tension bolt assembly of this utility model;

[0026] Figure 6 This is a schematic diagram of the internal retraction bolt assembly of this utility model;

[0027] Figure 7 This is a schematic diagram of the steering component of this utility model;

[0028] Figure 8 This is a schematic diagram of the dimensions of the test beam and the arrangement of the measuring points of this utility model;

[0029] Figure 9 This is a load-deflection curve of the test beam of this utility model.

[0030] In the diagram, 1 is the steering component; 2 is the anchor; 3 is the tensioning component; 4 is the through-hole sensor; 5 is the prestressed tendon; 6 is the fixed beam; 7 is the strain gauge; 8 is the displacement gauge; 11 is the first steel plate; 12 is the steel column; 21 is the second steel plate; 22 is the wedge-type anchor; 31 is the external tension bolt assembly; 32 is the internal tension bolt assembly; 311 is the first perforated plate; 312 is the first bolt; 313 is the first threaded joint; 314 is the first nut; 321 is the second perforated plate; 322 is the second bolt; 323 is the second threaded joint; and 324 is the second nut. Detailed Implementation

[0031] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0033] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0034] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0035] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0036] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0037] like Figure 4-7 As shown, a combination component for two-stage transverse prestressing tensioning consists of three parts: a steering component 1, a tensioning component 3, and an anchor component 2. There are two steering components, one tensioning component 3, and two anchor components 2.

[0038] The steering component 1 includes two parts: a first steel plate 11 and a steel column 12. The steel column 12 is semi-cylindrical and is arranged along the centerline of the length or width of the first steel plate 11. The steel column 12 is welded to the first steel plate 11 or is integral with the first steel plate 11.

[0039] The tensioning member 3 includes two external tensioning bolt assemblies 31 and one internal tensioning bolt assembly 32. The external tensioning bolt assembly 31 consists of two first perforated plates 311, four first bolts 312, two first threaded connectors 313, and four first nuts. The tails of each pair of first bolts 312 are opposite each other and connected by the first threaded connectors 313. Each first perforated plate 311 has two first bolt through holes on its surface perpendicular to the plate surface. The four first bolts 312 are connected to the first perforated plate 311 through the first bolt through holes. On the side of the two first perforated plates 311 that are close to each other, a first nut 314 is installed on each first bolt 312.

[0040] The internal bolt assembly 32 consists of two second perforated plates 321, four second bolts 322, two second threaded connectors 323, and four second nuts. The tails of each pair of second bolts 322 are opposite each other and connected by the second threaded connectors 323. Each second perforated plate 321 has two second bolt through holes on its surface perpendicular to the plate surface. The four second bolts 322 are connected to the second perforated plate 321 through the second bolt through holes. On the side of the two second perforated plates 321 that are far apart from each other, a second nut 324 is installed on each second bolt 322.

[0041] A two-section transverse prestressed tensioning structure with the above-mentioned assembly includes the above-mentioned assembly, a fixed beam 6, and two prestressing tendons 5.

[0042] Two steering components 1 are located on the fixed beam 6. The steel columns 12 of the two steering components 1 are parallel to the centerline of the fixed beam 6 in the length direction and are symmetrically arranged about the centerline of the fixed beam 6 in the length direction. Two anchors 2 are located on the two sides of the fixed beam 6 respectively. The second steel plate 21 of the two anchors 2 at least partially abuts against the two sides of the fixed beam 6 on the side wall away from the wedge-type anchor 22.

[0043] Two prestressing tendons 5 are located above the fixed beam 6. One end of each prestressing tendon 5 is inserted into a wedge-type anchor 22 of an anchor 2. The body portion of the two prestressing tendons 5 extends along the length of the fixed beam 6 until the other end of the two prestressing tendons 5 is inserted into a wedge-type anchor 22 of another anchor 2. The body portion of the two prestressing tendons 5 extending above the two deflecting members 1 abuts against the steel column 22. The two deflecting members 1 are configured to change the extension direction of the two prestressing tendons 5.

[0044] Tensioning member 3 is disposed between two prestressing tendons 5. An external tensioning bolt assembly 31 is disposed on one side of each of the two turning members 1. The two external tensioning bolt assemblies 31 are respectively arranged on the side of the two turning members 1 that are close to each other. The first perforated plate 311 on the same external tensioning bolt assembly 31 is located between the two prestressing tendons 5 and abuts against the prestressing tendons 5. The abutment between the prestressing tendon 5 and the first perforated plate 311 is located between the two first bolts 312 on the same first perforated plate 311. The inward bolt assembly 32 is disposed above the middle position of the fixed beam 6. The second perforated plate 321 on the inward bolt assembly 32 is located on the side of the two prestressing tendons 5 that are far from each other and abuts against the prestressing tendon 5. The abutment between the prestressing tendon 5 and the second perforated plate 321 is located between the two second bolts 322 on the same second perforated plate 321.

