Installation method of large-span floor arch structure with arch foot prestress balance cable

Abstract

The invention discloses a mounting method of a large-span floor arch structure with an arch springing prestress balance cable. The mounting method comprises the following steps: step 1, determining partitions; 2, the arch springing prestress is tensioned for the first time; 3, arch foot sections are installed; the integral hoisting sections are assembled and welded on the ground, temporary tensioning assemblies are installed on the lower chords of the integral hoisting sections, the integral hoisting sections are tensioned, and the tensioning value is the horizontal thrust value generated by the ends of the integral hoisting sections; lifting frames are installed at the two ends of an integral lifting section area of the floor arch structure correspondingly, a set of lifting frames are symmetrically arranged on the two sides of each end of the integral lifting section, lifting assemblies are installed on the lifting frames, and the integral lifting section is lifted in place through the lifting assemblies; step 5, mounting a closure section; step 6, unloading; and 7, tensioning is conducted. Through close combination of various construction technologies, the installation efficiency of the floor arch structure is improved, low measure cost investment is achieved, and the economical efficiency is good.

Description

Technical Field

[0001] The invention relates to the technical field of floor-standing arch installation, and in particular to an installation method of a large-span floor-standing arch structure with prestressed balancing cables at arch feet. Background Art

[0002] Ground arch structures are commonly seen in bridges, industrial buildings, gate arches and other buildings, such as the Zhaozhou Bridge in ancient and modern civilizations. Today, ground arch structures are also used in public buildings with large space functional requirements, as the entrances to landmark buildings such as exhibition halls and railway stations. This type of arch structure often solves the problem of lateral thrust of the arch structure by adding prestressed balance cables at the bottom, while optimizing the amount of steel used in the structure. However, in the face of the construction difficulties such as high structure, large span, and heavy component weight brought by this type of structure, the traditional construction plan has many problems such as high altitude operations, high construction measures cost, long construction period, and difficulty in safety and quality control. Summary of the invention

[0003] The present invention provides a method for installing a large-span ground-to-ground arch structure with prestressed balancing cables at arch feet. The method adopts a combination of in-situ installation of the arch feet, overall lifting of the middle section, and permanent and step-by-step tensioning of the prestressed cables, which solves the problems of frequent high-altitude operations, great positioning difficulty, and low construction efficiency, and realizes safe, efficient, and lean construction.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for installing a large-span ground-to-ground arch structure with a prestressed balancing cable at an arch foot, comprising the following steps:

[0006] Step 1: Partition determination: Divide the ground arch structure into a pier, an arch foot section, a closing section and an overall hoisting section. The arch foot section is installed on the pier, and the closing section connects the arch foot section and the overall hoisting section.

[0007] Step 2: The first prestressing of the arch foot: Connect a concrete tie beam between the two piers, set a prestressed cable in the concrete tie beam, and tension the prestressed cable for the first time. The tensioning value is the horizontal thrust value generated by the ground arch structure under its own weight;

[0008] Step 3: Installation of arch foot section: The arch foot section is installed by high-altitude in-situ bulk method;

[0009] Step 4: Construction of the overall lifting section: Assemble and weld the overall lifting section on the ground, install a temporary tensioning assembly on the lower chord of the overall lifting section, and tension the overall lifting section. The tensioning value is the horizontal thrust value generated at the end of the overall lifting section;

[0010] Lifting frames are installed at both ends of the overall lifting section area of ​​the ground arch structure. A set of lifting frames is symmetrically arranged on both sides of each end of the overall lifting section. Lifting components are installed on the lifting frames, and the overall lifting section is lifted into place by the lifting components.

[0011] Step 5: Installation of closing section: The closing section is divided into pieces, and the piece units are assembled on the ground. The piece units are inserted in the air using a lifting machine. When closing, the lower chord pieces are installed first, and then the upper chord pieces are installed. The closing sections at both ends of the floor-standing arch structure are closed synchronously, and after completion, a floor-standing arch structure effect is formed;

[0012] Step 6: Unloading: Unload the ground arch structure by lifting the components and unloading them step by step;

[0013] Step 7: Tensioning: After the ground arch structure is installed and unloaded, the prestressed cables are tensioned, and the tensioning value offsets the horizontal thrust of the ground arch structure.

