Construction method for unbalanced installation of arch ribs on two sides of middle pier of continuous concrete filled steel tube arch bridge

Abstract

The invention relates to the technical field of bridge construction, in particular to an unbalanced mounting construction method for arch ribs on two sides of a middle pier of a continuous concrete-filled steel tube arch bridge, which comprises the following steps of: (1) respectively mounting part of arch rib sections on each side of the middle pier of the continuous concrete-filled steel tube arch bridge, and tensioning buckle cables for the corresponding arch rib sections while mounting; and (2) the middle pier is made to deviate towards the arch rib section on one side of the middle pier through the stabilizing cable. And (3) starting from the opposite side of the stabilizing cable, continuing to install the arch rib section and tensioning the buckling cable of the arch rib section at the same time. And after finishing, mounting the arch rib section on the opposite side of the arch rib section, and simultaneously tensioning the buckle cables of the two groups of arch rib sections. And the steps are repeated until all the arch rib sections on the two sides of the middle pier are installed in a crossed mode. By means of the method, the problems that the pier top of the middle pier deviates and the pier bottom stress is too large when the arch ribs on the two sides are installed in a crossed mode are not effectively solved, and the risk brought by the unbalanced construction process can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, and in particular to an unbalanced installation construction method for arch ribs on both sides of a middle pier of a continuous steel tube concrete arch bridge. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Steel tube concrete arch bridges are widely used in the construction of bridges in mountainous areas due to their many advantages such as high rigidity, high bearing capacity and good durability. The segment installation of steel tube concrete arch bridges usually adopts the cable hoisting process. When installing the arch rib segments of a single-span steel tube concrete arch bridge, it is necessary to tension the cables and anchor cables at the same time. After the cables and anchor cables are anchored on both sides of the bridge pier, they transmit the force to the ground, thus forming a stable structural system. Due to terrain restrictions, sometimes an arch bridge needs to span two adjacent "V"-shaped canyons. At this time, a double-span continuous arch bridge comes into being (see the attached manual). Figure 1 ).

[0004] For the arch ribs on both sides of the middle pier of the double arch (i.e. the left arch rib and the right arch rib) (see the attached manual Figure 2 ), when the arch rib segments on both sides are installed and the cables are tensioned at the same time, the structure is in a balanced and safe state. However, the actual situation is that the cable lifting system can only transport one segment to the installation location at a time, especially when restricted by the terrain. As a result, the arch ribs on both sides of the middle pier cannot be installed at the same time. For example, when the left arch rib segment is installed first and the left cable is tensioned, the right side of the middle pier is in an unbalanced state due to the lack of symmetrical cable forces, which causes the top of the middle pier to deviate to the left, and tensile stress appears on the right side of the pier bottom. As the number of installed arch rib segments continues to increase, this construction method will cause excessive horizontal deformation at the top of the middle pier and excessive tensile stress at the bottom of the pier. In addition, some middle piers adopt hollow structures, especially for hollow middle piers. The above construction method brings potential safety problems to construction safety. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for unbalanced installation of arch ribs on both sides of the middle pier of a continuous steel tube concrete arch bridge, which effectively solves the problems of pier top deviation and excessive stress at the pier bottom caused by cross-installation of arch ribs on both sides, and helps to reduce the risks brought by the unbalanced construction process. Specifically, the technical solution of the present invention is as follows.

[0006] A construction method for unbalanced installation of arch ribs on both sides of the middle pier of a continuous steel tube concrete arch bridge comprises the following steps: (1) In view of the situation that the arch ribs on both sides of the middle pier of the steel tube concrete arch bridge cannot be installed at the same time due to terrain restrictions, during construction, some arch rib segments are first installed on each side of the middle pier, and the corresponding arch rib segments are tensioned with cables during installation to maintain the stability of these arch rib segments.

[0007] (2) Prepare a stabilizing cable, connect its upper end to the top of the middle pier, and then fix the lower end of the stabilizing cable on the base surface on one side of the middle pier and tension it, so that the middle pier is offset by a set amount to the side where the inclined stabilizing cable is located, and the stabilizing cable and a side arch rib segment of the middle pier are located on the same side.

[0008] (3) Then, starting from the opposite side of the stabilizing cable, continue to install the arch rib segment a and partially tension the cable a of the arch rib segment a, and use the partial cable force formed to partially pull the intermediate pier. After completion, install the arch rib segment b on the opposite side of the arch rib segment a, and tension the cable b of the arch rib segment b so that the partial cable force formed is the same as the partial cable force of the arch rib segment a. Then tension the cable a and the cable b at the same time until the same final cable force is reached. After completion, continue to install the arch rib segment from the opposite side of the stabilizing cable, and repeat this process until all the arch rib segments on both sides of the intermediate pier are cross-installed.

