Precise pre-burying method of steel guardrail U-shaped high-strength bolt

Abstract

The application discloses a precise pre-burying method for U-shaped high-strength bolts of steel guardrails, which comprises the following steps: using a first device to process two U-shaped high-strength bolts, four ordinary nuts and a four-hole positioning steel plate into standard pre-buried parts, using a second device to bear all construction loads, and using a third device and a guide steel wire rope to fix the relative positions of the pre-buried parts in batches. The application has the following advantages: 1. The application can effectively avoid welding points at the stress positions of the U-shaped high-strength bolts, ensure the pre-burying quality, improve the construction efficiency and improve the positioning accuracy; 2. The pre-buried parts processed by the first device are good in integrity and standard in size, and the positioning welding points only occur between the ordinary nuts and the four-hole positioning steel plate, so the U-shaped high-strength bolts are not damaged; 3. The third device is convenient to operate, the positions in all directions are adjusted through threads, the positioning accuracy can reach 2 mm, and the pre-burying effect of 'one line of bolts and one surface of steel plates' is easily achieved; and 4. Multiple pre-buried parts can be positioned at a time, and the application range is wide.

Description

Technical Field

[0001] This invention relates to the field of bridge construction, and in particular to a method for the precise pre-embedding of U-shaped high-strength bolts for steel guardrails. Background Technology

[0002] Bridge steel railings are not only safety facilities for bridges but also aesthetic projects that enhance the bridge's appearance. The installation quality of the steel railings directly affects the bridge's impact resistance and overall appearance. Since steel railings are installed on the railing base using pre-embedded bolts, the quality of these bolts directly impacts the railing's impact resistance and the overall construction alignment. In steel guardrail construction, two common methods are used for pre-embedding U-shaped high-strength bolts: First, before tying the reinforcing bars of the guardrail base, a simple self-made positioning device is used to help control the distance between the U-shaped high-strength bolts, and the bolts are directly spot-welded to the precast beam. This method not only makes it difficult to guarantee positioning accuracy, but also severely affects the quality of the U-shaped high-strength bolts after direct spot welding. Second, steel formwork is installed after the reinforcing bars of the guardrail base are tied, and the U-shaped high-strength bolts are positioned using the formwork and a simple device. While this method improves the control of the alignment and elevation of the pre-embedded U-shaped high-strength bolts, the reinforcing bars of the guardrail base are the main load-bearing structure, with large diameters, numerous bolts, and small spacing. Pre-embedding the U-shaped high-strength bolts after tying the reinforcing bars leads to many positional conflicts between the reinforcing bars and the pre-embedded U-shaped high-strength bolts. This requires cutting the already tied reinforcing bars of the guardrail base, and the work must be done within a narrow formwork, affecting both efficiency and overall quality. Summary of the Invention

[0003] The purpose of this invention is to provide a precise pre-embedding method that is applicable to both straight and curved bridges, improves the positioning accuracy of U-shaped high-strength bolts for steel guardrails, avoids welding of the stress-bearing parts of the U-shaped high-strength bolts, speeds up the installation of the U-shaped high-strength bolts, and improves construction efficiency.

[0004] The objective of this invention is achieved as follows:

[0005] A precise pre-embedding method for U-shaped high-strength bolts in steel guardrails, the specific steps of which are as follows:

[0006] A. Using device No. 1, two U-shaped high-strength bolts, four ordinary nuts, and a four-hole positioning steel plate are processed into embedded parts for steel guardrails;

[0007] B. Using device No. 2, place the embedded part in the design position of the bridge in the horizontal direction, place the embedded part on device No. 2, with the thread of the U-shaped high-strength bolt of the embedded part facing upward, and place the two U-shaped high-strength bolts in parallel in the horizontal direction.

[0008] C. Using device No. 3, place it on the four-hole positioning steel plate of the embedded part, and use vertical G-type clamps to fix the embedded part and device No. 3. The two threads of the two U-shaped high-strength bolts on the embedded part in the horizontal bridge direction are laterally pressed against the short rod of device No. 3, and the threads of the two U-shaped high-strength bolts on the embedded part in the longitudinal bridge direction are laterally pressed against the long rod of device No. 3.

