A construction method for pre-unloading of a cable-stayed structure support frame.

Abstract

This invention relates to a construction method for pre-unloading a support frame for a cable-stayed structure. A core tube is set within the construction area, a steel structure is installed on the side of the core tube, and the support frame is installed at the bottom of the steel structure. The construction method includes the following steps: providing several tension cables and connecting them between the side of the core tube and the top of the steel structure; pre-tensioning the tension cables; disconnecting the support frame from the steel structure; providing support pads and placing the support pads between the support frame and the steel structure; continuing to tension the tension cables until the top of the steel structure separates from the support frame; and finally, dismantling the support frame.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and specifically to a construction method for the pre-unloading of a cable-stayed structure support frame. Background Technology

[0002] During the installation of long-span cable-stayed structures, the support frame is the main support and load-bearing component before the structure becomes a whole. The top adjustment section of the support frame is fixed to the upper steel structure by welding or other methods. The load of the main structure is transferred to the foundation through the support frame, ensuring the safety of structural construction. However, to avoid affecting the cable tension, the structure cannot be constrained by the support frame during cable tensioning. Therefore, the support frame must be pre-unloaded before the cable tensioning is completed. Summary of the Invention

[0003] The purpose of this invention is to overcome the defects of the prior art and provide a construction method for the pre-unloading of the support frame of the cable-stayed structure. This method involves first setting the tension cable between the core tube and the steel support and pre-tensioning it, then cutting off the connection between the steel support and the core tube, then tensioning the tension cable, and finally dismantling the support frame, thereby enabling the support frame to be pre-unloaded.

[0004] The technical solution to achieve the above objectives is a construction method for pre-unloading of a cable-stayed structure support frame. A core tube is set within the construction area, a steel structure is set on the side of the core tube, and the support frame is set at the bottom of the steel structure. The construction method includes the following steps:

[0005] Several tension cables are provided to be connected between the side of the core tube and the top of the steel structure;

[0006] The tension cable is pre-tensioned;

[0007] The connection between the support frame and the steel structure is severed, a support pad is provided, and the support pad is placed between the support frame and the steel structure;

[0008] Continue tensioning the tensioning cable until the top of the steel structure separates from the supporting frame, then remove the supporting frame.

[0009] Furthermore, a support adjustment rod is provided between the support frame and the steel structure, and the support adjustment rod is cut when the connection between the support frame and the steel structure is severed.

[0010] Furthermore, before dismantling the support frame, the side of the support adjustment rod closest to the steel structure is cut into sections, so that the steel structure is released from the support adjustment rod's support, and then the support frame is dismantled.

[0011] Furthermore, when segmenting the support adjustment rod, a predetermined cutting length and observation time are provided. The top of the support adjustment rod is cut according to the cutting length to confirm whether the steel structure corresponding to the position of the support adjustment rod bends downward within the observation time. If bending occurs, the cutting continues according to the predetermined cutting length after the observation time ends until the steel structure no longer bends downward. If no bending occurs, the remaining part of the support adjustment rod is removed.

[0012] Furthermore, when cutting the support adjustment rod, an oxy-acetylene welding cutter is provided, and the support adjustment rod is cut using the oxy-acetylene welding cutter.

[0013] Furthermore, before pre-tensioning the tension cable, the tensioning process of the tension cable is simulated and analyzed based on the on-site construction conditions to determine the load changes of each support frame during the tensioning process.

[0014] Furthermore, before pre-tensioning the tension cables, the tensioning process of the tension cables is simulated and analyzed based on the on-site construction conditions to determine the tension force of each tension cable.

[0015] Furthermore, when dismantling the support frame, it is dismantled in order from the position closest to the core tube to the position furthest from the core tube.

[0016] Furthermore, when dismantling the support frame, the support frames on both sides of the core tube are dismantled simultaneously and symmetrically.

