Construction slow bond prestressed extrusion anchor device

Abstract

The utility model relates to a kind of construction with slow-bonding prestressed extrusion anchor device, using slow-bonding steel strand as prestressed tendon, one end of the slow-bonding steel strand is equipped with stripping section, the end of the stripping section is fixed with extrusion anchor, the outside of the extrusion anchor is equipped with positioning sleeve, the outer surface of the stripping section is located positioning sleeve side and is equipped with anchor pad, the middle part of the anchor pad is opened and has tapered hole, the locking sleeve is suitably fitted in the tapered hole, the locking sleeve is coaxially arranged with positioning sleeve, stripping section is connected in locking sleeve and positioning sleeve, and the extrusion anchor of its end portion is out of positioning sleeve. The utility model can significantly reduce prestress loss, guarantee long-term durability, device overall construction is convenient and reliable, wide application range, high structural strength, can effectively guarantee the long-term stability and safety of construction system.

Description

Technical Field

[0001] This utility model relates to the field of prestressed concrete construction structure technology, specifically to a slow-bonding prestressed extrusion anchor device for construction. Background Technology

[0002] Prestressed steel bars are widely used in the construction industry because they offer better tensile and compressive strength, effectively reducing temperature cracking caused by large spans. However, most existing prestressed steel bars are unbonded prestressed steel strands, which are bonded steel strands with a coating layer. They do not directly contact the concrete, making tensioning easier, but the bond strength with the concrete is insufficient, making them prone to loosening during use and affecting performance. Bonded prestressed steel strands, on the other hand, are in direct contact with the concrete without an outer plastic tube, resulting in stronger bond strength, but tensioning is difficult and may not meet construction requirements.

[0003] Delayed-bonding prestressing technology is a rapidly developing prestressing technology following bonded and unbonded prestressing. Delayed-bonding prestressing refers to a prestressing technique in which the prestressed steel strands expand and deform freely during the construction phase without bonding with the surrounding retarding adhesive. However, after construction is completed, within a predetermined period, the prestressing tendons bond with the surrounding concrete through the cured retarding adhesive, forming a unified whole that shares the load.

[0004] However, existing slow-bonded prestressed systems still use traditional extrusion anchor devices at the fixed end. This device has a key technical defect: the extrusion anchor and the anchor plate lack a reliable positioning and sealing structure, resulting in poor contact between the two during tensioning. Consequently, the extrusion anchor is prone to slight displacement during tensioning. After tensioning is completed and the load is unloaded, the prestressing tendons shrink back due to the loss of effective restraint, leading to severe prestress loss. This not only weakens the prestress of the structure but may also increase the risk of structural cracking, failing to fully realize the performance advantages of slow-bonded prestressed technology.

[0005] Therefore, it is necessary to study a slow-bonding prestressed extrusion anchor device for construction. Utility Model Content

[0006] Therefore, the purpose of this utility model is to provide a construction-use slow-bonding prestressed extrusion anchor device, which effectively solves the problems of large stress loss and poor positioning and sealing performance caused by the retraction of existing prestressed tendons.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a construction-use slow-bonding prestressed extrusion anchor device, which uses slow-bonding steel strand as prestressing tendon. One end of the slow-bonding steel strand is provided with a stripping section, and an extrusion anchor is fixed at the end of the stripping section. A positioning sleeve is provided on the outer side of the extrusion anchor. An anchor pad is provided on the outer surface of the stripping section on one side of the positioning sleeve. A conical hole is opened in the middle of the anchor pad. A locking sleeve is appropriately installed in the conical hole. The locking sleeve and the positioning sleeve are coaxially arranged. The stripping section is connected through the locking sleeve and the positioning sleeve, and the extrusion anchor at its end passes through the positioning sleeve.

[0008] Furthermore, the positioning sleeve includes a main body, a connecting section integrally formed on both sides of the main body, and a sleeve section. The connecting section is used for threaded connection with the locking sleeve, and the extrusion anchor is fixedly sleeved in the sleeve section.

