Construction Method for External Demolition of Diaphragm Bracket and Formwork of Hollow Pier

Abstract

The present invention relates to the field of bridge construction and specifically discloses a method for removing hollow pier diaphragm supports and external formwork, including the steps of pre-treating the hollow pier, placing a load-bearing device, building a formwork system, pouring, removing the load-bearing device, removing the formwork system, and sealing holes. The present invention addresses the difficulty and high safety risks associated with removing diaphragm supports and bottom formwork within hollow piers.

Description

Technical Field

[0001] The invention belongs to the field of bridge construction, and in particular relates to a hollow pier diaphragm bracket and a formwork external dismantling construction method. Background Art

[0002] The shape of the high piers of large bridges adopts hollow thin-walled high piers (hereinafter referred to as hollow piers) in consideration of material conservation and stress conditions. The pier body adopts a cross-sectional structure with a larger bottom and a smaller top and a tapering slope. In order to improve its stress resistance, a number of horizontal diaphragms are arranged vertically at certain intervals in the inner cavity of the hollow pier. The diaphragms are cast using casting formwork. During the casting process, load-bearing devices are required to support the casting formwork to withstand construction loads. However, the diaphragms are large in size, which requires a high load-bearing capacity of the load-bearing devices. Therefore, a load-bearing device of a certain size is required to meet the load-bearing requirements. The existing construction method generally adopts the method of setting up a full-floor scaffolding to complete the load-bearing system for pouring concrete of the diaphragm. The erection of the full-floor scaffolding is labor-intensive and time-consuming. In particular, when dismantling, workers are required to enter the hollow cavity below the diaphragm through the center hole reserved in the middle of the diaphragm to remove the load-bearing device. The dismantling is difficult and the safety risk is high. When dismantling the casting formwork, the bottom formwork located below the cast diaphragm also requires workers to enter the hollow cavity for removal. Summary of the Invention

[0003] In response to the deficiencies in the prior art, the present invention provides a hollow pier diaphragm bracket and external formwork dismantling construction method to solve the problem of difficulty and high safety risk in removing the load-bearing device and bottom formwork from the hollow cavity below the diaphragm.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The hollow pier diaphragm bracket and formwork external dismantling construction method includes the following steps:

[0006] S1. Pretreatment of hollow piers:

[0007] During the construction of the hollow pier, multiple sets of parallel supporting members are pre-buried below the designed elevation where the transverse diaphragm needs to be constructed. Each set of supporting members includes two members located on the inner walls of the pier on opposite sides, with the ends of the supporting members extending out of the inner walls of the pier.

[0008] S2. Place the load-bearing device:

[0009] After the concrete of the hollow pier wall has been cured to the required standard, multiple sets of load-bearing devices are sequentially hoisted into the hollow pier, and both ends of the load-bearing devices are placed on the support members, with the multiple sets of load-bearing devices corresponding to the multiple sets of support members. The load-bearing devices include a load-bearing beam, telescopic members installed at both ends of the load-bearing beam and extending and retracting along the length of the load-bearing beam, and lifting members installed on the telescopic members and extending and retracting in a direction perpendicular to the extension direction of the telescopic members. When placing the load-bearing device, the telescopic members are first extended so that the load-bearing device can be placed on the support members, and then the lifting members are activated so that the top elevation of the load-bearing device reaches the bottom elevation of the diaphragm to be cast minus the height of the bottom formwork.

[0010] A first steel wire rope and a second steel wire rope are respectively installed at both ends of the load-bearing device, and a third steel wire rope is installed at the end of the load-bearing device connected to the first steel wire rope;

[0011] S3. Build a template system:

[0012] A bottom formwork is placed above the load-bearing device, and the bottom formwork includes several bottom plates arranged in parallel and in the shape of a rectangular parallelepiped. The multiple bottom plates are assembled to form a shape consistent with the shape and size of the lower end of the diaphragm to be cast. The bottom plates are hoisted and placed above the load-bearing device, and the bottom plates are arranged in parallel to cover the space above the load-bearing device and form the bottom formwork; a fourth steel wire rope and a fifth steel wire rope are respectively installed at both ends of the bottom plate, and a sixth steel wire rope is installed at one end of the bottom plate connected to the fourth steel wire rope. A vertical second mounting tube is placed at the position where the fourth steel wire rope is connected and at the position where the fifth steel wire rope is connected on the bottom plate, so that the fourth steel wire rope and the fifth steel wire rope are both passed through upward and fixed at the top position of the side wall formwork, and the sixth steel wire rope is pulled from the bottom of the bottom plate to the bottom center hole, passed through and fixed at the top position of the side wall formwork;

