Connector and method for connecting unbonded prestressed steel strands in post-cast strips

Abstract

The present invention provides a connector and method for connecting unbonded prestressed steel strands in a post-cast strip. The connector includes: a first anchor plate arranged on one side of the post-cast strip and applying a tensioning force in a first direction to the first end steel strand, the first anchor plate being fixedly connected to the first end steel strand in the post-cast strip; and a second anchor ring fixedly connected to the second end steel strand in the post-cast strip and applying a tensioning force in a second direction to the second end steel strand; the first anchor plate and the second anchor ring are fixedly connected to the connecting structure at both ends. The steel strand and the first anchor plate of the present invention are connected by a clip, and this structure has low requirements on the embedding accuracy of the steel strand in the length direction. The anchor plate is enclosed in a sleeve, is not affected by the pouring of concrete in the post-cast strip, and has high reliability. The anchor plate is fixed in the anchor plate hole, and the anchor plate is subjected to uniform force, so there is no bending in the prestressed steel strand, and the steel bar will not generate normal stress in the concrete.

Description

Technical Field

[0001] The invention relates to the fields of construction and civil engineering, and in particular to a connector and a method for connecting unbonded prestressed steel strands in a post-cast zone. Background Art

[0002] Existing common prestressed steel bar connectors, such as OVM's L15 connector, usually use a common anchor plate for the two sides of the steel bar to connect. In the existing connector structure, one side of the steel bar is anchored by a clip and inserted into the hole of the anchor plate; the other side of the steel bar uses an extrusion head to anchor the prestressed steel strand and clip it into the U-shaped groove of the anchor plate. After tensioning, the steel strand is placed in a protective cover and fixed by grouting.

[0003] The above connectors are usually only suitable for connecting bonded prestressed steel bars or steel bar bundles. When it is used to connect a single unbonded prestressed steel bar in a post-cast strip, since the prestressed steel bars connected on both sides of the connector have been buried in the concrete soil, there is little room for adjusting the steel bars, and the design of the common anchor plate cannot be adjusted at the prestressed connection. Therefore, the existing connector structure has a small degree of freedom, and it is troublesome to adjust the steel strands according to the design requirements for prestressing. When the anchor extrusion head set in the U-shaped groove connects the unbonded prestressed bars without secondary grouting, there is a problem that the cast strip concrete after pouring is easy to disturb the extrusion head, affecting its positioning. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a connector and method for connecting unbonded prestressed steel strands in a post-cast zone. The present invention specifically adopts the following technical solutions.

[0005] Firstly, in order to achieve the above-mentioned purpose, a connector for connecting unbonded prestressed steel strands in a post-cast zone is proposed, which comprises:

[0006] The first anchor plate is arranged on one side of the post-cast strip, and is fixedly connected to the first end steel strand in the post-cast strip, and applies a tensioning force in a first direction to the first end steel strand.

[0007] The second anchor ring is fixedly connected to the second end steel strand in the post-cast strip and applies a tensioning force in a second direction to the second end steel strand, wherein the second direction is opposite to the first direction.

[0008] The connecting structure has two ends fixedly connected to the first anchor plate and the second anchor ring respectively, and is used to maintain the tension in the first direction applied by the first anchor plate to the first end steel strand inside it, and to maintain the tension in the second direction applied by the second anchor ring to the second end steel strand inside it.

[0009] Optionally, in the above-mentioned connector for connecting unbonded prestressed steel strands in a post-cast strip, the connection structure includes:

[0010] A connecting sleeve has a first end fixedly connected to the outer periphery of the first anchor plate.

[0011] The two ends of the connector are respectively arranged inside the connector sleeve and inside the second anchor ring, and are respectively fixedly connected to the inner circumference of the connector sleeve and the second anchor ring.

[0012] Optionally, in the above-mentioned connector for connecting unbonded prestressed steel strands in post-cast strips, the first anchor plate is a single-hole working anchor plate.

