Pre-tensioning method hollow slab steel strand positioning and protecting device

Abstract

The utility model discloses a pre-tensioning method hollow slab steel strand positioning and protecting device which is used for preventing and reducing the fracture risk possibly existing in the tensioning process of a steel strand and reducing the secondary risk problem caused by jumping and throwing of the steel strand after the fracture risk of the steel strand occurs. The problem that the vertical position and the horizontal distance of the steel strands are difficult to accurately control is solved. Comprising an upper comb tooth groove, a lower comb tooth groove, a fastening bolt, a fixing clamping plate and a positioning bolt. The corresponding U-shaped notches in the upper comb tooth groove and the lower comb tooth groove which are buckled form a steel strand clamping channel, and the two ends of the upper comb tooth groove and the two ends of the lower comb tooth groove are provided with bolt holes respectively and are fastened through locking bolts. When in use, the device is fixed on the top surface of a prefabricated pedestal, and the comb tooth structure is used for accurately positioning and fixing the steel strand; compared with traditional hollow slab prestress construction, after the product is additionally arranged, the arrangement precision of the steel strands is effectively improved, and the fracture impact risk of the steel strands is reduced.

Description

Technical Field

[0001] The utility model belongs to the field of bridge construction, and in particular relates to a positioning and protection device for pre-tensioned hollow slab steel strands. Background Art

[0002] Prefabricated hollow slabs are generally prefabricated in a centralized manner at a prefabrication site. Considering the construction efficiency and versatility, each slot of the pre-tensioned prefabricated pedestal can generally accommodate multiple hollow slab steel cages of the same specification, and synchronous tensioning construction is carried out after the steel strands are threaded.

[0003] The traditional prestressed hollow-core slab prefabrication process and facility layout are shown in Figure 1 In the figure, the tensioning table adopts a table-type tensioning table, in which the base 01 is polished and smoothed with terrazzo and coated with a release agent, and the base 01 is preset with external mold tension bolt sleeve holes. The tensioning table 02 is set at both ends of the base and connected to the prefabricated base 01 of the hollow plate as a whole. The through-type tensioning jack is used to tension the central steel strand 00, in which the two ends of the steel strand are fixed to the anchor plate 03 through anchor locking parts, and the numbers displayed on the oil pressure gauge are matched and tested, and the tension oil gauge reading curve is drawn to determine the oil gauge readings of different control tension forces to achieve the purpose of effective tensioning.

[0004] Due to the long length of the steel strands, for example, some beams are twenty meters long and the steel strands are also long. Therefore, there are many contact points between the steel strands and the steel cage within the effective length range, which can easily cause the following problems: 1. It is difficult to accurately control the vertical position and horizontal spacing of the steel strands; 2. If the steel strands break, the steel strands will bounce and swing, and the length of the steel strands is long. After the break, the free end of the steel strand is long, the impact force is large, and secondary disasters are likely to occur, posing a high safety risk.

[0005] After investigation and literature search, no technical information that can effectively solve this problem was found in the existing technology. Summary of the invention

[0006] In order to address the deficiencies in the prior art, the utility model provides a pre-tensioned hollow slab steel strand positioning and protection device as a preventive technical measure, which is used to prevent and reduce the risk of steel strand breakage that may exist during the tensioning process, and to reduce the secondary risk problem caused by the steel strand bouncing after the risk of steel strand breakage occurs. At the same time, through the application of the device, the problem of difficult precise control of the vertical position and horizontal spacing of the steel strands is solved.

[0007] The technical solution adopted by the utility model to solve its technical problems is:

[0008] A pre-tensioned hollow slab steel strand positioning and protection device, comprising an upper comb tooth groove, a lower comb tooth groove, a locking bolt, a fixed clamping plate and a positioning bolt, characterized in that the upper comb tooth groove and the lower comb tooth groove are channel steel structures with a U-shaped cross-section, and at least two groups of paired and relatively arranged U-shaped notches are respectively arranged on the upper comb tooth groove and the lower comb tooth groove, and the corresponding U-shaped notches on the upper comb tooth groove and the lower comb tooth groove after being buckled form a steel strand clamping channel, bolt holes are respectively arranged at both ends of the upper comb tooth groove and the lower comb tooth groove and fastened by locking bolts, the fixed clamping plate is an L-shaped steel plate component welded to the bottom of the lower comb tooth plate, and threaded holes are arranged on the fixed clamping plate and positioning bolts are installed, and the fixed clamping plate and the positioning bolts are used to engage with the clamping groove on the base.

