Bridge round pier column construction method based on reinforcement cage form control

Abstract

The invention discloses a bridge round pier column construction method based on reinforcement cage form control, which comprises the following steps: S1, breaking a pile head of a pile foundation to expose a pile head steel bar; s2, a concrete cushion block is arranged on the reinforcement cage; s3, the lower end of the reinforcement cage and pile head steel bars are centered, connected and fixed; s4, a plurality of pulleys are evenly arranged on the top of the last section of steel formwork in the circumferential direction in advance; s5, the steel formworks are installed section by section from bottom to top; s6, tensioning steel ropes are wound around the pulleys of the last section of steel formwork, one ends of the tensioning steel ropes are connected with the reinforcement cage main reinforcements, and the other ends of the tensioning steel ropes are connected with a tensioning device anchored to the ground; s7, concrete is poured while the tension of the tensioning device is kept; and S8, after the concrete is finally set, the pulling force of the tensioning device is relieved firstly, and then the tensioning device, the tensioning steel rope and the steel formwork are dismantled. The problems that when the bridge round pier column is constructed, due to bending deformation of the reinforcement cage, the thickness of a reinforcement protection layer is difficult to control, and the bearing capacity of the bridge round pier column is reduced are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building engineering, and particularly relates to a bridge round pier column construction method based on reinforcement cage form control. BACKGROUND

[0002] At present, in the construction of bridge round pier columns, the reinforcement cages of the round pier columns are basically processed in advance in a steel reinforcement centralized processing center in a centralized processing mode. During the construction of the pier columns, the reinforcement cages need to be transported to the site for installation. Since the steel reinforcement has a certain flexibility, when the reinforcement cage is hoisted or transported horizontally, the overall reinforcement cage will be bent to a certain extent. Meanwhile, after the reinforcement cage is connected with the pile head steel reinforcement, the reinforcement cage will be deformed due to the compression of the bending member under the action of its own gravity, so that the reinforcement cage is bent. And during the pouring of concrete, due to the impact and disturbance of the concrete, the reinforcement cage will also have the possibility of deformation. For the reinforcement cage of a higher bridge round pier column, the overall length is relatively long and needs to be made in sections, and generally one section is 12 m. In this case, the bending deformation of the reinforcement cage is more serious.

[0003] Since the reinforcement cage will be bent and deformed due to various factors, it will have the following adverse effects on the construction of the bridge round pier column:

[0004] Firstly, the bent and deformed reinforcement cage will affect the control of the thickness of the reinforcement cage protective layer. The reinforcement protective layer control is an important control parameter for the construction of bridge structures, and the reinforcement protective layer directly affects the durability and even the structural safety of the bridge structure. If the reinforcement protective layer is too large, cracks are likely to occur on the surface of the concrete, affecting the structural safety. If the protective layer is too small, the reinforcement cannot be effectively protected, and the reinforcement is prone to rust, volume expansion, and then expansion of the concrete, and the concrete is damaged, which will accelerate the rusting of the reinforcement, causing a vicious cycle of reinforcement rusting-concrete damage-reinforcement accelerated rusting. In the prior art, a certain thickness of concrete pad is usually fixed on the outside of the reinforcement cage using a wire to control the thickness of the reinforcement protective layer of the pier column. If the reinforcement cage is bent and deformed, when the formwork is installed after the concrete pad is installed, the formwork will cause excessive extrusion to the pad located at the bent concrete position of the reinforcement cage, which will cause the pad to be displaced, broken or fallen, so that the protective layer thickness control is not accurate.

[0005] Secondly, the bent and deformed reinforcement cage will reduce the bearing capacity of the bridge round pier column. If the reinforcement cage is bent, twisted and deformed, the spacing between the main reinforcement will be uneven or the position will be offset, so that the reinforcement cannot uniformly bear the tension or pressure as required by the design, and the bending, shearing and compressive resistance of the bridge round pier column will be weakened. SUMMARY

[0006] In view of the above problems, the purpose of the present application is to provide a bridge round pier column construction method based on reinforcement cage form control, aiming to solve the problems of difficult control of reinforcement cover thickness and decrease of bridge round pier column bearing capacity caused by bending deformation of the reinforcement cage during bridge round pier column construction.

[0007] The present application is realized by the following technical solutions.

[0008] The bridge round pier column construction method based on reinforcement cage form control is characterized by comprising the following steps.