[0013] Install the reinforcement of the diaphragm and the hollow pier above the bottom formwork, and then install the side wall formwork. The side wall formwork consists of two layers, the inner and outer layers. The space between the side wall formworks is used to cast the hollow pier body. Install the center formwork in the middle of the bottom formwork. The center formwork is used to leave a center hole on the diaphragm to be cast.

[0014] A bottom center hole is opened in the middle of the bottom template, a plurality of first mounting holes for the first steel wire rope to pass through are opened on the bottom template, a plurality of second mounting holes for the second steel wire rope to pass through are opened on the bottom template, a first mounting tube is placed at each of the first mounting holes and the second mounting holes, the first steel wire rope passes through the first mounting hole, the second steel wire rope passes through the second mounting hole, and the third steel wire rope passes through the bottom center hole and the center template, and is fixed at the top position of the side wall template;

[0015] S4. pouring concrete for the hollow pier wall and diaphragm;

[0016] S5. Remove the load-bearing device:

[0017] After the concrete of the diaphragm has reached the required curing standard, tighten and fix the fourth and fifth steel wire ropes, and then remove the multiple load-bearing devices in sequence. First, start the lifting member to lower the upper end of the load-bearing device and separate it from the bottom formwork. Then, retract the telescopic member so that the total length of the load-bearing device is less than the distance between the two side supports below the load-bearing device.

[0018] Lower the load-bearing device by using the first and second steel wire ropes. After lowering it a certain distance, keep the first steel wire rope stationary and slowly lower the second steel wire rope until the second steel wire rope is completely loosened and falls below the diaphragm. Then tighten the third steel wire rope and slowly lower the first steel wire rope until the first steel wire rope is also completely loosened and falls below the diaphragm. The load-bearing device is moved to the center hole of the diaphragm by the tension of the third steel wire rope. Pull the third steel wire rope upward to lift the load-bearing device out.

[0019] S6. Dismantle the formwork system:

[0020] After removing the load-bearing device, remove multiple bottom plates in sequence. First, lower the bottom plate using the fourth and fifth steel wire ropes. After lowering it a certain distance, keep the fourth steel wire rope stationary and slowly lower the fifth steel wire rope until it is completely loosened and falls below the diaphragm. Then tighten the sixth steel wire rope and slowly lower the fourth steel wire rope until it is also completely loosened and falls below the diaphragm. The bottom plate is pulled by the sixth steel wire rope to move to the center hole of the diaphragm. Pull the sixth steel wire rope upward to lift the bottom plate out. After all the bottom plates are lifted out, remove the side wall formwork and the center formwork.

[0021] S7. Sealing holes:

[0022] Fill all the first installation pipes and the second installation pipes with concrete.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The load-bearing device is equipped with telescopic parts and lifting parts. During the construction process, the control circuit or control system of the telescopic parts and lifting parts can be externalized (i.e., the position above the diaphragm). After the concrete strength of the diaphragm is qualified, the construction personnel can operate the telescopic parts and lifting parts of the load-bearing device through the external control circuit or control system, so that the purpose of dismantling the parts can be achieved without entering the space under the diaphragm.

[0025] 2. In step S5, the lifting and removal of the load-bearing device can be completed by the first steel wire rope, the second steel wire rope, and the third steel wire rope. In step S6, the lifting and removal of the bottom formwork can be completed by the fourth steel wire rope, the fifth steel wire rope, and the sixth steel wire rope. During the whole process, there is no need for manual entry into the hollow cavity below the diaphragm. The construction can be conveniently completed on the hollow cavity, thereby improving construction efficiency and reducing safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a formal cross-sectional view of the overall structure of an embodiment of the present invention.

[0027] Figure 2 for Figure 1 Top view of the mid-bottom template.

