A method for constructing a steel pipe with few supports for a side-span cast-in-place section

Abstract

The application discloses a kind of side span cast-in-place section steel pipe few support construction methods, by the support steel pipe pile setting into certain inclination angle, so as to let support span reach requirement, while, steel pipe pile bottom can be on pier cap, steel pipe pile on cap does not need to treat support foundation, to save material and manpower, shorten construction period, reduce to support steel pipe pile foundation treatment range, without additional setting cap under support steel pipe pile.Utilize winch and cantilever beam fixed on cast-in-place section other side approach bridge T beam, realize steel pipe pile hoisting installation, can avoid the adverse effects caused by long process connection period, difficult access of required hoisting equipment etc..By pre-burying arc positioning device on cap, positioning flat link is welded in advance on pier, when support steel pipe pile hoisting, lifting device can be lifted along the spatial position of steel pipe pile, when reaching design position, arc positioning device and positioning flat link can be used to quickly lock the spatial position of support steel pipe pile.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of bridge construction, and particularly relates to a steel pipe few support construction method for side span cast-in-place section. BACKGROUND

[0002] The cast-in-place section of a concrete cable-stayed bridge is usually constructed by using a support method or a corbel bracket method. The corbel bracket method often needs to increase counterweights on the other side of the cast-in-place section due to its stress characteristics, and the structure performs poorly in terms of stiffness and stability when the cast-in-place section has a large span. The support method commonly used includes full-support and steel pipe few support, etc. The full-support is not as economical and safe as the steel pipe few support when the cast-in-place section has a high height, and the steel pipe few support needs to be erected with the aid of large-tonnage hoisting equipment.

[0003] According to previous engineering experience, the hoisting equipment used for erecting the steel pipe few support of the cast-in-place section mainly includes tower cranes, truck cranes, caterpillar cranes, and span-pier gantry cranes, etc. After comparing and analyzing these schemes, the following conclusions can be obtained:

[0004] 1. The construction using a tower crane or a span-pier gantry crane is mainly affected by the connection between the pier construction and the cast-in-place section construction process. If there is a long idle period from the completion of the pier construction to the construction of the cast-in-place section, the rental cost of the support will be increased if the support is erected in advance, and the difference in the concrete age of the cast-in-place section and the closure section may be too large. At the same time, if the support is not erected in advance, the rental period of the tower crane or the span-pier gantry crane will be affected. From the construction cost and construction technology, this erection method is not appropriate.

[0005] 2. The hoisting equipment such as truck cranes and caterpillar cranes is mainly affected by two factors, i.e. the terrain and the erection height of the support. The steel pipe pile, as the main stress structure, is often heavy, and needs large hoisting equipment or segmented hoisting in the installation and construction. If the segmented hoisting is adopted, it is difficult to connect and position in the air, and the verticality of the steel pipe pile is difficult to guarantee. However, in mountainous areas, the equipment hoisting capacity may be insufficient or it is difficult for large-tonnage equipment to enter the site due to the terrain factor. SUMMARY

[0006] The purpose of the present application is to provide a steel pipe few support construction method for side span cast-in-place section, so as to solve the negative effects caused by the long process connection period, the difficult access of hoisting equipment, and the large amount of support materials in the conventional construction method, increase the practical operability of the project, and reduce the construction cost.

[0007] The purpose of the present application is achieved by the following technical means, a steel pipe few support construction method for side span cast-in-place section, comprising the following steps:

[0008] Step one, hoist the positioning flat link on the approach bridge T beam on the high platform on the top of the pier body, and install the positioning flat link on the other side of the pier body opposite to the approach bridge T beam, and install the fixed support on the pier body above the positioning flat link;

[0009] Step two, install the lifting device and the Bailey frame to the approach bridge T beam;

[0010] Step three, hoist the support steel pipe pile by the lifting device, and tilt the support steel pipe pile after hoisting, the bottom end of the support steel pipe pile is connected to the pile cap, and the pile body of the support steel pipe pile is connected to the positioning flat link;

[0011] Step four, install other support steel pipe piles on the pier body, install the transverse fixed flat link after the installation of the two adjacent support steel pipe piles is completed, and the two adjacent support steel pipe piles are fixed;

[0012] Step five, connect the unloading device on the top of the support steel pipe pile, connect the pile top bearing beam on the unloading device and the fixed support respectively, the top heights of the pile top bearing beams on the unloading device and the fixed support are consistent, hoist and connect the Bailey frame to the two pile top bearing beams as a distribution beam of the few supports;

[0013] Step six, continue to install the rest structure of the few supports, and the few support erection construction is completed.