[0009] S1, breaking the pile head of the pile foundation to expose the reinforcement of the pile head;

[0010] S2, setting a concrete cushion on the reinforcement cage;

[0011] S3, lifting the reinforcement cage by a crane and lowering it, and connecting and fixing the lower end of the reinforcement cage to the reinforcement of the pile head;

[0012] S4, determining the number of sections of the required steel formwork, so that the position of the top of the steel formwork after installation is higher than the reinforcement cage, and a plurality of pulleys are uniformly and previously arranged on the top of the last section of the steel formwork in the circumferential direction;

[0013] S5, installing the steel formwork section by section from bottom to top, when the bending position of the reinforcement cage is encountered, the reinforcement cage at the bending position is pulled straight by the crane, the corresponding steel formwork at the position is installed, and the current pulling force of the crane is always maintained until the installation of the last section of the steel formwork is completed;

[0014] S6, winding a tensioning steel rope on each pulley of the last section of the steel formwork, connecting one end of the tensioning steel rope to the main reinforcement of the reinforcement cage below the pulley, and connecting the other end to a tensioning device anchored to the ground, and synchronously and slowly applying tensioning force by each tensioning device, while slowly releasing the pulling force of the crane, to complete the stress conversion of the straightened reinforcement cage;

[0015] S7, pouring concrete while maintaining the tensioning force of the tensioning device;

[0016] S8, after the concrete is finally cured, the tensioning force of the tensioning device is released first, and then the tensioning device, the tensioning steel rope and the steel formwork are removed.

[0017] Preferably, in step S1, the form of the reinforcement of the pile head is adjusted to match the reinforcement cage.

[0018] Preferably, the method for adjusting the form of the reinforcement of the pile head is to first straighten the main reinforcement of the pile head, then adjust the spacing between the main reinforcement, and horizontally weld two layers of circular reinforcement rings with the same inner diameter as the reinforcement cage inside the reinforcement of the pile head, and weld three diagonal bracing rods intersecting at one point between the two layers of circular reinforcement rings.

[0019] Preferably, in step S4, the number of pulleys is 4, and the pulleys are arranged at positions above the edges of the reinforcement cage after the steel formwork is installed.

[0020] Preferably,

[0021] In step S3, the top end of the main reinforcement of the reinforcement cage is reserved with a thread.

[0022] In step S6, the end of the tensioning steel rope connected with the main reinforcement of the reinforcement cage is provided with a threaded sleeve matched with the reserved thread.

[0023] Preferably, in step S5, when the reinforcement cage is straightened by the traction force of the crane, the lifting point of the crane connected with the reinforcement cage is located on the center line of the reinforcement cage.

[0024] In step S5, the bending position of the reinforcement cage is determined by the following condition: the position where the verticality deviation of the reinforcement cage is greater than 0.1% of the height of the reinforcement cage is the position where the reinforcement cage is bent and deformed.

[0025] Preferably, the tensioning device comprises a ground anchor anchored to the ground and a flower basket bolt, one end of the flower basket bolt is connected with the ground anchor, and the other end is connected with the tensioning steel rope.

[0026] Preferably, the tensioning device comprises a concrete pile anchored to the ground, a tensioning hole penetrating the concrete pile, and a steel strand tensioning machine, the steel strand tensioning machine is arranged on one side of the tensioning hole and is connected with the tensioning steel rope penetrating the tensioning hole.

[0027] Preferably, in step S6, the total of the synchronous tensioning forces applied by the tensioning devices is 1-1.2 times of the traction force released by the crane, and the synchronous tensioning forces applied by the tensioning devices are the same.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] 1) In the present application, when the reinforcement cage does not have the straightening conditions before the steel formwork construction, the reinforcement cage is temporarily pulled by the crane, and after the steel formwork construction is completed, the top of the steel formwork is used as a fulcrum, and the reinforcement cage is pulled by the tensioning device, the pulley and the tensioning steel rope for a long time, so that the stress conversion of the reinforcement cage is completed, and the reinforcement cage can be kept in a straightened state during the installation of the formwork, the pouring and solidification of the concrete, thereby solving many adverse effects of the bending of the reinforcement cage on the construction of the round pier column of the bridge. Specifically, the present application changes the shape of the reinforcement cage by pulling, which makes the thickness adjustment of the reinforcement cage easier and more uniform, and greatly reduces the use amount of the concrete cushion block. In addition, the reinforcement cage after pulling can improve the bearing capacity of the bridge round pier column after construction.

[0030] 2) In the present application, the shape of the pile head reinforcement is adjusted by setting the reinforcement ring and the inclined strut, which can guarantee the positioning accuracy of the center position of the pier column and ensure the accurate connection of the pile head reinforcement and the reinforcement cage, so as to ensure the construction quality.