[0009] Furthermore, in step (1), the number of the partial arch rib segments is based on the following: when a certain arch rib segment is installed on one side of the middle pier and a symmetrical arch rib segment has not been installed on the opposite side, the pier top offset generated by the middle pier is not greater than 3 cm and the pier bottom stress is not greater than 1.6 MPa. It should be understood that the installation of this part of the rib segments can be carried out in an unbalanced state.

[0010] Furthermore, in step (1), the cable is tilted, with its upper end connected to the side wall of the middle pier and its lower end connected to the corresponding arch rib segment. Optionally, the angle between the cable and the horizontal plane is 2.5-37°.

[0011] Furthermore, in step (2), a connecting buckle for detachably connecting to the lower end of the stabilizing cable is anchored in the base surface.

[0012] Furthermore, in step (2), the set amount is to cause the top of the middle pier to shift 2 to 4 cm toward the side where the stabilizing rope is located by pulling the stabilizing rope.

[0013] Furthermore, in step (2), the angle between the stabilizing cable and the horizontal plane is 10-45°, which can be determined according to the topography of the construction site. Generally speaking, the smaller the angle, the easier it is to form an effective pulling effect on the middle pier, so that when the arch rib segments on both sides of the middle pier are installed, the stabilizing cable can more effectively limit the horizontal deformation of the middle pier.

[0014] Furthermore, in step (3), the partial cable force is not greater than 60% of the final cable force. In the process of tensioning the cable a, since the offset of the intermediate pier will decrease under the action of the cable force, if the cable force of the cable a is tensioned once to reach the final cable force, the offset of the intermediate pier will return to zero or even become negative, that is, it will deviate to the side of the arch rib segment a, causing excessive horizontal deformation of the intermediate pier and excessive tensile stress at the bottom of the pier. To this end, the present invention proposes a method of first partially tensioning the cable a to form a partial cable force, thereby ensuring that the intermediate pier maintains a certain offset. In this way, not only can the installation requirements of the arch rib segment a be met, but also the balanced state formed after the arch rib segment b is installed can be utilized to tension the cable a and the cable b at the same time until the same final cable force is reached. In this way, when the installation of the arch rib segment a and the arch rib segment b is completed, the offset of the intermediate pier is restored to the initial state, which is convenient for the installation of the subsequent arch rib segments.

[0015] Furthermore, in step (3), after all the arch rib segments are installed, the stabilizing cables can be removed.

[0016] Furthermore, in step (2), the stabilizing cable comprises at least two ropes arranged in parallel, and after all the arch rib segments are installed in step (3), only the lower end of the stabilizing cable is removed, and the upper end remains connected to the middle pier. Then, the ropes obtained by separating the stabilizing cable are distributed to both sides of the middle pier, and are respectively connected to the bridge deck columns fixed on the arch rib segments, and the ropes are tensioned.

[0017] Furthermore, after the bridge deck pavement construction supported on the bridge deck columns is completed, the stabilizing cables are removed from the middle piers and the bridge deck columns.

[0018] Furthermore, the buckle cable and the stabilizing cable are both steel strands formed by twisting a number of steel wires, which have not only high strength but also high toughness. Preferably, the surface of the steel strand has an anti-corrosion layer.

[0019] Compared with the prior art, the present invention has at least the following beneficial technical effects: The present invention proposes a method of using a stabilizing cable to increase the anti-thrust stiffness of the intermediate pier of a continuous steel tube concrete arch bridge, thereby resisting the horizontal force of the unbalanced installation state of the arch rib segment, thereby well realizing the control of the deformation and stress of the intermediate pier, preventing the intermediate pier from becoming unstable during the installation of the arch rib segment, thereby causing engineering safety problems. At the same time, after completing the installation of the arch rib segment, the present invention also uses the convenience provided by the stabilizing cable to limit the deviation of the bridge deck column, enhance the stability of the structure, and thus help to further improve the safety of the construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0021] Figure 1 It is a structural schematic diagram of the double-span continuous arch bridge in the aforementioned background technology.

[0022] Figure 2 It is a schematic structural diagram of the middle pier of the double-span continuous arch bridge in the aforementioned background technology.

[0023] Figure 3 It is a schematic structural diagram of a double-arch middle pier with stabilizing cables tensioned in the following embodiments.

[0024] Figure 4 It is a schematic diagram of installing the left arch rib segment in the following embodiment.

[0025] Figure 5 It is a schematic diagram of installing the right arch rib segment in the following embodiment.

