JP3284366B2 - Flexible arch construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible arch construction having a high degree of freedom in shell shape.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for incorporating sunlight into a large building space to obtain a comfortable space under natural light. In response to such demands, there are attempts to provide a stairwell in a high-rise building so that a top light can be obtained, or to form an atrium space as a part of the building.

[0003]

As described above, when designing a structure that can receive sunlight, the design image of the structure is considered to be a transparent frame and a free shape. Often. However, the structural system adopted for constructing this structure is usually a space truss, so the number of members is large, and the structure is crowded together with the sash. It was different.

In view of the above circumstances, it is an object of the present invention to provide a structure that covers a space without using many members as in the case of a space truss. The purpose is to obtain a space to take in natural light with a high structure.

[0005]

Means for Solving the Problems The present invention has been made in consideration of the problems described above, one end and the pin fulcrum to the installation surface is installed at the other end as the roller supporting point, the vertical direction
For an arch frame having a plurality of bent portions, a bundle extending downward from each of a plurality of arbitrary points of the arch frame is fixed, and a tension member stretched along a longitudinal lower portion of the arch frame. Connected to each of the bundles, with the same connection angle between the tension member and the bundle from the connection point of the tension member in each of the bundles, and at the fixed point of the bundle, an equal distribution applied over the longitudinal direction of the arch frame A flexible arch construction method characterized by having a configuration in which a bending moment due to a load and a bending moment at a fixed point where the tension of the tension member is applied to the bundle are equal to each other and cancel each other, It is to solve the problem that has been done.

[0006]

As shown in FIG. 3A, one end of the arch frame 1 of any frame shape is
When the other end is set as the roller fulcrum 3 and the interval between them is set as l, an evenly distributed load ω is applied, so that the bending moment dM gives dMb
= Ωl ^2/8 and b point on the arch frame 1 is maximized made, other points a point of the arch frame 1, moments dM bending at the point c is also determined.

In order to minimize the bending moment dM generated in the arch frame 1, a prestress is introduced into the arch frame 1 to generate an upward stress state as shown in FIG. It can respond by doing. That is, the bending moments dMa, dMb, and dMc on the lower side at the points a, b, and c shown in FIG. 3A are different from the bending moments pMa, pMb on the upper side due to the introduction of the prestress. , PMc, pMa = dMa, pMb
= DMb, pMc = dMc.

By doing so, (c) of FIG.
As shown in (1), the bending moment dM toward the lower side and the bending moment pM toward the upper side cancel each other, and a state is obtained in which the bending moment is zero and only the axial force is applied. For this reason, by making the arch frame 1 have high strength and rigidity with respect to the axial force, a rational structure system can be obtained.

In the present invention, as shown in FIG. 1, a tension T from a tension member 6 is applied to connection points 5a, 5b,... Of bundles 4a, 4b,. , Each point (fixed point) a point, b point, ...
The bending stress state at is pMa = la · T = dMa, pM
b = lb · T = dMb,... (1 is the length from the fixed point of the bundle to the connection point), and each point is introduced by the introduction of the prestress caused by the tension T from the tension member 6 applied to the bundle. (Fixed point) The bending moments at points a, b,... Become zero. In other words, the bending moment caused by an evenly distributed load (self-weight of the arch frame member) applied along the longitudinal direction of the arch frame and the bending moment caused by the tension from the tension member applied to the bundle are balanced and cancel each other. It becomes zero.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail based on one embodiment shown in FIGS. The structural body 10 is constructed by using a plurality of arch frames 1 provided so as to obtain a required arch shape as structural members , and is illustrated.
With multiple bends that bend vertically.
And, in each of which arch frame 1, one end and the pin fulcrum 2 to the installation surface is installed at the other end as the roller supporting point 3. And in the arch frame 1,
Bundles 4a and 4b extending downward are fixed to a plurality of appropriately set points a and b, respectively, and a tension member 6 made of a cable stretched along the longitudinal lower side of the arch frame 1 is provided. The bundles 4a, 4b are connected to the connection points 5a, 5b at the respective ends. The bundles 4a and 4b are adjustable in length and provided so that their lengths can be changed. Although FIG. 1 shows a state in which the bundles 4a and 4b are extended downward from the respective points a and b as fixed points, the same applies to parts not shown.

In each bundle, the connection angle with the tension member 6 in two directions from the connection point is provided to be the same (θa = θa ′, θb = θb ′). Have been added. Thereby, the upward bending moment pMa, at the fixed points a, b,
pMb is expressed as pMa = la · T, pMb = lb · T (l
a, lb are the lengths of the bundles 4a, 4b), and the upward bending moments pMa, pMb are pMa = dM
a, pMb = dMb, that is, la · T
= DMa, lb · T = dMb is the connection point 5a,
The length of the bundles 4a and 4b is adjusted so as to be 5b. As described above, the bending moment is set to zero at each of the fixed points of the plurality of bundles provided on the arch frame 1.

[0012]

As described above, according to the present invention,
It is installed with one end as a pin fulcrum and the other end as a roller fulcrum with respect to the installation surface, and has multiple bends that bend vertically.
For the arch frame, a bundle extending downward from each of a plurality of arbitrary points of the arch frame is fixed, and a tension member stretched along a longitudinal lower portion of the arch frame is connected to each of the bundles. From the connection point of the tension member in each bundle, the connection angle between the tension member and the bundle is the same, and at the fixed point of the bundle, a bending moment due to an evenly distributed load applied in the longitudinal direction of the arch frame,
The present invention is characterized in that the bending moment at a fixed point where the tension of the tensile material is applied to the bundle is equal to the bending moment at the fixed point, and the bundle is canceled.

As a result, the degree of freedom of the shape of the arch frame is increased, that is, the degree of freedom of the shape of the structure is increased, so that it is possible to cope with a design image. Also, when designing a structure that covers the space, bend the part that bends vertically.
An arch frame having a plurality of irregular shapes can be regarded as an element of a complete axial resistance system that resists an axial force. In addition, it becomes easier to cope with a concentrated load when a speaker or the like is suspended, and horizontal thrust can be eliminated, so that the lower structure is simplified and economical. The small number of members in comparison with the structure, such as a conventional three-dimensional truss and so comfortable that the inner surface side and clean can be obtained, in which excellent effects in practical use.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a main part of an embodiment of a flexible arch construction method according to the present invention.

FIG. 2 is an explanatory diagram showing an arch frame according to one embodiment.

FIGS. 3A and 3B are explanatory diagrams showing the concept of canceling a bending moment. FIG. 3A shows a downward bending moment due to an evenly distributed load, and FIG. 3B shows an upward bending moment due to the introduction of prestress. (C) shows a state in which the bending moment has been canceled.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Arch frame 2 ... Pin fulcrum 3 ... Roller fulcrum 4a, 4b ... Bundle 5a, 5b ... Connection point 6 ... Tensile material a, b ... Fixed point 10 ... Structure

Claims (1)

(57) [Claims] 1. A bend which is installed at one end with a pin fulcrum and the other end with a roller fulcrum with respect to an installation surface, and bends vertically.
A bundle extending downward from each of a plurality of arbitrary points of the arch frame is fixed to an arch frame having a plurality of portions , and a tension member stretched along a longitudinal lower portion of the arch frame is fixed to each of the bundles. The same angle of connection between the tension member and the bundle from the connection point of the tension member in each of the bundles, and bending at a fixed point of the bundle by an evenly distributed load applied in the longitudinal direction of the arch frame. A flexible arch construction method, wherein a moment and a bending moment at a fixed point where the tension of the tension member is applied to the bundle are equal to each other to cancel each other.