Anti-floating anchor rod and construction method thereof

Abstract

The application provides an anti-floating anchor rod and a construction method thereof. The anti-floating anchor rod comprises a rod body, a prestressed steel strand arranged in the rod body along the length direction of the rod body, an upper bearing plate, a clamping anchor, a supporting spring, an anchor pad and an extrusion anchor. The prestressed steel strand has a plurality of anchor bars. The anchor bars of the prestressed steel strand pass through the upper bearing plate one by one and are tensioned at the upper bearing plate. The clamping anchor locks the tensioned steel strand at the upper bearing plate. The supporting spring is sleeved on the prestressed steel strand and is located between the anchor pad and the clamping anchor in a tension support mode. The anchor bars of the prestressed steel strand pass through the anchor pad one by one and the extrusion anchor is arranged at the end of each anchor bar. The application makes full use of the advantages of the clamping anchor and the extrusion anchor, makes tension locking easier, is simple in construction, reliable in quality and good in economy.

Description

Technical Field

[0001] This invention relates to the field of anti-buoyancy technology for basements, and in particular to an anti-buoyancy anchor rod and its construction method. Background Technology

[0002] Most basements have buoyancy issues. According to the "Technical Standard for Buoyancy Resistance of Building Engineering" JGJ476-2019, projects with a buoyancy resistance design level of A should be designed to prevent cracking and use prestressed anchor rods.

[0003] a. If the ordinary post-tensioned prestressing process is adopted, and the basement slab is used as the tensioning end after the basement slab is completed, the following problems will occur: tensioning can only be carried out after the basement slab is completed and reaches the corresponding strength, which will affect the construction progress.

[0004] b. The above-mentioned traditional prestressed steel strands require the pre-reservation of tensioning channels on the base plate, which results in a tensioning hole being generated at the corresponding position of each anti-buoyancy anchor rod on the structural base plate, posing a risk of water seepage.

[0005] Existing patents, such as the anti-buoyancy anchor bolt and its construction method disclosed in patent publication number CN112575823A, have the following drawbacks in their anchor bolt structure:

[0006] (i) The upper section of the anchor rod is equipped with a sleeve as a free section, and the lower section uses the grout wrapping force to anchor the prestressed cable. It is a "tension type" prestressed anchor rod, which cannot completely guarantee that the anchoring section will not crack.

[0007] (ii) The anchoring end of the anchor bolt adopts the form of a steel force transmission cylinder. The steel force transmission cylinder is installed at the top of the hole, and prestress is applied and locked at the top of the steel force transmission cylinder. This is limited by the fact that the force transmission cylinder is an important pressure-bearing component, requiring high strength and load-bearing capacity, thus resulting in higher costs.

[0008] (iii) Steel force transmission cylinders need to be cut and welded from steel profiles, which involves complex processing procedures. Force transmission cylinders of different heights also need to be shaped and processed separately.

[0009] (iv) Since the height of the steel force transmission cylinder is a fixed value, the requirements for the anchor bolt hole elevation are very strict. Especially when the anchor bolt hole elevation is lower than the design, it is almost impossible to install. The rod body needs to be lengthened or a custom-made force transmission component needs to be added, which results in higher costs.

[0010] (v) A steel force transmission cylinder is used, which requires an opening in the middle to make the concrete inside the force transmission cylinder dense. In addition, the density of the concrete cannot be guaranteed. Summary of the Invention

[0011] The purpose of this invention is to provide an anti-buoyancy anchor rod and its construction method to solve the above-mentioned problems of steel force transmission cylinders.

[0012] The technical solution of the present invention is as follows: an anti-buoyancy anchor rod includes a rod body, prestressed steel strands arranged along the length of the rod body, an upper bearing plate, a wedge anchor, a support spring, an anchor plate, and a compression anchor; the prestressed steel strands have multiple anchor bars, each of which passes through the upper bearing plate and is tensioned at the upper bearing plate; the wedge anchor locks the tensioned steel strands at the upper bearing plate; the support spring is fitted onto the prestressed steel strands and is located between the anchor plate and the wedge anchor in a tension-supported manner; each of the multiple anchor bars of the prestressed steel strands passes through the anchor plate, and a compression anchor is provided at the end of each anchor bar.