[0028] In the figure: 1. Hollow pier; 2. Support member; 3. Lifting member; 4. Telescopic member; 5. Load-bearing beam; 6. Bottom plate; 7. Side wall formwork; 9. Center formwork; 10. First steel wire rope; 11. Third steel wire rope; 12. Second steel wire rope; 13. First mounting tube; 14. Bottom center hole; 15. First mounting hole; 16. Second mounting hole; 17. Third mounting hole; 18. Fourth steel wire rope; 19. Fifth steel wire rope; 20. Sixth steel wire rope. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to the accompanying drawings, and specific implementation methods will be given.

[0030] like Figure 1 As shown, the hollow pier diaphragm bracket and formwork external dismantling construction method includes the following steps:

[0031] S1. Pretreatment of hollow pier 1:

[0032] During the construction of the hollow pier 1, multiple groups of support members 2 arranged in parallel are pre-buried below the design elevation position where the transverse partition needs to be constructed. Each group of support members 2 includes two support members 2 located on the inner walls of the hollow pier 1 on opposite sides. The ends of the support members 2 extend out of the inner walls of the hollow pier 1 to support the two ends of the load-bearing device. The support members 2 are made of I-beams. By pre-buried I-beams in the inner wall of the hollow pier 1, a fulcrum can be provided for the load-bearing device, which can withstand a large load. By transferring the force to the body of the hollow pier 1, the size of the load-bearing device can be reduced to a certain extent, and the convenience of building and dismantling the load-bearing device can be improved. Multiple groups of support members 2 are used to support multiple groups of load-bearing devices respectively. The load-bearing devices are supported by the support members 2. The load-bearing devices are arranged in parallel in multiple groups. While ensuring the load-bearing capacity, it is convenient to build and dismantle multiple groups of load-bearing devices in sequence, making it easier to build and dismantle.

[0033] S2. Place the load-bearing device:

[0034] After the concrete of the hollow pier 1 has been cured to the required standard, multiple sets of load-bearing devices are sequentially hoisted into the hollow pier 1, and the two ends of the load-bearing devices are placed on the support members 2, with the multiple sets of load-bearing devices corresponding to the multiple sets of support members 2. The load-bearing devices include a load-bearing beam 5, a telescopic member 4 installed at both ends of the load-bearing beam 5 and extending and retracting along the length direction of the load-bearing beam 5, and a lifting member 3 installed on the telescopic member 4 and extending and retracting in a direction perpendicular to the extension direction of the telescopic member 4. The telescopic member 4 includes a transverse support block slidably connected to the end of the load-bearing beam 5 in the length direction of the load-bearing beam 5, and the lifting member 3 includes a vertical support block slidably connected to the transverse support block. The sliding direction of the vertical support block is perpendicular to the sliding direction of the transverse support block. The sliding drive of the transverse support block and the vertical support block is achieved by a conventional control system in the prior art, such as by a cylinder or an electric telescopic rod.

[0035] When placing the load-bearing device, first extend the telescopic part 4, that is, slide the horizontal support block so that the load-bearing device can be erected on the support member 2, that is, the horizontal support blocks at both ends of the load-bearing beam 5 are erected on the support members 2 on both sides of the pier wall, and then start the lifting part 3 so that the top elevation of the load-bearing device reaches the bottom elevation of the diaphragm to be cast minus the height of the bottom formwork, that is, slide the vertical support block so that the height of the load-bearing beam 5 reaches the required position.

[0036] A pressure sensor is installed at the end of the telescopic member 4. Specifically, the pressure sensor is fixed to the free end of the transverse support block. After the lifting member 3 is raised to the required height, the telescopic member 4 is extended again so that the end of the telescopic member 4 is against the pier wall of the hollow pier 1. The pressure sensor senses the pressure between the end of the telescopic member 4 and the pier wall of the hollow pier 1, and detects the force between the end of the transverse support block and the inner wall of the hollow pier 1 to avoid damage caused by excessive pressure between the two. It can also make the transverse support block better against the pier wall, and the load-bearing beam 5 is constrained by the pier wall and cannot move.

[0037] A first steel wire rope 10 and a second steel wire rope 12 are respectively installed at both ends of the load-bearing beam 5 of the load-bearing device, and a third steel wire rope 11 is installed at the end of the load-bearing beam 5 of the load-bearing device connected to the first steel wire rope 10 .

