JPH07216820A - Arched bridge - Google Patents

Abstract

PURPOSE:To improve the constructing performance of a bridge by changing the stiffening girder of the bridge for an arch member so as to impart tension to the stiffening girder largely influenced by bending force. CONSTITUTION:An arch member 1 is suspended and held through cable members 2 stretched obliquely from a pair of towers 3, 3 serving as erection members, and the arch members 1 thus suspended from the respective towers 3 are connected to each other. After the completion of construction, the respective towers 3 and cables 2 are left as permant construction members. Flexural shearing force is hardly generated to the parabolic arch member 1 receiving distributed load and the active load of autombobiles and the like. and resisted mainly by the tension of the arch member 1. The tension of the arch member 1 is partially transmitted to the towers 3 through the cables 2. Inner surface buckling caused by tension is coped with by the rigidity of the cables 2, and the rise of the arch member 1 is also lowered by the cables 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arch bridge structure.

[0002]

2. Description of the Related Art As a conventional structural type of a bridge, as shown in FIG. 7, an arch-shaped stiffening member a made of a parabolic line-shaped or arc-shaped chord member and an axial force member b are used to construct a bridge surface A An arch-type bridge that bears the load from the bridge, a stiffening girder d is diagonally hung by a cable e from a tower c as shown in FIG. A cable-stayed bridge that supports the load from A is common.

[0003]

However, in the former arch type bridge, the arch rise becomes higher as the span becomes longer, which is practically difficult to apply to the bridge having a span exceeding 200 m. In the latter cable-stayed bridge, the bending moment acts on the stiffening girder, and the effect of the cable is relatively small, so the economic effect is low.

Further, in terms of construction, when constructing an arch-type bridge, as shown in FIG. 5, a tower c and a cable e are used to diagonally suspend each half of both sides of the arch, and to erect the half of each arch by erection. The hanging method is generally used, and it is uneconomical because the inner erection structure portion B composed of the tower c and the cable e is not left up to the completed system. The present invention has been proposed in view of the above problems of the prior art, and the object of the present invention is to provide an arch-type bridge with improved workability, structurally rational and economically superior. It is in.

[0005]

In order to achieve the above object, in an arch bridge according to the present invention, an arch-shaped stiffening girder is arranged between a pair of opposing main towers which also serve as a erection member. In addition, a main cable, which also serves as a erection member, is stretched in an oblique direction between the stiffening girder and each of the towers.

[0006]

According to the present invention, as described above, by forming the stiffening girder, which has hitherto been largely affected by the bending moment due to the vertical load, into an arched shape, an axial force is introduced into the stiffening girder to prevent arch rise. It can be kept low, which is structurally advantageous. Moreover, since the arch-shaped stiffening girders are obliquely hung between the opposing towers via the cables, the buckling prevention effect by the rigidity of the cables is expected with respect to the in-plane buckling of the arch-shaped stiffening girders. .

Further, when the arch-shaped stiffening girder is installed, the diagonal suspension method is applied by utilizing the tower and the cable. When the installation of the arch-shaped stiffening girder is completed, the tower and the cable are installed. It is advantageous from the standpoint of construction as well as the economic aspect by leaving the above as it is and making it a permanent member.

[0008]

The present invention will be described below with reference to the illustrated embodiments. 1 and 2 show a first embodiment of the present invention,
Reference numeral 1 denotes an arch member formed between the towers 3 and 3 facing each other and formed in a parabolic line shape. The arch member 1 is provided with a cable 2 obliquely arranged between the tower 3 and the towers 3. It is suspended obliquely from 3. In the drawing, 2'is a stay cable for each tower, 5 is an anchor of the cable 2 ', and 4 is a bridge work such as a road work.

The parabolic wire-shaped arch member which receives the distributed load or the live load such as an automobile does not generate bending shearing force and resists mainly by the arch member axial force. Part of the axial force of this member is transmitted through the cable 2 that is stretched obliquely to the tower 3
The in-plane buckling due to the axial force of the arch member 1 is countered by the rigidity of the cable 2, and the rise of the arch member 1 is reduced by the cable 2 so that the arch member 1 can be extended and supported. Yes, an efficient structural system is constructed.

When the arch member 1 is installed,
The arch member 1 is suspended from both towers 3 via a cable 2 and held, and the arch members suspended from the respective towers 3 are closed. After completion of the construction, the respective towers 3 and cables 2 are permanently installed. Leave it as is. FIG. 3 shows a second embodiment of the present invention, in which the tower 3 is composed of an inclined tower. FIG. 4 shows a third embodiment of the present invention, in which a cable 2 is stretched between a tower 3 and arch members 1 on both sides of the tower 3. 6 (a) and (b) as well as (c) show a cable-stayed bridge with a span of 200 m and a conventional arch bridge as well as the arch bridge according to the present invention. According to the present invention, arch materials having the same cross section are used. It was shown that the arch rise was significantly reduced under the same load condition.

[0011]

As described above, according to the present invention, the stiffening girder of the bridge is formed of an arch member, so that the axial force is introduced into the stiffening girder, which has been largely affected by the bending force.
Since the cross section of the member is reduced and the cable is stretched obliquely between the stiffening girder composed of the arch member and the tower,
The rise of the arch member can be lowered by the cable rigidity, and the rigidity of the cable can be expected in terms of preventing in-plane buckling due to the axial force of the arch-shaped stiffening girder.

When the stiffening girder is erected, the arch members are suspended and held by using the tower and the cable as in the conventional oblique suspension construction method, and the arch members are closed to form an arch-shaped stiffener. The rigid girder is completed, and after the completion, the tower and the cable are used as members for permanent installation to improve workability.

[Brief description of drawings]

FIG. 1 is a side view showing a first embodiment of an arch bridge according to the present invention.

FIG. 2 is a central sectional view of FIG.

FIG. 3 is a front view showing a second embodiment of the arch bridge according to the present invention.

FIG. 4 is a front view showing a third embodiment of the arch bridge according to the present invention.

FIG. 5 is an explanatory diagram showing a method of constructing an arch bridge by an oblique suspension method.

6 (a), (b) and (c) are explanatory diagrams showing an example of dimensions of a main portion of a cable-stayed bridge and a conventional arch bridge in a bridge with a span of 200 m, as well as the arch bridge according to the present invention. Is.

FIG. 7 is a front view showing a conventional arch bridge.

FIG. 8 is a front view showing a conventional cable-stayed bridge.

[Explanation of symbols]

 1 Arch member 2 Cable 2'Stay cable 3 Tower 4 Bridge surface work 5 Anchor

Claims (1)

[Claims] 1. An arc-shaped stiffening girder is arranged between a pair of opposing main towers that also serve as a erection member, and a book that also serves as a erection member between the stiffening girder and each of the towers. An arch-type bridge, which is constructed by stretching the installed cables in an oblique direction.