JPH07122286B2 - Three-dimensional frame structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to, for example, a dome, a thrust shell, a four-sided folded plate structure, and a general three-dimensional frame structure.

[Conventional technology and problems]

In the three-dimensional frame structure, the triangular mesh structure is a stable structure and has been widely used conventionally.

On the other hand, in the lattice shape, that is, in the square mesh structure, when the peripheral deformation is constrained, the displacement of each node of the lattice in the three axis directions (X axis direction, Y axis direction, Z axis direction) is small, and therefore the bending stress Becomes smaller and the cross section of the member can be made smaller, which is economical.

However, in reality, it is difficult to constrain the deformation around,
In most cases, only the vertical direction is the supporting condition, and as a result, the displacement becomes large and the bending stress also increases.

An object of the present invention is to solve the above-mentioned problems in a three-dimensional frame structure in which a grid-like mesh is formed by rods and node members.

[Means for Solving the Problems]

The present invention is envisaged in advance for a three-dimensional frame structure in which rods in two directions that connect between the node members have a lattice-like mesh that is substantially orthogonal to each other, are supported vertically in the periphery, and are allowed to be displaced in the horizontal direction. The displacement of each node is calculated under the specified load and support conditions, and the displacement between nodes is calculated by the following equation (1). The distance between nodes where the displacement Δ between nodes becomes a positive value, that is, the distance between nodes increases. The tensile resistance member is installed only at the location to reduce the displacement.

Δ = (DX _j −DX _i ) · 1 _ij ＋ (DY _j −DY _i ) · m _ij ＋ (DZ _j −D
Z _i ) ・ n _ij ) ・ n _ij … (1) (However, DX, DY, DZ: Node displacement 1, m, n: Direction cosine of the straight line connecting the nodes) 1, m, n: Connecting the nodes Directional cosine of a straight line) By reducing the displacement between the nodes, the bending moment of the member is greatly reduced and the member shape can be made smaller, which is economical.

The number of locations where the internode displacement Δ has a positive value is 1 or more, and it is considered that there are usually a plurality of locations. However, it is not necessary to install the tensile resistance members at all locations, and it is also possible to install them at a part thereof.

As the load condition, it is necessary to consider not only its own weight but also snow load in a snowy area. Further, the supporting condition is a case where there is no horizontal constraint in the peripheral portion, that is, a case where horizontal displacement is allowed.

A wire or the like is used as the tensile resistance member, and as a general rule, it is attached separately for each required node. That is, although it is possible to connect a plurality of nodes with a single tensile resistance member, the displacement between the nodes is usually different, and the tensile load required for the tensile resistance member is also different. Is desirable. The tensile resistance member does not have to be resistant to compressive force, and is not particularly limited as long as it is a member other than the wire and that exhibits the required tensile strength.

〔Example〕

 Next, the illustrated embodiment will be described.

1 and 2 show an embodiment in which the present invention is applied to a dome having a lattice-shaped three-dimensional frame.
In the figure, 1 is a rod forming a grid, 2 is a node, 3 is a node 2
A tensile resistance member such as a wire installed between the two (shown by the broken line)
Is. Further, 4 is a ring frame formed around the dome roof.

As described in the previous section, the tensile resistance member 3 is provided at a position where elongation is generated by obtaining the displacement between the nodes.
Omitting the small stretch position, cross the grid diagonally,
It is arranged in a substantially rectangular shape inscribed in the ring frame 4.

FIG. 3 shows the amount of displacement (hatched portion) around the dome roof when the tensile resistance member 3 is not inserted. On the other hand, by arranging the tensile resistance member 3 as shown in FIG. The displacement around the dome roof (hatched area in Fig. 1) is greatly reduced.

4 to 7 show an embodiment when the present invention is applied to a thrust shell type three-dimensional frame. The arrangement of the tensile resistance member 3 is shown in FIGS. 4 and 5, and the tensile resistance member 3 is compared with the displacement amount (hatched portion extending to the upper right in the drawings) without the tensile resistance member 3. It can be seen that, by arranging them, the amount of displacement (hatched portion extending to the lower right in the figure) is significantly reduced.

