Installation method of arch foot structure

Abstract

The invention discloses a mounting method of an arch springing structure. The mounting method comprises the following steps that 1, the arch springing structure is divided; step 2, arch foot concrete structure construction; step 3, support jig frame and operation platform installation: the support jig frames are installed, and the operation platforms are erected between the upper concrete foundation and the support jig frames and between the support jig frames; 4, arch foot structure installation, wherein lower chords are hoisted, and web members between the lower chords are hoisted; the diagonal web members between the lower chord members and the bottommost upper chord members are firstly installed on the lower chord members, the bottommost upper chord members are hoisted, the upper chord members are fixed to the arch foot supports and the diagonal web members at the corresponding positions, and then the web members between the bottommost upper chord members and between the bottommost upper chord members and the lower chord members are installed. The operation platform is arranged on the upper portion of the supporting jig frame in the most economical supporting mode, the supports are combined with the platform, high-altitude in-situ bulk loading is carried out on the arch springing, the installation cost and the installation difficulty are greatly reduced, and meanwhile the safety of constructors is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of arch foot installation, and in particular to an installation method of an arch foot structure. Background Art

[0002] The main entrance of a large-scale exhibition project has a magnificent shape, a span of hundreds of meters, a beautiful shape, and complex and diverse structural forms, complex forces, and a large overall weight, making the structural construction quite difficult.

[0003] The arch foot of the ground-standing arch in this project is a quadrilateral tube truss structure with four chords on the ground. The landing point is fixed with an earthquake-resistant spherical hinge support. Steel columns and steel beams are arranged in the foundation under the column foot. Four concrete tension beams are arranged between the concrete foundations of the two arch feet to offset part of the thrust of the arch frame on the arch foot and reduce the requirements of the foundation on the lateral stiffness. The concrete tension beam adopts bonded prestressed technology, and three bundles of prestressed tendons are arranged in each concrete tension beam.

[0004] At present, the installation of the arch foot structure generally adopts the scheme of ground assembly, overall hoisting or the scheme of in-situ assembly using full-height brackets. The above schemes have the following defects:

[0005] 1. Adopting the overall hoisting scheme, since the local maximum cross-section of the truss structure of this application is Φ1500×40, the material is Q420GJC-Z15, the maximum weight of a single member is 23t, and the weight of the entire section hoisted after the ground assembly is completed is about 150t. The on-site hoisting machinery cannot meet the hoisting requirements, and it is difficult to choose the hoisting method; after the overall ground assembly, large-scale temporary machinery is used for installation, which has high construction costs and poor economy;

[0006] 2. The full-hall support in-situ assembly scheme is adopted. The full-hall scaffolding support is a load-bearing scaffolding, which takes a long time to set up, has a large number, a long structural construction period, and a high cost. The labor and material costs are huge, often in the millions; the arch foot is heavy, requiring a lot of construction simulation calculations;

[0007] The installation scheme adopts a supporting tire frame combined with a boom truck. Due to the large installation height of the arch foot, the arch foot slope is 45°, and the complex shape of the arch foot, the boom truck is inconvenient to use, the workers are difficult to operate and install, and the construction safety cannot be guaranteed. Summary of the invention

[0008] In order to reduce installation costs and installation difficulty while ensuring the safety of construction workers, the present application provides an installation method for an arch foot structure.

[0009] The present application provides an installation method for an arch foot structure, which adopts the following technical solution:

[0010] A method for installing an arch foot structure comprises the following steps:

[0011] Step 1: Divide the arch foot structure;

[0012] The arch foot is decomposed into a lower chord, an upper chord, a diagonal web and a web, wherein the upper chord is arranged in sections;

[0013] Step 2: Arch foot concrete structure construction:

[0014] Carry out the lower concrete foundation construction, hoisting steel frame columns, installing steel frame beams, pouring the upper concrete foundation, constructing concrete tension beams and installing the cables inside the concrete tension beams in sequence;

[0015] Step 3: Install the support frame and operating platform:

[0016] Locate the installation position of the support tire frame, install the tire frame base, assemble and install the lattice support tire frame on the tire frame base, and set up an operating platform between the upper concrete foundation and the support tire frame and between each row of support tire frames;

[0017] Step 4: Arch foot structure installation:

[0018] Lift the lower chord and fix it to the arch foot support and support frame at the corresponding position, lift the web between the lower chords, and the staff will position and install the web on the operating platform;

[0019] First install the diagonal brace between the lower chord and the bottom upper chord on the lower chord, hoist the bottom upper chord, and fix the upper chord to the arch foot support and diagonal brace at the corresponding position, and then install the brace between the bottom upper chord and between the bottom upper chord and the lower chord;

[0020] Install the remaining upper chords and the web members between the upper and lower chords from bottom to top, and finally fill in the web member between the two upper chords.