[0014] By adopting the above scheme, the ground arch structure is rationally divided into sections, and a combination of high-altitude in-situ installation of the arch foot section, overall hoisting of the middle section, and block hoisting of the closing section is adopted. The ground arch structure is installed in combination with a combination of permanent prestressed cables and step-by-step tensioning. This ensures the installation accuracy and structural performance of the ground arch structure, and solves the problems of frequent high-altitude operations, difficult positioning, and low construction efficiency.

[0015] The present invention provides a method for installing a large-span ground-to-ground arch structure with prestressed balancing cables at arch feet. Further, in step 2, the prestressed cables are tensioned at both ends. After one end is tensioned, the other end is tensioned. During the tensioning process, the prestressed cables in all channels are tensioned in sequence from bottom to top.

[0016] The present invention provides a method for installing a large-span ground-to-ground arch structure with a prestressed balancing cable at an arch foot. Further, in step 3, a temporary support frame is arranged below the arch foot section to support the arch foot section, and a steel plate mesh platform is set up below the arch foot section for workers to stand on the steel plate mesh platform to install the arch foot section.

[0017] By adopting the above scheme, in order to solve the problem that the local cross-section of the arch foot section is large, the weight of a single component is large, and the overall lifting and hoisting is difficult, a high-altitude in-situ installation scheme is adopted, and a steel mesh platform is installed based on a temporary support frame to assist in the installation of the arch foot section, solving the problem that the arch foot section has a complex structure and it is inconvenient to use a boom truck.

[0018] The present invention provides a method for installing a large-span ground-to-ground arch structure with prestressed balancing cables at arch feet. Further, the steel plate mesh platform includes longitudinal beams, transverse beams and steel meshes. The longitudinal beams are connected between the pier seat and the temporary support frame, and between the temporary support frame and the temporary support frame. The transverse beams are connected between the longitudinal beams to connect multiple longitudinal beams into a whole. The steel mesh is laid on the frame structure composed of the longitudinal beams and the transverse beams to form a working platform.

[0019] By adopting the above solution, a simple working platform is formed by connecting the longitudinal beam to the temporary supporting frame. The workers stand on the working platform to install the arch foot section. The working platform has a simple structure and is easy to install, which improves the installation efficiency of the arch foot section.

[0020] The present invention provides a method for installing a large-span ground-standing arch structure with a prestressed balance cable at an arch foot. Further, in step 4, the temporary tensioning assembly includes temporary cables connected to both ends of the lower chord of the overall lifting section, oil cylinders installed at both ends of the temporary cables, and anchors connecting the oil cylinders and the overall lifting section.

[0021] By adopting the above solution, since there will be tension in the overall hoisting section during the lifting stage, and because the horizontal heights of the inner and outer arches are inconsistent, there is a problem of inconsistent tension values ​​on both sides. By installing temporary cables, the tension of the overall hoisting section is controlled, which makes it easier to control the aerial shape and stable state during the lifting process and facilitate the installation of the closing section.

[0022] The present invention provides a method for installing a large-span ground-to-ground arch structure with prestressed balancing cables at arch feet. Further, in step 4, the lifting frame is assembled from multiple groups of lattice-type standard section structures, and the top and top of each group of lifting frames are respectively provided with steel conversion platforms.

[0023] By adopting the above scheme, a standard structure is used for assembly, which is convenient for installation and disassembly and can be recycled.

[0024] The present invention provides a method for installing a large-span ground-to-ground arch structure with a prestressed balance cable at an arch foot. Further, the lifting assembly comprises a transition beam, a conversion beam, a joist beam, a lifting beam and a lifting cylinder. The joist beam is installed on the conversion beam across two lifting frames. The conversion beam is installed on at least two groups of transition beams on the same lifting frame. The transition beam is installed on a steel platform.

[0025] The lifting beams are installed on the supporting beams at intervals, and the lifting cylinders are installed on the lifting beams for lifting the entire lifting section.