[0013] The first end of the first anchor plate abuts against the side wall surface of the concrete structure on one side of the post-cast strip, and the outer peripheral surface of the second end is provided with an anchor plate external thread, and the second end of the first anchor plate is threadedly connected to the first end of the connecting sleeve.

[0014] Optionally, in the above-mentioned connector for connecting unbonded prestressed steel strands in a post-cast strip, the second anchor ring has an inner circumferential surface of the first end thereof provided with an anchor ring internal thread, and the first end of the second anchor ring is threadedly connected to the second end of the connector.

[0015] The outer peripheral surface of the first end of the connector is provided with a connector external thread, and the first end of the connector is threadedly connected to the second end of the connecting sleeve.

[0016] Optionally, in the above-mentioned connector for connecting unbonded prestressed steel strands in a post-cast strip, a fixing ring protruding outward is also provided in the middle of the connecting head, and two sides of the fixing ring respectively abut against the first end face of the second anchor ring and the second end face of the connecting sleeve.

[0017] Optionally, in the above-mentioned connector for connecting unbonded prestressed steel strands in a post-cast strip, the outer peripheral surfaces of the fixing ring and the second anchor ring are also respectively provided with columnar slots, and the columnar slots are used to install screw buckles to fix the connector.

[0018] Optionally, in the above-mentioned connector for connecting unbonded prestressed steel strands in a post-cast strip, a first clip is further provided in the first anchor plate, and the first clip abuts between the outer periphery of the first end steel strand and the mounting hole inside the first anchor plate.

[0019] A second clip is also provided in the second anchor ring, and the second clip abuts between the outer periphery of the second end steel strand and the mounting hole inside the second anchor ring.

[0020] Optionally, in the above-mentioned connector for connecting unbonded prestressed steel strands in the post-cast strip, a second-end steel strand accommodating cavity is formed between the second anchor ring and the connecting head, and a step is formed on the inner side of the connecting head at the first end of the second-end steel strand accommodating cavity, and a return spring is also arranged in the second-end steel strand accommodating cavity, and the first end of the return spring abuts against the step on the inner side of the connecting head, and the second end of the return spring abuts against the end of the second clip, so as to apply an extrusion force in a first direction to the second clip to fix the second-end steel strand.

[0021] At the same time, in order to achieve the above object, the present invention also provides a method for connecting unbonded prestressed steel strands in a post-cast strip, which comprises the following steps:

[0022] The first step is to, after the concrete strength on both sides of the post-cast strip meets the design requirements, abut the first anchor plate against the side wall surface of the concrete structure on one side of the post-cast strip, fix the first anchor plate to the outer periphery of the first end steel strand in the post-cast strip, prestress the first end steel strand according to the design requirements, and set a first clip between the first anchor plate and the first end steel strand to anchor the first end steel strand.

[0023] The second step is to perform anti-corrosion treatment on the structure, and then install a connecting sleeve on the outer side of the first anchor plate.

[0024] The third step is to fix the second anchor ring to the outer periphery of the second end steel strand in the post-cast strip, and to arrange a second clip between the second anchor ring and the second end steel strand to anchor the second end steel strand.

[0025] The fourth step is to insert the return spring between the second clip and the connector, screw the two ends of the connector into the connecting sleeve and the second anchor ring respectively, and tighten the return spring.

[0026] The fifth step is to seal the post-cast joint concrete. After the concrete strength of the post-cast joint meets the design requirements, prestress and anchor the far end of the second end steel strand according to the design requirements.

[0027] Optionally, in the above-mentioned method for connecting unbonded prestressed steel strands in a post-cast strip, in the first step, before fixing the first anchor plate to the periphery of the first end steel strand in the post-cast strip, the following steps are also included: removing the 50 mm long plastic sheath at the end of the first end steel strand and cleaning the grease.

