Shell-shaped large-span net rack construction method

Abstract

The application provides a shell-shaped large-span net rack construction method and relates to the field of high-altitude scattered assembly construction technology of net rack. The method comprises the following steps: preparation work before installation, plane arrangement, erection of a scaffold, erection of a middle truss and installation of a ring beam, assembly of a double-layer net rack, installation of a fixed hinge support, installation of a net shell and unloading and removal of the scaffold. The method effectively solves the problem of high-altitude installation, guarantees installation quality and reduces engineering cost.

Description

Technical Field

[0001] This invention relates to the field of high-altitude modular construction technology for space frame structures, and more specifically, to a construction method for a shell-shaped large-span space frame. Background Technology

[0002] With social development and technological advancements, building facades are becoming increasingly personalized and diverse. Unique designs can leave a deeper impression, generating greater popularity and economic benefits. However, they also place higher demands on construction techniques. Further research into the construction technology of large-span canopies combining shell-shaped reticulated shells and double-layered three-dimensional space frames will lead to mature and feasible construction methods, promoting technological progress and enhancing market competitiveness for enterprises.

[0003] Taking a large urban complex with 3 underground floors, 21-30 floors above ground, and a total construction area of ​​approximately 220,000 square meters as an example, the atrium canopy consists of a double-layer three-way steel grid structure and two single-layer shell-shaped steel grid shells embedded in the grid structure. The planar projection is close to a rectangle, with a concave corner in the northwest. It is about 78.5m long and 34.5m wide. The single-layer steel grid shell is hinged to the double-layer grid structure. The double-layer grid structure is supported on the corbels of the surrounding towers on the south, north, and west sides by friction pendulum supports.

[0004] The installation of steel space frames using the high-altitude assembly method involves first erecting assembly scaffolding at the designed location, then using a crane to lift the space frame components (or sections) to the designed location in the air, where they are assembled on the scaffolding. This method sometimes does not require large lifting equipment, but it requires a large number of assembly scaffolding units and involves a significant amount of high-altitude work.

[0005] The integral installation method involves first assembling the space frame into a whole on the ground, and then using lifting equipment to lift it to the designed position and fix it in place. This construction method does not require tall assembly scaffolds, involves less high-altitude work, and makes it easier to ensure welding quality. However, it requires lifting equipment with a large lifting capacity and is technically more complex. It is more suitable for steel space frames with ball joints (especially space frames with many members such as three-way space frames).

[0006] The high-altitude parallel sliding method involves assembling the space frame on an assembly platform (framework). After the first assembly unit is completed, it is lowered onto the sliding track and slid forward a certain distance using traction equipment. The second unit is then assembled on the platform, and together with the first unit, they are slid forward. This process of assembling and sliding segment by segment continues until the entire space frame is assembled and slid into place. Summary of the Invention

[0007] In view of the shortcomings in the prior art, the purpose of this invention is to provide a construction method for a shell-shaped large-span space frame.

[0008] This invention is implemented as follows:

[0009] This application provides a construction method for a shell-shaped large-span space frame, which consists of a double-layer three-dimensional space frame and a single-layer reticulated shell, and includes the following steps:

[0010] S1, Installation preparation work; S2, Layout and scaffolding erection; S3, Erecting the central truss and installing the ring beam; S4, Assembling the double-layer space frame; S5, Installing the fixed hinge support; S6, Installing the space shell; S7, Unloading and dismantling the scaffolding.

[0011] In this invention, in step S1 above, before installation, the axis and elevation of the space frame support are checked and the concrete strength of the support is tested; a full-span scaffold is erected, with the scaffold height being 300mm below the elevation of the lower chord ball of the space frame; the positions and elevations of each support point are laid out, and temporary support points are designed and arranged.

[0012] In this invention, in step S2 above, the plan layout is based on the arrangement of the assembly site and the construction route. The shell-shaped large-span space frame is assembled on the full-span scaffolding, and a construction passage is set under the scaffolding.

[0013] In this invention, in step S3 above, the intermediate core truss is first installed, and then the auxiliary structural system is installed sequentially using the main structure that has been constructed around it and the closed ring beam of the reticulated shell.

[0014] In this invention, in step S4 above, the high-altitude bulk method is used for installation. The space frame components are vertically transported to the installation platform and stacked in a dispersed manner, and installed according to the installation drawing numbers.

