A large-span single- and double-layer composite reticulated shell structure and its design method

Abstract

This invention provides a large-span single- and double-layer composite reticulated shell structure and its design method, which has lower requirements for the curvature of the building roof surface and the lower support structure and foundation. The left-side and right-side open double-layer reticulated shells are both spherical double-layer reticulated shells with a central opening, while the middle-side open double-layer reticulated shell is a cylindrical double-layer reticulated shell with a central opening. The left-side open double-layer reticulated shell is connected to the left-side single-layer reticulated shell to form a left-side single- and double-layer composite reticulated shell with a perimeter double-layer and a middle single-layer. The middle-side open double-layer reticulated shell is connected to the middle single-layer reticulated shell to form a middle-side single- and double-layer composite reticulated shell with a perimeter double-layer and a middle single-layer. The right-side open double-layer reticulated shell is connected to the right-side single-layer reticulated shell to form a right-side single- and double-layer composite reticulated shell with a perimeter double-layer and a middle single-layer. The lower support structure of the large-span single- and double-layer composite reticulated shell consists of perimeter point supports and middle point supports. The middle point supports are two-point supports located at the intersections of the left and right side-open double-layer reticulated shells and the middle-side open double-layer reticulated shell.

Description

Technical Field

[0001] This invention belongs to the field of "large-span spatial structure technology", and in particular relates to a large-span single and double-layer combined reticulated shell structure and its design method. Background Technology

[0002] As a typical large-span spatial structure, the reticulated shell structure features reasonable stress distribution, flexible layout, light weight, and good seismic performance. Furthermore, reticulated shell structures are easy to construct and install, with a high degree of prefabrication of members and nodes, meeting the requirements of modern industrialized construction.

[0003] In engineering applications, double-layer reticulated shell structures are more common, followed by single-layer reticulated shell structures. Double-layer reticulated shell structures have good overall load-bearing performance and large span capacity, but the denser members and nodes can lead to problems such as large structural space occupation and poor building light transmission. Single-layer reticulated shell structures have fewer members and a simple and aesthetically pleasing structural form, but they have limitations such as relatively poor overall structural stability and generally smaller spans. In addition, some projects combine single-layer and double-layer reticulated shells to form partial double-layer reticulated shell structures based on structural load-bearing characteristics and building functional requirements, but these are mostly single, regular geometric shapes.

[0004] In practical engineering, to improve the utilization rate of building space, building roofs tend to have a flatter shape with a relatively small curvature. However, a small roof curvature makes it difficult to fully utilize the overall spatial mechanical properties of the grid shell. Furthermore, the substructure supporting this type of roof generally needs to provide sufficient lateral stiffness for the roof structure, resulting in the substructure and foundation often requiring special reinforcement and enlargement. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings in the prior art and to provide a large-span single and double-layer combined reticulated shell structure with reasonable structural design and its design method, which has lower requirements for the curvature of the building roof surface and the lower supporting structure and foundation.

[0006] The technical solution adopted by the present invention to solve the above problems is:

[0007] A large-span single- and double-layer composite reticulated shell, characterized by comprising a left single-layer reticulated shell, a middle single-layer reticulated shell, a right single-layer reticulated shell, a left-opening double-layer reticulated shell, a middle-opening double-layer reticulated shell, and a right-opening double-layer reticulated shell; the left-opening double-layer reticulated shell and the right-opening double-layer reticulated shell are both spherical double-layer reticulated shells with a central opening, and the middle-opening double-layer reticulated shell is a cylindrical double-layer reticulated shell with a central opening; the left single-layer reticulated shell covers the opening area of ​​the left-opening double-layer reticulated shell, and the left-opening double-layer reticulated shell is connected to the left single-layer reticulated shell to form a left-side single- and double-layer composite reticulated shell with a peripheral double layer and a middle single layer; the middle single-layer reticulated shell covers and is fixed to the opening area of ​​the middle opening double-layer reticulated shell, and the middle opening double-layer reticulated shell is connected to the middle single-layer reticulated shell to form... A perimeter double-layered, middle single-layered combined reticulated shell; a right-side single-layered reticulated shell covers and is fixed to the opening area of ​​the right-side open double-layered reticulated shell, and the right-side open double-layered reticulated shell is connected to the right-side single-layered reticulated shell to form a perimeter double-layered, middle single-layered combined reticulated shell; the left-side single-layered combined reticulated shell, the middle single-layered combined reticulated shell, and the right-side single-layered combined reticulated shell are connected together from left to right to form a whole, constituting a large-span single-layered combined reticulated shell; the large-span single-layered combined reticulated shell is provided with a lower support structure, which is a perimeter point support and a middle point support. The middle point support adopts a middle 2-point support, and the middle point supports are respectively set at the intersection of the left and right side open double-layered reticulated shells and the middle open double-layered reticulated shell.