[0026] By adopting the above scheme, the overall hoisting section is lifted into place by the lifting cylinder, and the lifting cylinder can also be used for subsequent unloading of the landing arch structure, which makes the operation more convenient.

[0027] The present invention provides a method for installing a large-span ground-to-ground arch structure with a prestressed balancing cable at an arch foot. Further, in step 6, the lifting reaction forces of all lifting cylinders are adjusted simultaneously at intervals of 10%, decreasing in sequence, and the lifting reaction forces of all lifting cylinders are adjusted to 0 kN in ten times; the lifting components and the lifting frame are removed, and the unloading is completed.

[0028] The present invention provides a method for installing a large-span ground-to-ceiling arch structure with a prestressed balancing cable at an arch foot, further comprising:

[0029] By adopting the above solution, the lifting cylinder is unloaded step by step, so as to ensure the stability of the ground arch structure when it is converted from the lifting state to the deadweight state.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. This application improves the installation efficiency of the ground-to-ground arch structure through the close combination of multiple construction techniques, achieves low investment in measures, and has good economic efficiency;

[0032] 2. Compared with conventional methods, this application requires less overhead work for operators and lowers the safety risk for construction workers;

[0033] 3. The present application adopts a construction process that combines temporary cables with permanent prestressed cable tensioning procedures, which improves quality control and structural safety during the construction process; quality control is reflected in the ground arch of the overall lifting section during the construction process. The structural deformation that will be generated during the lifting is offset by temporary cables, so that after the lifting is in place, the structure is not affected by deformation; regarding structural safety, permanent prestressed cables are used to offset the horizontal thrust that will be generated when the ground arch structure enters the designed deadweight state after the construction is completed, thereby avoiding permanent structural deformation.

[0034] The present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a structural schematic diagram of the ground-to-ceiling arch structure of the present invention after installation;

[0036] Figure 2 A schematic diagram of the structure of installing a temporary support frame and a steel plate mesh platform at the arch foot section of the present invention;

[0037] Figure 3 This is a schematic diagram of the distribution structure of the tire support frame of the present invention;

[0038] Figure 4 This is a schematic diagram of the ground assembly structure of the integral hoisting section of the present invention;

[0039] Figure 5 This is a schematic diagram of the installation structure of the lifting frame and the lifting assembly of the present invention;

[0040] Figure 6 It is a schematic diagram of the lifting structure of the integral hoisting section of the present invention;

[0041] Figure 7 This is a schematic diagram of the installation structure of the closing section of the present invention;

[0042] Figure 8 It is a schematic diagram of the structure of the lifting frame and the lifting assembly of the present invention;

[0043] Fig. 9 It is a structural schematic diagram of the lifting assembly of the present invention;

[0044] Fig.10 This is a schematic diagram of the tire support structure of the present invention;

[0045] Fig.11 It is a schematic diagram of the structure of the temporary tensioning assembly of the present invention.

[0046] Reference numerals:

[0047] 1. Pier seat; 2. Arch foot section; 3. Closing section; 4. Overall lifting section; 5. Prestressed cable; 6. Temporary support frame; 7. Steel mesh platform; 7.1. Longitudinal beam; 7.2. Cross beam; 8. Support frame; 9. Temporary tensioning assembly; 9.1. Temporary cable; 9.2. Cylinder; 9.3. Anchor; 10. Lifting frame; 11. Steel platform; 12. Lifting assembly; 12.1. Transition beam; 12.2. Transfer beam; 12.3. Support beam; 12.4. Lifting beam; 12.5. Lifting cylinder; 12.6. Lifting cable. DETAILED DESCRIPTION

[0048] like Figure 1-Figure 11 As shown, the present invention discloses a method for installing a large-span ground-to-ground arch structure with a prestressed balance cable at an arch foot, comprising the following steps:

[0049] Step 1: Zoning determination: The ground-mounted arch structure of this application is a gradient quadrilateral structure with its two ends installed on piers. The ground-mounted arch structure is divided into an arch foot section, a closing section and an overall hoisting section. The ground-mounted arch structure is divided into three sections: in-situ installation, block lifting, and high-altitude closing. The entire construction process is verified using construction simulation software to ensure the feasibility of the plan. Calculations and analyses must be performed on the stages of prestressing the arch foot, lifting the middle section in blocks, closing at high altitude, and unloading to ensure that the construction completion status is consistent with the design status. Determine the relevant construction measure parameters, which are mainly for the specific specification parameter values ​​of tooling materials, machinery, etc. for each construction measure, to derive the bearing capacity requirements of the work site and the installation and removal sequence of temporary measures, and to provide guidance for actual construction.