[0045] To ensure the strength and stiffness requirements of the prestressed structure, the thickness of the second steel plate must be at least 15mm, the thickness of the first steel plate at least 10mm, and the thickness of the first and second perforated plates at least 6mm. In actual engineering projects, the external tensioning bolt assemblies can be arranged at a distance of l / 5-l / 6 from the mid-span section of the fixed beam, where l is the beam length. According to the "Technical Specification for Unbonded Prestressed Concrete Structures (JGJ 92-2016)," the bending angle of the prestressing tendons should not exceed 15°.

[0046] Each clip-type anchor 22 is equipped with a through-hole sensor 4.

[0047] The steering component 1 is made of Q235 steel and is welded from a square first steel plate 11 and a semi-circular steel column 12. The tensioning component 3 consists of an inward-shrinking bolt assembly 32 located at the mid-span of the fixed beam 6 and an outward-shrinking bolt assembly 31 located near the beam end. It mainly consists of four M10 bolts, an M10 internal threaded connector, and two perforated steel plates. During the test, the nuts are tightened with a wrench to generate inward shrinkage force and outward tension, thereby achieving the lateral tensioning effect. The anchor 2 consists of a second steel plate 21 and two sets of wedge-type anchors 22 to ensure that the steel strands do not slip during the tensioning process.

[0048] This utility model verifies the reasonable structural requirements for reinforcement through experiments. After fixing the assembly in the designated position by hammering the anchors 2 at both ends, as shown... Figure 1-2 As shown. Special bolt components are used, and tightening a wrench forces the prestressing tendons to deform, thereby achieving the effect of applying prestress. The bolt components are divided into two types: an inward-retracting bolt assembly 32 at the mid-span of the beam and an outward-tensioning bolt assembly 31 spaced at equal intervals from the span, as shown... Figure 3 As shown. The reinforcement is completed once the designed inward and outward contractions are achieved.

[0049] To verify the rationality of the invention, this utility model uses four ordinary reinforced concrete beams as test objects. One beam (RC1-0-0) serves as a control group without reinforcement using this device, while the other three are reinforced beams. The cross-sectional dimensions are 105mm × 205mm, and the length is 1.2m. Each test beam has two 10mm diameter reinforcing bars at the bottom and top, with stirrups of φ8mm@80mm. The concrete cover thickness is 15mm. The experiment investigates the effect of the spacing of three different external tension bolt assemblies 31 on the beam reinforcement effect. During the experiment, displacement sensors were used to collect deflection at mid-span and turning points, resistance strain gauges were used to collect strain in the tensile reinforcement, and a through-hole sensor was used to collect the stress increment in the prestressed reinforcement.

[0050] like Figure 8 The diagram shows the dimensions of the test beam and the arrangement of the measuring points for this invention. The test uses a four-point loading method, with the loading points located at the third-third points of the beam. The span is 1100 mm, and the shear span ratio is 1.93. The loading scheme is as follows: Figure 8 As shown in the figure. Force-controlled loading was used in the experiment. The loading rate before cracking was 20 N / s, and after cracking, it was 40 N / s. To observe crack propagation, a graded loading method was adopted, with each grade loading for 4 minutes and held for 5 minutes. After the reinforcement yielded, loading was applied at a rate of 50 N / s until the specimen failed.

[0051] The main observations include:

[0052] 1) Crack development trend and number of main cracks;

[0053] 2) Special changes in the beam and external prestressing tendons under each load level (e.g., whether the steel strands experience local necking, whether the present invention undergoes significant deformation during the test, etc.).

[0054] The experimental results show that, as defined in this paper, the mid-span deflection at the beginning of beam yielding is the yield displacement Δ. y The mid-span deflection corresponding to the maximum load is the maximum displacement Δ. max The ductility coefficient is Δ y / Δ maxThe results are shown in Table 1. The ductility coefficient of the unreinforced beam is 4.4. The ductility index of the reinforced beam with an external tension bolt assembly spacing of 200mm is 3.0, and the increase in ultimate load is the largest compared to the unreinforced beam, reaching 260%. This is related to the fact that the bolt assembly is closer to the mid-span section, allowing for a higher rate of stress increment. After the reinforcement yields, the beam deflection increases rapidly, and the higher increase in stress increment can steadily improve the beam's bearing capacity. In the reinforced beam with an external tension bolt assembly spacing of 300mm, the ductility index is 5.0. Before failure, the mid-span deflection increases sharply, showing obvious signs of failure. This is because after the reinforcement yields, the beam deflection increases rapidly, and the stress increment of the prestressed tendons in the reinforced beam begins to increase rapidly. At this time, the height of the compression zone continuously decreases. After the concrete in the compression zone enters the plastic stage, the concrete in the compression zone is crushed, leading to beam failure, which exhibits good ductility. The ultimate load improvement effect of the reinforced beam with an external tension bolt assembly spacing of 400mm is 230%, and its ductility index is 4.3. It can be seen that by appropriately increasing the spacing of the external tension bolt assembly 31, the ductility of the beam can be effectively improved without reducing the ultimate bearing capacity of the beam too much. The test results are shown in Table 1.