[0008] The double-layer reticulated shell with an opening on the left, the double-layer reticulated shell with an opening in the middle, and the double-layer reticulated shell with an opening on the right are all provided with closed trusses in their inner and outer rings. The double-layer reticulated shell with an opening on the left is connected to the single-layer reticulated shell on the left through the closed truss in the inner ring, the double-layer reticulated shell with an opening in the middle is connected to the single-layer reticulated shell on the middle through the closed truss in the inner ring, and the double-layer reticulated shell with an opening on the right is connected to the single-layer reticulated shell on the right through the closed truss in the inner ring.

[0009] The rods of the left single-layer reticulated shell, the rods of the middle single-layer reticulated shell, the rods of the right single-layer reticulated shell, the upper chord rods of the left open double-layer reticulated shell, the upper chord rods of the middle open double-layer reticulated shell, and the upper chord rods of the right open double-layer reticulated shell are combined together to form the upper chord rods of the large-span single-double-layer combined reticulated shell. The curved surface on which the upper chord rods of the large-span single-double-layer combined reticulated shell are located is the upper chord curved surface.

[0010] The lower chord members of the left-side open double-layer reticulated shell, the middle-side open double-layer reticulated shell, and the right-side open double-layer reticulated shell are combined together to form the lower chord members of the large-span single and double-layer combined reticulated shell. The curved surface on which the lower chord members of the large-span single and double-layer combined reticulated shell are located is the lower chord curved surface.

[0011] The web members of the left-side open double-layer reticulated shell, the middle-side open double-layer reticulated shell, and the right-side open double-layer reticulated shell are combined to form the web members of the large-span combined single and double-layer reticulated shell.

[0012] The upper chord surface described in this invention is a relatively gentle curved surface designed to meet architectural design requirements; the curvature of the lower chord surface is greater than that of the upper chord surface.

[0013] The geometric shapes of the lower chord surface described in this invention, from left to right, are sphere, cylinder, and sphere.

[0014] The single- and double-layer combined mesh shells on the left, the middle, and the right are all variable-thickness mesh shells. The middle of the variable-thickness mesh shell is thinner, and the periphery is thicker.

[0015] The peripheral point support and the intermediate point support of the present invention adopt structural columns; the peripheral point support adopts a two-way elastic ball joint support, and the intermediate point support adopts a fixed ball joint support.

[0016] The outline projections of the left single-layer mesh shell, the middle single-layer mesh shell, and the right single-layer mesh shell described in this invention are circular or elliptical.

[0017] A design method for a large-span single- or double-layer composite reticulated shell structure, characterized by the following steps:

[0018] 1) Based on the building roof shape and the thickness of the building surface layer, the upper chord curved surface of the large-span single and double layer combined grid shell is obtained by offsetting the original building roof curved surface by a certain distance.

[0019] 2) Based on the geometric shape characteristics and dimensions of the building's plan outline, draw the projection line of the large-span single and double-layer combined reticulated shell outline on the plane, and fit a lower chord surface with reasonable curvature from the perspective of structural stress; the curvature of the lower chord surface is larger than that of the upper chord surface; the geometric shape of the lower chord surface from left to right is sphere, cylinder, sphere;

[0020] 3) Draw the projection lines of the left single-layer reticulated shell, the middle single-layer reticulated shell, and the right single-layer reticulated shell on the plane. The outline projection of the left single-layer reticulated shell, the middle single-layer reticulated shell, and the right single-layer reticulated shell is a circle or an ellipse.

[0021] 4) The lower chord surface of the large-span single and double-layer composite reticulated shell is divided into grids, and the resulting grid lines are the structural lines of the lower chord members of the large-span single and double-layer composite reticulated shell.

[0022] 5) Mesh the upper chord surface of the large-span single- and double-layer composite reticulated shell; mesh the upper chord surfaces corresponding to the left single-layer reticulated shell, the middle single-layer reticulated shell, and the right single-layer reticulated shell in sequence; the upper chord meshes of the left open double-layer reticulated shell, the middle open double-layer reticulated shell, and the right open double-layer reticulated shell are based on the already divided lower chord surface mesh. Extract the center point of each surface region of the lower chord surface mesh and map it to the upper chord surface. Adjust the connection of the mapping points to form the upper chord mesh; combine the upper chord meshes of the single-layer and double-layer reticulated shell parts to form the structural line of the upper chord member of the large-span single- and double-layer composite reticulated shell;

[0023] 6) Connect the lower chord grid points of the large-span single and double-layer composite reticulated shell to the three nearest upper chord grid points of the same large-span single and double-layer composite reticulated shell to form the structural lines of the web members of the large-span single and double-layer composite reticulated shell;

[0024] 7) Combining the structural lines of the lower chord members, the upper chord members, and the web members together forms the structural lines of the large-span single and double-layer composite reticulated shell.

