JPS58522B2 - pipe bridge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pipe bridge installed in a suspension bridge type or the like for transporting water, gas, oil, etc.

When an object with a circular cross section is placed in a fluid such as water or air, Karman vortices are periodically generated on the downstream side of the object, and the forcing force of these vortices can cause the object to vibrate. This is known and has been experimentally confirmed.

Examples of the object include the above-mentioned pipe bridge.

Since pipe bridges are installed at relatively high places, they are extremely susceptible to the effects of wind, and the vortices described above generate a large amount of vibration.

Therefore, in the past, a major problem in pipe bridges was how to suppress the influence of wind, that is, the vibration caused by wind.

This invention has been made to solve the above-mentioned problems, and includes a plurality of rectangular flat plates arranged at an interval from the pipe bridge at the upper or lower part of the pipe bridge, and arranged along the central axis of the pipe bridge. It is characterized by being horizontally fixed at intervals in the direction of the central axis, symmetrically with respect to a vertical line passing through the center axis.

The present invention will be described by way of examples with reference to the drawings.

FIG. 1 is a partial perspective view of an embodiment of the invention, and FIG.
It is a front view of the same.

As shown in FIGS. 1 and 2, the pipe bridge 1 of this embodiment has a plurality of rectangular flat plates (width a) on its upper part spaced apart from the center axis 3 of the pipe bridge 1 by a distance e.

The length b)2 is fixed horizontally at intervals g in the direction of the central axis 3, symmetrically with respect to the vertical line Y-Y' passing through the central axis 3.

FIG. 3a shows that the pipe bridge 1 configured as described above has a first
Pipe bridge 1 when wind is blown from the direction indicated by the arrow in the figure
The results of the flexural vibrations that occur in the conventional example, that is, the results of the flexural vibrations that occur in a pipe bridge in which a net-like walkway member is continuously provided along the pipe axis direction on the top of the pipe bridge, are shown together with the results of the flexural vibrations that occur in the pipe bridge. The figure shows the results of torsional vibration.

In this experiment, the diameter d of the pipe bridge 1, the distance e between the rectangular plate 2 and the horizontal line x-x' passing through the central axis 3 of the pipe bridge 1, the width a and length b of the rectangular plate 2, and the The relationship with the interval g was as follows.

e/d:0.72. a/d: 0.83. b/d: 4.1
．． , g/d: 4.1 As is clear from FIGS. 3a and 3b, the pipe bridge of the present invention does not generate any flexural vibration or torsional vibration, and is not affected by wind at all.

In the above example, the rectangular flat plate 2 is fixed to the upper part of the pipe bridge 1, but the same effect can be obtained even if the flat plate 2 is fixed to the lower part of the pipe bridge 1 in the same manner as in the above example.

In addition, in reality, as shown in FIG.
A net-like walkway floor member 4 is installed between them.

As described above, it has been confirmed through experiments that even if the floor member 4 is attached between the flat plates 2, it does not cause flexural vibration or torsional vibration.

As explained above, according to the present invention, bending vibrations and torsional vibrations caused by wind do not occur, and since a rectangular flat plate for vibration prevention can be used as a part of the floor member for the walkway, installation of the walkway is facilitated. It brings about useful effects such as being able to do things.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view of an embodiment of the invention, and FIG.
The same front view, FIG. 3a is a diagram showing the relationship between wind speed and deflection, the same diagram is a diagram showing the relationship between wind speed and twist angle, and FIG. 4 is a diagram showing another embodiment of the present invention. FIG. In the drawings, 1...pipe bridge, 2...flat plate, 3...center axis, 4...floor member.

Claims (1)

[Claims] A plurality of rectangular flat plates are arranged on the upper or lower part of the pipe bridge at intervals from the pipe bridge, symmetrically with respect to a vertical line passing through the center axis of the pipe bridge, and spaced apart in the direction of the center axis. A pipe bridge characterized by being fixed horizontally.