A non-retractable anchor for post-tensioned prestressed steel strand and a method of using the same

Abstract

The present invention relates to a non-retractable anchor for post-tensioned prestressed steel strands and a method for using the same. The anchor can eliminate the prestress loss caused by the retraction of the clip, and can greatly improve the prestress effect of the prestressed steel strand with a shorter length. The anchor of the present invention can solve the problem of excessive prestress loss when the prestressed steel strand with a shorter length is anchored by the clip anchor.

Description

Technical Field

[0001] The invention relates to the field of civil engineering, and in particular to a non-retractable anchor for post-tensioned prestressed steel strands and a use method thereof. Background Art

[0002] At present, the anchoring of post-tensioned prestressed steel strands mainly adopts clip anchors, and its construction sequence is mainly: use jacks to tension the steel strands to control the stress, then the retraction of the steel strands drives the clips into the anchor plate, and finally the clips clamp and anchor the steel strands. The use of this anchoring method will inevitably cause prestress loss caused by the retraction of the clips. Since the retraction deformation value at the anchor is approximately a fixed value, it is generally believed that it is 4mm when there is top pressure and 6mm when there is no top pressure. For short lengths of steel strands, the retraction strain caused by this fixed retraction value will be considerable, resulting in a large loss of prestress. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a non-retraction anchor for post-tensioned prestressed steel strands.

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] A non-retractable anchor for post-tensioned prestressed steel strands, characterized in that the anchor comprises an anchor plate, an inner thread is provided on the inner side of one end of the anchor plate, an outer thread is provided on the outer side, a clip hole is provided on the other end of the anchor plate, an anchor ring is outerly provided on one end of the anchor plate, an inner thread is provided on the inner side of the anchor ring for threaded connection with the outer thread at one end of the anchor plate, the anchor ring changes its position in the thickness direction of the anchor plate by means of the thread, and a clip that cooperates with it is provided in the clip hole at the rear end of the anchor plate.

[0006] Furthermore, one end of the anchor plate with a clip hole is used to anchor the steel strand, and the anchoring method is clip anchoring, and the number of clip holes is greater than or equal to one; one end of the anchor plate with an internal thread is used to anchor a threaded steel rod, and the anchoring method is threaded anchoring.

[0007] The method of using the anchor is as follows:

[0008] Step 1: Insert the steel strand into one end of the anchor plate with a clip hole, clamp the clip and cut off the excess steel strand;

[0009] Step 2: Screw the threaded steel rod into the inner threaded end of the anchor plate;

[0010] Step 3: Use a jack to pull the steel rod for tensioning;

[0011] Step 4: After tensioning and straightening to control stress, rotate the anchor ring until it is in close contact with the anchor pad. At this time, the clip is completely clamped, and there will be no relative displacement between the clip and the steel strand, and between the clip and the anchor plate.

[0012] Step 5: Operate the jack to release the sheet;

[0013] Step 6: After the tension is completed, rotate the steel rod out of the anchor plate;

[0014] Step 7: Seal the anchor.

[0015] Compared with the prior art, the non-retractable anchor for post-tensioned prestressed steel strands of the present invention can greatly reduce or even eliminate the prestress loss of the prestressed steel strands caused by the retraction of the anchor clips, thereby improving the applicability of the steel strands in short cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The prestressed member in embodiment 1 of the present invention;

[0017] Figure 2 It is a partial enlarged view of the non-retractable anchor area of ​​the present invention used at the tensioning end of the prestressed member in Example 1 of the present invention;

[0018] Figure 3 It is a three-dimensional perspective view of the non-retractable anchor in Example 1 of the present invention.

[0019] In the figure, 1-anchor plate, 11-anchor plate internal thread, 12-anchor plate external thread, 2-clip, 3-anchor ring, 4-steel strand, 5-threaded steel rod, 21-concrete, 22-prestressed hole, 23-ordinary clip anchor, 24-anchor pad. DETAILED DESCRIPTION

[0020] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1

[0022] A post-tensioned prestressed concrete member, 1.5m long, 0.3m wide, 0.3m high, equipped with 1 steel strand, C50 concrete, its structure is as follows Figure 1 shown.

[0023] The post-tensioned prestressed member adopts single-end tensioning, and the tensioning end adopts the single-hole anchor of the present invention. The anchor comprises an anchor plate 1, a clip 2, and an anchor ring 3.

[0024] Furthermore, the anchor plate has an internal thread, an external thread and a clip hole, the clip hole and the internal thread are respectively located at two ends of the anchor plate, and the external thread is located on the outside of the anchor plate.

[0025] Furthermore, one end of the anchor plate with a clip hole is used to anchor the steel strand, and the anchoring method is clip anchoring, and the number of clip holes is greater than or equal to one; one end of the anchor plate with an internal thread is used to anchor a threaded steel rod, and the anchoring method is threaded anchoring.

[0026] Furthermore, the anchor ring is provided with an internal thread, and the internal thread of the anchor ring matches the external thread of the anchor plate. The anchor ring is connected to the anchor plate through the thread, and the anchor ring can arbitrarily change its position by rotating in the thickness direction of the anchor plate through the thread.

[0027] The main construction steps of the post-tensioned precast component are as follows:

[0028] Step 1: Set up the formwork to pour concrete and reserve prestressed channels;

[0029] Step 2: Insert the steel strands and clamp the steel strands with traditional clip anchors at the non-tensioning end of the component;

[0030] Step 3: The tensioning end of the component adopts the anchor of the present invention, inserts the steel strand into one end of the hole of the anchor plate with the clip, and clamps the clip and cuts off the excess steel strand;

[0031] Step 4: Screw the threaded steel rod into the inner threaded end of the anchor plate;

[0032] Step 5: Use a jack to pull the steel rod for tensioning. After tensioning to the controlled stress, rotate the anchor ring until it is in close contact with the anchor pad. At this time, the clip is completely clamped, and there will be no relative displacement between the clip and the steel strand, and between the clip and the anchor plate.

[0033] Step 6: Operate the jack to release the sheet;

[0034] Step 7: After the release is completed, rotate the steel rod out of the anchor;

[0035] Step 8: Grouting and anchor sealing.

[0036] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for using a non-retractable anchor for post-tensioned prestressed steel strand, characterized in that: The anchor comprises an anchor plate, wherein one end of the anchor plate is provided with an internal thread inside and an external thread outside, a clip hole is provided at the other end of the anchor plate, an anchor ring is provided on the outer sleeve of one end of the anchor plate, an internal thread is provided on the inner side of the anchor ring, which is used for threaded connection with the external thread at one end of the anchor plate, and the anchor ring changes its position in the thickness direction of the anchor plate by means of a thread, a clip matching with it is provided in the clip hole at the rear end of the anchor plate, and the end of the anchor plate with the internal thread is used for anchoring a steel rod with a thread, and the anchoring method is threaded anchoring, and the use method is as follows: the first step: inserting the steel strand into one end of the anchor plate with the clip hole, clamping the clip and cutting off the excess steel strand; Step 2: Screw the threaded steel rod into the inner threaded end of the anchor plate; Step 3: Use a jack to pull the steel rod for tensioning; Step 4: After tensioning to the controlled stress, rotate the anchor ring until it is in close contact with the anchor pad. At this time, the clip is completely clamped, and there will be no relative displacement between the clip and the steel strand, and between the clip and the anchor plate. Step 5: Operate the jack to release the sheet; Step 6: After the tension is completed, rotate the steel rod out of the anchor plate; Step 7: Seal the anchor.

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