[0028] Beneficial effects:

[0029] The present invention provides a connector and method for connecting unbonded prestressed steel strands in a post-cast strip. The connector includes: a first anchor plate arranged on one side of the post-cast strip and applying a tensioning force in a first direction to the first end steel strand, the first anchor plate being fixedly connected to the first end steel strand in the post-cast strip; and a second anchor ring being fixedly connected to the second end steel strand in the post-cast strip and applying a tensioning force in a second direction to the second end steel strand. The connector also includes a connecting structure, the two ends of which are fixedly connected to the first anchor plate and the second anchor ring, respectively. The steel strand and the first anchor plate of the present invention are connected by a clip, and this structure has low requirements on the embedding accuracy of the steel strand in the length direction. The anchor plate of the present invention can be enclosed in a sleeve, is not disturbed by the pouring of concrete in the post-cast strip, and has high reliability. The anchor plate is fixed in the anchor plate hole, and the anchor plate is subjected to uniform force, so there is no bending in the prestressed steel strand, and the steel bar will not generate normal stress in the concrete.

[0030] Preferably, the present invention adopts a screw buckle method to fix the anchor ring and a sleeve-type connection structure connected between the anchor ring and the anchor plate, which can be used in the post-casting strip to achieve non-bonded steel strand connection, can meet the requirements of the design tensioning sequence, and also has the advantages of high reliability and convenient construction. Although other connection methods such as welding or flanges can also be used to connect the anchor plate, they are not as clear as the present invention in terms of force, simple construction, safety and reliability.

[0031] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 is a schematic diagram of the structure of the present invention under a force acting in a first direction;

[0034] Figure 2 is a schematic diagram of the structure of the present invention under the force in the second direction;

[0035] In the figure, 1 represents the first anchor plate; 21 represents the first clip; 22 represents the second clip; 3 represents the connecting sleeve; 4 represents the connecting head; 5 represents the return spring; 6 represents the second anchor ring; 71 represents the first end steel strand; 72 represents the second end steel strand; and 8 represents the columnar slot. DETAILED DESCRIPTION

[0036] In order to make the purpose and technical solution of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the field to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0038] The meaning of "and / or" in the present invention means that both the cases where each exists alone or both exist at the same time are included.

[0039] The meaning of “inside” and “outside” in the present invention refers to the direction pointing to the inside of the connector as inside, and the opposite direction as outside, relative to the connector itself; it is not a specific limitation on the device mechanism of the present invention.

[0040] The term “connection” as used in the present invention may mean a direct connection between components or an indirect connection between components via other components.

[0041] The “first direction” mentioned in the present invention refers to the direction from the first end steel strand to the second end steel strand, and the second direction is opposite to the first direction.

[0042] A connector for connecting unbonded prestressed steel strands in a post-cast zone, comprising:

[0043] The first anchor plate 1, such as Figure 1As shown, it is arranged on one side of the post-cast strip, and the anchor plate 1 is fixedly connected to the first end steel strand 71 in the post-cast strip, and applies a tensioning force in the first direction to the first end steel strand. The first anchor plate 1 can specifically adopt a single-hole working anchor plate, the first end of which abuts against the side wall surface of the concrete structure on one side of the post-cast strip, and the outer peripheral surface of the second end is provided with an anchor plate external thread, and the second end of the first anchor plate 1 is threadedly connected with the first end of the connecting sleeve 3. A first clamp 21 is also provided inside the first anchor plate 1, and the first clamp abuts between the outer periphery of the first end steel strand 71 and the mounting hole inside the first anchor plate 1. Under the action of the friction and tension of the first end steel strand 71, the first clamp is tightly matched with the first end steel strand 71 and the first anchor plate 1, so as to realize the fixed connection between the anchor plate 1 and the first end steel strand 71, and provide a more reliable tensioning force in the first direction for the first end steel strand 71.