[0038] S3. Build a template system:

[0039] Place the bottom template above the load-bearing device to facilitate the removal of the bottom template. Figure 2As shown, the bottom formwork includes a plurality of bottom plates 6 arranged in parallel and in the shape of a rectangular parallelepiped. The bottom plates 6 are hoisted and placed above the load-bearing device, and the bottom plates 6 are arranged in parallel to fill the space above the load-bearing device and form the bottom formwork. The multiple bottom plates 6 are assembled to form a shape that is consistent with the shape and size of the lower end of the diaphragm to be cast, that is, the length of the bottom plate 6 is consistent with the length of the diaphragm to be cast, and the total width of the multiple bottom plates 6 after assembly is consistent with the width of the diaphragm to be cast. The length direction of the bottom plate 6 and the length direction of the load-bearing device are perpendicular to each other, so that the load-bearing device can better support the bottom plate 6. Laying a film on the bottom formwork can ensure that the concrete does not leak through the gaps between the multiple bottom plates 6, and through the setting of the film, there will be no adhesion between the concrete and the bottom plate 6. The bottom plate 6 can fall downward by its own weight without the support of the load-bearing device.

[0040] The steel bars for embedding in the diaphragm to be cast and the steel bars for embedding in the side walls of the hollow pier 1 are installed above the bottom formwork respectively, and then the side wall formwork 7 is installed. The side wall formwork 7 includes two layers, an inner layer and an outer layer. The hollow pier 1 body is cast between the side wall formworks 7 on both sides. The center formwork 9 is installed in the middle of the bottom formwork. The center formwork 9 is used to leave a center hole on the diaphragm to be cast.

[0041] A fourth steel wire rope 18 and a fifth steel wire rope 19 are installed at both ends of the bottom plate 6, and a sixth steel wire rope 20 is installed at one end of the bottom plate 6 connected to the fourth steel wire rope 18. A vertical second installation pipe is placed at the position where the fourth steel wire rope 18 is connected on the bottom plate 6 and the position where the fifth steel wire rope 19 is connected on the bottom plate 6, so that the fourth steel wire rope 18 and the fifth steel wire rope 19 are both passed upward through the second installation pipe to a height higher than the upper end of the diaphragm to be cast. The sixth steel wire rope 20 is pulled from the bottom of the bottom plate 6 to the bottom center hole 14 and passed through. It also reaches a height higher than the upper end of the diaphragm to be cast. During the actual construction process, the fourth steel wire rope 18, the fifth steel wire rope 19, and the sixth steel wire rope 20 can all be fixed at the top of the side wall formwork 7. During actual use, the second mounting pipe is a steel pipe with a length greater than the thickness of the diaphragm to be cast. A through groove for the sixth steel wire rope 20 to pass through can be opened at the lower end of the bottom formwork. The sixth steel wire rope 20 passes from the bottom of the bottom plate 6 to the bottom center hole 14 to avoid the sixth steel wire rope 20 being located in the casting cavity and affecting the casting.

[0042] A bottom center hole 14 is opened in the middle of the bottom template, and a plurality of first mounting holes 15 for the first steel wire rope 10 to pass through are opened on the bottom template, and a plurality of second mounting holes 16 for the second steel wire rope 12 to pass through are opened on the bottom template, that is, the first mounting holes 15 are opened on the bottom plate 6 above the first steel wire rope 10, and the second mounting holes 16 are opened on the bottom plate 6 above the second steel wire rope 12. The first mounting hole 15 and the second mounting hole 16 are both provided with a first mounting tube 13. The first steel wire rope 10 passes through the first mounting hole 15 and the first mounting tube 13 located at the first mounting hole 15, the second steel wire rope 12 passes through the second mounting hole 16 and the first mounting tube 13 located at the second mounting hole 16, and the third steel wire rope 11 passes through the bottom center hole 14 and the center template 9, all reaching a height higher than the upper end of the diaphragm to be cast. During actual construction, the fourth steel wire rope 18, the fifth steel wire rope 19, and the sixth steel wire rope 20 can all be fixed at the top of the side wall template 7. During actual use, the first mounting tube 13 is selected from steel pipes with a length greater than the thickness of the diaphragm to be cast. In order to facilitate pulling the third steel wire rope 11 to the bottom center hole 14, a transverse third mounting hole 17 is opened on the bottom template. The third mounting hole 17 is connected to the bottom center hole 14. The third steel wire rope 11 passes through the third mounting hole 17 to the bottom center hole 14, and passes through the bottom center hole 14 and the center template 9 to reach a height higher than the upper end of the diaphragm to be cast.