[0017] Furthermore, after severing the connection between the support frame and the steel structure, the tensioning cables are tensioned according to the on-site construction requirements.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] By first setting the tensioning cables between the core tube and the steel support and pre-tensioning them, then cutting off the connection between the steel support and the core tube, and then tensioning them with the tensioning cables, and finally removing the support frame, the support frame can be pre-unloaded. Attached Figure Description

[0020] Figure 1 This is an overall structural diagram of a construction method for an advanced unloading of a cable-stayed support frame.

[0021] Figure 2 This diagram illustrates the connection between the steel structure and the supporting frame in a construction method for an advanced unloading of a cable-stayed structure support frame.

[0022] Figure 3This is a cutaway diagram of the steel structure and support frame used in a construction method for an advanced unloading of a cable-stayed structure support frame.

[0023] Figure 4 This is a diagram illustrating the segmented cutting effect of the steel structure and support frame as part of a construction method for an advanced unloading of a cable-stayed structure support frame.

[0024] Legend: 1. Steel structure; 2. Support adjustment rod; 3. Support frame; 4. Core tube; 5. Tension cable; 6. Support pad. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] See Figure 1 A construction method for pre-unloading of a cable-stayed structure support frame is disclosed. A core tube 4 is set within the construction area, a steel structure 1 is set on the side of the core tube 4, and the support frame 3 is set at the bottom of the steel structure 1. The construction method includes the following steps: providing several tension cables 5 and connecting them between the side of the core tube 4 and the top of the steel structure 1; pre-tensioning the tension cables 5; cutting the connection between the support frame 3 and the steel structure 1; providing support pads 6 and placing them between the support frame 3 and the steel structure 1; continuing to tension the tension cables 5 until the top of the steel structure 1 separates from the support frame; and dismantling the support frame 3.

[0027] In a preferred embodiment of this invention, after the steel structure 1 is installed, tension cables 5 are installed between the steel structure 1 and the core tube 4. Before tensioning the tension cables 5, a simulated tensioning process is performed to determine the load changes of each support frame 3 during the tensioning process. That is, it is confirmed whether the tension cables 5 still bear the support load of the support frame 3 after tensioning. Based on the load change conditions, the construction process for each support frame 3 is specified, and the subsequent tensioning force for each tension cable 5 is determined. The connection between the steel structure 1 and the support frame 3 is cut off. A support pad 6 is placed between the steel structure 1 and the support frame 3 so that the support frame 3 continues to support the steel structure 1 and prevents the steel structure 1 from falling due to gravity. Then, the tension cable 5 is continued to be tensioned so that the tension cable 5 pulls the steel structure 1. Preferably, the tension force can be adjusted according to the load change of each support frame 3 during the first tensioning. When the tension cable 5 reaches the predetermined tension force, each support frame 3 is removed so that the support frame 3 is pre-unloaded.

[0028] Furthermore, the calculation method for the tension force of the tension cable 5 can be adopted from the calculation method in "Practical Calculation Method for Inclination Angle Correction and Main Parameters of Tension Cable 5 at the Tower End of Cable-Stayed Bridge".

[0029] Furthermore, a support adjustment rod 2 is provided between the support frame 3 and the steel structure 1. When the connection between the support frame 3 and the steel structure 1 is severed, the support adjustment rod 2 is cut. This support adjustment rod 2 facilitates the cutting work by construction personnel in subsequent construction. The length of the support adjustment rod 2 can be determined according to the on-site construction requirements.

[0030] Furthermore, before dismantling the support frame 3, the side of the support adjusting rod 2 closest to the steel structure 1 is segmented and cut, so that the steel structure 1 is released from the support adjusting rod 2, and then the support frame 3 is dismantled. Preferably, when pre-tensioning the tension cable 5, the support frame 3 can be divided into two categories: support frame 3 that no longer bears the upper load after cable tensioning and is far from the core tube 4 (first type of support frame 3), and support frame 3 that still bears the upper load after cable tensioning and is close to the core tube 4 (second type of support frame 3). The first type of support frame 3 is the support frame 3 that no longer bears the upper load after cable tensioning. The upper structure of this type of support frame 3 is greatly affected by tensioning. The support frame 3 and the upper structure... After the structure is cut and separated, the upper structure and the support frame separate as the cable is tensioned, thus completing the unloading of the support frame 3 on its own. The second type is the support frame 3 that still bears the upper load after the cable is tensioned. The upper structure of this type of support frame 3 is less affected by tensioning and remains in contact with the support frame 3 after tensioning. It cannot unload the support frame 3 on its own. This type of support frame 3 needs to be segmented and cut before the cable tensioning is completed to force the support frame 3 to separate from the upper structure, thus completing the unloading of the support frame 3.