[0025] 8) Determine the lower support form of the large-span single and double-layer combined reticulated shell, adopting a combination of peripheral point support and intermediate point support; the intermediate point support adopts two intermediate point supports, respectively set at the intersection of the left and right side opening double-layer reticulated shell and the intermediate opening double-layer reticulated shell; the peripheral point support adopts bidirectional elastic ball joint support, and the intermediate two point support adopts fixed ball joint support.

[0026] 9) Determine the form of the rod connection nodes for this large-span single and double-layer composite reticulated shell.

[0027] In step 9) of this invention, the member node connection form of the left open double-layer reticulated shell, the middle open double-layer reticulated shell and the right open double-layer reticulated shell is to adopt the form of intersecting node welding in the inner and outer closed trusses, and the rest adopt the form of bolt ball or welded ball connection; the member connection node form of the left single-layer reticulated shell, the middle single-layer reticulated shell and the right single-layer reticulated shell is to adopt the form of middle circular tube plus rectangular connecting plate.

[0028] Compared with the prior art, the present invention has the following advantages and effects:

[0029] 1. The components of this invention are clearly defined and rationally constructed. When the curvature of the building roof surface is relatively small, the upper chord surface can be used to maintain the roof curvature constant. By reasonably increasing the curvature of the lower chord surface of the combined grid shell, the overall spatial mechanical performance of the roof is improved, changing the load-bearing mode from a flat plate to a shell-type load-bearing mode. This solves the problem that "small roof curvature makes it difficult to fully utilize the overall spatial mechanical performance of the grid shell." The structure of this invention has relatively low requirements for the curvature of the building roof surface, can fully utilize the shell characteristics, has high material utilization, and can significantly reduce the amount of steel used in the roof compared to general large-span roof truss structures and grid structures.

[0030] 2. This invention utilizes the circumferential restraint of the outer closed trusses of the left and right spherical reticulated shells to provide overall structural stiffness. Furthermore, the two spherical reticulated shells provide lateral support to the central cylindrical reticulated shell, ensuring the overall composite reticulated shell structure itself has significant stiffness. This greatly reduces the stiffness requirements of the lower support structure and foundation, thus solving the problem that "the lower support structure and foundation often need to be specially strengthened and enlarged." The invention offers good overall structural stiffness, large span capacity, and low requirements for the lower support structure and foundation, resulting in good overall economic benefits.

[0031] 3. The three single-layer reticulated shell regions (left, center, and right) of this invention have a relatively large area, a simple and aesthetically pleasing structure, and good structural permeability, making them suitable as skylights for buildings and meeting high lighting requirements. The double-layer reticulated shell region of this invention can better adapt to complex boundary conditions, more easily conforms to the building's required outline, and allows for the addition of eaves and other external structures to meet design requirements. This invention has relatively wide applicability and easily balances the functionality and aesthetics of buildings.

[0032] In summary, this invention leverages the advantages of both single and double-layer reticulated shells in terms of stress distribution. First, it effectively combines them to form a single-layer / double-layer composite reticulated shell with a double-layer perimeter and a single-layer middle section. It fully utilizes the characteristic of the spherical reticulated shell where the internal forces are primarily membrane-based in the center, while the single-layer middle section provides a simple form that meets the building's high lighting requirements. Since the support edges exhibit boundary effects, resulting in complex and variable stresses, a thicker double-layer reticulated shell better adapts to these stress requirements and more easily conforms to the building's required outline. Geometrically, the left and right spherical reticulated shells are superimposed with a central cylindrical reticulated shell to create a composite reticulated shell with high overall stiffness. This effectively adapts to the usable space of large-span, near-oblong buildings, ultimately achieving a favorable overall spatial stress distribution pattern. Finally, static analysis and nonlinear analysis, along with calculations and analyses of system deformation, component stress, and stability, ensure the overall load-bearing performance of the structural system. This invention is suitable for building types with large-span, near-oblong spaces (length-to-width ratio greater than 2) and high roof lighting requirements, such as large stations, convention centers, water parks, and amusement parks, and has significant application prospects. Attached Figure Description

[0033] To more clearly illustrate the geometric features and technical solutions of the present invention, a detailed description is provided below using accompanying drawings. These drawings are merely illustrative and do not limit the present invention.