[0021] By adopting the above-mentioned technical scheme, the present application sets up a combination of a supporting frame and an operating platform, so that the staff can position and install the arch foot rods on the operating platform, providing a convenient operating and installation platform for the installation of the arch foot, solving the problem that personnel cannot operate and install due to the 45° angle of the arch foot, ensuring the personal safety of the construction personnel, and the operating platform is installed by relying on the arch foot concrete structure and the supporting frame, which simplifies the operating platform structure. On the premise of ensuring the normal progress of construction, it saves installation costs and is more economical.

[0022] Optionally, the upper chord is divided into a lower upper chord, a middle upper chord and an upper upper chord.

[0023] By adopting the above technical scheme, the present application reasonably decomposes the arch foot structure, adopts the overall hoisting of the low-position lower chord and the segmented hoisting of the high-position upper chord, and the installation of the upper chord is supported by the already installed lower chord and the previously installed upper chord. The construction sequence of the arch foot is reasonably arranged, and the existing installed structure is fully utilized as support to form the most economical support scheme, simplify the construction steps and construction difficulty, and at the same time greatly reduce the performance of the hoisting machinery.

[0024] Optionally, in step 3, a high pole is installed on a supporting frame near the end of the column foot, a supporting beam is installed on the upper end of the high pole, and the upper end of the upper chord is supported on the supporting beam.

[0025] By adopting the above technical solution, a high vertical pole and a supporting beam are arranged at the end of the arch foot to support the end of the upper chord, thereby ensuring the stability of the arch foot installation and controlling its installation accuracy.

[0026] Optionally, the operating platform includes longitudinal beams, steel meshes, upper pressure beams, safety vertical poles and safety cross bars. A group of longitudinal beams is correspondingly arranged at each supporting tire frame, and two longitudinal beams are arranged in each group. The steel mesh is laid on the longitudinal beams to form a working platform. The upper pressure beams are pressed on the steel meshes and fixed to the longitudinal beams, and multiple upper pressure beams are arranged at intervals along the length direction of the longitudinal beams. The multiple upper pressure beams connect the groups of longitudinal beams into one.

[0027] By adopting the above technical solution, the longitudinal beam is connected to the supporting frame to form a load-bearing skeleton, which ensures the structural stability of the operating platform, and cooperates with the steel mesh to form an operating plane to ensure the safety of workers working on the slope; in addition, the addition of an upper pressure beam can connect the two side-by-side operating platforms into a whole, further improving the safety performance of the operating platform.

[0028] Optionally, safety uprights are fixedly arranged on the longitudinal beams on both sides of the operating platform at intervals, safety cross bars are connected between the safety uprights, and the safety uprights and the safety cross bars are installed on both sides of the operating platform to form guardrails.

[0029] By adopting the above technical solution, the safety vertical pole and the installation cross bar form a guardrail to ensure the safety of high-altitude operations.

[0030] Optionally, additional cables are provided between step 2 and step 3 for preliminary tensioning. After the steel column is inspected and the concrete tension beam reaches the design strength, the cables are tensioned to 25% to control the tensioning force.

[0031] By adopting the above technical scheme, the horizontal thrust value generated by the deadweight of the ground arch is applied for the first time during the first tensioning before the arch foot is installed, so that the horizontal thrust after the ground arch single arch is installed and unloaded is offset by the prestress, so that the arch foot pile foundation is not affected by the horizontal thrust.

[0032] Optionally, after step 4 is completed, the main arch of the steel structure between the arch feet is installed. After the installation is completed, the cable tensioning is performed again in the following order;

[0033] The second stage of tensioning: after the construction of the main arch of the steel structure is completed and before the main arch of the steel structure is unloaded, the cables are tensioned and the prestressing force is tensioned to 50% to control the tensioning force;

[0034] The third pole is tensioning. After the main arch of the steel structure is completed and unloaded, the cables are tensioned and the prestressing force is controlled by 75%.

[0035] The fourth stage of tensioning: after the third stage of tensioning is completed, the cables are tensioned again, and the prestressing is tensioned to 105% to control the tensioning force.

[0036] By adopting the above technical solution, each subsequent loading can ensure that the tension value is just enough to offset the horizontal thrust applied by the vertical load of construction, ultimately minimizing the impact of the pile foundation and ensuring the safety of the structure.