[0009] D. For both straight and curved bridges, guide wire ropes are installed at the surveyed and laid-out points and tightened with turnbuckles. The first guide wire rope controls the planar position of the four-hole positioning steel plate on the embedded part, and the second guide wire rope controls the position of the U-shaped high-strength bolts on the embedded part along the inner side of the bridge. The ends of the two guide wire ropes are fixed to the reserved reinforcing bars on the bridge deck. The planar projection of the two guide wire ropes coincides with the ink line laid out on the bridge deck, and the elevation of the embedded part is checked with a steel ruler.

[0010] E. Adjust the foot screw of device No. 3 so that the top surface of the four-hole positioning steel plate of the embedded part is flush with the first guide steel wire rope in the longitudinal direction of the bridge. Use a spirit level to keep the four-hole positioning steel plate of the embedded part horizontal in the transverse direction of the bridge.

[0011] F. Use the horizontal G-type clamp to adjust the plane position of the embedded part and the No. 3 device that have been clamped together, so that the side of the U-shaped high-strength bolt is close to the second guide wire rope.

[0012] G. Use short steel bars to position and weld the embedded parts to the bridge deck steel bars. When welding, pay special attention to the two vertical legs of the U-shaped high-strength bolt 21, which are the main stress-bearing parts, and avoid weld points.

[0013] H. Remove the vertical and horizontal G-clamps, and install Device 2 and Device 3 in the corresponding positions of the next batch of embedded parts; among them, move the short rod at the beginning of Device 3 to the position of the short rod at the end of the previous batch; repeat the above work steps to complete the installation of all embedded parts of the bridge in sequence, and carry out other construction procedures for the guardrail base after acceptance.

[0014] In step A, device number one consists of a rectangular base plate, a four-hole positioning steel plate, three angle steels, and four short steel pipes. Both the rectangular base plate and the four-hole positioning steel plate are placed horizontally, with the rectangular base plate below and the four-hole positioning steel plate above. The rectangular base plate and the four-hole positioning steel plate are vertically supported and welded together by three angle steels of equal length. The four-hole positioning steel plate has four bolt holes at the designed positions of the U-shaped high-strength bolts, with each bolt hole having a diameter 2mm larger than the diameter of the U-shaped high-strength bolt. The rectangular base plate and the four-hole positioning steel plate have the same dimensions. The rectangular base plate does not have bolt holes, but a short steel pipe is welded to each of the four bolt hole positions corresponding to the four-hole positioning steel plate. The inner diameter of the short steel pipe is larger than that of the U-shaped high-strength bolt. The diameter is 2mm larger than the standard diameter; the axis of each short steel pipe is vertically aligned with the center of the bolt holes of the upper four-hole positioning steel plate; the lower end of the short steel pipe is cut with a 45° bevel along half of the cross-section, and the bevel is placed outward perpendicular to the diagonal of the rectangular base plate to facilitate observation of the contact between the U-shaped high-strength bolts inside the short steel pipe and the rectangular base plate; three angle steels are evenly arranged on the smallest inscribed circle formed by the four bolt holes, and the height of the angle steels is greater than the height of the short steel pipes; this device can effectively ensure that the four exposed threads of the two U-shaped high-strength bolts of the embedded part are of equal length and perpendicular to the four-hole positioning steel plate, avoiding the U-shaped high-strength bolts from affecting the normal installation of the subsequent steel guardrail due to non-parallelism and unequal length of the two limbs.

[0015] Further, in step A, first install a common nut on each of the two legs of the U-shaped high-strength bolt, and screw the common nuts to the bottom of the thread of the U-shaped high-strength bolt. Align and place another identical four-hole positioning steel plate on the four-hole positioning steel plate of device No. 1. Insert the U-shaped high-strength bolt with the opening facing down through the bolt holes of the two four-hole positioning steel plates into the short steel pipe of the rectangular base plate. Apply downward pressure to make the U-shaped high-strength bolt press against the rectangular base plate of device No. 1. After tightening the common nuts downward, spot weld the common nuts to the four-hole positioning steel plate added above. The embedded part is then processed. After taking it out, rotate the embedded part 180° so that the thread faces up and place it upright for batch processing.