[0034] Figure 1 This is an isometric schematic diagram of an embodiment of the present invention.

[0035] Figure 2 This is a planar top view of an embodiment of the present invention.

[0036] Figure 3 This is an isometric schematic diagram of the embodiment of the present invention after the addition of the roof eaves structure and the lower support structure.

[0037] Figure 4 This is an elevation view of the present invention after the addition of a roof eaves structure and a lower support structure.

[0038] Figure 5 This is a plan view of the upper chord member according to an embodiment of the present invention.

[0039] Figure 6 This is a plan view of the lower chord members according to an embodiment of the present invention.

[0040] Figure 7 This is a planar arrangement diagram of the web members according to an embodiment of the present invention.

[0041] Figure 8 This is a schematic diagram of the projection line positioning of the structural outline of an embodiment of the present invention on a plane.

[0042] Figure 9 This is a schematic diagram of the lower chord surface according to an embodiment of the present invention.

[0043] Figure 10 This is a schematic diagram of the projection lines of the left single-layer mesh shell, the middle single-layer mesh shell and the right single-layer mesh shell in an embodiment of the present invention on a plane.

[0044] Figure 11 This is an isometric schematic diagram of the lower chord member according to an embodiment of the present invention.

[0045] Figure 12 This is an isometric schematic diagram of the rods of the left single-layer reticulated shell, the middle single-layer reticulated shell, and the right single-layer reticulated shell according to an embodiment of the present invention.

[0046] Figure 13 This is an isometric schematic diagram of the upper chord members corresponding to the left-opening double-layer reticulated shell, the middle-opening double-layer reticulated shell, and the right-opening double-layer reticulated shell in an embodiment of the present invention.

[0047] Figure 14 This is an isometric schematic diagram of the web member according to an embodiment of the present invention.

[0048] Figure 15 This is a schematic diagram of the point arrangement of the lower support structure according to an embodiment of the present invention.

[0049] Icons: 1 is a single-layer reticulated shell on the left, 2 is a single-layer reticulated shell in the middle, 3 is a single-layer reticulated shell on the right, 4 is a double-layer reticulated shell with an opening on the left, 5 is a double-layer reticulated shell with an opening in the middle, 6 is a double-layer reticulated shell with an opening on the right, 7 is the opening area of ​​the double-layer reticulated shell with an opening on the left, 8 is the opening area of ​​the double-layer reticulated shell with an opening in the middle, 9 is the opening area of ​​the double-layer reticulated shell with an opening on the right, 10 is the inter-column ring beam, 11 is a schematic diagram of the roof eaves members, 12 is the lower support of the eaves, 13 is the peripheral point support, and 14 is the middle point support. Detailed Implementation

[0050] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0051] The accompanying drawings in this specification are schematic diagrams used to illustrate the concept of the invention, and schematically show the shapes of the various components and their interrelationships. Please note that, in order to clearly show the structure of the components in the embodiments of the invention, the drawings are not drawn to the same scale. The same reference numerals are used to indicate identical parts.

[0052] The embodiments of the present invention include a single-layer mesh shell 1 on the left, a single-layer mesh shell 2 in the middle, a single-layer mesh shell 3 on the right, a double-layer mesh shell with an opening on the left 4, a double-layer mesh shell with an opening in the middle 5, and a double-layer mesh shell with an opening on the right 6.

[0053] The left-opening double-layer reticulated shell 4, the middle-opening double-layer reticulated shell 5, and the right-opening double-layer reticulated shell 6 are all double-layer reticulated shell structures with a central opening. The left-opening double-layer reticulated shell 4 has an opening area 7, the middle-opening double-layer reticulated shell 5 has an opening area 8, and the right-opening double-layer reticulated shell 6 has an opening area 9. The left-opening double-layer reticulated shell 4 and the right-opening double-layer reticulated shell 6 are both spherical double-layer reticulated shells, while the middle-opening double-layer reticulated shell 5 is a cylindrical double-layer reticulated shell.