[0037] Optionally, a fixed support is connected between the tire frame base near the upper concrete foundation side and the upper concrete foundation.

[0038] By adopting the above technical solution, the fixed support connects the tire frame base with the upper concrete foundation, avoiding displacement of the tire frame base during construction and ensuring the accuracy and safety of the arch foot construction.

[0039] In summary, the present application includes at least one of the following beneficial technical effects:

[0040] 1. This application reasonably decomposes the arch foot structure, adopts the overall hoisting of the low-position lower chord rod and the segmented hoisting of the high-position upper chord rod. The installation of the upper chord rod uses the installed lower chord rod and the previously installed upper chord rod as support, reasonably arranges the construction sequence of the arch foot, fully utilizes the existing installed structure as support, forms the most economical support plan, simplifies the construction steps and construction difficulty, and greatly reduces the performance of the hoisting machinery;

[0041] 2. The support frame is combined with the operating platform, so that the staff can position and install the arch foot rods on the operating platform, providing a convenient operating and installation platform for the installation of the arch foot, solving the problem that the staff cannot operate and install due to the 45° angle of the arch foot, ensuring the personal safety of the construction staff, and the operating platform is installed by relying on the arch foot concrete structure and the support frame, which simplifies the operating platform structure, saves installation costs and is more economical while ensuring the normal construction.

[0042] 3. Insert the tensioning of the cables into the construction process of the arch foot. The first tensioning is performed before the installation of the arch foot to apply the horizontal thrust generated by the deadweight of the ground arch. This will offset the horizontal thrust and prestress after the installation and unloading of the ground arch, and the pile foundation of the arch foot will not be affected by the horizontal thrust. Through each subsequent loading, the tensioning value will be adjusted to offset the horizontal thrust applied by the vertical load of the construction, and finally minimize the impact of the pile foundation to ensure the safety of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the installation structure of the steel column and the steel beam of the present invention;

[0044] Figure 2 It is a schematic diagram of the upper concrete foundation and concrete tension beam installation structure of the present invention;

[0045] Figure 3 This is a schematic diagram of the installation structure of the tire support frame of the present invention;

[0046] Figure 4 This is a schematic diagram of the installation structure of the operating platform of the present invention;

[0047] Figure 5 It is a structural schematic diagram highlighting the operating platform of the present invention;

[0048] Figure 6 It is a schematic diagram of the installation structure of the lower chord and the web member of the present invention;

[0049] Figure 7 It is a schematic diagram of the installation structure of the lower upper chord and the diagonal web member of the present invention;

[0050] Figure 8 It is a schematic diagram of the installation structure of the web member at the lower upper chord of the present invention;

[0051] Fig. 9 It is a schematic diagram of the installation structure of the middle upper chord rod of the present invention;

[0052] Fig.10 It is a schematic diagram of the installation structure of the upper upper chord rod of the present invention;

[0053] Fig.11 The present invention is a schematic diagram of the installation structure of the web member between the middle upper chord member and the upper upper chord member.

[0054] Explanation of the reference numerals: 1. lower chord; 2. lower upper chord; 3. middle upper chord; 4. upper upper chord; 5. diagonal web; 6. web; 7. steel column; 8. steel beam; 9. upper concrete foundation; 10. concrete tension beam; 11. fixed support; 12. supporting frame; 13. high vertical pole; 14. supporting cross beam; 15. operating platform; 15.1. longitudinal beam; 15.2. steel mesh; 15.3. upper pressure beam; 15.4. safety vertical pole; 15.5. safety cross bar. DETAILED DESCRIPTION

[0055] like Figure 1-Figure 11 As shown, the present invention discloses a method for installing an arch foot structure, comprising the following steps:

[0056] Step 1: Divide the arch foot structure:

[0057] The arch foot is decomposed into a lower chord 1, a lower upper chord 2, a middle upper chord 3, an upper upper chord 4, a diagonal web 5 and a web 6 for subsequent decomposition and installation.

[0058] Step 2: Arch foot concrete structure construction:

[0059] The embedded anchor bolts and the lower concrete foundation are constructed, the steel column 7 is hoisted, and the steel column 7 is connected with the embedded anchor bolts, the steel beam 8 between the steel columns 7 is installed, the upper concrete foundation 9 is poured, the concrete tension beam 10 is constructed, and the cables inside the concrete tension beam 10 are installed.