[0013] The above scheme is designed with two anchorages. The first anchorage is a wedge anchorage that locks the prestress. The second anchorage is a compression anchorage set above the anchor plate, which makes the anchor rod reliably anchored in the base plate. The spring support only pushes the anchor plate upward, so that the anchor plate does not move downward and does not transmit pressure. The wedge anchorage and the compression anchorage are combined to allow the anchor rod to be constructed before the base plate.

[0014] The above solution uses a support spring instead of a steel force transmission cylinder, which gives the support spring the following advantages:

[0015] a. The support spring only relies on its elastic force to support the upper pressure plate and prevent it from moving down. It does not transmit pressure and does not need to bear pressure. The amount of steel used in a single spring is about 1 / 4 to 1 / 5 of that used in a steel force transmission cylinder.

[0016] b. The support spring is made of steel wire (steel bar) coiled into shape, and the length is very convenient to adjust;

[0017] c. The supporting spring itself has a strong ability to adapt to high expansion and contraction, which greatly reduces the construction accuracy requirements for the orifice elevation and has higher fault tolerance.

[0018] d. The supporting spring has no enclosed space inside, so there is no issue with the density of concrete.

[0019] Preferably, the anti-buoyancy anchor also includes a PVC sleeve, which is fitted onto the prestressed steel strand and located at the end of the upper bearing plate away from the wedge anchor.

[0020] PVC sleeves are used to determine the borehole elevation and ensure the quality of the borehole at the top.

[0021] Preferably, the upper bearing plate is provided with a grouting hole and a plurality of first positioning holes corresponding to the number of anchor bars, the plurality of first positioning holes are located in the middle region of the upper bearing plate, and the grouting hole is located on the side of the first positioning hole.

[0022] The first positioning hole for the anchor bar to pass through is set in the middle area of ​​the upper bearing plate, which facilitates the tensioning and locking by the wedge anchor.

[0023] Preferably, the anchor plate is provided with binding holes and a plurality of second positioning holes corresponding to the number of anchor bars, the plurality of second positioning holes being located in the central region of the anchor plate, and the binding holes being distributed around the perimeter of the anchor plate.

[0024] For anchor plates that have experienced elevation drops, the anchor plates can be tied and fixed to the reinforcing bars of the basement floor slab using the binding holes to ensure that the anchor plates are at the design elevation.

[0025] Preferably, the lower end of the upper bearing plate is provided with a spiral steel bar, which is fitted onto the prestressed steel strand.

[0026] Preferably, the anti-buoyancy anchor also includes a lower bearing plate, a limiting plate, and a guide cap. The anchor bars of the prestressed steel strands located at the lower end of the rod pass through the lower bearing plate and are locked by the compression anchor. The limiting plate is fixed at the lower end of the compression anchor, and the guide cap is located at the lower end of the lower bearing plate.

[0027] Preferably, the upper end of the lower bearing plate is provided with a spiral reinforcing bar, which is sleeved on the prestressed steel strand.

[0028] The present invention also provides a construction method for the above-mentioned anti-buoyancy anchor, comprising the following steps:

[0029] 1) Construct the anti-buoyancy anchor in the stratum below the area used to construct the basement floor slab, and extend the prestressed steel strand to be tensioned end of the anti-buoyancy anchor into the floor slab area;

[0030] 2) Install an upper bearing plate at the top of the hole in the stratum, so that each anchor bar of the prestressed steel strand passes through the upper bearing plate and is tensioned. Then install a wedge anchor to lock the tensioned anchor bar, so that prestress is generated inside the anchor bar.

[0031] 3) Install support springs on the prestressed steel strands, with the support springs abutting against the wedge anchor and the anchor plate;

[0032] 4) Each of the anchor bars passes through the anchor plate, and finally the compression anchor is installed at the end of the anchor bar;

[0033] 5) Concrete mixture is poured in the basement area to form the basement basement slab, so that the anti-buoyancy anchor is fixed in the basement basement basement slab.