[0054] The left-side open double-layer reticulated shell 4, the middle-side open double-layer reticulated shell 5, and the right-side open double-layer reticulated shell 6 are all equipped with enclosed trusses on their inner and outer rings. The left-side single-layer reticulated shell 1 covers the opening area 7 of the left-side open double-layer reticulated shell 4. The left-side open double-layer reticulated shell 4 is connected to the left-side single-layer reticulated shell 1 via the inner ring enclosed trusses, forming a left-side single-double-layer combined reticulated shell with a perimeter double-layer and a middle single-layer. The middle single-layer reticulated shell 2 covers and is fixed to the opening area 8 of the middle-side open double-layer reticulated shell 5. The middle-side open double-layer reticulated shell 5 is connected to the middle single-layer reticulated shell 2 via the inner ring enclosed trusses, forming a middle-side single-double-layer combined reticulated shell with a perimeter double-layer and a middle single-layer. The right-side single-layer reticulated shell 3 covers and is fixed to the opening area 9 of the right-side open double-layer reticulated shell 6. The right-side open double-layer reticulated shell 6 is connected to the right-side single-layer reticulated shell 3 via the inner ring enclosed trusses, forming a right-side single-double-layer combined reticulated shell with a perimeter double-layer and a middle single-layer. The left-side single-double layer combined reticulated shell, the middle-side single-double layer combined reticulated shell, and the right-side single-double layer combined reticulated shell are connected together from left to right to form a whole, constituting a large-span single-double layer combined reticulated shell. In this large-span single-double layer combined reticulated shell, the left-side open double-layer reticulated shell 4, the middle-side open double-layer reticulated shell 5, and the right-side open double-layer reticulated shell 6 are connected together from left to right to form a whole, while the left-side single-layer reticulated shell 1, the middle-side single-layer reticulated shell 2, and the right-side single-layer reticulated shell 3 are independently set up and not connected to each other.

[0055] The components of this large-span single and double-layer composite reticulated shell can be divided into upper chord members, lower chord members, and web members according to the type of components.

[0056] The members of the single-layer reticulated shell 1 on the left, the members of the single-layer reticulated shell 2 in the middle, the members of the single-layer reticulated shell 3 on the right, the upper chord members of the double-layer reticulated shell 4 with an opening on the left, the upper chord members of the double-layer reticulated shell 5 with an opening in the middle, and the upper chord members of the double-layer reticulated shell 6 with an opening on the right are combined to form the upper chord members of this large-span single- and double-layer combined reticulated shell. The curved surface on which the upper chord members are located is the upper chord surface, which is generally a relatively gentle curved surface designed to meet the architectural design requirements.

[0057] The lower chord members of the left-side open double-layer reticulated shell 4, the middle-side open double-layer reticulated shell 5, and the right-side open double-layer reticulated shell 6 are combined to form the lower chord members of this large-span single- and double-layer composite reticulated shell. The curved surface on which the lower chord members are located is the lower chord surface. The lower chord surface is the surface after the curvature is increased reasonably according to the structural requirements. Geometrically, it can be regarded as a combination of a sphere composed of the lower chord members of the left-side open double-layer reticulated shell 4, a cylinder composed of the lower chord members of the middle-side open double-layer reticulated shell 5, and a sphere composed of the lower chord members of the right-side open double-layer reticulated shell 6.

[0058] Since the curvature of the lower chord surface is greater than that of the upper chord surface, the single-double layer combined reticulated shell on the left, the single-double layer combined reticulated shell in the middle, and the single-double layer combined reticulated shell on the right are all variable thickness reticulated shells, with a smaller thickness in the middle and a larger thickness around the perimeter.

[0059] The lower support structure of this large-span single / double-layer composite reticulated shell consists of peripheral point supports 13 combined with intermediate point supports 14. The peripheral point supports 13 and intermediate point supports 14 are generally structural columns. The intermediate point supports 14 employ two intermediate point supports, located at the intersections of the left-side open double-layer reticulated shell 4 and the intermediate open double-layer reticulated shell 5, and at the intersections of the right-side open double-layer reticulated shell 6 and the intermediate open double-layer reticulated shell 5. The peripheral point supports 13 utilize bidirectional elastic ball joint supports, while the intermediate point supports 14 utilize fixed ball joint supports. The peripheral point supports 13 are connected by inter-column ring beams 10.

[0060] For the left-side open double-layer reticulated shell 4, the middle-side open double-layer reticulated shell 5, and the right-side open double-layer reticulated shell 6, the member node connection method uses intersecting welded nodes in the inner and outer closed trusses, and bolted ball or welded ball connections for the rest. The member node connection method for the left-side single-layer reticulated shell 1, the middle-side single-layer reticulated shell 2, and the right-side single-layer reticulated shell 3 can use a central circular tube with a rectangular connecting plate. The outline projection of the left-side single-layer reticulated shell 1, the middle-side single-layer reticulated shell 2, and the right-side single-layer reticulated shell 3 can be circular or elliptical.