[0043] The lines (such as power lines, etc.) used by the control system of the telescopic part 4 and the lifting part 3 (i.e., the electric structure such as the cylinder or electric telescopic rod used to control the movement of the telescopic part 4 and the lifting part 3) are also passed through the bottom center hole 14 and the center formwork 9, and all reach a height higher than the upper end of the diaphragm to be cast, so that the staff can operate above the diaphragm.

[0044] The gaps between the bottoms of the first and second mounting tubes 13 and the corresponding bottom plates 6 are all sealed. Taking the sealing of the first mounting tube 13 as an example, a vertical sealing plug is fixed on the bottom plate 6 so that the sealing plug is inserted into the first mounting tube 13 to seal the lower end of the first mounting tube 13 and at the same time position the first mounting tube 13 to prevent concrete from leaking through the gaps between the first and second mounting tubes and the formwork.

[0045] S4, pouring concrete between the two layers of side wall formwork 7, pouring concrete onto the bottom formwork to form a transverse diaphragm, and the concrete between the two layers of side wall formwork 7 forms the side wall of the hollow pier 1 of a certain height, Figure 1 Indicated by A in the figure is the diaphragm formed by casting and the side wall of the hollow pier 1 of a certain height. During the casting process, the third steel wire rope 11 and the sixth steel wire rope 20 always remain in a relaxed state, that is, no upward pulling force is provided to the load-bearing beam 5 or the bottom plate 6 to avoid causing the load-bearing beam 5 or the bottom plate 6 to move.

[0046] S5. Remove the load-bearing device:

[0047] After the concrete of the diaphragm has been cured to the required standard, first tighten and fix the fourth steel wire rope 18 and the fifth steel wire rope 19 so that the fourth steel wire rope 18 and the fifth steel wire rope 19 exert an upward pulling force on the bottom plate 6 to prevent the bottom plate 6 from falling directly downward after the load-bearing device is removed. Then remove multiple load-bearing devices in sequence. Specifically, remove multiple load-bearing devices in sequence from the direction close to the center hole of the diaphragm to the direction away from the center hole of the diaphragm. The steps for removing a single load-bearing device are as follows: first start the lifting member 3 so that the upper end of the load-bearing device descends and separates from the bottom formwork, then retract the telescopic member 4 so that the load-bearing device can pass through the support members 2 on both sides thereof and be lowered, that is, the total length of the load-bearing device is less than the distance between the support members 2 on both sides below the load-bearing device. At this time, the load-bearing beam 5 is not in contact with the bottom formwork, the inner wall of the hollow pier 1, and the support members 2, and can move freely.

[0048] The weight of the load-bearing device is borne by the first steel wire rope 10 and the second steel wire rope 12, and then the load-bearing device is lowered synchronously. After being lowered a certain distance, the first steel wire rope 10 is kept stationary and the second steel wire rope 12 is slowly lowered until the second steel wire rope 12 is completely loosened and falls below the transverse partition. At this time, the load-bearing device is subjected to the pulling force of the first steel wire rope 10 on its end, and is deflected from a horizontal state to a vertical state. Then tighten the third steel wire rope 11 so that the third steel wire rope 11 can provide tension to the load-bearing device, and then slowly lower the first steel wire rope 10 and make the first steel wire rope 10 also completely loosen and fall below the diaphragm. During this process, the load-bearing device gradually changes from being subjected to the joint tension of the first steel wire rope 10 and the third steel wire rope 11 to being subjected to only the tension of the third steel wire rope 11. The load-bearing device is moved to the center hole of the cast diaphragm (that is, the position of the center formwork 9) by the tension of the third steel wire rope 11, and then the third steel wire rope 11 is pulled upward to lift the load-bearing device out.