[0060] Step 3: Initial tensioning of cables:

[0061] The prestressing force in this application is tensioned at both ends. After tensioning one end of the cable, the other end is tensioned. After the steel column 7 is inspected and accepted and the strength of the concrete tension beam 10 reaches 100%, the cable is tensioned to 25% of the controlled tension force, that is, 0.25σcon, where σcon is the controlled tension force.

[0062] Step 4: Tire frame base installation:

[0063] The brace embedded parts are pre-embedded in advance with the pouring of the upper concrete foundation 9, and the arch foot support is installed after the pouring of the upper concrete foundation 9 is completed.

[0064] A tire frame base is installed on the ground below the arch foot, and a fixed support 11 is connected between the tire frame base near the upper concrete foundation 9 and the upper concrete foundation 9 to ensure the safety of the tire frame base and avoid displacement during the installation of the arch foot, which affects the installation accuracy of the arch foot and creates safety hazards.

[0065] Step 5: Install the support frame 12 and the operating platform 15:

[0066] A lattice support frame 12 is assembled and installed on the frame base, a load-bearing crossbeam and a support column are installed on the top of the support frame 12, and a high vertical pole 13 is installed on the support frame 12 near the end of the column foot. A support crossbeam 14 is installed on the upper end of the high vertical pole 13 to support the upper chord of the arch foot.

[0067] An operating platform 15 is set up between the upper concrete foundation 9 and the supporting tire frame 12, and between the supporting tire frame 12 and the supporting tire frame 12, wherein the operating platform 15 includes a longitudinal beam 15.1, a steel mesh 15.2, an upper pressure beam 15.3, a safety vertical pole 15.4 and a safety cross bar 15.5. Each supporting tire frame 12 is correspondingly provided with a group of longitudinal beams 15.1, and each group of longitudinal beams 15.1 is provided with two. When the operating platform 15 is located between the upper concrete foundation 9 and the supporting tire frame 12, one end of the longitudinal beam 15.1 is connected to the upper concrete foundation 9, and the other end is connected to the upper end of the supporting tire frame 12; when the operating platform 15 is located between the front and rear supporting tire frames 12 When the longitudinal beams 15.1 are in the working state, the two ends of the longitudinal beams 15.1 are respectively connected to the upper ends of the front and rear supporting tire frames 12; the steel mesh 15.2 is laid on each set of longitudinal beams 15.1 to form a working platform, the upper pressure beam 15.3 is installed on the two sets of longitudinal beams 15.1 and connects the two sets of longitudinal beams 15.1 as a whole, and the upper pressure beams 15.3 are arranged in multiple rows at intervals along the length direction of the longitudinal beams 15.1, pressed on the steel mesh 15.2 and connected and fixed to the longitudinal beams 15.1; the safety vertical poles 15.4 are fixed at intervals on the opposite side of the two sets of longitudinal beams 15.1, and the safety cross bars 15.5 are connected between the safety vertical poles 15.4 to form a guardrail to ensure the safety of the staff.

[0068] Step 6: Arch foot structure installation:

[0069] A crawler crane is used to respectively hoist the two lower chords 1, and the lower chords 1 are respectively fixed to the arch foot supports and the supporting tire frame 12 at the corresponding positions. A truck crane is used to hoist the web bar 6 between the lower chords 1, and the staff positions and installs the web bar 6 on the operating platform 15.

[0070] First, install the diagonal web member 5 between the lower upper chord 2 and the lower chord 1 on the lower chord 1, use the crawler crane to lift the lower upper chord 2, and fix the lower upper chord 2 to the arch foot support and the diagonal web member 5 respectively; then install the web member 6 between the lower upper chord 2 and between the lower upper chord 2 and the lower chord 1.

[0071] Hoist the middle upper chord 3, connect the middle upper chord 3 with the lower upper chord 2, install the web member 6 between the middle upper chord 3 and the lower chord 1, and finally hoist the upper upper chord 4, connect the lower end of the upper upper chord 4 with the upper end of the middle upper chord 3, and support the upper end of the upper upper chord 4 on the supporting beam 14; then install the web member 6 between the upper upper chord 4 and the lower chord 1.

[0072] Finally, the web members 6 are inserted between the middle upper chord members 3 and the middle upper chord members 3, and between the upper upper chord members 4 and the upper upper chord members 4.

[0073] Step 7: Tensioning:

[0074] Install the main arch of the steel structure between the arch feet. After installation, tension it in the following order.

[0075] The second stage tensioning, after the construction of the main arch of the steel structure is completed and before the main arch of the steel structure is unloaded, the cables are tensioned, and the prestressing is tensioned to 50% of the controlled tensioning force, that is, 0.5σcon, where σcon is the controlled tensioning force.