[0014] The positioning flat link comprises two cross beams connected to the pier body, the two cross beams are located at different heights, the length of the upper cross beam is greater than that of the lower cross beam, the inclination degree of the connecting line of the extending ends of the upper cross beam and the lower cross beam is consistent with the inclination degree of the support steel pipe pile, and a scissors support is further connected between the upper cross beam and the lower cross beam.

[0015] If there are several pier bodies on the same side, a plurality of vertical support steel pipe piles are connected to the pile cap between the two pier bodies, the positioning flat link is connected to the outermost support steel pipe pile, the support steel pipe pile is hoisted and connected to the positioning flat link, and when the Bailey frame is hoisted and connected to the pile top bearing beams of the unloading device and the fixed support, the pile top bearing beam of the support steel pipe pile is also connected with the Bailey frame.

[0016] The pile cap is connected with an arc-shaped positioning device, the positioning device is an arc-shaped plate, the inclination degree of the arc-shaped plate is consistent with the inclination degree of the support steel pipe pile, the arc-shaped plate is inserted into the inner side of the support steel pipe pile, and the arc-shaped plate is connected with the support steel pipe pile in a fit manner.

[0017] The steel pipe support column is connected to the low platform on the top of the pier body, the top end of the steel pipe support column is in contact with the Bailey frame, the steel pipe support column is used for supporting the Bailey frame, and the steel pipe support column is removed after the Bailey frame is hoisted and connected to the two pile top bearing beams.

[0018] The one end of the Bailey frame is anchored in the approach bridge T beam, and the other end is suspended in the air in the direction of the positioning flat connection; the traction ropes of a group of lifting devices are vertically lowered along the suspended end of the Bailey frame, and the traction ropes of another group of lifting devices are vertically lowered along the pier body.

[0019] The unloading device is a sand cylinder.

[0020] The fixed support includes a plurality of pre-embedded steel bars and positioning steel bars connected at one end in the pier body, and the other end of the pre-embedded steel bars and the positioning steel bars is provided with a second positioning plate and a first positioning plate, a plurality of through holes are formed in the second positioning plate and the first positioning plate for the pre-embedded steel bars and the positioning steel bars to pass through, the second positioning plate is connected with the pre-embedded steel bars and the positioning steel bars, a sleeve is sleeved on the steel bars between the second positioning plate and the first positioning plate, and the first positioning plate is fastened with the sleeve through bolts.

[0021] The top of the first positioning plate is further connected with a third positioning plate protruding outward, and a plurality of stiffening plates are further connected to the surface of the first positioning plate, the stiffening plates are connected with the third positioning plate, and the pile top bearing beam is connected at the top of the third positioning plate.

[0022] The beneficial effects of the present application are:

[0023] 1. By arranging the support steel pipe pile at a certain inclination angle, the support span can meet the requirements, and the bottom of the steel pipe pile can be on the pier column pile cap, so that the support foundation of the steel pipe pile on the pile cap does not need to be treated, material and manpower are saved, the construction period is shortened, the treatment range of the support steel pipe pile foundation is reduced, and the pile cap does not need to be additionally arranged under the support steel pipe pile.

[0024] 2. The steel pipe pile is hoisted and installed by using the winch fixed on the other side of the cast-in-place section of the approach bridge T beam and the cantilever beam, so that the adverse effects caused by the long process connection period and the difficulty in accessing the required hoisting equipment can be avoided.

[0025] 3. By pre-embedding the arc-shaped positioning device on the pile cap and welding the positioning flat connection in advance on the pier body, when the support steel pipe pile is hoisted, the lifting device can be lifted along the spatial position of the steel pipe pile, and when the steel pipe pile reaches the designed position, the spatial position of the steel pipe pile can be quickly locked by using the arc-shaped positioning device and the positioning flat connection.

