JPH0765294B2 - Cable-stayed bridge - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cable-stayed bridge.

[Prior art]

A cable-stayed bridge is one in which the main girder is suspended from the main tower by means of diagonal timber. Conventionally, various shapes have been adopted as the shape of the main tower. For example, an A-type main tower whose width becomes smaller as it goes upward, a gate-type main tower with the same upper and lower widths, and an inverted Y-type tower in which the lower part is divided into two but the upper part is narrowed to one. A main tower or a main tower whose upper part is inclined in a V shape has been developed.

[Problems to be Solved by the Invention]

Many of such conventional main towers have a shape in which the upper part is vertical or narrowed inward in the width direction of the main girder. Therefore, when the main girders are suspended by the diagonal members stretched from these main towers, the diagonal members extend along the widthwise side ends of the main girders.

Even when the main tower is inclined in a V shape, the upper end of the diagonal member is concentrated on the top of the main tower, and the inclination angle of the diagonal member is large, and such diagonal member has the largest effect on the central portion of the main girder. It cannot effectively resist the earthquake force. That is, when the seismic force in the direction orthogonal to the longitudinal direction of the main girder acts horizontally,
Little to bear the force in the orthogonal direction.

An object of the present invention is to provide a cable-stayed bridge with good seismic resistance that can effectively resist the force in the orthogonal direction acting on the main girder due to an earthquake.

[Means for Solving the Problems]

A cable-stayed bridge according to the present invention is a cable-stayed bridge in which a main girder is suspended by diagonal members stretched from a main tower that is erected at a predetermined interval, and the main girder is arranged on the base of the main tower. The upper and lower parts of the tower are curved in a curved shape so that they are separated from each other by a certain distance as they go upward, and the upper parts of the tower are connected by beams, and a predetermined distance is provided from the upper part of the tower to the main girder below. A diagonal member is stretched in front of the main girder so that a large tensile force is exerted on the stretched diagonal member in a direction orthogonal to the main girder.

〔Example〕

The present invention will be described in detail below based on an embodiment shown in the drawings.

In the figure, reference numeral 1 is a main tower, and a plurality of towers are erected at predetermined intervals. In FIG. 1, a main girder 4 is arranged at the center on the base of the main tower 1, and the upper and lower members are curved in a curved shape so as to be separated from each other by a certain distance as the left and right sides of the main girder 4 go upward. 2,2 are formed. Therefore, the main tower 1 is formed so as to project in the width direction as it goes upward, and the upper end portions of the tower upper portions 2, 2 are projecting portions A.
A beam 3 is connected between the upper parts 2 and 2 of the two towers.

A plurality of diagonal members 5 stretched from the tower upper part 2, 2 are connected and hung up. The diagonal members 5 are connected to each other at a predetermined interval in the longitudinal direction of the main girder 4, and the diagonal members 5 stretched from the overhanging portions A, A, which are the upper ends of the upper parts 2, 2, are the main towers 1. It is connected to the middle part away from.

As described above, the overhanging portions A, A are portions that largely extend to the left and right in the width direction of the main tower 1, and extend to the left and right more than the width of the main girder 4. Therefore, the slant members 5 stretched from the overhanging portions A, A are attached to the main girder 4 at an angle intersecting from the left and right of the main girder 4 in the width direction.
Connected to. In this way, the diagonal members 5 connected from the left and right in the width direction of the main girder 4 have a configuration in which they are greatly inclined toward the central portion of the main girder 4, and are in a direction orthogonal to the main girder 4 acting on the middle portion of the main girder 4. The force can be received by the pulling force of the diagonal member 5 which is inclined corresponding to the magnitude of the force. Therefore, the seismic force acting on the main girder 4 can be received by the tensile force of the diagonal member 5, resulting in a cable-stayed bridge with great earthquake resistance.

〔The invention's effect〕

This invention arranges a main girder on the main tower base, forms a tower upper part that is curved in a curved shape so as to be separated by a certain amount or more from both sides of the main girder as it goes upward, and divides into two forks, and The upper parts are connected by beams, and diagonal members are stretched from the tower upper part to the lower main girders with a predetermined interval, and the horizontal direction in the direction orthogonal to the main girders extends to the center of the main girders. Since it is arranged so as to exert a large tensile force, the horizontal tensile force of the diagonal member to the main girder can be exerted to the central part of the main girder, and the earthquake in the orthogonal direction acting on the main girder can be applied. Since the force is received by the tensile force of the diagonal member corresponding to the magnitude of the seismic force, the force acting on the main girder is reduced and the cable-stayed bridge has good earthquake resistance.

Furthermore, since the upper part of the main tower is curved in a curved shape, it is formed so that the left and right widths are apart from each other by a certain amount or more and wide open as it goes upward, so that stress is transmitted in an arch-like manner, and it is a bifurcated branch. There is no stress concentration and the main tower can be overhanged in the direction orthogonal to the main girder at the same tower height in the same tower height, as compared with the case where the main tower is simply slanted.

[Brief description of drawings]

FIG. 1 is a perspective view of a cable-stayed bridge of the present invention, and FIG. 2 is a plan view thereof. A: Overhang, 1 ... Main tower, 2 ... Top of tower, 3 ... Beam, 4 ... Main girder, 5
... diagonal materials.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kei Suzuki, 1-2-7 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. (56) Reference JP-A-51-85239 (JP, A) JP Sho 60-261811 (JP, A) Japanese Patent Sho 44-27783 (JP, B1) Actual Sho 36-33755 (JP, Y1)

Claims (1)

[Claims] 1. In a cable-stayed bridge in which a main girder is suspended from a main tower which is erected from a main tower that is erected at a predetermined distance, the main girder is arranged on the base of the main tower, and the space between the main girders on both sides is left and right. Are curved at a certain distance as they go upwards to form a bifurcated upper part of the tower, and the upper part of the tower is connected by a beam, with a predetermined distance from the upper part of the tower to the lower main girder. A cable-stayed bridge, in which members are stretched and arranged so as to exert a large horizontal tensile force in a direction orthogonal to the main girder on the stretched diagonal member toward the center of the main girder.