[0016] In step B, the second device is an iron stool welded from channel steel and reinforcing bars; the stool surface is made of channel steel with the flat side facing up and the opening facing down; the stool legs are A-shaped reinforcing bars, and the stool surface and stool legs are welded together with short diagonal reinforcing bars to form two triangular stable structures; the function of the iron stool is to bear the entire construction load, reduce the relative height between the third device and the bridge deck, and increase the stability of the third device.

[0017] In step C, device number three is a frame-shaped positioning device composed of two long rods, multiple short rods, and multiple anchor screws. The short rods are positioned above the long rods and perpendicular to each other. Both the long and short rods are welded from square tubing with a flat cross-section and the long side of the cross-section is horizontal. The maximum width of the two long rods is 5mm smaller than the clear distance between the openings of the U-shaped high-strength bolts, facilitating the placement and removal of device number three. The distance between the two short rods is 1500 mm. A short rod is used to position an embedded part. The length of the short rod is 100mm longer than the width of the four-hole positioning steel plate. A vertical auger is welded to each end of the short rod. The auger consists of a auger rod with a handle, a short auger steel pipe, and two auger nuts. The two auger nuts are welded to the side of the end of the short rod after clamping the short auger steel pipe from the top and bottom. The threaded end of the auger rod with the handle is screwed into the short auger steel pipe. The top surface of the threaded end of the auger rod is pressed against the bench surface of the second device. The elevation of the third device can be adjusted by rotating the auger rod with the handle.

[0018] In step D, the distances between the coordinate and elevation measurement points are different for straight bridges and curved bridges during the measurement and layout process, and the distances for curved bridges need to be increased.

[0019] This invention uses device number one to process two U-shaped high-strength bolts, four ordinary nuts, and a four-hole positioning steel plate into standard embedded parts; device number two bears the entire construction load; and device number three and guide wire ropes are used to batch fix the relative positions of the embedded parts. This invention has the following advantages:

[0020] 1. It can effectively avoid the appearance of weld points in the stressed parts of U-shaped high-strength bolts, improve construction efficiency, and enhance positioning accuracy;

[0021] 2. Embedded parts processed using device No. 1 have good integrity and standard dimensions. The positioning welding points only occur between ordinary nuts and four-hole positioning steel plates, and will not damage the U-shaped high-strength bolts.

[0022] 3. The No. 3 device has a simple structure and is easy to operate. The position in each direction can be adjusted by threads, and the positioning accuracy can reach 2mm, easily achieving the pre-embedding effect of "bolts in a line and steel plates on a surface".

[0023] 4. Multiple embedded parts can be positioned at a time, resulting in high construction efficiency and wide applicability. Attached Figure Description

[0024] Figure 1 This is a front view of device number one.

[0025] Figure 2 This is a side view of device number one;

[0026] Figure 3 This is a plan view of device number one;

[0027] Figure 4 This is a schematic diagram of the assembly of the embedded parts;

[0028] Figure 5 A schematic diagram of the elevation of two embedded parts placed upright;

[0029] Figure 6 This is a front view of device number two;

[0030] Figure 7 This is a side view of device number two;

[0031] Figure 8 This is a schematic diagram of the elevation of device No. 3;

[0032] Figure 9 This is a plan view of device number three;

[0033] Figure 10 This is a cross-sectional schematic diagram of the present invention;

[0034] Figure 11 This is a schematic elevation view of the present invention;

[0035] Figure 12 This is a planar schematic diagram of the present invention;

[0036] Figure 13 This is an elevation view of the invention in use.