[0026] 4. By using the fixed support to replace the steel bracket or the steel pipe pile column, about 1 / 4 of the steel material can be saved. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a schematic diagram of step one;

[0028] Figure 2 It is a side view of step two;

[0029] Figure 3 It is a front view of step two;

[0030] Figure 4 is a schematic diagram of the lifting device;

[0031] Figure 5 is a schematic diagram of step three;

[0032] Figure 6 is a schematic diagram of step four;

[0033] Figure 7 is a schematic diagram of step five;

[0034] Figure 8 is a schematic diagram of step six;

[0035] Figure 9 is a front view of the composition of the lifting device and construction arrangement;

[0036] Figure 10 is a side view of the composition of the lifting device and construction arrangement;

[0037] Figure 11 is a side view of the arc-shaped positioning device;

[0038] Figure 12 is a top view of the arc-shaped positioning device;

[0039] Figure 13 is a side view of the fixed support;

[0040] Figure 14 is a front view of the fixed support;

[0041] Figure 15 is a comparison diagram of the support steel pipe pile and the pier body structure.

[0042] Figure 1 is a pier body; 2 is a high platform; 3 is a positioning flat link; 4 is a fixed support; 5 is a Bailey frame; 6 is a support steel pipe pile; 7 is a transverse fixed flat link; 8 is an unloading device; 9 is a pile top bearing beam; 10 is a support steel pipe pile; 11 is a pile cap; 12 is an arc-shaped positioning device; 13 is a low platform; 14 is a steel pipe support column; 15 is a pre-embedded steel bar; 16 is a positioning steel bar; 17 is a second positioning plate; 18 is a first positioning plate; 19 is a sleeve; 20 is a third positioning plate; 21 is a stiffened plate; 22 is a winch; 23 is an upper anchoring cross beam; 24 is a lower anchoring cross beam; 25 is a cable wind rope.

[0043] The application will be further described in detail below in combination with the drawings and examples. DETAILED DESCRIPTION

[0044]

Example 1

[0045] A steel pipe few-support construction method for a side span cast-in-place section, comprising the following steps:

[0046] Step one, the positioning flat link 3 is hoisted on the approach bridge T beam on the high platform 2 on the top of the pier body 1, and the positioning flat link 3 is installed on the other side of the pier body 1 relative to the approach bridge T beam, and the fixed support 4 is installed on the pier body 1 above the positioning flat link 3;

[0047] As shown in Figure 10 , the existing construction is divided into high platform 2 and low platform 13 on the top of the pier body 1, and the approach bridge T beam is located on the high platform 2.

[0048] As shown in Figure 1 , in the first step, the structure size of the completed positioning flat link 3 is compounded, and after the compound is not a problem, the positioning flat link 3 is installed, and the small car hoist is installed on the approach bridge T beam of the cast-in-place section.

[0049] After installation, as shown in Figure 3 , because a plurality of support steel pipe piles 6 are arranged on each pier body 1, a plurality of groups of positioning flat links 3 and fixed supports 4 are connected on the pier body 1.

[0050] The positioning flat link 3 comprises two cross beams connected to the pier body 1, the two cross beams are located at different heights, the upper cross beam is longer than the lower cross beam, the inclination of the connecting line of the upper cross beam and the lower cross beam is consistent with the inclination of the support steel pipe pile 6, and a scissors support is further connected between the upper cross beam and the lower cross beam.

[0051] Because the lengths are inconsistent, the support steel pipe pile 6 can be connected to the positioning flat link 3 obliquely.

[0052] The fixed support 4 comprises a plurality of pre-embedded steel bars 15 and positioning steel bars 16 connected to the pier body 1 at one end, and the other end of the pre-embedded steel bars 15 and the positioning steel bars 16 is provided with a second positioning plate 17 and a first positioning plate 18, a plurality of through holes are formed in the second positioning plate 17 and the first positioning plate 18 for the pre-embedded steel bars 15 and the positioning steel bars 16 to pass through, the second positioning plate 17 is connected with the pre-embedded steel bars 15 and the positioning steel bars 16, a sleeve 19 is sleeved on the steel bars between the second positioning plate 17 and the first positioning plate 18, and the first positioning plate 18 is fastened with the sleeve 19 through bolts.