[0034] Preferably, step 2) further includes a PVC sleeve installed inside the top of the hole to determine the elevation of the hole opening and ensure the quality of the hole formation at the top of the hole, and the PVC sleeve is fitted onto the rod body.

[0035] The above scheme uses two anchors. The first anchor locks the prestress, and the second anchor prevents the upper bearing plate from falling off. It makes full use of the advantages of wedge anchors and squeeze anchors, and better realizes the construction of anchor rods before the base plate.

[0036] The supporting spring is fixed inside the concrete, further enhancing the concrete's resistance to localized pressure.

[0037] Compared with related technologies, the beneficial effects of the present invention are as follows:

[0038] 1. The anti-buoyancy anchor rod is equipped with a bearing plate and a matching extrusion anchor at the top position of the prestressed steel strand hole. If necessary, a spiral steel bar for resisting local pressure is set. The present invention makes full use of the advantages of wedge anchor and extrusion anchor, making tensioning and locking easier, construction simple, quality reliable and economical.

[0039] Second, after the basement floor slab is constructed, the prestress within the anchor bolt can effectively suppress the generation of cracks.

[0040] 3. Reduce overlapping work processes before basement floor slab construction and improve construction progress;

[0041] Fourth, avoiding the need to reserve tensioning channels in the basement floor slab reduces the construction process of high-pressure grouting for tensioning holes;

[0042] 5. The basement floor slab is cast in one piece to avoid leakage caused by tensioning holes;

[0043] VI. After the basement floor slab is completed, the anti-buoyancy anchor rods are fixed in the basement floor slab to ensure durability and not affect the use of the basement. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the anti-buoyancy anchor provided by the present invention;

[0045] Figure 2 This is a schematic diagram of the anchoring device in the base plate area.

[0046] Figure 3 A schematic diagram of the upper bearing plate in the anti-buoyancy anchor provided by the present invention;

[0047] Figure 4 This is a schematic diagram of the structure of the anchor plate in the anti-buoyancy anchor provided by the present invention.

[0048] In the attached diagram: 1. Rod body; 2. Prestressed steel strand; 21. Anchor bar; 3. Upper bearing plate; 31. Grouting hole; 32. First positioning hole; 4. Wedge anchor; 5. Support spring; 6. Anchor plate; 61. Binding hole; 62. Second positioning hole; 7. Extrusion anchor; 8. PVC sleeve; 9. Bottom plate area; 10. Spiral reinforcement; 11. Lower bearing plate; 12. Limiting plate; 13. Guide cap. Detailed Implementation

[0049] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. For ease of description, the terms "upper," "lower," "left," and "right" used below only indicate that they correspond to the upper, lower, left, and right directions in the accompanying drawings and do not limit the structure.

[0050] like Figure 1 , Figure 2 As shown, this embodiment provides an anti-buoyancy anchor rod comprising a rod body 1, prestressed steel strands 2, an upper bearing plate 3, a wedge anchor 4, a support spring 5, an anchor pad 6, a compression anchor 7, a PVC sleeve 8, a spiral steel bar 10, a lower bearing plate 11, a limiting plate 12, and a guide cap 13. The upper bearing plate 3, the wedge anchor 4, the support spring 5, the anchor pad 6, the compression anchor 7, and the PVC sleeve 8 form an anchoring device.

[0051] The prestressed steel strand 2 is arranged along the length of the pole 1 and within the pole 1. The prestressed steel strand 2 has multiple anchor bars 21. In this embodiment, the number of anchor bars 21 is three.

[0052] like Figure 3 As shown, the upper bearing plate 3 has one grouting hole 31 and three first positioning holes 32. The first positioning holes 32 are aligned with the anchor holes of the clamping pieces and are located in the middle area of ​​the upper bearing plate 3. The diameter of the grouting hole 31 is φ30mm.