[0061] In this embodiment, a roof eaves structure 11 is provided according to the architectural design requirements, and a lower support structure 12 for the eaves structure 11 is provided at the point where the span is the largest.

[0062] A design method for a large-span single- or double-layer composite reticulated shell structure includes the following steps:

[0063] 1) Based on the building roof shape and the thickness of the building surface layer, the original building roof curved surface (allowing the overall curvature of the roof to be relatively gentle) is offset by a certain distance to obtain the upper chord curved surface of the large-span single and double layer combined grid shell.

[0064] 2) Based on the geometric shape and dimensions of the building's plan outline, draw the projection lines of the large-span single- and double-layer composite reticulated shell outline on the plane, and fit a lower chord surface with reasonable curvature from the perspective of structural stress (the curvature of the lower chord surface is slightly larger than that of the upper chord surface). The geometric shapes of the lower chord surface from left to right are sphere, cylinder, and sphere.

[0065] In a specific embodiment, the radii R1 of the left-opening double-layer mesh shell 4 and the right-opening double-layer mesh shell 6 can be set (i.e., Figure 8 The radii R1 of the circles on the left and right sides, the sag f1 of the double-layer reticulated shell 4 with opening on the left and the double-layer reticulated shell 6 with opening on the right, and the span X2 of the double-layer reticulated shell 5 with opening in the middle (i.e., Figure 8 The annotation X2), the sag f2 of the double-layer reticulated shell 5 with the middle opening, and the radius R2 of the end arc segment of the double-layer reticulated shell 5 with the middle opening (i.e., Figure 8 The radius of the arc in the middle region (R2), and the height of the arc segment of the double-layer reticulated shell 5 with the middle opening (H2). Figure 8The height of the middle region H2 is used as a parameter. These parameters determine the control curves of the lower chord surface; the corresponding lower chord surface can be fitted from these control curves, such as... Figure 9 .

[0066] 3) Draw the projection lines of the left single-layer mesh shell 1, the middle single-layer mesh shell 2, and the right single-layer mesh shell 3 on the plane. The outline projection of the left single-layer mesh shell 1, the middle single-layer mesh shell 2, and the right single-layer mesh shell 3 can be circular or elliptical. In this embodiment, it is elliptical.

[0067] In a specific embodiment, the minor axis (La, Lc), major axis (Lb, Ld), and ellipse tilt angle (α) of the ellipse can be specified, such as... Figure 10 .

[0068] 4) Mesh the lower chord surfaces, specifically the lower chord surfaces containing the lower chord members of the left-opening double-layer reticulated shell 4, the middle-opening double-layer reticulated shell 5, and the right-opening double-layer reticulated shell 6. For example... Figure 11 There are various methods for mesh generation. Considering that the curvature of the lower chord surface is relatively gentle, the projection method can be used for mesh generation, which simplifies the mesh generation of the curved surface to the mesh generation on a plane.

[0069] 5) Mesh the upper chord surfaces. Mesh the upper chord surfaces corresponding to the left single-layer mesh shell 1, the middle single-layer mesh shell 2, and the right single-layer mesh shell 3 sequentially, as follows: Figure 12 The upper chord meshes of the left-opening double-layer reticulated shell 4, the middle-opening double-layer reticulated shell 5, and the right-opening double-layer reticulated shell 6 can be based on the pre-divided lower chord surface mesh. The center points of each surface region of the lower chord surface mesh are extracted and mapped to the upper chord surface. The lines connecting the mapped points are then appropriately adjusted to form the upper chord mesh. Figure 13 Combining the upper chord grids of the single-layer and double-layer reticulated shell sections together forms the structural line of the upper chord member, as shown below. Figure 5 .

[0070] 6) Connect the lower chord grid points of the large-span single / double-layer composite reticulated shell to the three nearest upper chord grid points of the same shell to form the structural lines of the web members of the large-span single / double-layer composite reticulated shell, such as... Figure 14 .

[0071] 7) Combining the structural lines of the lower chord members, upper chord members, and web members together forms the structural lines of a large-span single / double-layer composite reticulated shell, such as... Figure 1 It can be used to import data into structural calculation software for calculation and analysis.