[0044] The second anchor ring 6, such as Figure 2 As shown, it is fixedly connected with the second end steel strand 72 in the post-cast strip, and applies a tensioning force in a second direction to the second end steel strand, and the second direction is opposite to the first direction. Specifically, the inner circumferential surface of the first end of the second anchor ring 6 is provided with an anchor ring internal thread, and the first end of the second anchor ring 6 is threadedly connected with the second end of the connector 4. A second clip 22 is also provided inside the second anchor ring 6, and the second clip abuts between the outer circumference of the second end steel strand 72 and the mounting hole inside the second anchor ring 6. Under the action of the friction and tension of the second end steel strand 72, the second clip is tightly matched with the second end steel strand 72 and the second anchor ring 6, so as to realize the fixed connection between the second anchor ring 6 and the second end steel strand 72, and provide a more reliable tensioning force in the second direction for the second end steel strand 72.

[0045] The connection structure, whose two ends are respectively fixedly connected to the first anchor plate 1 and the second anchor ring 6, is used to maintain the tension in the first direction applied by the first anchor plate 1 to the first end steel strand 71 inside it, and to maintain the tension in the second direction applied by the second anchor ring 6 to the second end steel strand 72 inside it. Wherein, the connection structure includes: a connection sleeve 3, whose first end is fixedly connected to the outer periphery of the first anchor plate 1. The connection structure also includes: a connector 4, whose two ends are respectively arranged inside the connection sleeve 3 and inside the second anchor ring 6, and are respectively fixedly connected to the inner peripheries of the connection sleeve 3 and the second anchor ring 6. The connector 4 can be specifically provided with connector external threads on the outer peripheral surfaces of the first end and the second end thereof, so as to realize threaded connection with the second end of the connection sleeve 3 and the first end of the second anchor ring 6, respectively.

[0046] A fixing ring protruding outward may be further provided in the middle of the connector 4, and the two sides of the fixing ring respectively abut against the first end surface of the second anchor ring 6 and the second end surface of the connecting sleeve 3. The outer peripheral surfaces of the fixing ring and the second anchor ring 6 are also respectively provided with columnar slots 8, and the columnar slots 8 are used to install screw buckles to fix the connector.

[0047] A second-end steel strand accommodating cavity is formed between the second anchor ring 6 and the connector 4, and a step is formed on the inner side of the connector 4 at the first end of the second-end steel strand accommodating cavity to form a stepped hole. A return spring 5 is also arranged in the second-end steel strand accommodating cavity, and the first end of the return spring 5 abuts against the step on the inner side of the connector 4, and the second end of the return spring 5 abuts against the end of the second clamp 22, so as to apply a first-direction extrusion force to the second clamp 22 to fix the second-end steel strand 72.

[0048] The present invention provides a connector for connecting non-bonded prestressed steel strands in a post-cast zone, such as Figure 1 Figure 2 As shown, the main components include: a single-hole working anchor plate with external threads, a connecting sleeve 3 with internal threads on both sides, a connecting head 4 with external threads on both sides, a second anchor ring 6 with internal threads, a second clip 22 matched with the second anchor ring, a first clip 21 matched with the first anchor plate 1, and a return spring 5. The first anchor plate, the second anchor ring, and the connecting sleeve are all rotating bodies, and columnar slots are also provided around the second anchor ring and the connecting head to facilitate the fixing of the clamp when installing the screw buckle.

[0049] In order to cooperate with the connector proposed in the present application, a method for connecting unbonded prestressed steel strands in a post-cast strip is also disclosed, comprising the following steps:

[0050] Preparatory steps: Before installation, the anchor system needs to be subjected to a destructive test in accordance with the specifications, and attention should be paid to reserving an appropriate length in the post-cast zone when pre-embedded unbonded prestressed steel bars.

[0051] The first step is to remove the 50mm long plastic sheath at the end of the first end steel strand 71 and clean the grease after the concrete strength on both sides of the post-cast strip meets the design requirements. Then the first anchor plate 1 can be abutted against the side wall surface of the concrete structure on one side of the post-cast strip, and the first anchor plate 1 can be fixed to the periphery of the first end steel strand 71 in the post-cast strip. The first end steel strand 71 is prestressed according to the design requirements, and a first clamp 21 is set between the first anchor plate 1 and the first end steel strand 71 to anchor the first end steel strand 71.