[0037] Figure 14 This is a cross-sectional schematic diagram of the present invention in use;

[0038] In the diagram: 1. Device No. 1; 11. Four-hole positioning steel plate; 12. Rectangular base plate; 13. Angle steel; 14. Short steel pipe; 15. Bolt hole; 2. Embedded part; 21. U-shaped high-strength bolt; 22. Ordinary nut; 3. Device No. 2; 31. Stool surface; 32. Stool leg; 33. Inclined short steel bar; 4. Device No. 3; 41. Long rod; 42. Short rod; 43. Foot screw; 431. Foot screw nut; 432. Foot screw short steel pipe; 433. Foot screw rod; 44. G-clamp; 45. Level; 5. Guide wire rope; 51. Turnbuckle; 52. Reserved steel bar; 53. Short steel bar; 54. Bridge deck. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the embodiments and the accompanying drawings.

[0040] Example 1:

[0041] A precise pre-embedding method for U-shaped high-strength bolts in steel guardrails, applied to straight bridges, includes the following specific steps:

[0042] A. Using device 1, two U-shaped high-strength bolts 21, four ordinary nuts 22 and a four-hole positioning steel plate 11 are processed into embedded parts 2 for steel guardrails;

[0043] B. Using device 3, place it horizontally at the design position of embedded part 2, place embedded part 2 on device 3, with the threads of U-shaped high-strength bolts 21 of embedded part 2 facing upwards, and place the two U-shaped high-strength bolts 21 horizontally parallel.

[0044] C. Using device 4, place it on the four-hole positioning steel plate 11 of the embedded part 2, that is: the two long rods 41 of device 4 are placed on the four-hole positioning steel plate 11, and the five short rods 42 of device 4 are placed between the two U-shaped high-strength bolts 21 of the embedded part 2; device 4 uses vertical G-type clamps 44 to fix the embedded part 2 to device 4, the threads of the two U-shaped high-strength bolts 21 in the horizontal direction of the embedded part 2 are pressed against the short rods 42 of device 4, and the threads of the two U-shaped high-strength bolts 21 in the longitudinal direction of the embedded part 2 are pressed against the long rods 41 of device 4.

[0045] D. Install guide wire rope 5 and tighten it with turnbuckle 51; the first guide wire rope 5 controls the plane position of the four-hole positioning steel plate 11 on the embedded part 2, and the second guide wire rope 5 controls the plane position of the U-shaped high-strength bolt 21 on the inner side of the embedded part 2 along the bridge. The ends of the two guide wire ropes 5 are respectively fixed on the reserved steel bars 52 on the bridge deck; the plane projection of the two guide wire ropes 5 coincides with the ink line of the bridge deck layout, and the elevation of the embedded part 2 is checked with a steel ruler.

[0046] E. Adjust the foot screw 433 of device 3 4 so that the top surface of the four-hole positioning steel plate 11 of the embedded part 2 is flush with the first guide steel wire rope 5 in the longitudinal direction of the bridge. Use a spirit level 45 to keep the four-hole positioning steel plate 11 of the embedded part 2 horizontal in the transverse direction of the bridge.

[0047] F. Use the horizontal G-type clamp 44 to adjust the plane position of the embedded part 2 and the No. 3 device 4 that have been clamped together, so that the side of the U-shaped high-strength bolt 21 is close to the second guide wire rope 5.

[0048] G. Use short steel bars to position and weld the embedded part 2 to the bridge deck steel bars. When welding, pay special attention to the two vertical legs of the U-shaped high-strength bolt 21, which are the main stress-bearing parts, and avoid weld points.

[0049] H. Remove the vertical G-clamp 44 and the horizontal G-clamp 44, and install the second device 3 and the third device 4 in the corresponding positions of the next batch of embedded parts 2; among them, the short rod 42 at the beginning of the third device 4 is moved to the position of the short rod 42 at the end of the previous batch; repeat the above work steps to complete the installation of the embedded parts of the entire bridge in sequence, and carry out the construction of other processes of the guardrail base after acceptance.