[0050] Step 2: The first prestressing of the arch foot: Due to the large span and load area of ​​the ground arch structure, the horizontal thrust of the arch foot puts a heavy burden on the pile foundation. In order to resist the horizontal thrust of the arch foot, a concrete tie beam is connected between the two piers, and prestressed cables are installed in the concrete tie beam to balance the horizontal thrust generated by the ground arch structure. The piers must be completely separated from the basement structures on both sides, and the pier concrete pouring, the installation of the lower steel frame of the ground arch structure, the concrete tie beam pouring and the prestressed cable installation construction must be completed. After the concrete strength of the piers and concrete tie beams reaches 100%, the prestressed cables are tensioned for the first time. The prestressed cables are tensioned at both ends. After one end is tensioned, the other end is tensioned. During the tensioning process, the prestressed cables in all the channels are tensioned from bottom to top, and the tensioning is stopped until the prestress value reaches the value that offsets the horizontal thrust generated by the ground arch structure.

[0051] Step 3: Installation of arch foot section: In view of the large local cross-section of the ground-standing arch structure and the heavy weight of a single component, the heavy weight of the entire section after ground assembly is completed, and the difficulty in lifting, the method of setting up a temporary support frame for high-altitude in-situ bulk construction is adopted; due to the complex structure of the arch foot section and the inconvenience of using a boom truck, a steel plate mesh platform is set up under the arch foot section to cooperate with the installation, welding, inspection and high-altitude docking of the arch foot section. The steel plate mesh platform includes longitudinal beams, transverse beams and steel mesh. The longitudinal beams are connected between the pier and the temporary support frame, and between the temporary support frame and the temporary support frame. The transverse beams are connected between the longitudinal beams to connect multiple longitudinal beams as a whole. The steel mesh is laid on the frame structure composed of the longitudinal beams and the transverse beams to form a working platform, and the staff stand on the working platform to install the arch foot section.

[0052] Step 4: Construction of the overall hoisting section: In order to facilitate the rapid docking of the ground arch structure at high altitude and reduce the construction period of the entire ground arch structure, the overall hoisting section is lifted into place at one time after being assembled and welded on the support frame. Due to the large cross-section of the ground arch structure rods and the heavy weight of a single component, all components are distributed to the site for assembly. After the overall hoisting section is assembled and welded on the ground, the segmented overall hoisting section is hoisted to the support frame for assembly and welding using a lifting machine. After welding is completed, a temporary tensioning assembly is installed on the lower chord of the overall hoisting section. The temporary tensioning assembly includes temporary cables connected to both ends of the lower chord of the overall hoisting section, oil cylinders installed at both ends of the temporary cables, and anchors connecting the oil cylinder and the overall hoisting section; after the overall hoisting section is assembled, the overall hoisting section is tensioned by the temporary tensioning assembly, and the tensioning value is the horizontal thrust value generated at the end of the overall hoisting section. The purpose of temporary cable tensioning is to control the aerial posture or structural deformation of the overall lifting section. After the overall lifting section is separated from the supporting frame, the arch structure will generate tension on both sides. Temporary cable tensioning is used to offset the horizontal thrust generated by the overall lifting section arch structure under its own weight and lifting loading state, so that the arch structure will not produce structural deformation caused by construction during the lifting process and after it is in place. After the entire ground arch is closed, the tension of the temporary construction cable is released.

[0053] The supporting tyre frame uses the roadbed box as its foundation. To facilitate the setting of the cables of the overall lifting section, three rows of columns are set at each supporting point. Support beams are installed on the columns, and steel sections are used to adjust the elevation between the support beams and the overall lifting section.