[0072] 8) Install supports for the large-span single / double-layer composite reticulated shell. In this embodiment, 26 structural columns are used as peripheral point supports 13, and 2 central structural columns are used as intermediate point supports 14, arranged in the following plan. Figure 15 The two structural columns of the intermediate point support 14 are located at the intersection of the left-side open double-layer reticulated shell 4 and the middle-side open double-layer reticulated shell 5, respectively, and at the intersection of the right-side open double-layer reticulated shell 6 and the middle-side open double-layer reticulated shell 5. The peripheral point support 13 uses a bidirectional elastic ball joint support, while the intermediate point support 14 uses a fixed ball joint support.

[0073] 9) Determine the member connection node form of the large-span single and double-layer composite reticulated shell. The member connection node form of the left open double-layer reticulated shell 4, the middle open double-layer reticulated shell 5, and the right open double-layer reticulated shell 6 is to use intersecting node welding in the inner and outer closed trusses, and the rest use bolt ball or welded ball connection forms. In this embodiment, the member connection node form of the left single-layer reticulated shell 1, the middle single-layer reticulated shell 2, and the right single-layer reticulated shell 3 adopts the form of a middle circular tube plus a rectangular connecting plate.

[0074] Furthermore, it should be noted that the specific embodiments described in this specification may differ in the shape and name of their components, and the above description is merely illustrative of the structure of the present invention. All equivalent or simple variations made based on the structure, features, and principles described in this patent concept are included within the scope of protection of this patent.

Claims

1. A large-span single / double-layer composite reticulated shell structure, characterized in that: This includes a single-layer reticulated shell on the left, a single-layer reticulated shell in the middle, a single-layer reticulated shell on the right, a double-layer reticulated shell with an opening on the left, a double-layer reticulated shell with an opening in the middle, and a double-layer reticulated shell with an opening on the right. The double-layer reticulated shells with openings on the left and right are both spherical double-layer reticulated shells with a central opening, while the double-layer reticulated shell with an opening in the middle is a cylindrical double-layer reticulated shell with a central opening. The single-layer reticulated shell on the left covers the opening area of ​​the double-layer reticulated shell on the left, and the double-layer reticulated shell on the left connects with the single-layer reticulated shell on the left to form a combined single-layer and double-layer reticulated shell with a double-layer perimeter and a single-layer central opening. The single-layer reticulated shell in the middle covers and is fixed to the opening area of ​​the double-layer reticulated shell in the middle. A double-layered reticulated shell with a central opening is connected to a single-layered reticulated shell in the middle to form a double-layered reticulated shell with a central single-layered reticulated shell. A single-layered reticulated shell on the right side covers and is fixed to the opening area of ​​the double-layered reticulated shell on the right side. The double-layered reticulated shell on the right side is connected to the single-layered reticulated shell on the right side to form a double-layered reticulated shell with a central single-layered reticulated shell. The single-layered reticulated shell on the left, the middle, and the right sides are connected from left to right to form a whole, constituting a large-span single-layered reticulated shell. The large-span single-layered reticulated shell is equipped with a lower support structure, which is... The structure consists of peripheral point supports and intermediate point supports, with the intermediate point supports employing two intermediate points. These intermediate point supports are respectively located at the intersections of the left and right open double-layer reticulated shells and the intermediate open double-layer reticulated shell. The members of the left single-layer reticulated shell, the intermediate single-layer reticulated shell, the right single-layer reticulated shell, the upper chord members of the left open double-layer reticulated shell, the upper chord members of the intermediate open double-layer reticulated shell, and the upper chord members of the right open double-layer reticulated shell are combined to form the upper chord members of the large-span single-double-layer combined reticulated shell. The curved surface on which the upper chord members of the large-span single-double-layer combined reticulated shell are located is the upper chord curved surface. The left open double-layer reticulated shell... The lower chord members of the shell, the lower chord members of the middle-opening double-layered grid shell, and the lower chord members of the right-side-opening double-layered grid shell are combined to form the lower chord members of the large-span single- and double-layered combined grid shell. The curved surface on which the lower chord members of the large-span single- and double-layered combined grid shell are located is the lower chord surface. The web members of the left-side-opening double-layered grid shell, the web members of the middle-opening double-layered grid shell, and the web members of the right-side-opening double-layered grid shell are combined to form the web members of the large-span combined single- and double-layered grid shell. The upper chord surface is a relatively gentle curved surface designed to meet architectural design requirements. The curvature of the lower chord surface is greater than that of the upper chord surface.

2. The large-span single / double-layer composite reticulated shell structure according to claim 1, characterized in that: The double-layer reticulated shell with an opening on the left, the double-layer reticulated shell with an opening in the middle, and the double-layer reticulated shell with an opening on the right are all equipped with closed trusses in their inner and outer rings. The double-layer reticulated shell with an opening on the left is connected to the single-layer reticulated shell on the left through the closed truss in the inner ring, the double-layer reticulated shell with an opening in the middle is connected to the single-layer reticulated shell on the middle through the closed truss in the inner ring, and the double-layer reticulated shell with an opening on the right is connected to the single-layer reticulated shell on the right through the closed truss in the inner ring.