[0050] In step A, device 1 consists of a rectangular base plate 12, a four-hole positioning steel plate 11, three angle steels 13, and four short steel pipes 14. The rectangular base plate 12 and the four-hole positioning steel plate 11 are placed horizontally, with the rectangular base plate 12 below and the four-hole positioning steel plate 11 above. The rectangular base plate 12 and the four-hole positioning steel plate 11 are vertically supported and welded together by three angle steels 13 of equal length. The four-hole positioning steel plate 11 has four bolt holes 15 at the designed positions of the U-shaped high-strength bolts 21, with the diameter of each bolt hole 15 being 2mm larger than the diameter of the U-shaped high-strength bolt 21. The rectangular base plate 12 has the same dimensions as the four-hole positioning steel plate 11. The rectangular base plate 12 does not have bolt holes 15, but a short steel pipe 14 is welded to each of the four bolt hole 15 positions corresponding to the four-hole positioning steel plate 11. The inner surface of the short steel pipe 14... The diameter of the U-shaped high-strength bolt 21 is 2mm larger than that of the other two short steel pipes 14. The axis of each short steel pipe 14 is vertically aligned with the center of the bolt hole 15 of the upper four-hole positioning steel plate 11. The lower end of the short steel pipe 14 is cut with a 45° bevel along half of the cross section. The bevel is placed outward perpendicular to the diagonal of the rectangular base plate 12 to facilitate observation of the contact between the U-shaped high-strength bolt 21 inside the short steel pipe 14 and the rectangular base plate 12. Three angle steels 13 are evenly arranged on the smallest inscribed circle formed by the four bolt holes 15. The height of the angle steels 13 is greater than the height of the short steel pipe 14. This device can effectively ensure that the four exposed threads of the two U-shaped high-strength bolts 21 of the embedded part 2 are of equal length and perpendicular to the four-hole positioning steel plate 11, avoiding the U-shaped high-strength bolts 21 from affecting the normal installation of the subsequent steel guardrail due to non-parallelism and unequal length of the two limbs.

[0051] Further, in step A, first install a common nut 22 on each of the two legs of the U-shaped high-strength bolt 21, and screw the common nut 22 to the bottom of the thread of the U-shaped high-strength bolt 21. Then, align and place another identical four-hole positioning steel plate 11 on the four-hole positioning steel plate of device 1. Insert the U-shaped high-strength bolt 21 with its opening facing down through the bolt holes 15 of the two four-hole positioning steel plates 11 into the short steel pipe 14 of the rectangular base plate 12. Apply downward pressure to make the U-shaped high-strength bolt 21 press against the rectangular base plate 12 of device 1. After tightening the common nut 22 downward, spot weld the common nut 22 to the four-hole positioning steel plate 11 added above. The embedded part 2 is then processed. After taking it out, rotate the embedded part 180° so that the thread faces upward and place it upright for batch processing.

[0052] In step B, device 3 is an iron stool welded from channel steel and reinforcing bars; the stool surface 31 is made of channel steel with the flat side facing up and the opening facing down; the stool legs 32 are A-shaped reinforcing bars, and the stool surface 31 and stool legs 32 are welded together with short diagonal reinforcing bars 33 to form two triangular stable structures; the function of the iron stool is to bear the entire construction load, reduce the relative height between device 4 and the bridge deck, and increase the stability of device 4.

[0053] In step C, the third device 4 used for the straight bridge is a frame-shaped positioning device composed of two long rods 41, five short rods 42, and ten anchor screws 43. The short rods 42 are located above the long rods 41 and are perpendicular to each other. Both the long rods 41 and the short rods 42 are welded from square tubes with a flat cross-section and the long side of the cross-section is horizontal. The maximum width of the two long rods 41 is 5mm smaller than the clear distance between the openings of the U-shaped high-strength bolts 21, which facilitates the placement and removal of the third device 4. The distance between the two short rods 42 is 1500 mm. A short rod 42 is used to position an embedded part 2. The length of the short rod 42 is 100mm longer than the width of the four-hole positioning steel plate 11. A vertical foot screw 43 is welded to each end of the short rod 42. The foot screw 43 consists of a foot screw rod 433 with a handle, a short foot screw steel pipe 432, and two foot screw nuts 431. The two foot screw nuts 431 are welded to the side of the end of the short rod 42 after clamping the short foot screw steel pipe 432 from the top and bottom. The threaded end of the foot screw rod 433 with a handle is screwed into the short foot screw steel pipe 432. The top surface of the threaded end of the foot screw rod 433 is pressed against the seat surface 31 of the second device 3. The elevation of the third device 4 can be adjusted by rotating the foot screw rod 433 with a handle.