[0054] Lifting frames are installed at both ends of the overall lifting section area of ​​the ground arch structure. A group of lifting frames are symmetrically arranged on both sides of each end of the overall lifting section. The lifting frames are assembled from multiple groups of lattice standard sections, and the lattice standard sections are assembled and connected by flanges and screws. H-shaped steel conversion platforms are respectively provided at the top and bottom of each group of lifting frames. The steel platforms are mainly used to bear the force of the columns of the lifting frames and transfer the force to the roadbed box foundation. The bottom of the lifting frame uses the roadbed box as the foundation. Note that the placement of the roadbed box needs to avoid the prestressed cables between the piers.

[0055] A lifting assembly is installed on the top of the lifting frame, which includes a transition beam, a transfer beam, a supporting beam, a lifting beam and a lifting cylinder. The transition beam is installed on a steel platform, and the transfer beam is erected on two sets of transition beams on the same lifting frame. The supporting beam spans two lifting frames and is installed on the transfer beam. The supporting beam is a double-split setting, and a space is formed between the two supporting beams for the lifting rope of the lifting cylinder to pass through. The lifting beam is installed on the supporting beam, and the lifting cylinder is installed on the lifting beam. One end of the lifting rope is connected to the lifting cylinder, and the other end is connected to the overall lifting section. The number of lifting points and the type of lifting cylinder are determined according to the lifting weight, and the safety factor is not less than 1.2.

[0056] Step 5: Installation of closing sections: Due to the long span of the large-span ground-to-ceiling arch structure, the steel structure has high thermal conductivity and is greatly affected by temperature loads. The highest and lowest temperatures at the project site should be analyzed with reference to the temperature. The closing temperature should be 15°C ± 5°C. The closing section should be divided into pieces and assembled into small units on the ground. Use lifting machinery to fill the pieces in the air. When closing, install the lower chord pieces first, and then the upper chord pieces. The closing sections at both ends of the ground-to-ceiling arch structure need to be closed simultaneously. After completion, a ground-to-ceiling arch structure effect is formed.

[0057] Step 6: Unloading: The unloading process of the floor arch structure is actually the process of the structure changing from a lifting system to a self-supporting system. The unloading is carried out by using the lifting cylinder to reduce the load step by step. The unloading process is divided into three steps:

[0058] 1) The floor arch structure is fully installed, and the welding work at all positions must be completed. The weld flaw detection personnel must conduct 100% inspection on the welds. The weld quality meets the design requirements. Unloading can begin after the quality inspection is qualified and the overall stability is achieved;

[0059] 2) Adjust the lifting reaction force of all lifting cylinders at the same time in intervals of 10%, decreasing in sequence, and adjust the lifting reaction force of all lifting cylinders to 0 kN in ten times;

[0060] 3) Remove the lifting assembly and lifting frame to complete the unloading.

[0061] Step 7: Tensioning: The tensioning of the prestressed cables is adjusted according to the construction progress and the actual changes in the load of the ground arch structure to ensure the structural stability and safety of the ground arch structure during the entire construction process. After the ground arch structure is installed and unloaded, the prestressed cables are tensioned. The tensioning value offsets the horizontal thrust of the ground arch structure to reduce the influence of the self-weight of the entire ground arch structure on the horizontal thrust of the pile foundation; the first tensioning is to meet the pre-tensioning to offset the self-weight of the ground arch structure itself, and the second tensioning is to offset the pre-tensioning of other loads applied to the ground arch structure.