[0009] Furthermore, spiral reinforcement bars are spaced out on the side of the slow-bonding steel strands near the anchor pad.

[0010] Furthermore, the slow-bonding steel strand includes a sheath, a prestressed steel strand bundle, and a slow-bonding adhesive. The sheath is fitted over the prestressed steel strand bundle, and the slow-bonding adhesive is filled between the prestressed steel strand bundle and the sheath to form the slow-bonding steel strand.

[0011] Furthermore, the diameter of the slow-bonding steel strand is ≥28.6mm and the strength is greater than 1860Mpa.

[0012] Furthermore, a rubber sealing gasket is provided between the locking sleeve and the loosely bonded steel strand.

[0013] The beneficial effects of the above technical solution are as follows: The construction-use slow-bonding prestressed extrusion anchor device provided by this utility model adopts large-diameter slow-bonding steel strands as prestressing tendons. The diameter of the slow-bonding steel strands is ≥28.6mm. Compared with other prestressing forms, its outstanding advantage is that in structures with high reinforcement ratios or small beam cross sections, it can effectively reduce the density and bundle division of prestressing tendons. The large-diameter slow-bonding prestressing requires less tensioning space, is flexible in construction, and has stable performance. It has strong technical advantages in ultra-long span structures, ultra-long cantilever structures, ultra-large area hollow slab structures, and complex irregular structures with dense reinforcement.

[0014] In this invention, the tapered hole of the anchor plate 3 and the outer tapered surface of the locking sleeve 6 form a wedge-tight structure. After tensioning and unloading, the retraction tendency of the steel strand causes the locking sleeve 6 to generate a radial tightening force. Through the self-locking effect of the tapered surface, the retraction amount is controlled within 2mm, which can avoid causing more serious prestress loss compared with traditional extrusion anchors.

[0015] A rubber sealing gasket is added between the locking sleeve and the slow-setting steel strand to form an effective sealing barrier, preventing leakage of the slow-setting adhesive and the intrusion of external moisture and impurities. On the one hand, this ensures that the slow-setting adhesive inside the slow-setting steel strand cures according to the predetermined time and performance, maintaining the stability of the slow-setting prestressed system; on the other hand, it prevents moisture and impurities from corroding the steel strand, extending its service life. This avoids the drawbacks of reduced bonding, anchoring, and corrosion resistance caused by the flow of slow-setting adhesive in the vertical slow-setting steel strand, resulting in insufficient adhesive filling inside the sheath. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model in an embodiment. Figure 2 This is a schematic diagram of the assembly structure of this utility model; Figure 3 Cross-sectional view and schematic diagram of the implementation structure for the slow-bonding steel strand; Figure 4 This is a cross-sectional structural diagram of the present invention.

[0017] Reference numerals: 1-Slow-setting steel strand, 11-Sheath, 12-Slow-setting adhesive, 13-Prestressed steel strand bundle, 2-Helical reinforcement, 3-Anchor pad, 4-Positioning sleeve, 41-Connecting section, 42-Main body, 43-Setting section, 5-Extrusion anchor, 6-Locking sleeve, 7-Sealing gasket, 8-Stripping section. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Example 1: This example aims to provide a construction-use slow-bonding prestressed extrusion anchor device, mainly applied to the construction of the fixed end of prestressed steel bars, thereby achieving reliable anchoring of prestressed steel bars, effective anti-retraction and sealing protection, and fully leveraging the performance advantages of slow-bonding prestressing technology.