[0054] In step D, when laying out the bridge deck of the straight bridge, a coordinate point is measured every 10m. In the vertical curve section, the layout is densified, and an elevation point is measured every other embedded part 2. The length of the guide steel wire rope 5 is not less than 20m.

[0055] Example 2:

[0056] The method in Example 2 is basically the same as that in Example 1, except that:

[0057] In step C, the third device 4 used for the curved bridge is a frame-shaped positioning device consisting of two long rods 41, three short rods 42, and six foot screws 43. When this third device 4 is used on the curved bridge, it applies the working principle of straight lines instead of arcs. Therefore, its long rods 41 are shorter than those in Embodiment 1, and the number of short rods 42 and foot screws 43 are less than those in Embodiment 1.

[0058] In step D, when laying out the curved bridge deck, a coordinate point is measured every 3m. In the vertical curve section, the layout is densified. An elevation point is measured every other embedded part 2. The length of the guide steel wire rope 5 does not exceed 12m.

[0059] It should be noted that specific examples have been used in this specification to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for precise pre-embedding of U-shaped high-strength bolts for steel guardrails, characterized in that, The specific steps are as follows: A. Using device No. 1, two U-shaped high-strength bolts, four ordinary nuts, and a four-hole positioning steel plate are processed into embedded parts for steel guardrails; B. Using device No. 2, place the embedded part in the design position of the bridge in the horizontal direction, place the embedded part on device No. 2, with the thread of the U-shaped high-strength bolt of the embedded part facing upward, and place the two U-shaped high-strength bolts in parallel in the horizontal direction. C. Using device No. 3, place it on the four-hole positioning steel plate of the embedded part, and use vertical G-type clamps to fix the embedded part and device No.

3. The two threads of the two U-shaped high-strength bolts on the embedded part in the horizontal bridge direction are laterally pressed against the short rod of device No. 3, and the threads of the two U-shaped high-strength bolts on the embedded part in the longitudinal bridge direction are laterally pressed against the long rod of device No.

3. The No. 3 device is a frame-shaped positioning device composed of two long rods, multiple short rods, and multiple foot screws. The short rods are located on top of the long rods and are perpendicular to each other. The maximum width of the two long rods is 5mm smaller than the net opening distance of the U-shaped high-strength bolts, which facilitates the placement and removal of the No. 3 device. The distance between the two short rods is 1500mm. Each short rod is used to position one embedded part. The length of the short rod is 100mm longer than the width of the four-hole positioning steel plate. A vertical foot screw is welded to each end of the short rod. The foot screw consists of a foot screw rod with a handle, a short foot screw steel pipe, and two foot screw nuts. The two foot screw nuts are welded to the side of the end of the short rod after clamping the short foot screw steel pipe from the top and bottom. The threaded end of the foot screw rod with the handle is screwed into the short foot screw steel pipe. The top surface of the threaded end of the foot screw rod is pressed against the seat surface of the No. 2 device. The elevation of the No. 3 device can be adjusted by rotating the foot screw rod with the handle. D. For both straight and curved bridges, guide wire ropes are installed at the surveyed and laid-out points and tightened with turnbuckles. The first guide wire rope controls the planar position of the four-hole positioning steel plate on the embedded part, and the second guide wire rope controls the position of the U-shaped high-strength bolts on the embedded part along the inner side of the bridge. The ends of the two guide wire ropes are fixed to the reserved reinforcing bars on the bridge deck. The planar projection of the two guide wire ropes coincides with the ink line laid out on the bridge deck, and the elevation of the embedded part is checked with a steel ruler. E. Adjust the foot screw of device No. 3 so that the top surface of the four-hole positioning steel plate of the embedded part is flush with the first guide steel wire rope in the longitudinal direction of the bridge. Use a spirit level to keep the four-hole positioning steel plate of the embedded part horizontal in the transverse direction of the bridge. F. Use the horizontal G-type clamp to adjust the plane position of the embedded part and the No. 3 device that have been clamped together, so that the side of the U-shaped high-strength bolt is close to the second guide wire rope. G. Use short steel bars to position and weld the embedded parts to the bridge deck steel bars. When welding, pay special attention to the two vertical legs of the U-shaped high-strength bolts, which are the main stress-bearing parts, and avoid weld points. H. Remove the vertical and horizontal G-clamps, and install Device 2 and Device 3 in the corresponding positions of the next batch of embedded parts; among them, move the short rod at the beginning of Device 3 to the position of the short rod at the end of the previous batch; repeat the above work steps to complete the installation of all embedded parts of the bridge in sequence, and carry out other construction procedures for the guardrail base after acceptance.