3. The large-span single / double-layer combined reticulated shell structure according to claim 1, characterized in that: The geometric shapes of the lower chord surface, from left to right, are sphere, cylinder, and sphere.

4. The large-span single / double-layer composite reticulated shell structure according to claim 1, characterized in that: The single- and double-layer combined reticulated shells on the left, in the middle, and on the right are all variable-thickness reticulated shells. The thickness of the variable-thickness reticulated shells is smaller in the middle and larger at the periphery.

5. The large-span single / double-layer combined reticulated shell structure according to claim 1, characterized in that: The peripheral point supports and the intermediate point supports are structural columns; the peripheral point supports are bidirectional elastic ball joint supports, and the intermediate point supports are fixed ball joint supports.

6. The large-span single / double-layer composite reticulated shell structure according to claim 1, characterized in that: The outline projections of the left single-layer reticulated shell, the middle single-layer reticulated shell, and the right single-layer reticulated shell are circular or elliptical.

7. A design method for a large-span single / double-layer composite reticulated shell structure as described in any one of claims 1-6, characterized in that: The steps include: 1) Based on the building roof shape and the thickness of the building surface layer, the upper chord curved surface of the large-span single and double layer combined grid shell is obtained by offsetting the original building roof curved surface by a certain distance. 2) Based on the geometric shape characteristics and dimensions of the building's plan outline, draw the projection line of the large-span single and double-layer combined reticulated shell outline on the plane, and fit a lower chord surface with reasonable curvature from the perspective of structural stress; the curvature of the lower chord surface is larger than that of the upper chord surface; the geometric shape of the lower chord surface from left to right is sphere, cylinder, sphere; 3) Draw the projection lines of the left single-layer reticulated shell, the middle single-layer reticulated shell, and the right single-layer reticulated shell on the plane. The outline projection of the left single-layer reticulated shell, the middle single-layer reticulated shell, and the right single-layer reticulated shell is a circle or an ellipse. 4) The lower chord surface of the large-span single and double-layer composite reticulated shell is divided into grids, and the resulting grid lines are the structural lines of the lower chord members of the large-span single and double-layer composite reticulated shell. 5) Mesh the upper chord surface of the large-span single- and double-layer composite reticulated shell; mesh the upper chord surfaces corresponding to the left single-layer reticulated shell, the middle single-layer reticulated shell, and the right single-layer reticulated shell in sequence; the upper chord meshes of the left open double-layer reticulated shell, the middle open double-layer reticulated shell, and the right open double-layer reticulated shell are based on the already divided lower chord surface mesh. Extract the center point of each surface region of the lower chord surface mesh and map it to the upper chord surface. Adjust the connection of the mapping points to form the upper chord mesh; combine the upper chord meshes of the single-layer and double-layer reticulated shell parts to form the structural line of the upper chord member of the large-span single- and double-layer composite reticulated shell; 6) Connect the lower chord grid points of the large-span single and double-layer composite reticulated shell to the three nearest upper chord grid points of the same large-span single and double-layer composite reticulated shell to form the structural lines of the web members of the large-span single and double-layer composite reticulated shell; 7) Combining the structural lines of the lower chord members, the upper chord members, and the web members together forms the structural lines of the large-span single and double-layer composite reticulated shell. 8) Determine the lower support form of the large-span single and double-layer combined reticulated shell, adopting a combination of peripheral point support and intermediate point support; the intermediate point support adopts two intermediate point supports, respectively set at the intersection of the left and right side opening double-layer reticulated shell and the intermediate opening double-layer reticulated shell; the peripheral point support adopts bidirectional elastic ball joint support, and the intermediate two point support adopts fixed ball joint support. 9) Determine the form of the rod connection nodes for this large-span single and double-layer composite reticulated shell.

8. The design method for a large-span single / double-layer composite reticulated shell structure according to claim 7, characterized in that: In step 9), the member node connection form of the left open double-layer reticulated shell, the middle open double-layer reticulated shell and the right open double-layer reticulated shell is to use the intersecting node welding form in the inner and outer closed trusses, and the rest are connected by bolt ball or welded ball; the member connection node form of the left single-layer reticulated shell, the middle single-layer reticulated shell and the right single-layer reticulated shell is to use the form of middle circular tube plus rectangular connecting plate.

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