[0076] The third pole is tensioning. After the construction of the main arch of the steel structure is completed and after the main arch of the steel structure is unloaded, the cables are tensioned and the prestressing is tensioned to 75% to control the tensioning force, that is, 0.75σcon, where σcon is the controlled tensioning force.

[0077] The fourth stage of tensioning: after the third stage of tensioning is completed, the cables are tensioned again, and the prestressing is tensioned to 105% to control the tensioning force, that is, 1.05σcon, where σcon is the controlled tensioning force.

[0078] The main arch of the steel structure is unloaded so that the supporting frame 12 does not bear the loads such as the deadweight of the main arch of the steel structure.

[0079] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for installing an arch foot structure, characterized in that: The following steps are involved: Step 1: Divide the arch foot structure: The arch foot is decomposed into a lower chord, an upper chord, a diagonal web and a web, wherein the upper chord is arranged in sections; Step 2: Arch foot concrete structure construction: Carry out the lower concrete foundation construction, hoisting steel frame columns, installing steel frame beams, pouring the upper concrete foundation, constructing concrete tension beams and installing the cables inside the concrete tension beams in sequence; Step 3: Install the support frame and operating platform: Locate the installation position of the support tire frame, install the tire frame base, assemble and install the lattice support tire frame on the tire frame base, and set up an operating platform between the upper concrete foundation and the support tire frame and between each row of support tire frames; Step 4: Arch foot structure installation: Lift the lower chord and fix it to the arch foot support and support frame at the corresponding position, lift the web between the lower chords, and the staff will position and install the web on the operating platform; First install the diagonal brace between the lower chord and the bottom upper chord on the lower chord, hoist the bottom upper chord, and fix the upper chord to the arch foot support and diagonal brace at the corresponding position, and then install the brace between the bottom upper chord and between the bottom upper chord and the lower chord; Install the remaining upper chords and the web members between the upper and lower chords from bottom to top, and finally fill in the web member between the two upper chords.

2. The method for installing an arch foot structure according to claim 1, characterized in that: The upper chord is divided into a lower upper chord, a middle upper chord and an upper upper chord.

3. The method for installing an arch foot structure according to claim 1, characterized in that: In step 3, a high pole is installed on a supporting frame near the end of the column foot, a supporting crossbeam is installed on the upper end of the high pole, and the upper end of the upper chord is supported on the supporting crossbeam.

4. The method for installing an arch foot structure according to claim 1, characterized in that: The operating platform includes longitudinal beams, steel meshes, upper pressure beams, safety vertical poles and safety cross bars. A group of longitudinal beams is correspondingly arranged at each supporting tire frame, and two longitudinal beams are arranged in each group. The steel mesh is laid on the longitudinal beams to form a working platform. The upper pressure beams are pressed on the steel meshes and fixedly connected to the longitudinal beams, and multiple upper pressure beams are arranged at intervals along the length direction of the longitudinal beams. The multiple upper pressure beams connect the groups of longitudinal beams into one.

5. The method for installing an arch foot structure according to claim 4, characterized in that: Safety uprights are fixedly arranged on the longitudinal beams at both sides of the operating platform at intervals, and safety cross bars are connected between the safety uprights. The safety uprights and the safety cross bars are installed on both sides of the operating platform to form guardrails.

6. The method for installing an arch foot structure according to claim 1, characterized in that: Additional cables are added between step 2 and step 3 for preliminary tensioning. After the steel column is inspected and the concrete tension beam reaches the design strength, the cables are tensioned to 25% to control the tension force.

7. The method for installing an arch foot structure according to claim 6, characterized in that: After step 4 is completed, the main arch of the steel structure between the arch feet is installed. After the installation is completed, the cable tensioning is performed again in the following order; The second stage of tensioning: after the construction of the main arch of the steel structure is completed and before the main arch of the steel structure is unloaded, the cables are tensioned and the prestressing force is tensioned to 50% to control the tensioning force; The third pole is tensioning. After the main arch of the steel structure is completed and unloaded, the cables are tensioned and the prestressing force is controlled by 75%. The fourth stage of tensioning: after the third stage of tensioning is completed, the cables are tensioned again, and the prestressing is tensioned to 105% to control the tensioning force.

8. The method for installing an arch foot structure according to claim 1, characterized in that: A fixed support is connected between the tire frame base close to the upper concrete foundation side and the upper concrete foundation.

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