[0052] In the second step, the above structure is subjected to anti-corrosion treatment. Epoxy-coated prestressed steel strands may be used. In order to increase the bonding strength between the epoxy coating and concrete, sand particles may be embedded in the coating surface when the product is manufactured. Then, a connecting sleeve 3 is installed on the outer side of the first anchor plate 1.

[0053] The third step is to fix the second anchor ring 6 to the outer periphery of the second end steel strand 72 in the post-cast strip, and to arrange the second clamping piece 22 between the second anchor ring 6 and the second end steel strand 72 to anchor the second end steel strand 72 .

[0054] The fourth step is to insert the return spring 5 between the second clip 22 and the connector 4, screw the two ends of the connector 4 into the connecting sleeve 3 and the second anchor ring 6 respectively, and press the return spring 5. After the connection is completed, connect the return spring 5 to press the second clip 22. Because the second end steel strand 72 does not have a pulling force in the first direction at this time, the second clip 22 cannot rely on itself to provide enough pressure to fix the second end steel strand 72, so the return spring 5 is relied on to apply a squeezing force in the first direction to the second clip 22 to fix the second end steel strand 72.

[0055] The fifth step is to seal the post-casting strip concrete. After the post-casting strip concrete strength meets the design requirements, the far end of the second end steel strand 72 is prestressed and anchored according to the design requirements. At this time, the connector provides a tensioning force in the first direction to the first end steel strand 71 and also provides a tensioning force in the second direction to the second end steel strand 72. The far end here refers to the end of the second end steel strand 72 that is not fixed.

[0056] Therefore, the present invention respectively sets anchor plates and anchor rings for the ends of the steel strands that need to be connected, and uses screw buckles to fix the anchor rings and the connection structure between them and the anchor plates. Such a fixing method can facilitate the construction according to the requirements of the design tensioning sequence, and has the characteristics of high reliability and convenient construction. This structure also has relatively low requirements for the embedding accuracy of the steel strands in the length direction. In addition, since the anchor plate and the connection structure of the present invention are both enclosed in the sleeve and are not affected by the pouring of the post-casting zone concrete, the connector provided by the present invention has high reliability. The anchor plate is fixed in the anchor plate hole, and the anchor plate is subjected to uniform and clear force, so there is no bending in the prestressed steel strand, and no normal stress is generated in the concrete.

[0057] The above is only an embodiment of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for connecting unbonded prestressed steel strands in a post-cast zone, characterized in that: A connector for connecting unbonded prestressed steel strands in a post-cast strip of the following structure, the connector for connecting unbonded prestressed steel strands in a post-cast strip comprising: A first anchor plate (1) is arranged on one side of the post-cast strip, the first anchor plate (1) being fixedly connected to a first end steel strand (71) in the post-cast strip and applying a tensioning force in a first direction to the first end steel strand; A second anchor ring (6) is fixedly connected to the second end steel strand (72) in the post-cast strip and applies a tensioning force in a second direction to the second end steel strand, the second direction being opposite to the first direction; A connecting structure, comprising: a connecting sleeve (3), a first end of which is fixedly connected to the outer periphery of the first anchor plate (1); A connecting head (4), two ends of which are respectively arranged inside the connecting sleeve (3) and inside the second anchor ring (6), and are respectively fixedly connected to the inner circumference of the connecting sleeve (3) and the second anchor ring (6); The method comprises the following steps: The first step is to, after the concrete strength on both sides of the post-cast strip meets the design requirements, place the first anchor plate (1) against the surface of the concrete structure side wall on one side of the post-cast strip, fix the first anchor plate (1) to the periphery of the first end steel strand (71) in the post-cast strip, perform prestress tensioning on the first end steel strand (71) according to the design requirements, and arrange a first clamping piece (21) between the first anchor plate (1) and the first end steel strand (71) to anchor the first end steel strand (71); The second step is to perform anti-corrosion treatment on the structure, and then install a connecting sleeve (3) on the outer side of the first anchor plate (1); The third step is to fix the second anchor ring (6) to the outer periphery of the second end steel strand (72) in the post-cast strip, and to arrange a second clamping piece (22) between the second anchor ring (6) and the second end steel strand (72) to anchor the second end steel strand (72); The fourth step is to insert the return spring (5) between the second clamp (22) and the connector (4), screw the two ends of the connector (4) into the connecting sleeve (3) and the second anchor ring (6) respectively, and tighten the return spring (5); The fifth step is to seal the post-casting strip concrete. After the post-casting strip concrete strength meets the design requirements, the far end of the second end steel strand (72) is prestressed and anchored according to the design requirements.