[0009] Furthermore, a semicircular steel pipe groove is welded in each of the U-shaped notches, and the inner diameter of the semicircular steel pipe groove is equal to the diameter of the steel strand.

[0010] Furthermore, a bolt hole is arranged at the center of the flat plate of the upper comb tooth groove, a steel plate is welded and fixed inside the lower comb tooth groove, the steel plate has a threaded hole, and the hexagonal bolt passes through the bolt hole from top to bottom and the lower end cooperates with the threaded hole.

[0011] Furthermore, the entire surface of the device is corrosion-resistant.

[0012] Furthermore, the upper comb tooth groove and the lower comb tooth groove have sufficient clamping force on the steel strand when clamped by the locking bolt.

[0013] The beneficial effects of the utility model are:

[0014] The utility model creatively proposes a steel strand positioning and protection device, which is fixed on the prefabricated pedestal of the prestressed hollow slab as an auxiliary device. The device has preset steel strand perforations for constraint, which not only realizes the precise positioning of the vertical height and horizontal spacing of the steel strand, but also effectively improves the qualified rate of the steel strand spacing and the thickness of the protective layer. Moreover, the application of the device effectively supports the middle section of the steel strand, so that the middle section of the steel strand is temporarily fixed and constrained. By reducing the length of the free end of the steel strand after the steel strand breaks, the impact risk after the steel strand breaks can be effectively reduced, and the secondary damage caused by the steel strand break can be reduced.

[0015] At the same time, the device also has the advantages of simple structure, high efficiency and easy operation, which will not be described one by one here, and will be understood in detail in conjunction with the embodiments below. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the layout diagram of the existing prestressed hollow-core slab prefabrication facilities.

[0017] Figure 2 This is the layout diagram of the hollow slab prefabrication facilities corresponding to the present utility model.

[0018] Figure 3 Schematic diagram of the structure of the steel strand positioning protection device.

[0019] Figure 4 for Figure 3 Schematic diagram of the middle and upper comb grooves.

[0020] Figure 5 for Figure 3 Schematic diagram of the middle and lower comb grooves.

[0021] Figure 6 for Figure 3 Schematic diagram of fastening bolts.

[0022] Figure 7 for Figure 3 Schematic diagram of the fixed card plate.

[0023] Figure 8 for Figure 3 Schematic diagram of the positioning bolt.

[0024] Fig. 9 Schematic diagram of explosion positioning guard for steel strands.

[0025] Fig.10 Schematic diagram of the usage scenario of the steel strand positioning protection device.

[0026] Fig.11 It is a structural diagram of the upper and lower comb grooves corresponding to the second embodiment.

[0027] In the figure:

[0028] 01 pedestal, 011 slot, 02 tensioning table, 00 steel strand, 03 anchor plate,

[0029] 20 Steel strand positioning protection device,

[0030] 1 upper comb groove, 101 No. 1 U-shaped notch,

[0031] 2 lower comb groove, 201 No. 2 U-shaped notch, 202 steel plate,

[0032] 3 locking bolts, 301 screws, 302 nuts, 303 upper washers, 304 lower washers,

[0033] 4Fix the card board,

[0034] 5 positioning bolts,

[0035] 6 semicircular steel pipe grooves,

[0036] 7 Hexagon bolts. DETAILED DESCRIPTION

[0037] Specific technical reproduction implementation route 1

[0038] See also Figures 2 to 9 , a pre-tensioned hollow slab steel strand positioning and protection device, Figure 2 In the figure, the steel strand positioning and protection device is replaced by the label 20 to form the described style, that is, it is marked as the steel strand positioning and protection device 20. The device is preferably installed in the middle section of the pedestal 01, centrally arranged, and installed on the pedestal through temporary fixation. After fixation, it becomes one with the pedestal. The detailed composition and functional principle of the device are described in detail below.