[0053] The fixed support replaces the steel bracket or the steel pipe pile column, and about 1 / 4 of the steel material can be saved.

[0054] The top of the first positioning plate 18 is further connected with a third positioning plate 20 protruding outward, and a plurality of stiffening plates 21 are further connected to the surface of the first positioning plate 18, the stiffening plates 21 are connected with the third positioning plate 20, and the pile top bearing beam 9 is connected to the top of the third positioning plate 20.

[0055] As shown in Figure 13 and Figure 14As shown, during construction of the pier 1, several pre-embedded reinforcing bars 15 and positioning reinforcing bars 16 are pre-embedded at the designed height. The fixing bracket 4 includes multiple rows of reinforcing bars, each row including the top and bottom pre-embedded reinforcing bars 15 and two positioning reinforcing bars 16 in between. The second positioning plate 17 and the first positioning plate 18 both have several holes. The second positioning plate 17 and the first positioning plate 18 are inserted into an array of reinforcing bars. The second positioning plate 17 is fixed to the reinforcing bars. A sleeve 19 is fitted on the reinforcing bar between the second positioning plate 17 and the first positioning plate 18. The first positioning plate 18 is fastened to the sleeve 19 by screwing bolts into the reinforcing bars on the outside. The positioning reinforcing bars 16 are also connected to the pre-embedded reinforcing bars 15.

[0056] The top of the first positioning plate 18 also has a third positioning plate 20 extending outward. The third positioning plate 20 is used for subsequent placement and connection of the pile top bearing beam 9. The outer surface of the first positioning plate 18 also has several stiffening plates 21 that simultaneously connect the first positioning plate 18 and the third positioning plate 20.

[0057] like Figure 2 , Figure 3 , Figure 9 and Figure 10 As shown, in step two, the lifting device and Bailey bridge 5 are installed onto the approach bridge T-beam;

[0058] One end of the Bailey bridge 5 is anchored to the approach bridge T-beam, and the other end extends out in the direction of the positioning flat link 3 and is suspended in the air; the traction rope of one set of lifting devices hangs down along the suspended end of the Bailey bridge 5, and the traction rope of another set of lifting devices hangs down along the pier body 1.

[0059] According to the design drawing, the lifting device and Bailey bridge 5 are assembled at the location of the paper steel pipe pile 6 and anchored to the T-beam on the side of the approach bridge.

[0060] The suspended end of Bailey bridge 5 is also connected to guy rope 25, and the other end of guy rope 25 is connected to the T-beam bridge deck of the approach bridge.

[0061] Bailey bridge 5 is placed on the approach bridge T-beam, with one end extending outward and suspended in the air. The part on the approach bridge T-beam is anchored to the T-beam. Specifically, Bailey bridge 5 is anchored by the upper anchoring beam 23 above Bailey bridge 5 and the lower anchoring beam 24 below the approach bridge T-beam, as well as the anchoring threaded steel that passes through the two anchoring beams.

[0062] like Figure 4 As shown, the lifting device is a winch 22. The traction rope of one winch 22 is wound down from the outermost suspended part of the Bailey bridge 5 to connect to the front end of the support steel pipe pile 6. The traction rope of the other winch 22 hangs down from the middle of the Bailey bridge 5 at the pier body 1 to connect to the rear end of the support steel pipe pile 6. By using the two winches 22, the support steel pipe pile 6 can be pulled into the following position: Figure 5 The tilted posture shown.

[0063] By using a winch and cantilever beam fixed on the T-beam of the approach bridge on the other side of the cast-in-place section, the steel pipe piles can be lifted and installed, which can avoid the adverse effects caused by long process connection cycles and difficulties in bringing in compliant lifting equipment.

