JPH02232484A - Air film structure roof - Google Patents

Abstract

PURPOSE:To unify shapes and dimensions of film panels rationalize production by extending the film panels further to concentric circle cables of the central part without discounting immediately at the intersections with the concentric circle cables in case of thinning-out. CONSTITUTION:When air film construction cables composed of concentric circle cables 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. Accordingly, by adopting the method of forming multistage ring shaped equal ruled-off square division zones, allowable stress intensity of film materials c can be demonstrated to the maximum, the number of different kinds of panels are lessened to reduce the manufacturing number of film panels, manufacturing dimensions of the film panels are unified, and economical production can be achieved.

Description

[Detailed description of the invention] This invention relates to an air membrane structure roof.

An air membrane structure is a structure in which cables are crossed over the roof surface and stretched in a net shape, and the membrane material is fixed to the squares around the four sides of the roof.When the membrane material has been applied to the roof surface, air is released into the room. and increase the indoor air pressure to 0.0 below atmospheric pressure.
This is an air support structure that inflates the roof surface at a pressure of about 0.025 atm (25 kg/ft), and the conventional technology for arranging its cables is often in two directions.

This two-way arrangement is the most convenient cable arrangement in the United States as a method to minimize bending stress on the combination ring as a boundary structure when the plan shape of the building is rectangular or super elliptical. It was adopted as

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 although the membrane sections created with two-way cable arrangement have the same dimensions on the projected plane, the roof has a curved surface, so each membrane panel actually manufactured has a slightly different dimension. are different.

In order to solve this problem, there is a case in the United States where the dimensions of IIW production were purposely standardized, but in this case the roof did not have the expected curved surface, but instead became flat, and when it snowed, snow accumulated in the center and the roof fell down. There was an accident in which the panels were built after that, and after that, the conventional method was used again, and instead of standardizing the dimensions of the R-root panels, they were manufactured one by one based on predetermined dimensions and shapes.

The second example is a case in which two-way cables were placed on the entire roof surface, but the cable length is shorter in the peripheral area and the cable tension does not increase, so the peripheral cable is omitted and the number of cables is reduced. are increasing. This has the advantage of reducing roof construction costs and roof weight, but judging from the material strength of the membrane material, the diamond-shaped part in the center can reduce membrane stress in two directions. On the other hand, 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 section 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 was made in view of the above-mentioned problems, and its gist is that cables are arranged radially and concentrically, and the radial cables arranged at the periphery are Installed so as to thin out the
In the cable arrangement where membrane material is attached to the square sections formed by these cables, when thinning out the cables, the cables are not cut off immediately at the intersection of the seven concentric cables, but are further extended to the concentric cable in the center and fixed. The shape and dimensions of the panels should be unified as much as possible, and the number of membrane panels should be reduced by 1 per roof area, in order to rationalize and make production more economical, and to make maximum use of the allowable stress of the membrane and cables. However, the membrane has a considerable negative biaxial stress #! 1
It is characterized by using cables of the same size so that the tension can be shared evenly.
．． From here on, this is detailed numbered based on the figure. 9. In other words, in the United States, there are many stadiums with roofs built for sports such as funtoball, and the planar shape is often rectangular or super elliptical, but in Japan, baseball is the main sport, so It often has a nearly circular underside.

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

However, such concentric and radial cables b,
In the case of a distribution, 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 distance between the radial cables a becomes narrower, and the membrane The area of the membrane 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 attachments and attachments between the cable and the membrane material increases unnecessarily. , it becomes uneconomical.

For this reason, regarding the air membrane structure cable arrangement constituted by the concentric cables b and the radial cables a, the radial cables a are thinned out in the center, and the cable sections in the center are made into appropriate sections.

Note that O in the figure indicates a combrenotion 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 becomes possible to produce economically.

When implementing what is shown in FIG. 2, it may be necessary to provide a reinforcement method J1 that meets each design condition before putting it into practical use.

The first reason is that among cables arranged radially and concentrically, in the case of radial cables, as the cables arranged at the periphery move towards the center, the distance between the gables becomes denser. , it is rational to thin out the number of radial cables, but when actually thinning out radial cables, in order to transmit the tension at the end of the thinned-out cable to the concentric cable, it is necessary to thin out the concentric circle using a restraining metal fitting with a considerably large restraining force. Unless the cable is fixed to the cable, the end of the cable cannot be restrained, and a joining method using such a large restraint hardware is impractical.

The second reason is that when the radial cable and concentric cable are joined in a T-shape, the stress state applied to the membrane material is different from the membrane stress of the two-way cable net method used in a normal air membrane structure. , considerable concentrated stress acts on the membrane material on the opposite side of the thinned-out radial cable terminal, causing a result different from the initial intention of equalizing stress in the membrane material, resulting in L2. 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 shown in Fig. 3, this process involves not immediately terminating the thinned out radial cable a' at the intersection with the concentric cable b, but extending it further to the concentric cable b in the center as an extension cable e and fixing it. Try to disperse the tensile force.

The purpose of the extension cable e is to process the cable tension in stages, and the extension cable e does not subdivide the crotch 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, the stress treatment at the end of the thinned radial cable a' becomes smooth, and excessive stress during construction does not act on the membrane stress.

In addition, in order to manage the stress at the center, a radial cable a is connected from the outermost circumference to the concentric cable at the innermost core.
may be further extended and converged at the center point O.

[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 air membrane structure roof of the present invention. DESCRIPTION OF SYMBOLS 1... Membrane, 2... Cable net, a... Radial cable, a'... Radial cable, b.
...Concentric cable, C...Membrane material, e...
extension cable. Buzowo Azu

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. Cable arrangement on an air membrane structure roof, characterized in that when thinning out cables, the cables are not cut off immediately at the intersection with the concentric cable, but are further extended and fixed to the concentric cable in the center. .