2. The method for connecting unbonded prestressed steel strands in a post-cast zone according to claim 1, characterized in that: In the first step, before the first anchor plate (1) is fixed to the outer periphery of the first end steel strand (71) in the post-cast strip, the following steps are also included: Remove the 50mm long plastic sheath from the end of the first strand (71) and clean off the grease.

3. The method for connecting unbonded prestressed steel strands in a post-cast zone according to claim 1, characterized in that: In the connector for connecting unbonded prestressed steel strands in a post-cast strip, the first anchor plate (1) is a single-hole working anchor plate, the first end of which abuts against the side wall surface of the concrete structure on one side of the post-cast strip, the outer peripheral surface of the second end of which is provided with an anchor plate external thread, and the second end of the first anchor plate (1) is threadedly connected to the first end of the connecting sleeve (3).

4. The method for connecting unbonded prestressed steel strands in a post-cast zone according to claim 3, characterized in that The connector for connecting unbonded prestressed steel strands in a post-cast strip, wherein the inner circumferential surface of the first end of the second anchor ring (6) is provided with an anchor ring internal thread, and the first end of the second anchor ring (6) is threadedly connected to the second end of the connector (4); The outer peripheral surface of the first end of the connecting head (4) is provided with a connecting head external thread, and the first end of the connecting head (4) is threadedly connected to the second end of the connecting sleeve (3).

5. The method for connecting unbonded prestressed steel strands in a post-cast zone according to claim 1, characterized in that: The connector for connecting unbonded prestressed steel strands in a post-cast strip is provided with a fixing ring protruding outward in the middle of the connecting head (4), and the two sides of the fixing ring are respectively abutted against the second anchor ring (6). and a first end surface of the connecting sleeve (3).

6. The method for connecting unbonded prestressed steel strands in a post-cast zone according to claim 5, characterized in that: The connector for connecting unbonded prestressed steel strands in a post-cast zone, wherein the outer peripheral surfaces of the fixing ring and the second anchor ring (6) are respectively provided with columnar slots (8), wherein the columnar slots (8) are Used to install screw buckles to fix the connector.

7. The method for connecting unbonded prestressed steel strands in a post-cast zone according to claim 1, characterized in that: The connector for connecting unbonded prestressed steel strands in a post-cast strip further comprises a first clip (21) disposed in the first anchor plate (1), the first clip abutting against the outer surface of the first end steel strand (71). Between the periphery and the mounting hole inside the first anchor plate (1); A second clamping piece (22) is also provided inside the second anchor ring (6), and the second clamping piece abuts between the outer periphery of the second end steel strand (72) and the mounting hole inside the second anchor ring (6).

8. The method for connecting unbonded prestressed steel strands in a post-cast zone according to claim 1, characterized in that: The connector for connecting unbonded prestressed steel strands in a post-cast strip has a second-end steel strand accommodating cavity formed between the second anchor ring (6) and the connector (4), a step is formed on the inner side of the connector (4) at the first end of the second-end steel strand accommodating cavity, and a return spring (5) is provided in the second-end steel strand accommodating cavity, the first end of the return spring (5) abuts against the step on the inner side of the connector (4), and the second end of the return spring (5) abuts against the end of the second clamp (22), so as to apply a first-direction extrusion force to the second clamp (22) to fix the second-end steel strand (72).

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