[0064] like Figure 10 As shown, a steel pipe support column 14 is connected to the low platform 13 at the top of the pier body 1. The top of the steel pipe support column 14 contacts the Bailey bridge 5 and is used to support the Bailey bridge 5. It is removed after the Bailey bridge 5 is hoisted and connected to the two pile top bearing beams 9. Alternatively, it can be removed after the support steel pipe pile 6 is positioned.

[0065] When the Bailey bridge 5 is anchored to the approach bridge T-beam, steel pipe support columns 14 are connected to the low platform 13 to support the Bailey bridge 5. The steel pipe support columns 14 can be removed when the Bailey bridge 5 is connected to the pile top load-bearing beam 9.

[0066] Step 3: Using the lifting device, lift the support steel pipe pile 6 and after lifting, turn the support steel pipe pile 6 into an inclined state. The bottom end of the support steel pipe pile 6 is connected to the pile cap 11, and the pile body of the support steel pipe pile 6 is connected to the positioning flat connector 3.

[0067] like Figure 4 As shown, before the formal hoisting of the steel pipe pile 6 of the support, a trial hoisting can be performed using a lifting device. The weight of the trial hoisting object is 1.25 times the maximum weight of the object to be hoisted. After the performance of the lifting device is determined, the formal hoisting can proceed.

[0068] The hoisting results are as follows Figure 5 As shown, the support steel pipe pile 6 maintains an inclined posture, with its bottom connected to the pile cap 11, and the pile body connected to the positioning flat connector 3.

[0069] To facilitate the determination of the bottom position and inclination of the support steel pipe pile 6, an arc-shaped positioning device 12 is pre-embedded on the pile cap 11.

[0070] An arc-shaped positioning device 12 is connected to the pier. The positioning device is an arc-shaped plate with the same inclination as the support steel pipe pile 6. The arc-shaped plate is inserted into the inside of the support steel pipe pile 6 and fits and connects with the support steel pipe pile 6.

[0071] like Figure 11 and Figure 12 As shown, the main structure of the arc-shaped positioning device 12 is an arc-shaped plate. Below the arc-shaped plate is an embedded part plate for pre-embedding in the foundation 11. The inclination of the arc-shaped plate is consistent with the inclination of the support steel pipe pile 6 designed. During hoisting, the support steel pipe pile 6 is aligned with the arc-shaped plate, and the arc-shaped plate is inserted into the inside of the support steel pipe pile 6 and fits against the inner wall of the support steel pipe pile 6. This indicates that the bottom position and inclination angle are correct, and the position of the support steel pipe pile 6 can be quickly positioned. Subsequently, the arc-shaped plate and the support steel pipe pile 6 are welded and fixed.

[0072] Step 4: Install the other support steel pipe piles 6 on the pier body 1. After the two adjacent support steel pipe piles 6 are installed, install the horizontal fixing tie 7 to fix the two adjacent support steel pipe piles 6.

[0073] like Figure 6 As shown, after the other support steel pipe piles 6 are installed, several support steel pipe piles 6 are horizontally fixed by the horizontal fixing flat bracing 7.

[0074] If there are several piers 1 on the same side, several vertical supporting steel pipe piles 10 are connected to the abutment 11 between the two piers. The outermost supporting steel pipe pile 10 is connected to the positioning flat tie 3, and the hoisting support steel pipe pile 6 is connected to the positioning flat tie 3. The supporting steel pipe pile 10 is connected to the pile top bearing beam 9. When the Bailey bridge 5 is hoisted and connected to the unloading device 8 and the pile top bearing beam 9 of the fixed bracket 4, the pile top bearing beam 9 of the supporting steel pipe pile 10 is also connected to the Bailey bridge 5.

[0075] like Figure 8 As shown, a pile top bearing beam 9 is connected to several unloading devices 8 in the same row. The pile top bearing beam 9 is supported by several unloading devices 8. The fixed bracket 4 also supports another pile top bearing beam 9. The Bailey bridge 5 is supported by two pile top bearing beams 9, one in front and one behind.