[0015] First, install the corresponding support points to connect one frame of the space frame. After the support positions are corrected, install from one side to the other. First, install the lower chord, then the upper chord ball and web members, and finally the upper chord.

[0016] For assembling the lower chord and the lower chord ball, first fix the lower chord ball according to the number on the installation drawing, find the center line and connect the lower chord, measure the diagonal dimensions with the other side horizontally, and connect them after confirming that there are no errors.

[0017] When assembling the web members, the positions of the upper and lower chords must be corrected before installation, and then tightened. The combination of the web members and the lower chord ball forms a downward quadrangular pyramid. The web members and the upper chord ball are tightened with high-strength bolts.

[0018] Assemble the upper chord members. The four upper chord members are combined to form four upward cones. The upper chord members are installed from the inside out. According to the arrangement of the already installed web member cones, tighten the high-strength bolts.

[0019] After one unit is installed, repeat the above method to install the next unit in sequence until all units are installed.

[0020] In this invention, during the S5 step above, when the support is installed, cross center lines should be marked on the four sides of its upper and lower base plates. During installation, the upper base plate of the support is welded to the steel plate of the upper structure or connected by high-strength bolts.

[0021] Once the support position is determined, it can be welded on top and bottom or connected by high-strength bolts. When welding is used, a pre-embedded steel plate must be installed, and anchor bars should be welded to the surface in contact with the concrete. The pre-embedded steel plate should have multiple vent holes. Welding should be done in an intermittent manner to gradually fill the gap. After the fixed hinge support is installed, the upper and lower connecting plates should be removed.

[0022] In this invention, in step S6 above, the shell-shaped mesh shell is constructed in bulk, with a top support set on the top of the scaffolding and a tower crane arranged on site for installation;

[0023] During installation, the top support is placed under the scaffold beforehand. Some scaffolds are equipped with double-layer poles, and the upper blade is used as an elevation adjustment device.

[0024] The assembly of the reticulated shell follows the sequence of installing the edge supports, installing the edge chords, installing the assembly sections, and filling in any missing intermediate members.

[0025] In this invention, in step S7 above, the main structure is unloaded after installation, and unloading is carried out in the order from the middle to the surrounding area. The unloading is carried out by using a cutting blade. Before unloading, a calculation model is established to calculate 1.2 times the self-weight.

[0026] Compared with the prior art, the present invention has at least the following advantages or beneficial effects:

[0027] This invention proposes a construction method for a shell-shaped large-span space frame, including preparatory work before installation, layout and scaffolding erection, erection of the central truss and installation of the ring beam, assembly of the double-layer space frame, installation of fixed hinge supports, installation of the space shell, and unloading and dismantling of the scaffolding. It effectively solves the problem of high-altitude installation, ensures installation quality while reducing project costs. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the overall process flow of an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of a shell-shaped mesh shell according to an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the space frame according to an embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of the combination of the mesh shell and the space frame in an embodiment of the present invention. Detailed Implementation

[0033] Example

[0034] Please refer to Figures 1-4 The figure shown is an embodiment of the present invention.

[0035] The space frame is mainly a welded spherical space frame, primarily with circular tube cross-sections. The main cross-sectional dimensions are P60x4, P76x4, P89x4, P114x5, P133x6, P159x8, P219x10, P245x12, P299x14, P351x20, and P426x20. The shell-shaped space frame cross-section is mainly a box-shaped cross-section, with dimensions primarily B300X150X8X8. Given these construction technical characteristics, practical and feasible construction methods are required to ensure the quality, safety, and smooth implementation of the project.

[0036] This embodiment provides a construction method for a shell-shaped large-span space frame. The shell-shaped large-span space frame consists of a double-layer three-dimensional space frame and a single-layer reticulated shell, and includes the following steps:

[0037] S1, Installation Preparation:

[0038] Before installation, the axis and elevation of the space frame supports were checked and verified, and the concrete strength of the supports was tested. The test data must meet the requirements. Full-span scaffolding was erected, with the scaffolding height set 300mm below the elevation of the lower chord ball of the space frame. The positions and elevations of each support point were laid out, and temporary supports were designed and arranged. The temporary supports were adjusted step-by-step using specialized support tools. All incoming finished components were counted, categorized, and stacked.