[0031] 3) In the present application, the tensioning steel rope used for pulling can be used as a cable wind rope, which can improve the stability of the reinforcement cage and the pier column formwork during concrete pouring. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 Schematic diagram of the three-dimensional structure for adjusting the shape of the pile head reinforcement;

[0033] Figure 2 Schematic diagram of the connection of the reinforcement ring and the inclined strut;

[0034] Figure 3 Schematic diagram of the step-by-step installation of the steel formwork;

[0035] Figure 4 Schematic diagram of the installation of the last section of the steel formwork;

[0036] Figure 5 Schematic diagram of force conversion;

[0037] Figure 6 Schematic diagram of long-term tensioning of the reinforcement cage by the tensioning device, pulley and tensioning steel rope;

[0038] Figure 7 Schematic diagram of long-term tensioning of the reinforcement cage by the tensioning device, pulley and tensioning steel rope;

[0039] Figure 8 Schematic diagram of Figure 7 Enlarged schematic diagram of point C;

[0040] Figure 9 Schematic diagram of the connection of the tensioning steel rope and the main reinforcement of the reinforcement cage;

[0041] Figure 10 Schematic diagram of one of the preferred structures of the tensioning device;

[0042] Figure 11 Schematic diagram of the second preferred structure of the tensioning device;

[0043] The meanings of the various indications in the above figures are as follows: pile head reinforcement 1, crane 2, reinforcement cage 3, wire teeth 301, ground 4, steel formwork 5, pulley 6, tensioning steel rope 7, threaded sleeve 701, tensioning device 8, ground anchor rod 801, flower basket bolt 802, concrete pile 803, tensioning hole 804, steel strand tensioning machine 805, reinforcement ring 9, inclined strut 10, pile foundation 11. DETAILED DESCRIPTION

[0044] The application will be further described in the following detailed description with reference to the drawings. It should be noted that the following embodiments are only illustrative of the application and are not intended to limit the scope of the application. The described embodiments are only a part of the embodiments of the application, not all the embodiments. Based on the embodiments of the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the application.

[0045] The embodiment provides a bridge round column construction method based on reinforcement cage form control.

[0046] S1, refer to Figure 1 and Figure 2 , break the pile head of the pile foundation, expose the pile head reinforcement 1, adjust the form of the pile head reinforcement 1 to match the reinforcement cage 3. The method for adjusting the form of the pile head reinforcement is to first straighten the main reinforcement of the pile head reinforcement 1, then adjust the spacing between the main reinforcement to be the same as the spacing of the reinforcement cage, and horizontally weld two layers of circular reinforcement rings 9 with the same inner diameter and coaxial with the reinforcement cage 3 at the top and bottom of the pile head reinforcement 1, and weld three inclined struts 10 connected to one point between the two layers of circular reinforcement rings 9, so as to ensure that the outer diameter of the pile head reinforcement and the spacing between the main reinforcement meet the design requirements and match the reinforcement cage of the pier column.

[0047] S2, the concrete cushion is arranged on the reinforcement cage 3. In the conventional method, the concrete cushion is fixed by using a wire on the outer side of the reinforcement cage 3, and the concrete cushion is arranged in a quincunx shape and is not less than 4 per square meter, and the wire head is bent inward. In the embodiment, the above method is also used, but the number of concrete cushions is reduced. It has been proved in practice that only 2-3 concrete cushions per square meter are needed, so that the use amount of concrete cushions can be saved by at least 40%.

[0048] S3, refer to Figure 3 and Figure 9 , the reinforcement cage 3 is lifted and lowered by the crane 2, and the lower end of the reinforcement cage 3 is connected and fixed to the pile head reinforcement 1 by welding. The top end of the main reinforcement of the reinforcement cage 3 is reserved with a wire tooth 301.

[0049] S4, refer to Figures 6-8, according to the length of the reinforcement cage 3 and the pile head reinforcement 1, the number of steel formwork 5 required is determined, so that the position of the top of the steel formwork 5 after installation is higher than the reinforcement cage 0.5-1m, and a plurality of pulleys 6 are uniformly arranged on the top of the last section of the steel formwork 5 in the circumferential direction; in the prior art, the top end of the reinforcement cage is generally higher than the steel formwork 5 after the reinforcement cage is installed, so it is difficult to directly apply tension to the reinforcement cage, and the present application raises the steel formwork 5, and installs the pulley at the top of the last section of the steel formwork 5 as a fulcrum, so that the direction of the force can be changed by means of the pulley, and the tension of the tensioning device 8 is transmitted through the tensioning steel rope 7;