[0031] Furthermore, when segmenting the support adjustment rod 2, a predetermined cutting length and observation time are provided. The top of the support adjustment rod 2 is cut according to the cutting length to confirm whether the steel structure 1 corresponding to the position of the support adjustment rod 2 bends downward within the observation time. If bending occurs, the cutting continues according to the predetermined cutting length after the observation time ends until the steel structure 1 no longer bends downward. If no bending occurs, the remaining part of the support adjustment rod 2 is removed.

[0032] Preferably, in this invention, a preferred embodiment is as follows: when the second type of support frame 3 is disassembled, since the second type of support frame 3 cannot be separated from the upper structure with the tensioning of the tension cable, it still participates in the structural stress after the tensioning is completed. At this time, disassembling the support frame 3 will again affect the cable force and structural safety. Therefore, in addition to cutting and separating the support frame 3 after the pre-tensioning of the cable, the upper adjustment section also needs to be segmented before the tensioning is completed. This forces the unloading of the support frame 3 and prevents any physical contact between the support frame 3 and the upper structure. To ensure construction safety, the segmented cutting of the support adjustment section should be carried out before the last stage of cable tensioning. The bending deformation value of the upper structure after the second type of support frame 3 is unloaded under the tension of the cable 5 is calculated. Based on the deformation value, the required cutting length for the segmented unloading of the support frame 3 adjustment section is determined and marked on the support adjustment section in advance. In this embodiment, the top of the support adjustment section is cut off and unloaded by 1cm, and observed for 10 minutes. If the steel structure 1 does not bend downward, the support adjustment section is cut 20cm from the root, and then the other areas of the support frame 3 are cut. If a downward bend occurs during unloading, cut the support adjustment rod 2 to half of the marked cutting length, then observe for 10 minutes. If no downward bend occurs, cut the support adjustment section 20cm from the root, and then unload the other areas of the support frame 3. If a downward bend occurs, cut the support adjustment rod 2 to the marked cutting length mark, and continue to observe for 10 minutes. If the steel structure 1 does not bend downward, cut the support adjustment section 20cm from the root, and then unload the other areas of the support frame 3. If a downward bend occurs, continue to cut downward by 2cm and observe for 10 minutes. If a downward bend occurs, repeat the above steps of cutting downward by 2cm and observing for 10 minutes until no downward bend occurs. When no downward bend occurs, cut the support adjustment section 20cm from the root, and then unload the other areas of the support frame 3.

[0033] Furthermore, when cutting the support adjustment rod 2, an oxy-acetylene welding cutter is provided, and the support adjustment rod 2 is cut by the oxy-acetylene welding cutter.

[0034] Furthermore, before pre-tensioning the tension cable 5, the tensioning process of the tension cable 5 is simulated and analyzed according to the on-site construction conditions to determine the load changes of each of the support frames 3 during the tensioning process.

[0035] Furthermore, before pre-tensioning the tension cables 5, the tensioning process of the tension cables 5 is simulated and analyzed based on the on-site construction conditions to determine the tension force of each tension cable 5.

[0036] Furthermore, when dismantling the support frame 3, it is dismantled in the order from the position closest to the core tube 4 to the position furthest from the core tube 4.

[0037] Furthermore, when dismantling the support frame 3, the support frames 3 on both sides of the core tube 4 are dismantled simultaneously and symmetrically.

[0038] Furthermore, after severing the connection between the support frame 3 and the steel structure 1, the tension cable 5 is tensioned according to the on-site construction requirements.

[0039] The following describes the application process of the construction method for the pre-unloading of a cable-stayed structure support frame according to the present invention.