[0039] S2, Site layout and scaffolding erection:

[0040] The layout is based on the assembly site and construction route. The shell-shaped large-span space frame is assembled piecemeal on the full-span scaffolding, and a construction passage is set up under the scaffolding to ensure the normal passage of construction vehicles.

[0041] Full-span scaffolding can use steel pipes The scaffolding should be spaced 1.0m x 1.0m apart, with a step distance of 1.5m. The scaffolding surface should be fully covered with scaffolding panels, and the load-bearing capacity of the scaffolding should not be less than 200kg / m2. The temporary material storage area should be free of obstacles to facilitate the storage of materials and components at any time. The storage area should at least ensure the normal stacking and operation of cranes, materials, and equipment.

[0042] The ground bearing capacity should be sufficient to ensure the safe operation of the truck crane, and the truck crane should be able to rotate 360 ​​degrees after lifting the glass panel, meaning that it should not be affected by obstacles when rotating.

[0043] S3, erect the central truss and install the ring beam;

[0044] First, the central core truss (main load-bearing system) is installed, and then the auxiliary structural system is installed sequentially using the main structure and the closed ring beam of the grid shell that have been constructed around it.

[0045] S4, assembled double-layer space frame;

[0046] The installation was carried out using the high-altitude bulk loading method. The space frame components were vertically transported to the installation platform and stacked in a dispersed manner. They were then installed according to the numbering on the installation drawings.

[0047] To ensure the correct installation axis of the space frame, first install one frame at each corresponding support point. After the support positions are corrected, install from one side to the other to reduce accumulated errors. First install the lower chord, then the upper chord balls and web members, and finally the upper chord.

[0048] For assembling the lower chord and the lower chord ball, first fix the lower chord ball according to the installation drawing number, find the center line, connect the lower chord to the other end, and connect after measuring the diagonal dimensions to ensure they are correct.

[0049] When assembling the web members, the positions of the upper and lower chords must be corrected before installation, and then tightened. The combination of the web members and the lower chord ball forms a downward quadrangular pyramid, and the web members and the upper chord ball are tightened with high-strength bolts.

[0050] The upper chord is assembled by combining four upper chords to form four upward cones. The upper chords are installed from the inside out, according to the arrangement of the already installed web cones, and the high-strength bolts are tightened.

[0051] After one unit is installed, repeat the above method to install the next unit in sequence until all units are installed.

[0052] Throughout the installation process, it is essential to continuously check the tightness of bolts, welding quality, deviation of support point axes, and deflection generated during space frame installation. Any problems encountered must be addressed and resolved promptly.

[0053] S5, Install fixed hinge support;

[0054] Fixed hinge supports are assembled by the manufacturer and shipped as a whole. Before installation, a comprehensive inspection should be carried out to check for any missing or damaged parts. Check whether the bolt hole spacing and diameter of the superstructure and the support plate are consistent, whether the selected model is correct, and whether the rotation angle and displacement in each direction are consistent with the design. The inspection should be based on the design drawings.

[0055] When installing the support, mark the center lines of the cross on the four sides of the upper and lower base plates to facilitate installation and alignment. During installation, weld the upper base plate of the support to the steel plate of the upper structure or use high-strength bolts for connection.

[0056] Once the support position is determined, it can be welded from top to bottom or connected with high-strength bolts, or both methods can be used simultaneously. When welding is used, a pre-embedded steel plate must be installed, and anchor bars should be welded to the surface in contact with the concrete. The pre-embedded steel plate should have multiple vent holes. Welding should be done intermittently to gradually fill the gap, in order to avoid localized overheating during welding, which could deform the support or the pre-embedded steel plate. After the fixed hinge support is installed, the upper and lower connecting plates should be removed.

[0057] S6, Install the mesh shell;

[0058] The shell-shaped mesh shell was constructed in bulk, with a top support set up at the top of the scaffolding, and installed using a tower crane arranged on site.

[0059] During installation, the top support is placed under the scaffold beforehand. Some scaffolds are equipped with double-layer poles, and the upper blade is used as an elevation adjustment device.

[0060] The assembly of the reticulated shell follows the sequence of installing the edge supports, installing the edge chords, installing the assembly sections, and filling in any missing intermediate members.

[0061] S7, Unload and dismantle the scaffolding.

[0062] After the main structure is installed, it will be unloaded in the order from the center to the surrounding areas. The unloading will be carried out by cutting blades. Before unloading, a calculation model will be built using MIDAS to calculate 1.2 times its own weight.