[0026] Figure 6 It is a schematic diagram of the structure of using stabilizing cables to enhance the stability of bridge deck columns in the following embodiments.

[0027] Figure 7 The following are the finite element simulation test results of the unbalanced installation construction method with the stabilizing cable installed in the following embodiment.

[0028] Figure 8 The following are finite element simulation test results of the unbalanced installation construction method without the stabilizing cable installed in the following embodiments.

[0029] The marks in the above figure represent: 1-middle pier, 2-left arch rib segment, 3-right arch rib segment, 4-cable, 5-stabilizing cable, 6-connecting buckle, 7-bridge deck column, 8-bridge deck. DETAILED DESCRIPTION

[0030] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0032] For the convenience of description, if the words "up", "down", "left" and "right" appear in the present invention, they only indicate that they are consistent with the up, down, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or component needs to have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0033] Now, the unbalanced installation construction method of the arch ribs on both sides of the middle pier of the continuous steel tube concrete arch bridge of the present invention is further described in combination with the drawings and specific embodiments of the specification. Specifically, the method includes the following steps: (1) Reference Figure 2 In view of the situation that the arch rib segments on both sides of the middle pier 1 of the continuous steel tube concrete arch bridge cannot be installed at the same time due to terrain restrictions, the method adopted in this embodiment is: firstly, four arch rib segments (i.e., four left arch rib segments 2 and four right arch rib segments 3) are installed on the left and right sides of the middle pier 1 respectively by using a cable hoisting system, and the left and right sides are cross-installed. At the same time, the buckle cable 4 is tensioned on the left arch rib segment 2 and the right arch rib segment 3 to ensure the stability of these arch rib segments. The buckle cable 4 is inclined, and its upper end is connected to the side wall of the middle pier 1, and its lower end is connected to the corresponding arch rib segment. The angle between the buckle cable 4 and the horizontal plane ranges from 2.5 to 37°. As the number of the installed arch rib segment pairs increases, the arch rib cantilever length formed by them increases, and the angle between the buckle cable and the horizontal plane decreases at this time, so the horizontal force caused by the weight of the arch rib segment is also greater, and the horizontal deformation of the middle pier top and the stress at the pier bottom caused by unbalanced hoisting are also greater. In this embodiment, the angles between the buckling cables 4 corresponding to the four arch rib segments and the horizontal plane are 37°, 30°, 20°, and 15° from bottom to top. The buckling cables 4 are steel strands formed by twisting a number of steel wires, which not only have high strength but also high toughness, so as to provide good buckling force for the arch rib segments.

[0034] (2) As the number of arch rib segments installed on both sides of the middle pier 1 increases, the connection position between the buckle cable 4 and the middle pier 1 becomes higher and higher. When the arch rib segments on one side of the middle pier 1 are installed, the buckle cable 4 may be tightened to pull the middle pier 1, causing it to deviate and resulting in tensile stress at the bottom of the middle pier 1. In particular, as the number of arch rib segments increases, it will eventually lead to excessive horizontal deformation at the top of the middle pier 1 and excessive tensile stress at the bottom of the pier (based on the pier top displacement of the middle pier being greater than 3 cm and the pier bottom stress exceeding 1.6 MPa), affecting construction safety.

[0035] For this purpose, refer to Figure 3 In this embodiment, a tensioned inclined stabilizing cable 5 (a steel strand formed by twisting a plurality of steel wires) is arranged on the right side of the middle pier 1: its upper end is connected to the top of the middle pier 1, and its lower end is fixed to the foundation surface on the right side of the middle pier 1, so that the middle pier 1 is offset to the right by a set amount (such as 2 cm, 3 cm, 4 cm, etc.). The angle between the stabilizing cable 5 and the horizontal plane can be arbitrarily selected within the range of 10 to 45°, such as 10°, 20°, 30°, 45°, etc., and an angle outside the above range can also be selected according to the actual terrain characteristics.

[0036] (3) Reference Figure 4 , starting from the left side of the middle pier 1, that is, the opposite side of the stabilizing cable 5, install the fifth section left arch rib segment 2 and its corresponding buckle cable 4, and partially tension the buckle cable 4 to form a partial buckle force (50% of the final buckle force) on the fifth section left arch rib segment 2. At this time, due to the restriction of the stabilizing cable 5 on the middle pier 1, the anti-thrust stiffness of the middle pier is enhanced, and the pier top deviation and excessive tensile stress at the pier bottom are limited during the unbalanced installation of the arch rib segments on both sides of the middle pier 1. After completion, install the fifth section right arch rib segment 3 and its corresponding buckle cable 4 on the right side of the middle pier 1 (refer to Figure 5 ), and then tension the cable 4 so that its cable force is the same as the partial cable force of the fifth section left arch rib segment 2. After completion, the cable 4 of the fifth section left arch rib segment 2 and the fifth section right arch rib segment 3 are tensioned at the same time to form symmetrical cable forces. At this time, the middle pier 1 restores the equilibrium state, so that after the fifth section right arch rib segment 3 is installed, the middle pier 1 returns to the initial offset to the right. Continue to install the sixth section left arch rib segment 2 and its corresponding cable 4 on the left side of the middle pier 1 according to the above method until all the arch rib segments on both sides of the middle pier 1 are cross-installed.