[0019] In the specific implementation structure, such as Figure 1-4 As shown, a construction-grade slow-bonding prestressed extrusion anchor device uses slow-bonding steel strand 1 as prestressing tendon. The slow-bonding steel strand 1 includes a sheath 11, a prestressed steel strand bundle 13, and a slow-setting adhesive 12. The sheath 11 is fitted over the prestressed steel strand bundle 13, and the slow-setting adhesive 12 fills the space between the prestressed steel strand bundle 13 and the sheath 11 to form the slow-bonding steel strand 1. In this embodiment, the slow-bonding steel strand 1 has a diameter ≥ 28.6 mm and a strength greater than 1860 MPa, which is significantly different from traditional small-diameter steel strands such as 15.2 mm. In densely reinforced structures, it can reduce the number of reinforcements by more than 30%. Furthermore, in densely reinforced irregular structures, it significantly reduces construction difficulty, reduces the number of bundles, and improves the overall structural integrity.

[0020] One end of the slow-bonding steel strand 1 is provided with a stripping section 8, the position of which is as follows: Figure 3 and 4 At the right side of the dividing line, at the anchoring end of the loosely bonded steel strand 1, the end of the stripped section 8 is fixed with an extrusion anchor 5, which applies radial pressure through a special extrusion machine to cause the sleeve to undergo plastic deformation and tightly engage with the smooth steel strand bundle of the stripped section 8, meeting the ultimate pull-out resistance requirements and forming a permanent anchor head.

[0021] like Figure 3 and 4 As shown, a positioning sleeve 4 is provided on the outer side of the extrusion anchor 5, and an anchor pad 3 is provided on the outer surface of the stripping section 8 on one side of the positioning sleeve 4. Spiral reinforcement 2 is provided on the outer side of the slow-bonding steel strand 1 near the anchor pad 3. A conical hole is opened in the middle of the anchor pad 3, and a locking sleeve 6 is fitted in the conical hole. Thus, the anchor pad 3 and the locking sleeve 6 cooperate to form a wedge-tight structure, which is used to transfer prestress and prevent the steel strand from shrinking back; and the locking sleeve 6 is coaxially arranged with the positioning sleeve 4.

[0022] Furthermore, in this embodiment, the positioning sleeve 4 includes a main body 42, a connecting section 41 integrally formed on both sides of the main body 42, and a fitting section 43. The inner wall of the connecting section 41 is threaded internally, and the outer wall of the locking sleeve 6 is threaded externally. Thus, when the locking sleeve 6 is installed in the tapered hole of the anchor pad 3, its end near the positioning sleeve 4 is threadedly connected to the connecting section 41 on the positioning sleeve 4, and a rigid connection with the positioning sleeve 4 is achieved through the thread preload. The fitting section 43 is used to fix the fitting extrusion anchor 5, so that the stripping section 8 is connected through the locking sleeve 6 and the positioning sleeve 4, and the extrusion anchor 5 at its end protrudes from the positioning sleeve 4. A rubber sealing gasket 7 is fitted between the locking sleeve 6 and the slow-setting steel strand 1. The radial extrusion of the locking sleeve 6 generates elastic deformation, achieving a sealing effect to prevent leakage of the slow-setting adhesive 12 and intrusion of external media.

[0023] The positioning sleeve of this utility model is designed such that the connecting section 41 is threadedly connected to the locking sleeve 6, and the sleeve section 43 fixes the extrusion anchor 5 to form a coaxial positioning system. This solves the problem of poor contact and positioning deviation between the extrusion anchor and the anchor pad 3 in traditional devices, and ensures the stability of the component under force during the tensioning process.

[0024] The construction-use slow-bonding prestressed extrusion anchor device provided by this utility model involves inspecting the quality of the slow-bonding steel strand 1 upon its arrival at the site and cutting it to a single length according to the calculation results of the design drawings. Then, positioning steel bars are welded on the non-prestressed steel reinforcement skeleton of the beam according to the coordinate position and sag (curve elevation) of the prestressing tendon duct indicated in the design drawings. After that, spiral reinforcement 2 is inserted into the anchoring end of the steel strand. A certain length of sheath 11 and slow-bonding adhesive 12 are peeled off at the end to form the peeling section 8.