FIG. 8 and FIG. 9 show examples of lattices in a three-dimensional frame to which the present invention is applied. Whereas Fig. 8 shows the case of a single layer composed only of rod 1 and node 2, as shown in Fig. 9, the upper chord member 12, the lower chord member 13 and the diagonal member 14 form the truss frame member 11. In some cases, it is a double layer that is constructed and assembled into a lattice. In this case, for example, the upper and lower tensile resistance members 3 are arranged at the height of the upper chord member 12 and the lower chord member 13 at the node 2.

Similarly, FIGS. 10 to 12 show an embodiment in which the present invention is applied to a four-sided folded plate type three-dimensional frame. The arrangement of the tensile resistance member 3 is shown in FIGS. 10 and 11,
By arranging the tensile resistance member 3, the displacement amount (hatched portion extending to the lower right in the figure) is smaller than that when the tensile resistance member 3 is not provided (hatched portion extending to the upper right in the figure). It can be seen that it is significantly reduced.

An example of the procedure for determining the tensile resistance member installation position in the three-dimensional frame structure of the present invention will be described below.

First, the nodal displacement without a tensile resistance member is calculated only by the members constituting the lattice, and the position where the internodal displacement is positive, that is, the internodal distance extends is calculated by the above-mentioned formula (1), and the displacement amount is calculated. Decide the position that is considered effective for reduction. Next, a stress analysis is performed with the tensile resistance member installed, and it is confirmed that the tension acts on all the tensile resistance members, and the final tensile resistance member installation position is determined. If there is a position where the compressive force acts on the tensile resistance member by the stress analysis, the tensile resistance member at that position is removed and the stress analysis is performed again to determine the tensile resistance member installation position.

[Advantages of the Invention] Under a supporting condition in which horizontal displacement in the periphery is allowed, the displacement between the nodes is reduced, so that the stress acting on the rod or the node member forming the grid-like mesh is significantly reduced. It is possible to reduce the number and reduce the cross section of the member. Therefore, the amount of steel and the like can be reduced, and economical design can be achieved.

Since the tensile resistance member is used only in the minimum necessary area, the increase in the amount of steel material as the tensile resistance member can be suppressed to the minimum.

[Brief description of drawings]

1 and 2 are a plan view and a longitudinal sectional view of a frame showing an embodiment when the present invention is applied to a dome, FIG. 3 is a plan view showing a comparative example, and FIGS. 4 to 7 are books. An embodiment in which the invention is applied to a thrust shell type three-dimensional frame is shown. FIGS. 4 and 5 are perspective views and plan views of the frame, and FIGS. 6 and 7 are longitudinal sectional views and 8 and 9
The figure is a perspective view showing an example of a lattice in a three-dimensional frame to which the present invention is applied, and FIGS. 10 to 12 show an example when the present invention is applied to a four-sided folded plate type three-dimensional frame. , First
Figures 10 and 11 are perspective and plan views of the frame, Figure 12
The figure is a longitudinal sectional view. DESCRIPTION OF SYMBOLS 1 ... Rod material, 2 ... Node, 3 ... Tensile resistance member, 4 ... Ring frame, 11 ... Truss frame material

Claims (1)

[Claims] 1. A three-dimensional frame structure in which rods in two directions connecting the node members have a mesh of grids that are substantially orthogonal to each other, are supported in the vertical direction in the periphery, and are allowed to be displaced in the horizontal direction. From the nodal displacements calculated under the specified load and supporting conditions, the internodal displacement Δ is calculated by the following equation (1), and Δ = (DX _j −DX _i ) · 1 _ij + (DY _j −DY _i ) ・ m _ij ＋ (DZ _j −D
Z _i ) ・ n _ij … (1) (However, DX, DY, DZ: Node displacement l, m, n: Direction cosine of the straight line connecting the nodes) One or more that the displacement Δ between the nodes is a positive value A three-dimensional frame structure characterized in that a tensile resistance member is interposed in a part or all of only between the nodes.