[0063] Taking the project overview in the background technology as an example, the calculation results show that the maximum displacement of the structure is mainly at the mid-span position, with a maximum displacement of about 59mm and a peripheral deformation of about 9mm. Therefore, when unloading, it is recommended to cut the blade plate in the middle position first. Since the displacement in the middle position is larger, the initial cutting length can be 15mm without load, and the peripheral cutting length is about 5mm. Then, cut in sequence, and the cutting length in the middle position should be reduced each time until the structure is completely removed from the jig.

[0064] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A construction method for a shell-shaped large-span space frame, characterized in that, The shell-shaped large-span space frame consists of a double-layer three-way steel space frame and two single-layer shell-shaped steel space shells embedded in the space frame. The single-layer steel space shells are hingedly supported on the double-layer space frame, and the process includes the following steps: S1, Installation preparation work; S2, site layout and scaffolding erection; S3, erect the central truss and install the ring beam; S4, Assemble a double-layer space frame; use a high-altitude bulk assembly method for installation, with space frame components transported vertically to the installation platform and stacked separately. Install components according to the numbers on the installation drawings; first install the corresponding support points to connect one space frame section, and after the support positions are corrected, install from one side to the other. First install the lower chord, then the upper chord spheres and web members, and finally the upper chord; for the assembly of the lower chord and lower chord spheres, fix the lower chord spheres according to the numbers on the installation drawings, find the center line and connect the lower chord, and connect it to the other side of the water... Measure the diagonal dimensions and connect them after confirming they are correct. For the web members, the positions of the upper and lower chords must be corrected before installation, and then tightened. The web members and the lower chord ball form a downward-facing quadrangular pyramid. The web members and the upper chord ball are tightened with high-strength bolts. For the upper chords, the four upper chords form an upward-facing quadrangular pyramid. The upper chords are installed from the inside out, according to the arrangement of the already installed web member pyramids, and the high-strength bolts are tightened. After one frame is installed, repeat the above method to install the next frame in sequence until all frames are installed. S5, Install fixed hinge support; S6, Install the space frame; the shell-shaped space frame is installed in bulk, with a top support set at the top of the scaffolding, and a tower crane arranged on site is used for installation; during installation, the top support is placed under the scaffolding in advance, and some scaffolding is equipped with double-layer poles, with the upper blade plate used as an elevation adjustment device; the bulk installation of the space frame follows the sequence of installing the edge support, installing the edge chord, installing the combined section, and filling in the missing intermediate members; S7, Unloading and dismantling of scaffolding; after the main structure is installed, unloading is carried out in the order from the middle to the surrounding areas, using a cutting blade method for unloading. Before unloading, a calculation model is established to calculate 1.2 times the self-weight.

2. The construction method for a shell-shaped large-span space frame according to claim 1, characterized in that, In step S1, before installation, the axis and elevation of the space frame support are checked and the concrete strength of the support is tested; a full-span scaffold is erected, with the scaffold height being 300mm below the elevation of the lower chord ball of the space frame; the positions and elevations of each support point are laid out, and temporary support points are designed and arranged.

3. The construction method for a shell-shaped large-span space frame according to claim 1, characterized in that, In step S2, the plan layout is based on the arrangement of the assembly site and the construction route. The shell-shaped large-span space frame is assembled piecemeal on the full-span scaffolding, and a construction passage is set up under the scaffolding.

4. The construction method for a shell-shaped large-span space frame according to claim 1, characterized in that, In step S3, the intermediate core truss is first installed, and then the auxiliary structural system is installed sequentially using the main structure that has been constructed around it and the closed ring beam of the reticulated shell.

5. The construction method for a shell-shaped large-span space frame according to claim 1, characterized in that, In step S5, when installing the support, cross center lines should be marked on the four sides of its upper and lower base plates. During installation, the upper base plate of the support should be welded to the steel plate of the upper structure or connected with high-strength bolts. Once the support position is determined, it can be welded from top to bottom or connected by high-strength bolts. When welding is used, a pre-embedded steel plate must be installed, and anchor bars should be welded to the surface in contact with the concrete. The pre-embedded steel plate should have multiple vent holes. Welding should be done in an intermittent manner to gradually fill the gap. After the fixed hinge support is installed, remove the upper and lower connecting plates.

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