[0025] Then, the compression spring is placed on the end of the stripping section 8, and a sleeve is put on. High pressure is applied using a special hydraulic extrusion press (such as a 28 series extrusion press) to cause the sleeve to undergo plastic deformation and tightly engage with the steel strand to form a strong extrusion anchor 5. Next, the slow-bonded steel strand 1 is hoisted to the construction site and inserted into the beam reinforcement skeleton with welded positioning bars to ensure that the steel strand is arranged according to the design coordinates and sag.

[0026] Next, the locking sleeve 6 is fitted into the conical hole of the anchor pad, ensuring the outer conical surface of the locking sleeve 6 is flush with the conical hole of the pad and fitted into the stripping section 8. A rubber sealing gasket 7 is pre-installed in the inner hole of the locking sleeve 6, and then fitted into the stripping section 8. The fitting section 43 of the positioning sleeve 4 is fitted onto the outside of the compression anchor 5, and the locking sleeve 6 is screwed into the connecting section 41 of the positioning sleeve 4. Initial fixation is achieved through threaded connection, completing the overall assembly of the fixed end. After the concrete strength of the beam reaches the preset value, prestressing is performed at the tensioning end. The tension force is transmitted to the compression anchor 5 through the anchor pad 3 and the locking sleeve 6. After tensioning, the locking sleeve 6 self-locks in the conical hole, effectively limiting the retraction of the steel strand and significantly reducing prestress loss.

[0027] The prestressed extrusion anchor device for construction provided by this utility model has a conical locking structure and an extrusion anchor working together to significantly reduce prestress loss. The rubber sealing gasket prevents adhesive leakage and external corrosion, ensuring long-term durability. The device is easy and reliable to construct, has a wide range of applications, and high structural strength, which can effectively ensure the long-term stability and safety of the construction system.

[0028] The embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A construction-use, slow-bonding prestressed extrusion anchor device, characterized in that: Slow-bonded steel strand (1) is used as prestressing tendon. One end of the slow-bonded steel strand (1) is provided with a stripping section (8). The end of the stripping section (8) is fixed with a compression anchor (5). The outer side of the compression anchor (5) is provided with a positioning sleeve (4). The outer surface of the stripping section (8) is provided with an anchor pad (3) on one side of the positioning sleeve. The middle part of the anchor pad (3) has a conical hole. A locking sleeve (6) is fitted in the conical hole. The locking sleeve (6) and the positioning sleeve (4) are coaxially arranged. The stripping section (8) is connected through the locking sleeve (6) and the positioning sleeve (4), and the compression anchor (5) at its end passes through the positioning sleeve (4).

2. The construction-use slow-bonding prestressed extrusion anchor device according to claim 1, characterized in that: The positioning sleeve (4) includes a main body (42), a connecting section (41) integrally formed on both sides of the main body (42), and a fitting section (43). The connecting section (41) is used to be threadedly connected to the locking sleeve (6), and the extrusion anchor (5) is fixedly fitted in the fitting section (43).

3. The construction-use slow-bonding prestressed extrusion anchor device according to claim 1, characterized in that: Spiral reinforcement (2) is installed at intervals on the outer side of the loosely bonded steel strand (1) near the anchor pad (3).

4. The construction-use slow-bonding prestressed extrusion anchor device according to claim 1, characterized in that: The slow-bonding steel strand (1) includes a sheath (11), a prestressed steel strand bundle (13), and a slow-bonding adhesive (12). The sheath (11) is fitted over the prestressed steel strand bundle (13), and the slow-bonding adhesive (12) is filled between the prestressed steel strand bundle (13) and the sheath (11) to form the slow-bonding steel strand (1).

5. The construction-use slow-bonding prestressed extrusion anchor device according to claim 4, characterized in that: The diameter of the slow-bonding steel strand is ≥28.6mm and the strength is greater than 1860Mpa.

6. The construction-use slow-bonding prestressed extrusion anchor device according to claim 1, characterized in that: A rubber sealing gasket (7) is fitted between the locking sleeve (6) and the loosely bonded steel strand.

Images