[0076] like Figure 5 As shown, there are two piers 1. There is no fixed positioning bracing 3 between the two piers 1, and the Bailey bridge needs to be hoisted onto the support steel pipe piles 6 in subsequent steps. Since there is a lack of support between the two piers 1, several vertical support steel pipe piles 10 are connected in this space to provide support. The outermost support steel pipe pile 10 is also connected to a positioning bracing 3, and the support steel pipe piles 6 are hoisted and connected to support the Bailey bridge 5. Figure 15 As shown, the left side shows the Bailey bridge 5 supported by a supporting steel pipe pile 10 instead of a fixed bracket 4, and the right side shows a supporting structure with a pier body 1. The supporting steel pipe pile 10 is connected to an unloading device 8 and a pile top bearing beam 9, which is consistent with the bracket steel pipe pile 6.

[0077] Step 5: Connect the unloading device 8 to the top of the steel pipe pile 6 of the support, and connect the pile top bearing beam 9 to the unloading device 8 and the fixed support 4 respectively. The top height of the pile top bearing beam 9 on the unloading device 8 and the fixed support 4 is the same. Hoist the Bailey frame 5 and connect it to the two pile top bearing beams 9 as the distribution beam of the less support.

[0078] The unloading device 8 is a sand cylinder.

[0079] like Figure 7As shown, the anchorage of Bailey bridge 5 is removed, a sand cylinder is connected to the top of the support steel pipe pile 6, and the pile top bearing beam 9 is connected to the sand cylinder and the fixed support 4. The top of the sand cylinder and the top bearing beam 9 on the fixed support 4 are on the same horizontal plane. Bailey bridge 5 is lifted to the pile top bearing beam 9 by a truck crane and connected. Bailey bridge serves as the distribution beam of the less-supported system.

[0080] like Figure 8 As shown, in step six, continue installing the remaining structures of the bracket until the bracket erection is completed.

[0081] Continue installing the steel distribution beams and bottom system with minimal supports until the construction of the minimal support structure is completed.

[0082] By setting the support steel pipe piles at a certain inclination angle, the span of the support can be met while the bottom of the steel pipe piles can be placed on the pier foundation. The steel pipe piles on the foundation do not require additional support foundation treatment, thus saving materials and manpower, shortening the construction period, reducing the scope of support steel pipe pile foundation treatment, and eliminating the need to set up an additional foundation under the support steel pipe piles.

[0083] Suitable for high piers and sloping surfaces, where straight steel pipe supports are not feasible, inclined steel pipe supports are employed. These inclined steel pipe supports utilize permanent structures such as bridge abutments and piers. An arc-shaped positioning plate is installed on the abutment, and the steel pipe pile is encased in the arc-shaped positioning plate to achieve rapid positioning of the bottom of the steel pipe pile. Embedded parts are installed on the pier body, and positioning couplings are installed to achieve rapid positioning of the top of the steel pipe pile. A bolted fixing frame with embedded parts is installed at the top of the pier column, reducing the number of steel pipe piles, improving efficiency, and facilitating later removal and repair of the structural surface. Both embedded parts and positioning couplings can be prefabricated, shortening the construction cycle. For steel pipe pile installation, while a truck crane can be used to assist in the installation of the positioning coupling components due to their small size, the large diameter and length of the steel pipe piles, the heavy weight of a single component, and the large lifting height require coordinated positioning at both ends. Due to site limitations, two truck cranes cannot be used for installation; therefore, a winch and cantilever beams are designed to assist in the lifting of the steel pipe piles.