[0049] In the above process, the load-bearing device is lowered or hoisted upward, and the first steel wire rope 10, the second steel wire rope 12 or the third steel wire rope 11 can be controlled by a winch in the prior art.

[0050] S6. Dismantle the formwork system:

[0051] After removing the load-bearing device, multiple bottom plates 6 are removed in sequence. Specifically, they are removed in sequence from the direction close to the center hole of the diaphragm to the direction away from the center hole of the diaphragm. The steps for removing a single bottom plate 6 device are as follows: first, the weight of the bottom plate 6 is supported by the fourth steel wire rope 18 and the fifth steel wire rope 19, and the bottom plate 6 is lowered synchronously. After being lowered a certain distance, that is, after the bottom plate 6 and the diaphragm are completely separated, the fourth steel wire rope 18 is kept stationary and the fifth steel wire rope 19 is slowly lowered until the fifth steel wire rope 19 is completely loosened and falls below the diaphragm. At this time, the bottom plate 6 is subjected to the pulling force of the fourth steel wire rope 18 on its end, and is deflected from a horizontal state to a vertical state. Then tighten the sixth steel wire rope 20 so that it can provide tension to the bottom plate 6, and then slowly lower the fourth steel wire rope 18 so that the fourth steel wire rope 18 is also completely loosened and falls below the diaphragm. During this process, the bottom plate 6 gradually changes from being subjected to the joint tension of the fourth steel wire rope 18 and the sixth steel wire rope 20 to being subjected to only the tension of the sixth steel wire rope 20. The bottom plate 6 is moved to the center hole of the diaphragm by the tension of the sixth steel wire rope 20, and then the sixth steel wire rope 20 is pulled upward to lift out the bottom template.

[0052] During the above process, when the bottom plate 6 is lowered or hoisted upward, the fourth steel rope 18, the fifth steel rope 19 or the sixth steel rope 20 can be controlled by a winch in the prior art.

[0053] After the bottom formwork is removed, the side wall formwork 7 and the center formwork 9 are removed by conventional formwork removal methods in the prior art.

[0054] S7. Sealing holes:

[0055] All of the first installation pipes 13 and the second installation pipes are filled with concrete.