[0039] According to the functional components of the device, the device includes an upper comb tooth groove 1, a lower comb tooth groove 2, a locking bolt 3, a fixed clamping plate 4 and a positioning bolt 5. Among them, the upper comb tooth groove 1 and the lower comb tooth groove 2 are channel steel structures with a U-shaped cross section, and the length direction of the channel steel is perpendicular to the length direction of the base. The above-mentioned upper comb tooth groove 1 and the lower comb tooth groove 2 span the base 01, and the two ends extend out. Since the upper comb tooth groove 1 and the lower comb tooth groove 2 are open structures, and the notch of the upper comb tooth groove 1 is set downward, and the notch of the lower comb tooth groove 2 is set upward, and U-shaped notches are respectively set on the above-mentioned upper comb tooth groove 1 and the lower comb tooth groove 2, that is, a No. 1 U-shaped notch 101 is set on the notch wall of the upper comb tooth groove 1, and a No. 2 U-shaped notch 201 is set on the notch wall of the lower comb tooth groove 2. The above-mentioned No. 1 U-shaped notch 101 and No. 2 U-shaped notch 201 are set correspondingly, that is, one-to-one corresponding in the upper and lower buckled state. In the specific construction process, each pair of U-shaped notches (101, 201) corresponds to a steel strand. It is easy to understand that the spacing between two adjacent pairs of U-shaped notches is set according to the steel strands in the hollow slab drawings to ensure the positioning of the spacing distance of the steel strands.

[0040] The cross-sectional positions and dimensions of the upper comb tooth groove 1 and the lower comb tooth groove 2 are set according to the dimensions of the steel strands and the allowable deviations in the design specifications. The upper comb tooth groove 1 faces downwards, and the lower comb tooth groove 2 faces upwards. The upper comb tooth groove 1 is buckled outside the lower comb tooth groove 2. After buckling, each pair of U-shaped notches (101, 201) clamps a steel strand.

[0041] The locking bolt 3 includes a screw rod 301, a nut 302, an upper gasket 303, and a lower gasket 304, and is a locking component. The installation position of the locking bolt 3 is preferably located at the two end portions of the upper comb tooth groove 1 and the lower comb tooth groove 2 in the length direction, and extends to the outside of the base.

[0042] That is to say, bolt holes are set at corresponding positions at both ends of the upper comb tooth groove 1 and the lower comb tooth groove 2, and the locking bolts 3 are used to fix and lock. It is easy to understand that the upper comb tooth groove 1 and the lower comb tooth groove 2 are connected into an integrated structure through the locking bolts.

[0043] The fixed card plate 4 is an L-shaped steel plate member, which is welded to the bottom of the lower comb plate 2, and its function is to cooperate with the card slot 011 on the pedestal 01. In a more detailed design, a bolt hole with a thread is set on the horizontal surface of the fixed card plate 4 that cooperates with the card slot, and a positioning bolt 5 is installed inside it through thread cooperation. The positioning bolt 5 can pass through the threaded bolt hole to adjust up and down, and the device can be positioned and locked or removed and moved, that is, the device is locked on the pedestal through the positioning bolt 5 and the fixed card plate 4.

[0044] It is easy to understand that the number of the above-mentioned fixed clamping plates 4 is two, one on the left and one on the right, to achieve rapid clamping of the clamping slot 011 on the base.

[0045] The process of this device in the construction process is as follows:

[0046] During construction, the lower comb plate 2 and the fixed clamp plate 4 are first installed on the top surface of the prefabricated pedestal, for example, by on-site welding. Then, the relative position of the lower comb groove 2 is adjusted according to the design position of the steel strand in the hollow slab drawing, and the positioning bolts 5 are used to tighten and fix the relative position of the lower comb groove. Then, the steel strands are arranged and threaded, and each steel strand corresponds to the No. 2 U-shaped notch 201. After one threading, the upper comb tooth groove 1 is installed in position, and the No. 1 U-shaped notch and the No. 2 U-shaped notch correspond one to one. The upper comb tooth groove 1 and the lower comb tooth groove 2 are temporarily limited and preliminarily fixed by the locking bolt 3. This fixation is not complete fixation. Finally, the steel strand is tensioned. After the tensioning force of the steel strand meets the design requirements, the locking bolts 3 at both ends of the wrench are used to tighten. During this process, the upper comb tooth groove 1 is clamped relative to the lower comb tooth groove 2 and clamps the steel strand so that the middle part of the steel strand is clamped. In this way, in addition to the anchor plates at both ends of the steel strand, a temporary clamp is formed in the middle part of the steel strand, and then the subsequent steel cage adjustment, formwork installation and concrete pouring construction are carried out. The temporary clamping of the middle section of the steel strand can effectively ensure the construction safety during the subsequent steel cage adjustment, formwork installation and concrete pouring construction, as well as ensure the relative stability of the position of the steel strand during the subsequent steel cage adjustment, formwork installation and concrete pouring construction.