Claims

1. A method for constructing a steel pipe with few supports for a side-span cast-in-place section, characterized by, The method comprises the following steps: Step one, hoist the positioning flat link (3) on the approach bridge T beam on the high platform (2) on the top of the pier body (1), and install the positioning flat link (3) on the other side of the pier body (1) opposite to the approach bridge T beam, and install the fixed support (4) on the pier body (1) above the positioning flat link (3); Step two, install the lifting device and the Bailey frame (5) on the approach bridge T beam; Step three, hoist the support steel pipe pile (6) by the lifting device, and tilt the support steel pipe pile (6) after hoisting, the bottom end of the support steel pipe pile (6) is connected to the pile cap (11), the pile body of the support steel pipe pile (6) is connected to the positioning flat link (3), the pile cap (11) is connected to the arc-shaped positioning device (12), the positioning device is an arc-shaped plate, the arc-shaped plate is consistent with the tilting degree of the support steel pipe pile (6), the arc-shaped plate is inserted into the inner side of the support steel pipe pile (6), and the arc-shaped plate is attached to and connected to the support steel pipe pile (6); Step four, install other support steel pipe piles (6) on the pier body (1), install the transverse fixed flat link (7) after the installation of two adjacent support steel pipe piles (6) is completed, and the two adjacent support steel pipe piles (6) are fixed; Step five, connect the unloading device (8) to the top of the support steel pipe pile (6), connect the pile top bearing beam (9) to the unloading device (8) and the fixed support (4) respectively, the top heights of the pile top bearing beams (9) on the unloading device (8) and the fixed support (4) are consistent, hoist the Bailey frame (5) and connect the Bailey frame (5) to the two pile top bearing beams (9) as a distribution beam of the few supports; Step six, continue to install the remaining structure of the few supports, and the construction of the few supports is completed.

2. The method according to claim 1, characterized in that: The positioning flat link (3) comprises two cross beams connected to the pier body (1), the two cross beams are located at different heights, the length of the upper cross beam is greater than that of the lower cross beam, the tilting degree of the connecting line of the extending ends of the upper cross beam and the lower cross beam is consistent with the tilting degree of the support steel pipe pile (6), and a scissor brace is further connected between the upper cross beam and the lower cross beam.

3. The method according to claim 1, characterized in that: If there are a plurality of pier bodies (1) on the same side, a plurality of vertical support steel pipe piles (10) are connected to the pile cap (11) between the two pier bodies (1), the outermost support steel pipe pile (10) is connected to the positioning flat link (3), and the support steel pipe pile (6) is hoisted and connected to the positioning flat link (3), the pile top bearing beam (9) is connected to the support steel pipe pile (10), and when the Bailey frame (5) is hoisted and connected to the pile top bearing beams (9) of the unloading device (8) and the fixed support (4), the pile top bearing beam (9) of the support steel pipe pile (10) is also connected to the Bailey frame (5).

4. The method according to claim 1, characterized in that: The low platform (13) on the top of the pier body (1) is connected to the steel pipe support column (14), the top end of the steel pipe support column (14) is in contact with the Bailey frame (5), and the steel pipe support column (14) is used for supporting the Bailey frame (5), and the steel pipe support column (14) is removed after the Bailey frame (5) is hoisted and connected to the two pile top bearing beams (9).

5. The method according to claim 1, wherein the method is characterized by: One end of the Bailey frame (5) is anchored to the approach bridge T beam, and the other end extends in the direction of the positioning flat link (3) and hangs in the air; the traction ropes of one group of lifting devices hang down along the hanging end of the Bailey frame (5), and the traction ropes of the other group of lifting devices hang down along the pier body (1).

6. The method according to claim 1, wherein the method is characterized by: The unloading device (8) is a sand cylinder.

7. The method according to claim 1, wherein the method is characterized by: The fixed support (4) comprises a plurality of embedded steel bars (15) and positioning steel bars (16) connected at one end to the pier body (1), the embedded steel bars (15) and the positioning steel bars (16) being provided with second positioning plates (17) and first positioning plates (18) at the other end, the second positioning plates (17) and the first positioning plates (18) being provided with a plurality of through holes for the embedded steel bars (15) and the positioning steel bars (16) to pass through, the second positioning plates (17) being connected to the embedded steel bars (15) and the positioning steel bars (16), sleeves (19) being sleeved on the steel bars between the second positioning plates (17) and the first positioning plates (18), and the first positioning plates (18) being fastened to the sleeves (19) through bolts.

8. The method according to claim 7, characterized in that: The first positioning plates (18) are further connected to outwardly protruding third positioning plates (20) at the top, and the surfaces of the first positioning plates (18) are further connected to a plurality of stiffening plates (21) connected to the third positioning plates (20), and the pile top load-bearing beams (9) are connected to the top of the third positioning plates (20).

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