JPH02232483A - Air film structure roof - Google Patents

Abstract

PURPOSE:To unify shapes and dimensions of panels as many as possible to rationalize production by expanding and dividing a thinned-out radial cable into two in a nonfixation state with respect to film materials to expand, and fixing next adjacent radial cables to parts intersecting with concentric circle cables. CONSTITUTION:When air film structure cables composed of concentric circle cable b' and radial cables a' are arranged, the radial cables a' are thinned out at the central part of them, and cable divisions of the central part are proper divisions. The thinned-out radial cables a' are divided into two expansion cables d to d to expand, and they are fixed to parts where next adjacent radial cables a or a' are intersected with the concentric circle cables b. Stress treatment in terminals of the cables a' is smoothly made, and excessive concentrated stress does not also impose on film stress.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air membrane structure roof. The air membrane structure is made by crossing cables on the roof surface and stretching them in the shape of a net, and then fixing the membrane material around the squares of the grid on all four sides. is introduced, and the indoor air pressure becomes 0.0 below atmospheric pressure.
This is an air support structure that inflates the roof surface by about 0.025 atm (25 kg/ffl), and the conventional technology for cable arrangement is often two-way arrangement.

In the United States, this two-way arrangement is the most convenient cable arrangement when the building has a rectangular or super-elliptical plan shape, as it minimizes bending stress on the compression ring as a boundary structure. It was adopted.

There are over a dozen examples of this two-way cable in the United States, and it has been gradually improved with each building, but some problems remain.

Firstly, with an air support structure that obtains a balanced curved surface by internal pressure, the shape is easily changed by wind or snow after the shape is determined, as shown in Figure 1. Geometric nonlinear analysis must be performed under conditions that maintain balance, but the membrane panels attached to the compartments made of these two-way cables are mostly manufactured in different shapes, and it is difficult to manufacture the same product in mass production. It is not possible to do so, and the production costs are relatively high. The reason for this is that the membrane sections created with two-way cable arrangement have the same dimensions on the projected plane, but since the roof has a curved surface, each membrane panel actually manufactured has slightly different dimensions. They are different.

In order to solve this problem, there is a case in the United States where the dimensions of membrane production were intentionally standardized, but in this case, the roof did not have the expected curved surface but became flat, and when it snowed next door, snow accumulated in the center and the roof fell down. There was an accident in which the roof panels were damaged, and after that, the conventional method was used again, and instead of standardizing the dimensions of the roof panels, each roof panel was manufactured one by one based on the predetermined dimensions and shape.

Second, there were cases in which two-way cables were placed on the entire roof surface, but the cable length was shorter in the peripheral area, and the cable tension was not large, so the peripheral cable was omitted to reduce the number of cables. are increasing. This has the advantage of reducing roof construction costs and roof weight, but on the other hand, judging from the material strength of the membrane material, the diamond-shaped part in the center can bear membrane stress in two directions. The rectangular portion at the periphery bears membrane stress in the short side direction.

Therefore, in the rectangular part, the membrane material is designed based on the uniaxial allowable stress of the membrane material, and when using the same membrane material,
The membrane panel in the diamond-shaped part is over-designed. Third, although this two-way cable arrangement is approximately equally spaced, in very large roof areas, the maximum wind load on the roof surface will also vary depending on the roof area, and the membrane panels cannot be under the same stress.

This results from the two-way equally spaced cable arrangement.

The present invention has been made in view of the above-mentioned problems, and its gist is to arrange cables radially and concentrically, and to thin out the number of radial cables arranged at the periphery toward the center. In the cable arrangement in which the membrane material is attached to the square sections formed by these cables, the thinned out radial cables are stretched in half without being fixed to the membrane material, and the adjacent By fixing the next radial cable at the point where it intersects with the concentric cable, the shape and dimensions of the membrane panels are unified as much as possible, and the number of membrane panels is reduced relative to the roof area, in order to rationalize and make production more economical. In order to make the most of the allowable stress of the membrane and cable, the membrane bears a considerable amount of biaxial stress, and the cables are of equal size, so that the tension can be shared evenly. This feature is described below in detail based on the drawings.