[0037] (4) After all the arch rib segments are installed, the stabilizing cable 5 can be removed. It should be understood that the stabilizing cable 5 can also be set on the left side of the middle pier 1. The difference is that the installation order of the subsequent arch rib segments is opposite to the above step (3). This embodiment uses the stabilizing cable 5 to increase the anti-thrust stiffness of the middle pier 1 of the continuous steel tube concrete arch bridge, which is equivalent to adding external prestressed steel bars to resist the horizontal force of the unbalanced installation state of the arch rib segments, and well realizes the control of the deformation and stress of the middle pier, preventing the middle pier from becoming unstable during the installation of the arch rib segments. At the same time, the stabilizing cable 5 and the middle pier 1 form a stable triangular structure, so that the construction can be carried out when the cross section of the middle pier is built to a smaller size, which can save materials and reduce costs.

[0038] In another implementation manner, in the unbalanced installation construction method of the above embodiment, the surface of the steel strand has an anti-corrosion layer to increase the service life of the buckle cable 4 and the stabilizing cable 5.

[0039] For another embodiment, refer to Figure 3 , Figure 4 or Figure 5 In step (2) of the unbalanced installation construction method of the above embodiment, a connecting buckle 6 is anchored in the base surface so as to be detachably connected to the lower end of the stabilizing cable 5, thereby facilitating the connection and removal of the stabilizing cable 5.

[0040] For another embodiment, refer to Figure 6 In the unbalanced installation construction method of the above embodiment, the stabilizing cable 5 used in step (2) includes at least two ropes arranged in parallel (each rope is a steel strand formed by twisting a plurality of steel wires). On the one hand, the overall strength of the stabilizing cable 5 can be enhanced, so as to provide a more sufficient pulling effect. On the other hand, after all the arch rib segments are installed in the above step (3), this embodiment adopts a method of only removing the lower end of the stabilizing cable 5, and the upper end is still connected to the middle pier 1. Then, after the ropes obtained by separating the stabilizing cable 5 are distributed to both sides of the middle pier 1, they are respectively connected to the bridge deck columns 7 fixed on the left arch rib segment 2 and the right arch rib segment 3, and the ropes are tensioned, so that the middle pier 1 with greater rigidity can be used to limit the possible deviation of the bridge deck columns 7 during the laying process of the bridge deck 8, thereby enhancing the overall stability of the supporting structure formed by the arch rib segments and the bridge deck columns 7. After the paving construction of the bridge deck 8 is completed, the two ends of the stabilizing cable 5 are removed from the middle pier 1 and the bridge deck columns 7 respectively.

[0041] In a further implementation, this embodiment uses finite element simulation technology to simulate the unbalanced installation construction method of the arch ribs on both sides of the middle pier of the above-mentioned continuous steel tube concrete arch bridge. The results are as follows Figure 7 and Figure 8As shown. Among them: Figure 7 The test results obtained after the above-mentioned stabilizing cable 5 was installed on the middle pier 1 show that when the twelfth left arch rib segment of the middle pier 1 was installed and its cable force was tensioned to 50% of the final cable force, the middle pier 1 deviated 23mm to the left, and the stress at the pier bottom was -0.4MPa, that is, there was no tensile stress at the pier bottom. Figure 8 The test results obtained without the above-mentioned stabilizing cable 5 on the middle pier 1 show that when the twelfth left arch rib segment of the middle pier 1 is installed and its cable force is tensioned to 50% of the final cable force, the middle pier 1 deviates to the left by 99mm, and the tensile stress at the bottom of the pier is 2.6MPa, that is, tensile stress appears at the bottom of the pier. This proves that the stabilizing cable 5 can effectively limit the generation of stress at the bottom of the pier, which helps to prevent the problem of instability of the middle pier during the installation of the arch rib segment.

[0042] Finally, it should be noted that any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. Although the above describes the specific implementation of the present invention in conjunction with the drawings, it is not a limitation of the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, various modifications or deformations that can be made by those skilled in the art without creative labor are still within the protection scope of the present invention.