2. The precise pre-embedding method for U-shaped high-strength bolts in steel guardrails according to claim 1, characterized in that: In step A, device number one consists of a rectangular base plate, a four-hole positioning steel plate, three angle steels, and four short steel pipes. Both the rectangular base plate and the four-hole positioning steel plate are placed horizontally, with the rectangular base plate below and the four-hole positioning steel plate above. The rectangular base plate and the four-hole positioning steel plate are vertically supported and welded together by three angle steels of equal length. The four-hole positioning steel plate has four bolt holes at the designed positions for U-shaped high-strength bolts, with each bolt hole having a diameter 2mm larger than the diameter of the U-shaped high-strength bolt. The rectangular base plate and the four-hole positioning steel plate have the same dimensions. The rectangular base plate does not have bolt holes, but bolt holes are present in the corresponding positions... A short steel pipe is welded to each of the four bolt holes of the four-hole positioning steel plate. The inner diameter of the short steel pipe is 2mm larger than the diameter of the U-shaped high-strength bolt. The axis of each short steel pipe is vertically aligned with the center of the bolt hole of the upper four-hole positioning steel plate. The lower end of the short steel pipe is cut with a 45° bevel along half of the cross-section. The bevel is placed outward perpendicular to the diagonal of the rectangular base plate to facilitate observation of the contact between the U-shaped high-strength bolt inside the short steel pipe and the rectangular base plate. Three angle steels are evenly arranged on the smallest inscribed circle formed by the four bolt holes. The height of the angle steels is greater than the height of the short steel pipes.

3. The precise pre-embedding method for U-shaped high-strength bolts in steel guardrails according to claim 2, characterized in that... In step A, first install a regular nut on each of the two legs of the U-shaped high-strength bolt, and screw the regular nuts to the bottom of the thread of the U-shaped high-strength bolt. Align and place another identical four-hole positioning steel plate on the four-hole positioning steel plate of device No.

1. Insert the U-shaped high-strength bolt with the opening facing down through the bolt holes of the two four-hole positioning steel plates into the short steel pipe of the rectangular base plate. Apply downward pressure to make the U-shaped high-strength bolt press against the rectangular base plate of device No.

1. After tightening the regular nuts downward, spot weld the regular nuts to the four-hole positioning steel plate added above. The embedded part is now processed. After taking it out, rotate the embedded part 180° so that the thread faces up and place it upright for batch processing.

4. The precise pre-embedding method for U-shaped high-strength bolts in steel guardrails according to claim 1, characterized in that: In step B, the second device is an iron stool welded from channel steel and reinforcing bars; the stool surface is made of channel steel with the flat side facing up and the opening facing down; the stool legs are A-shaped reinforcing bars, and the stool surface and stool legs are welded together with short diagonal reinforcing bars to form two triangular stable structures; the function of the iron stool is to bear the entire construction load, reduce the relative height between the third device and the bridge deck, and increase the stability of the third device.

5. The precise pre-embedding method for U-shaped high-strength bolts in steel guardrails according to claim 1, characterized in that: In step C, both the long and short rods are welded from square tubes. The cross-section of the square tubes is flat, and the long side of the cross-section is placed horizontally.

6. The precise pre-embedding method for U-shaped high-strength bolts in steel guardrails according to claim 1, characterized in that: In step D, the distances between the coordinate and elevation measurement points are different for straight bridges and curved bridges during the measurement and layout process, and the distances for curved bridges need to be increased.

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