[0047] As a more advanced evolution, a second implementation is introduced below. Through the implementation of the second implementation, the application scenario and protection scope of the utility model are expanded, and both embodiments are within the protection scope of the utility model.

[0048] Specific technical reproduction implementation route 2

[0049] refer to Fig.11 The difference between this embodiment and the first embodiment is that the clamping effect between the upper and lower comb grooves is improved. In this embodiment, Fig.11As shown, a C-shaped semicircular steel pipe groove is welded and fixed at the bottom of the No. 1 U-shaped notch 101 and the No. 2 U-shaped notch 201 in the upper and lower comb tooth grooves, respectively. Specifically, a circular steel pipe with a suitable inner diameter is selected, and the inner diameter of the steel pipe is equivalent to the diameter of the steel strand. The circular steel pipe is divided into two by a cutting saw, and the two semicircular steel pipe grooves 6 formed after the division are respectively welded to the bottom of the No. 1 U-shaped notch 101 and the No. 2 U-shaped notch 201. This processing method can effectively improve the stress concentration formed on the steel strand by the upper and lower comb tooth grooves during the clamping process, and at the same time effectively increase the contact surface between the steel strand and the No. 1 U-shaped notch 101 and the No. 2 U-shaped notch 201, which can effectively increase the supporting effect on the steel strand and avoid the wire breakage phenomenon caused by the small contact area between the No. 1 U-shaped notch 101, the No. 2 U-shaped notch 201 and the steel strand.

[0050] At the same time, in view of the deflection and deformation of the upper and lower comb tooth grooves, especially in the prefabrication process of hollow slabs with a large width, due to the large design width of the hollow slab, a bolt hole is set in the center of the flat plate of the upper comb tooth groove, and a steel plate 202 is welded and fixed inside the lower comb tooth groove 2. The steel plate is tapped to form a threaded hole, and a hexagonal bolt 7 passes through the bolt hole from top to bottom and the lower end cooperates with the threaded hole. Through the hexagonal bolt, an auxiliary clamp is formed in the middle section of the upper and lower comb tooth grooves, that is, a constraint in the middle section is added, which can effectively improve the deflection and deformation of the upper and lower comb tooth grooves that are constrained only at the two ends.

[0051] The embodiments described above are merely descriptions of preferred implementations of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements to the present invention by relevant technical personnel in the field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A pre-tensioned hollow slab steel strand positioning and protection device, comprising an upper comb groove, a lower comb groove, a locking bolt, a fixing clamp and a positioning bolt, characterized in that: The upper comb tooth groove and the lower comb tooth groove are channel steel structures with U-shaped cross-sections, and at least two groups of paired and relatively arranged U-shaped notches are respectively arranged on the upper comb tooth groove and the lower comb tooth groove. The corresponding U-shaped notches on the upper comb tooth groove and the lower comb tooth groove after buckling form a steel strand clamping channel, and bolt holes are respectively arranged at both ends of the upper comb tooth groove and the lower comb tooth groove and fastened by locking bolts. The fixed clamping plate is an L-shaped steel plate component welded to the bottom of the lower comb tooth plate, and threaded holes are arranged on the fixed clamping plate and positioning bolts are installed, and the fixing clamping plate and the positioning bolts are used to engage with the clamping groove on the base.

2. A pre-tensioned hollow slab steel strand positioning and protection device according to claim 1, characterized in that: A semicircular steel pipe groove is welded in each of the U-shaped notches, and the inner diameter of the semicircular steel pipe groove is equal to the diameter of the steel strand.

3. A pre-tensioned hollow slab steel strand positioning and protection device according to claim 1, characterized in that: A bolt hole is arranged at the center of the flat plate of the upper comb tooth groove, and a steel plate is welded and fixed inside the lower comb tooth groove. The steel plate has a threaded hole, and the hexagonal bolt passes through the bolt hole from top to bottom and the lower end cooperates with the threaded hole.

4. A pre-tensioned hollow slab steel strand positioning and protection device according to claim 1, characterized in that: The entire surface of the device is corrosion-resistant.

5. The pre-tensioned hollow slab steel strand positioning and protection device according to claim 1, characterized in that: The upper comb tooth groove and the lower comb tooth groove have sufficient clamping force on the steel strand under the clamping of the locking bolt.

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