[0050] In the embodiment, the number of pulleys 6 is 4, and the arrangement position of the pulley should satisfy: after the steel formwork is installed, the position of the pulley 6 is directly above the edge of the reinforcement cage, so as to prevent the tensioning steel rope 7 from generating lateral tension on the reinforcement cage and causing deformation of the top of the reinforcement cage;

[0051] S5, please refer to Figures 3-4 , the steel formwork 5 is installed section by section from bottom to top, when the curved position of the reinforcement cage 3 is encountered, the reinforcement cage 3 at the curved position is straightened by the crane 2, then the steel formwork 5 corresponding to the position is installed, and the current traction force of the crane 2 is always maintained until the installation of the last section of the steel formwork 5 is completed; when the reinforcement cage 3 is straightened by the traction force of the crane 2, the lifting point of the crane 2 connected with the reinforcement cage 3 is located on the center line of the reinforcement cage 3, so as to avoid the lateral force of the traction force of the crane 2 on the reinforcement cage 3 as much as possible;

[0052] For the convenience of understanding, please refer to Figure 3 , after the reinforcement cage 3 is connected with the pile head reinforcement 1 by being hoisted and placed, the reinforcement cage 3 has two curved positions, which are the A area curved to the left and the B area curved to the right from bottom to top, respectively; below the A area, the steel formwork 5 is installed section by section from bottom to top by using the conventional method, when the installation position of the next section of the steel formwork reaches the A area, the reinforcement cage 3 at the A area is straightened by the traction force of the crane 2 first, then the steel formwork 5 corresponding to the A area is installed, and then the current traction force N A of the crane 2 is maintained; B When the installation position of the next section of the steel formwork reaches the B area, the reinforcement cage 3 at the B area is straightened by the traction of the crane 2 first, then the steel formwork 5 corresponding to the B area is installed, and then the current traction force N A of the crane 2 is maintained; B ;

[0053] In this step, the bending position of the reinforcement cage is determined by the following condition: the position where the verticality deviation is greater than 0.1% of the height of the reinforcement cage is regarded as the position where the reinforcement cage is bent and deformed;

[0054] S6、Please refer to Figures 5-8 In the last section, the tensioning steel ropes 7 are wound around the pulleys 6 of the steel formwork 5, please refer to Figure 9 One end of the tensioning steel rope 7 connected with the main reinforcement of the reinforcement cage 3 is provided with a threaded sleeve 701 matched with the reserved thread 301, the threaded sleeve 701 at one end of the tensioning steel rope 7 is connected with the thread 301 on the main reinforcement of the nearest reinforcement cage 3 below the pulley 6 around which the tensioning steel rope 7 is wound, and the other end is connected with the tensioning device 8 anchored to the ground, the tensioning force is synchronously and slowly applied through each tensioning device 8, and the traction force of the crane 2 is slowly released at the same time, so as to complete the stress conversion of the straightened reinforcement cage 3; in order to ensure that the lateral forces of the tensioning devices 8 on the steel formwork 5 are offset to each other during the tensioning process, the tensioning forces synchronously applied by each tensioning device 8 are the same, and in order to ensure that the reinforcement cage is still in the straightened state after the stress conversion, the total tensioning force synchronously applied by each tensioning device 8 is 1-1.2 times of the traction force released by the crane 2;

[0055] In this embodiment, the tensioning device 8 can adopt the following two structures:

[0056] Please refer to Figure 11 The tensioning device 8 includes a ground anchor rod 801 anchored to the ground and a basket bolt 802; one end of the basket bolt 802 is connected with the ground anchor rod 801, and the other end is connected with the tensioning steel rope 7, and the tensioning force is provided for the reinforcement cage by adjusting the tightness of the basket bolt 802;

[0057] Or, please refer to Figure 10 The tensioning device 8 includes a concrete pile 803 anchored to the ground, a tensioning hole 804 penetrating the concrete pile 803, and a steel strand tensioning machine 805; the steel strand tensioning machine 805 is arranged on one side of the tensioning hole 804 and connected with the tensioning steel rope 7 penetrating the tensioning hole 804, and the tensioning force is provided for the reinforcement cage by tensioning the tensioning steel rope through the steel strand tensioning machine 805;

[0058] S7, while maintaining the tensioning force of the tensioning device 8, pouring the concrete;

[0059] S8, after the concrete is finally cured, the tensioning force of the tensioning device 8 is released, and then the tensioning device 8, the tensioning steel rope 7 and the steel formwork 5 are removed.