[0040] After the steel structure 1 is installed, tension cables 5 are installed between the steel structure 1 and the core tube 4. Before tensioning the tension cables 5, a simulated tensioning process is conducted to determine the load changes of each support frame 3 during the tensioning process. This confirms whether the tension cables 5 still bear the support load of the support frame 3 after tensioning. Based on this load change condition, the construction process for each support frame 3 is specified, and the subsequent tensioning force for each tension cable 5 is determined. The steel structure 1 and the support frame 4 are then connected. The connection of the support frame 3 is cut off, and a support pad 6 is set between the steel structure 1 and the support frame 3 so that the support frame 3 continues to support the steel structure 1 and prevents the steel structure 1 from falling due to gravity. Then, the tension cable 5 is continued to be tensioned so that the tension cable 5 pulls the steel structure 1. Preferably, the tension force can be adjusted according to the load change of each support frame 3 during the first tensioning. When the tension cable 5 reaches the predetermined tension force, each support frame 3 is removed so that the support frame 3 is pre-unloaded.

[0041] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. Those skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention shall be defined by the appended claims.

Claims

1. A construction method for pre-unloading of a cable-stayed structure support frame, wherein a core tube is set in the construction area, a steel structure is set on the side of the core tube, and the support frame is set at the bottom of the steel structure, characterized in that, The construction method includes the following steps: Several tension cables are provided to be connected between the side of the core tube and the top of the steel structure; The tension cable is pre-tensioned; The connection between the support frame and the steel structure is severed, a support pad is provided, and the support pad is placed between the support frame and the steel structure; Continue tensioning the tensioning cable until the top of the steel structure separates from the supporting frame, then remove the supporting frame.

2. The construction method for advance unloading of a cable-stayed structure support frame according to claim 1, characterized in that: A support adjustment rod is provided between the support frame and the steel structure. When the connection between the support frame and the steel structure is cut, the support adjustment rod is cut.

3. The construction method for advance unloading of a cable-stayed structure support frame according to claim 2, characterized in that: in Before dismantling the support frame, the side of the support adjustment rod closest to the steel structure is cut into sections, so that the steel structure is released from the support adjustment rod's support, and then the support frame is dismantled.

4. The construction method for advance unloading of a cable-stayed structure support frame according to claim 3, characterized in that: in When the support adjustment rod is segmented, a predetermined cutting length and observation time are provided. The top of the support adjustment rod is cut according to the cutting length. It is confirmed whether the steel structure corresponding to the position of the support adjustment rod bends downward within the observation time. If bending occurs, the cutting continues according to the predetermined cutting length after the observation time ends until the steel structure no longer bends downward. If no bending occurs, the remaining part of the support adjustment rod is cut off.

5. The construction method for advance unloading of a cable-stayed structure support frame according to claim 2, characterized in that: in When cutting the support adjustment rod, an oxy-acetylene welding cutter is provided, and the support adjustment rod is cut using the oxy-acetylene welding cutter.

6. The construction method for advance unloading of a cable-stayed structure support frame according to claim 1, characterized in that: in Before pre-tensioning the tension cable, the tensioning process of the tension cable is simulated and analyzed according to the on-site construction conditions to determine the load changes of each support frame during the tensioning process.

7. The construction method for advance unloading of a cable-stayed structure support frame according to claim 1, characterized in that: in Before pre-tensioning the tension cables, the tensioning process of the tension cables is simulated and analyzed based on the on-site construction conditions to determine the tension force of each tension cable.

8. The construction method for advance unloading of a cable-stayed structure support frame according to claim 1, characterized in that: When dismantling the support frame, it is dismantled in order from the position closest to the core tube to the position furthest from the core tube.

9. The construction method for advance unloading of a cable-stayed structure support frame according to claim 1, characterized in that: When dismantling the support frame, the support frames on both sides of the core tube are dismantled simultaneously and symmetrically.

10. The construction method for advance unloading of a cable-stayed structure support frame according to claim 1, characterized in that: After disconnecting the support frame and the steel structure, the tensioning cables are tensioned according to the on-site construction requirements.

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