In other words, in the United States, there are many stadiums with roofs built for football games, etc., and the planar shape is often rectangular or super elliptical, but in Japan, where baseball is the main sport, stadiums with a roof are often built with a planar shape that is close to circular. often have.

Therefore, assuming this planar shape, it is possible to use both the radial cable a arrangement and the concentric cable b arrangement as shown in FIG.

However, such concentric and radial cables b,
With the arrangement a, the membrane panel dimensions can be set to maximize the allowable stress of the membrane material used at the circumference, but as it approaches the center, the spacing between the radial cables a narrows and the membrane Because the area is small, the existing stress of the membrane is small, and the strength of the membrane material cannot be utilized economically.In addition, the number of membrane panels increases, and the number of cables and mounting hardware for the membrane material increases unnecessarily, making it uneconomical. becomes.

For this reason, regarding the air membrane structure cable arrangement constituted by the concentric cable b and the radial gable a, the radial cable a is thinned out in the center, and the cable section in the center is made into an appropriate section.

Note that O in the figure indicates a compression ring as a boundary structure. By adopting this method of configuring the multi-stage ring-shaped uniform square partition zone, it is possible to maximize the allowable stress of the membrane material C, reduce the number of different types of panels, reduce the number of membrane panels produced, and reduce the number of membrane panels produced. By standardizing the manufacturing dimensions, it became possible to manufacture products economically.

When implementing what is shown in FIG. 2, it may be necessary to provide a reinforcing method that meets the requirements of each facility d1 for practical use.

The first reason for this is that among cables arranged radially and concentrically, in a radial cable, as the gables arranged at the periphery move toward the center, the distance between the adjacent sol becomes denser. It is reasonable to thin out the number of cables while taking into account the stress state, but when thinning radial cables with actual gap C, in order to transmit the tension at the end of each thinned cable to the concentric cable, Unless a considerably large restraining force is applied to the ゜ζ concentric cable by fixing it to the ゜ζ concentric cable using f'+slip restraining hardware, the end of the cable cannot be restrained, and joining method 2 using such large restraining hardware becomes unrealistic. That's true.

The second reason is that when the joint between the radial cable and the concentric cable is Ti-type joined, the stress state applied to the membrane material is different from the membrane stress of the two-way cape rene soto method used in the conventional air membrane structure. A considerable amount of concentrated stress acts on the membrane material on the opposite side of the thinned radial cable terminal, resulting in a result different from the initial intention of equalizing the stress in the membrane material. In order to solve this problem, it is necessary to rationally handle the tensile force generated at the end of the radial cable to be thinned out.

As this process, as shown in Fig. 3, the thinned out radial cable a' is divided into extension cables d and d and extended, and the next adjacent radial cable a or a' intersects the concentric cable b. Fix it in place. The purpose of the extension cable d is to process the cable tension in stages, and the extension cable d does not subdivide the membrane material C.
The cable is not fixed to the membrane material C, but extends and is restrained by itself to the next concentric cable b near the center.

By doing this, stress treatment at the end of the thinned radial cable a' becomes smooth, and excessive concentrated stress does not act on the membrane stress. Although not shown, the radial cable a connected from the outermost circumference to the concentric circular cable at the innermost core is further extended and connected to a beam at the center point in order to handle stress at the center.
It's okay if you get killed.

[Brief explanation of the drawing]

FIG. 1 is a roof curved surface diagram obtained by geometric nonlinear analysis, FIG. 2 is a plan view showing the basic configuration of the present invention, and FIG. 3 is a plan view showing the roof of the air section iS of the present invention. DESCRIPTION OF SYMBOLS 1... Membrane, 2... Cable net, a... Radial l-pull, a'... Radial cable, b...
・Concentric cable, C...Membrane material, d...Extension cable.

Claims (1)

[Claims] (1) Cables are arranged radially and concentrically, and the radial cables arranged at the periphery are thinned out in number toward the center, and the membrane material is installed in the square sections formed by these cables. In the cable arrangement, the thinned out radial cable is stretched in half without being fixed to the membrane material, and the next adjacent radial cable is fixed at the part where it intersects with the concentric cable. Features an air membrane structure roof.