[0062] The embodiments described above are merely descriptions of preferred implementation modes of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for installing a large-span ground-to-ground arch structure with a prestressed balance cable at an arch foot, characterized in that: The following steps are involved: Step 1: Partition determination: Divide the ground arch structure into a pier, an arch foot section, a closing section and an overall hoisting section. The arch foot section is installed on the pier, and the closing section connects the arch foot section and the overall hoisting section. Step 2: The first prestressing of the arch foot: Connect a concrete tie beam between the two piers, set a prestressed cable in the concrete tie beam, and tension the prestressed cable for the first time. The tensioning value is the horizontal thrust value generated by the ground arch structure under its own weight; Step 3: Installation of arch foot section: The arch foot section is installed by high-altitude in-situ bulk method; Step 4: Construction of the overall lifting section: Assemble and weld the overall lifting section on the ground, install a temporary tensioning assembly on the lower chord of the overall lifting section, and tension the overall lifting section. The tensioning value is the horizontal thrust value generated at the end of the overall lifting section; Lifting frames are installed at both ends of the overall lifting section area of ​​the ground arch structure. A set of lifting frames is symmetrically arranged on both sides of each end of the overall lifting section. Lifting components are installed on the lifting frames, and the overall lifting section is lifted into place by the lifting components. Step 5: Installation of closing section: The closing section is divided into pieces, and the piece units are assembled on the ground. The piece units are inserted in the air using a lifting machine. When closing, the lower chord pieces are installed first, and then the upper chord pieces are installed. The closing sections at both ends of the floor-standing arch structure are closed synchronously, and after completion, a floor-standing arch structure effect is formed; Step 6: Unloading: Unload the ground arch structure by lifting the components and unloading them step by step; Step 7: Tensioning: After the ground arch structure is installed and unloaded, the prestressed cables are tensioned, and the tensioning value offsets the horizontal thrust of the ground arch structure.

2. The method for installing a large-span ground-to-ground arch structure with prestressed balancing cables at arch feet according to claim 1, characterized in that: In step 2, the prestressed cables are tensioned at both ends. After one end is tensioned, the other end is tensioned. During the tensioning process, the prestressed cables in all the channels are tensioned in sequence from bottom to top.

3. The method for installing a large-span ground-to-ground arch structure with prestressed balancing cables at arch feet according to claim 1, characterized in that: In step 3, a temporary support frame is set below the arch foot section to support the arch foot section, and a steel plate mesh platform is set up below the arch foot section for workers to stand on the steel plate mesh platform to install the arch foot section.

4. The method for installing a large-span ground-to-ground arch structure with prestressed balancing cables at arch feet according to claim 3 is characterized in that: The steel plate mesh platform includes longitudinal beams, transverse beams and steel meshes. The longitudinal beams are connected between the pier and the temporary support frame, and between the temporary support frames. The transverse beams are connected between the longitudinal beams to connect multiple longitudinal beams into a whole. The steel mesh is laid on the frame structure composed of the longitudinal beams and the transverse beams to form a working platform.

5. The method for installing a large-span ground-to-ground arch structure with prestressed balancing cables at arch feet according to claim 1, characterized in that: In step 4, the temporary tensioning assembly includes temporary cables connected to both ends of the lower chord of the overall lifting section, oil cylinders installed at both ends of the temporary cables, and anchors connecting the oil cylinders and the overall lifting section.

6. The method for installing a large-span ground-to-ground arch structure with prestressed balancing cables at arch feet according to claim 1, characterized in that: In step 4, the lifting frame is assembled from multiple groups of lattice-type standard section structures, and the top and top of each group of lifting frames are respectively provided with steel conversion platforms.

7. The method for installing a large-span ground-to-ground arch structure with prestressed balancing cables at arch feet according to claim 1, characterized in that: The lifting assembly includes a transition beam, a transfer beam, a joist beam, a lifting beam and a lifting cylinder, wherein the joist beam is installed on the transfer beam across two lifting frames, the transfer beam is installed on at least two sets of transition beams on the same lifting frame, and the transition beam is installed on a steel platform; The lifting beams are installed on the supporting beams at intervals, and the lifting cylinders are installed on the lifting beams for lifting the entire lifting section.

8. The method for installing a large-span ground-to-ground arch structure with prestressed balancing cables at arch feet according to claim 1, characterized in that: In step 6, the lifting reaction forces of all lifting cylinders are adjusted at the same time with an interval of 10%, decreasing in sequence, and the lifting reaction forces of all lifting cylinders are adjusted to 0 kN in ten times; the lifting components and lifting frames are removed, and the unloading is completed.

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