Claims

1. A construction method for round bridge piers based on reinforcement cage shape control, characterized in that: The steps include: S1, breaking the pile head to expose the pile head steel bar (1); S2, setting a concrete pad on the steel cage (3); S3, lifting and lowering the steel cage (3) by means of a crane (2), and aligning and fixing the lower end of the steel cage (3) with the pile head steel bars (1); S4. Determine the number of sections of the required steel template (5) so that the top of the steel template (5) is higher than the steel cage (3) after installation, and pre-set a number of pulleys (6) evenly along the circumferential direction on the top of the last section of the steel template (5); S5, installing the steel formwork (5) section by section from bottom to top, and when encountering a bent position of the steel cage (3), straighten the steel cage (3) at the bent position by pulling with the crane (2), and then install the steel formwork (5) corresponding to the position, and always maintain the current pulling force of the crane (2) until the installation of the last section of the steel formwork (5) is completed; S6. Tensioning steel ropes (7) are respectively wound around the pulleys (6) of the last section of the steel formwork (5), one end of the tensioning steel rope (7) is connected to the main reinforcement of the steel cage (3) closest to the pulley (6) around which it is wound, and the other end is connected to a tensioning device (8) anchored on the ground, and tension is slowly applied synchronously through each tensioning device (8), while the traction force of the crane (2) is slowly released to complete the force conversion of straightening the steel cage (3); S7, pouring concrete while maintaining the tension of the tensioning device (8); S8. After the concrete has finally set, first release the tension of the tensioning device (8), and then remove the tensioning device (8), the tensioning steel rope (7) and the steel formwork (5).

2. The method for constructing a round bridge pier column based on reinforcement cage shape control according to claim 1, characterized in that: Step S1 also includes: adjusting the shape of the pile head reinforcement (1) to match the reinforcement cage (3).

3. The method for constructing a round bridge pier column based on reinforcement cage shape control according to claim 2, characterized in that: The method for adjusting the shape of the pile head reinforcement is to first straighten the main reinforcement of the pile head reinforcement (1), then adjust the spacing between the main reinforcements, and horizontally weld two layers of circular reinforcement rings (9) with the same inner diameter as the reinforcement cage (3) inside the pile head reinforcement (1), and weld three diagonal bracing rods (10) that are cross-connected at one point between the two layers of circular reinforcement rings (9).

4. The method for constructing a round bridge pier column based on reinforcement cage shape control according to claim 1, characterized in that: In step S4, the number of pulleys (6) is 4, and the pulleys are arranged at positions such that after the steel formwork is installed, the pulleys (6) are positioned directly above the edge of the steel cage.

5. The method for constructing a round bridge pier column based on reinforcement cage shape control according to claim 1, characterized in that: In step S3, a thread (301) is reserved at the top of the main reinforcement of the reinforcement cage (3); In step S6, one end of the tensioning steel rope (7) connected to the main reinforcement of the reinforcement cage (3) is installed with a threaded sleeve (701) that matches the reserved thread (301).

6. The method for constructing a round bridge pier column based on reinforcement cage shape control according to claim 1, characterized in that: In step S5, when the steel cage (3) is straightened by the traction force of the crane (2), the lifting point where the crane (2) and the steel cage (3) are connected is located on the center line of the steel cage (3).

7. The method for constructing a round bridge pier column based on reinforcement cage shape control according to claim 1, characterized in that: In step S5, the bending position of the steel cage is determined by the following condition: the position where the verticality deviation of the steel cage is greater than 0.1% of the height of the steel cage indicates that the steel cage at that position is bent and deformed.

8. The method for constructing a round bridge pier column based on reinforcement cage shape control according to claim 1, characterized in that: The tensioning device (8) comprises a ground anchor rod (801) anchored to the ground and a turnbuckle (802); one end of the turnbuckle (802) is connected to the ground anchor rod (801), and the other end is connected to the tensioning steel rope (7).

9. The method for constructing a round bridge pier column based on reinforcement cage shape control according to claim 1, characterized in that: The tensioning device (8) comprises a concrete pile (803) anchored on the ground, a tensioning hole (804) provided through the concrete pile (803), and a steel strand tensioning machine (805); the steel strand tensioning machine (805) is provided on one side of the tensioning hole (804) and is connected to a tensioning steel rope (7) passing through the tensioning hole (804).

10. The method for constructing a round bridge pier column based on reinforcement cage shape control according to claim 1, characterized in that: In step S6, the sum of the pulling forces synchronously applied by each tensioning device (8) is 1-1.2 times the traction force released by the crane (2), and the pulling forces synchronously applied by each tensioning device (8) are the same.

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