[0055] Table 1. Test Results and Failure Modes

[0056]

[0057] Note:

[0058] P cr P v and P max These are the cracking load, yield load, and ultimate load, respectively; α cr α y and α max To enhance the lifting effect of the reinforced beam compared to ordinary reinforced concrete beams; Δ v Δ max These are the mid-span deflections under yield load and ultimate load, respectively. For ductility index

[0059] The assembly provided by this utility model can effectively improve the ultimate bearing capacity of reinforced concrete beams, and the reinforced beam retains good ductility. The load-deflection diagram of the beam is shown below. Figure 9 As shown. To verify the practicality of the invention, this experiment was designed to test the beam by changing the spacing of the external tension bolt assembly 31 in the tensioning member 3. The spacing was set to 200mm (ERC2-200), 300mm (ERC3-300), and 400mm (ERC4-400). The test results show that the beam reinforcement effect is optimal in the group with a spacing of 300mm.

[0060] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the scope of the technology disclosed in the present utility model, based on the technical solution and inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An assembly for two-stage prestressed tensioning by the cross- stretching method, installed on a fixed beam (6), characterized in that, The utility model relates to a prestressed tendon (5) has two, two anchor (2) are installed respectively in two prestressed tendon (5) both ends along the main extension direction of fixed beam (6) are arranged, and two anchor (2) are close to the side of fixed beam (6) and the side of fixed beam (6) is abutted, two deflection piece (1) are arranged between fixed beam (6) and two prestressed tendon (5), are configured as the extension direction of two prestressed tendon (5) is changed, tensioning piece (3) are arranged on two prestressed tendon (5), are configured as two prestressed tendon (5) are fixed in the position of fixed beam (6). The deflection piece (1) includes a first steel plate (11), and an upper surface of the first steel plate (11) has a protruding steel column (12) in a semicircular shape. The steel column (12) is welded to the first steel plate (11) or integrated with the first steel plate (11). The anchor (2) includes a second steel plate (21), and two clip-type anchorage devices (22) are mounted on the second steel plate (21), and the second steel plate (21) is provided with through holes in communication with the clip-type anchorage devices (22). Each clip-type anchorage device (22) is mounted with a through sensor (4).

2. The assembly for two-stage cross stretching method of prestress tensioning according to claim 1, characterized in that, The tensioning piece (3) includes two outer tension bolt assemblies (31) and an inner retraction bolt assembly (32). The outer tension bolt assembly (31) includes two first punching plates (311), each of which is vertically provided with two first bolts (312). The two first punching plates (311) are oppositely arranged, and the first bolts (312) on different first punching plates (311) are oppositely arranged. Two pairs of first bolts (312) are connected by a first threaded joint (313). Each first bolt (312) is mounted with a first nut (314) on one side of the two first punching plates (311) that are close to each other. The inner retraction bolt assembly (32) includes two second punching plates (321), each of which is vertically provided with two second bolts (322). The two second punching plates (321) are oppositely arranged, and the second bolts (322) on different second punching plates (321) are oppositely arranged. Two pairs of second bolts (322) are connected by a second threaded joint (323). Each second bolt (322) is mounted with a second nut (324) on one side of the two second punching plates (321) that are away from each other. The inner retraction bolt assembly (32) is arranged between the two outer tension bolt assemblies (31). Each first punching plate (311) is located between the two prestressed tendons (5) and abuts against the prestressed tendons (5). Each second punching plate (321) is located on one side of the prestressed tendons (5) that are away from each other and abuts against the prestressed tendons (5).

3. The assembly for two-stage cross-section method prestressed tensioning according to claim 2, characterized in that, ​ 4. The assembly for two-stage cross-section method prestressed tensioning according to claim 3, characterized in that, ​ 5. The assembly for two-stage cross-section method prestressed tensioning according to claim 4, characterized in that, ​ 6. The assembly for two-stage cross stretching method of prestress tensioning according to claim 5, wherein, ​ 7. The assembly for two-stage cross-anchorage method of prestressed tensioning as claimed in claim 6, wherein, The first punching plate (311) and the second punching plate (321) are steel plates, the first bolt (312) and the second bolt (322) are M10 bolts, and the first threaded joint (313) and the second threaded joint (323) are M10 internal threaded joints.

8. The assembly for two-stage cross stretching of the prestressed tension according to claim 6, characterized in that, The thickness of the second steel plate (21) is greater than or equal to 15 mm, the thickness of the first steel plate (11) is greater than or equal to 10 mm, the thickness of the first punching plate (311) is greater than or equal to 6 mm, and the thickness of the second punching plate (321) is greater than or equal to 6 mm.

9. The assembly for two-stage cross stretching of the prestressed tension according to claim 6 or 7, characterized in that, The distance between the two outer bolt assemblies (31) is 200-400 mm.

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