Claims

1. Unbalanced installation construction method of arch ribs on both sides of the middle pier of a continuous steel tube concrete arch bridge, characterized in that: The steps include: (1) In the case where the arch ribs on both sides of the middle pier of the steel tube concrete arch bridge cannot be installed at the same time due to terrain restrictions, during construction, some arch rib segments are first installed on each side of the middle pier, and the corresponding arch rib segments are tensioned with cables during installation to maintain the stability of these arch rib segments; (2) preparing a stabilizing cable, connecting its upper end to the top of the intermediate pier, and then fixing the lower end of the stabilizing cable on the base surface on one side of the intermediate pier and tensioning it, so that the intermediate pier is offset by a set amount to the side where the inclined stabilizing cable is located, and the stabilizing cable and a side arch rib segment of the intermediate pier are located on the same side; (3) Then, starting from the opposite side of the stabilizing cable, continue to install the arch rib segment a and partially tension the cable a of the arch rib segment a, and use the partial cable force to partially pull the intermediate pier; After completion, the arch rib segment b on the opposite side of the arch rib segment a is installed, and the buckle cable b of the arch rib segment b is tensioned so that the partial buckle cable force formed is the same as the partial buckle cable force of the arch rib segment a; then the buckle cable a and the buckle cable b are tensioned simultaneously until the same final buckle cable force is reached; After completion, continue to install the arch rib segments from the opposite side of the stabilizing cable, and repeat this process until all the arch rib segments on both sides of the middle pier are cross-installed.

2. The unbalanced installation construction method for the arch ribs on both sides of the middle pier of a continuous steel tube concrete arch bridge according to claim 1 is characterized in that: In step (1), the number of the partial arch rib segments is based on the following: when a certain arch rib segment is installed on one side of the middle pier and a symmetrical arch rib segment has not been installed on the opposite side, the pier top offset generated by the middle pier is not greater than 3 cm and the pier bottom stress is not greater than 1.6 MPa.

3. The unbalanced installation construction method of the arch ribs on both sides of the middle pier of the continuous steel tube concrete arch bridge according to claim 2 is characterized in that: In step (1), the buckle cable is arranged obliquely, with its upper end connected to the side wall of the middle pier and its lower end connected to the corresponding arch rib segment; or, the angle between the buckle cable and the horizontal plane is 2.5~37°.

4. The unbalanced installation construction method of the arch ribs on both sides of the middle pier of a continuous steel tube concrete arch bridge according to claim 1 is characterized in that: The buckle cable and the stabilizing cable are both steel strands formed by twisting a number of steel wires; or, the surface of the steel strand has an anti-corrosion layer.

5. The unbalanced installation construction method of the arch ribs on both sides of the middle pier of the continuous steel tube concrete arch bridge according to claim 1 is characterized in that: In step (2), a connecting buckle for detachably connecting to the lower end of the stabilizing cable is anchored in the base surface.

6. The unbalanced installation construction method of the arch ribs on both sides of the middle pier of a continuous steel tube concrete arch bridge according to claim 1 is characterized in that: In step (2), the set amount is to cause the top of the intermediate pier to shift 2 to 4 cm toward the side where the stabilizing cable is located by pulling the stabilizing cable; or, in step (2), the angle between the stabilizing cable and the horizontal plane is 10 to 45°.

7. The unbalanced installation construction method for the arch ribs on both sides of the middle pier of a continuous steel tube concrete arch bridge according to claim 1 is characterized in that: In step (3), the partial cable force is no greater than 60% of the final cable force.

8. The unbalanced installation construction method for the arch ribs on both sides of the middle pier of a continuous steel tube concrete arch bridge according to any one of claims 1 to 7, characterized in that: In step (3), after all the arch rib segments are installed, the stabilizing cables can be removed.

9. The unbalanced installation construction method for the arch ribs on both sides of the middle pier of a continuous steel tube concrete arch bridge according to any one of claims 1 to 7, characterized in that: In step (2), the stabilizing cable comprises at least two ropes arranged in parallel. In step (3), after all the arch rib segments are installed, only the lower end of the stabilizing cable is removed, and the upper end remains connected to the middle pier. Then, the ropes obtained by separating the stabilizing cable are distributed to both sides of the middle pier, and are respectively connected to the bridge deck columns fixed on the arch rib segments, and the ropes are tensioned.

10. The unbalanced installation construction method for the arch ribs on both sides of the middle pier of a continuous steel tube concrete arch bridge according to claim 9 is characterized in that: After the bridge deck pavement construction supported on the bridge deck columns is completed, the stabilizing cables are removed from the middle piers and the bridge deck columns.

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