[0053] The multiple anchor bars 21 of the prestressed steel strand 2 pass through the first positioning holes 32 of the upper bearing plate 3 and are tensioned at the upper bearing plate 3. The wedge anchor 4 locks the tensioned prestressed steel strand 2 at the upper bearing plate 3. The wedge anchor 4 can be an externally purchased component. The position of the first positioning hole 32 is aligned with the hole of the wedge anchor.

[0054] The support spring 5 is fitted onto the prestressed steel strand 2, and is positioned between the anchor plate 6 and the wedge anchor 4 under tension. The support spring 5 is made of carbon steel or alloy steel, with both ends ground flat and tightened. The length of the support spring 5 is generally 1.2-1.5 times its compressed length. If sufficient construction quality can be guaranteed, a slightly longer spiral steel bar can also be used.

[0055] like Figure 4As shown, the anchor plate 6 is provided with binding holes 61 and three second positioning holes 62 corresponding to the number of anchor bars 21. The second positioning holes 62 are concentrated and evenly distributed in the central area of ​​the anchor plate 6, and the binding holes 61 are distributed at the four corners of the anchor plate 6. For anchor plates 6 that have sunk in elevation, they can be bound to the reinforcing bars in the base plate area 9 using the binding holes 61 to ensure that the anchor plate 6 is at the design elevation.

[0056] The multiple anchor bars 21 of the prestressed steel strand 2 pass through the second positioning hole 62 of the anchor plate 6, and the compression anchor 7 is set at the end of each anchor bar 21.

[0057] To ensure better anchoring, the cross-sectional area of ​​the anchor plate 6 is larger than that of the upper bearing plate 3. The upper bearing plate 3 is a steel plate.

[0058] The PVC sleeve 8 is fitted onto the prestressed steel strand 2 and is located at the end of the upper bearing plate 3 away from the wedge anchor 4.

[0059] The prestressed steel strands 2 at the lower end of the anti-buoyancy anchor rod pass through the lower bearing plate 11 and are locked by the compression anchor 7. The bottom of the compression anchor 7 is threadedly connected to the limiting plate 12. The guide cap 13 is located at the lower end of the lower bearing plate 11. At the same time, a spiral steel bar 10 is provided above the lower bearing plate 11, and the spiral steel bar 10 is sleeved on the prestressed steel strands 2. A grouting pipe is provided inside the anchor rod, passing through the upper bearing plate 3, the lower bearing plate 11 and the limiting plate 12 from bottom to top, and extending into the guide cap 13.

[0060] The present invention also provides a construction method, comprising the following steps:

[0061] 1) Construct the anti-buoyancy anchor rod in the stratum below the basement floor area 9, and extend the prestressed steel strand 2 inside the rod body 1 of the anti-buoyancy anchor rod to the floor area 9;

[0062] 2) A pressure plate 3 is installed at the top of the hole. A PVC sleeve 8 can be used at the top of the hole to determine the elevation of the hole opening and ensure the quality of the hole at the top of the hole.

[0063] 3) Pass each anchor bar 21 of the prestressed steel strand 2 through the upper bearing plate 3 and tension it, then install the wedge anchor 4 to lock the tensioned anchor bar 21, so that prestress is generated inside the anchor rod, thereby forming the first anchor to provide prestress to the anchor rod.

[0064] 4) A support spring 5 is fitted onto the prestressed steel strand 2, the support spring 5 abutting against the wedge anchor 4 and the anchor plate 6. The length of the support spring 5 must ensure that it can reliably support the upper anchor plate 6 to the design elevation when compressed. The tension of the support spring 5 supports the anchor plate 6 and simultaneously strengthens the anchor plate 6's resistance to local pressure.

[0065] 5) Each of the anchor bars 21 passes through the anchor plate 6, and finally the compression anchor 7 is installed at the end of the anchor bar 21. The anchor plate 6 is used to reliably anchor the anchor rod into the bottom plate area 9, thereby forming the second anchor.