[0056] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. The hollow pier diaphragm bracket and formwork external dismantling construction method is characterized by: The following steps are involved: S1. Pretreatment of hollow piers: During the construction of the hollow pier, multiple sets of parallel supporting members are pre-buried below the designed elevation where the transverse diaphragm needs to be constructed. Each set of supporting members includes two members located on the inner walls of the pier on opposite sides, with the ends of the supporting members extending out of the inner walls of the pier. S2. Place the load-bearing device: After the concrete of the hollow pier wall has been cured to the required standard, multiple sets of load-bearing devices are sequentially hoisted into the hollow pier, and both ends of the load-bearing devices are placed on the support members, with the multiple sets of load-bearing devices corresponding to the multiple sets of support members. The load-bearing devices include a load-bearing beam, telescopic members installed at both ends of the load-bearing beam and extending and retracting along the length of the load-bearing beam, and lifting members installed on the telescopic members and extending and retracting in a direction perpendicular to the extension direction of the telescopic members. When placing the load-bearing device, the telescopic members are first extended so that the load-bearing device can be placed on the support members, and then the lifting members are activated so that the top elevation of the load-bearing device reaches the bottom elevation of the diaphragm to be cast minus the height of the bottom formwork. A first steel wire rope and a second steel wire rope are respectively installed at both ends of the load-bearing device, and a third steel wire rope is installed at the end of the load-bearing device connected to the first steel wire rope; S3. Build a template system: A bottom formwork is placed above the load-bearing device, and the bottom formwork includes several bottom plates arranged in parallel and in the shape of a rectangular parallelepiped. The multiple bottom plates are assembled to form a shape consistent with the shape and size of the lower end of the diaphragm to be cast. The bottom plates are hoisted and placed above the load-bearing device, and the bottom plates are arranged in parallel to cover the space above the load-bearing device and form the bottom formwork; a fourth steel wire rope and a fifth steel wire rope are respectively installed at both ends of the bottom plate, and a sixth steel wire rope is installed at one end of the bottom plate connected to the fourth steel wire rope. A vertical second mounting tube is placed at the position where the fourth steel wire rope is connected and at the position where the fifth steel wire rope is connected on the bottom plate, so that the fourth steel wire rope and the fifth steel wire rope are both passed through upward and fixed at the top position of the side wall formwork, and the sixth steel wire rope is pulled from the bottom of the bottom plate to the bottom center hole, passed through and fixed at the top position of the side wall formwork; Install the reinforcement of the diaphragm and the hollow pier above the bottom formwork, and then install the side wall formwork. The side wall formwork consists of two layers, the inner and outer layers. The space between the side wall formworks is used to cast the hollow pier body. Install the center formwork in the middle of the bottom formwork. The center formwork is used to leave a center hole on the diaphragm to be cast. A bottom center hole is opened in the middle of the bottom template, a plurality of first mounting holes for the first steel wire rope to pass through are opened on the bottom template, a plurality of second mounting holes for the second steel wire rope to pass through are opened on the bottom template, a first mounting tube is placed at each of the first mounting holes and the second mounting holes, the first steel wire rope passes through the first mounting hole, the second steel wire rope passes through the second mounting hole, and the third steel wire rope passes through the bottom center hole and the center template, and is fixed at the top position of the side wall template; S4. pouring concrete for hollow pier wall and diaphragm; S5. Remove the load-bearing device: After the concrete of the diaphragm has reached the required curing standard, tighten and fix the fourth and fifth steel wire ropes, and then remove the multiple load-bearing devices in sequence. First, start the lifting member to lower the upper end of the load-bearing device and separate it from the bottom formwork. Then, retract the telescopic member so that the total length of the load-bearing device is less than the distance between the two side supports below the load-bearing device. Lower the load-bearing device by using the first and second steel wire ropes. After lowering it a certain distance, keep the first steel wire rope stationary and slowly lower the second steel wire rope until the second steel wire rope is completely loosened and falls below the diaphragm. Then tighten the third steel wire rope and slowly lower the first steel wire rope until the first steel wire rope is also completely loosened and falls below the diaphragm. The load-bearing device is moved to the center hole of the diaphragm by the tension of the third steel wire rope. Pull the third steel wire rope upward to lift the load-bearing device out. S6. Dismantle the formwork system: After removing the load-bearing device, remove multiple bottom plates in sequence. First, lower the bottom plate using the fourth and fifth steel wire ropes. After lowering it a certain distance, keep the fourth steel wire rope stationary and slowly lower the fifth steel wire rope until it is completely loosened and falls below the diaphragm. Then tighten the sixth steel wire rope and slowly lower the fourth steel wire rope until it is also completely loosened and falls below the diaphragm. The bottom plate is pulled by the sixth steel wire rope to move to the center hole of the diaphragm. Pull the sixth steel wire rope upward to lift the bottom plate out. After all the bottom plates are lifted out, remove the side wall formwork and the center formwork. S7. Sealing holes: Fill all the first installation pipes and the second installation pipes with concrete.

2. The hollow pier diaphragm support and formwork external dismantling construction method according to claim 1 is characterized by: A pressure sensor is installed at the end of the telescopic member. After the lifting member is raised to the required height, the telescopic member is extended again so that the end of the telescopic member rests on the pier wall of the hollow pier, and the pressure between the end of the telescopic member and the pier wall is sensed by the pressure sensor.

3. The hollow pier diaphragm support and formwork external dismantling construction method according to claim 1 is characterized by: In step S3, before building the steel bars, a film is laid on the bottom formwork.

4. The hollow pier diaphragm support and formwork external dismantling construction method according to claim 1 is characterized by: The length direction of the base plate and the length direction of the load-bearing device are perpendicular to each other.

5. The hollow pier diaphragm support and formwork external dismantling construction method according to claim 1 is characterized by: In step S3, the gaps between the bottoms of the first mounting tube and the second mounting tube and the corresponding bottom plates are sealed.

6. The hollow pier diaphragm support and formwork external dismantling construction method according to claim 1 is characterized by: In step S5, the order of removing the load-bearing device or removing the bottom template is: removing them in sequence from the direction close to the center hole of the diaphragm to the direction away from the center hole of the diaphragm.

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