[0066] 6) A concrete mixture is poured into the basement slab area 9 to form the basement floor slab, thus fixing the anti-buoyancy anchor rods into the basement floor slab. This ensures durability and does not affect the use of the basement.

[0067] The anti-buoyancy anchor provided by this invention uses prestressed steel strands with built-in anti-corrosion protection, on which a bearing body (pressure plate and matching extrusion anchor) is set, making the entire length a free section and providing pull-out resistance throughout the entire length; it is a full-length "pressure type" prestressed anchor, which can strictly ensure that the anchor will not crack.

[0068] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An anti-buoyancy anchor bolt, comprising a rod body and prestressed steel strands arranged within the rod body along its length, wherein the prestressed steel strands have multiple anchor bars, characterized in that, It also includes an upper bearing plate, a wedge anchor, a support spring, an anchor plate, and a compression anchor; multiple anchor bars of the prestressed steel strand pass through the upper bearing plate and are tensioned at the upper bearing plate; the wedge anchor locks the tensioned prestressed steel strand at the upper bearing plate; the support spring is fitted onto the prestressed steel strand and is located between the anchor plate and the wedge anchor in a tension-supported manner; multiple anchor bars of the prestressed steel strand pass through the anchor plate and the compression anchor is set at the end of each anchor bar.

2. The anti-buoyancy anchor bolt according to claim 1, characterized in that, It also includes a PVC sleeve, which is fitted onto the prestressed steel strand and located at the end of the upper bearing plate away from the wedge anchor.

3. The anti-buoyancy anchor bolt according to claim 1, characterized in that, The upper bearing plate is provided with a grouting hole and a plurality of first positioning holes corresponding to the number of anchor bars. The plurality of first positioning holes are located in the middle region of the upper bearing plate, and the grouting hole is located on the side of the first positioning hole.

4. The anti-buoyancy anchor bolt according to claim 1, characterized in that, The anchor plate is provided with binding holes and multiple second positioning holes corresponding to the number of anchor bars. The multiple second positioning holes are located in the central area of ​​the anchor plate, and the binding holes are distributed around the anchor plate.

5. The anti-buoyancy anchor bolt according to claim 1, characterized in that, The lower end of the upper bearing plate is provided with a spiral steel bar, which is fitted onto the prestressed steel strand.

6. The anti-buoyancy anchor bolt according to claim 1, characterized in that, It also includes a lower bearing plate, a limiting plate, and a guide cap. The anchor bars of the prestressed steel strands located at the lower end of the rod pass through the lower bearing plate and are locked by the compression anchor. The limiting plate is fixed at the lower end of the compression anchor, and the guide cap is located at the lower end of the lower bearing plate.

7. The anti-buoyancy anchor bolt according to claim 6, characterized in that, The upper end of the lower bearing plate is provided with a spiral steel bar, which is sleeved on the prestressed steel strand.

8. A construction method for an anti-buoyancy anchor bolt as described in any one of claims 1 to 7, characterized in that, Includes the following steps: 1) Construct the anti-buoyancy anchor rod in the stratum below the area used to construct the basement floor slab, and extend the prestressed steel strand to be tensioned end of the anti-buoyancy anchor rod into the floor slab area; 2) Install an upper bearing plate at the top of the hole in the stratum, so that each anchor bar of the prestressed steel strand passes through the upper bearing plate and is tensioned. Then install a wedge anchor to lock the tensioned anchor bar, so that prestress is generated inside the anchor bar. 3) Install support springs on the prestressed steel strands, with the support springs abutting against the wedge anchor and the anchor plate; 4) Each of the anchor bars passes through the anchor plate, and finally the compression anchor is installed at the end of the anchor bar; 5) A concrete mixture is poured in the basement area to form the basement basement slab, thereby fixing the anti-buoyancy anchor rods in the basement basement basement slab.

9. The construction method of the anti-buoyancy anchor bolt according to claim 8, characterized in that, Step 2) also includes a PVC sleeve installed inside the top of the hole to determine the elevation of the hole opening and ensure the quality of the hole formation at the top of the hole, and the PVC sleeve is fitted onto the rod body.

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