JP2002266315A - Bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently increase fluttering limit wind velocity, and to improve flutter-resistant performance. SOLUTION: A wind flowing on the top face and underside of a box girder 2 is introduced into an opening section 4 and passes through the underside and top face of the box girder 2 in the case of the wind (the wind blowing up and the wind blowing down to a horizontal wind) or the like within a range of an elevation of ±3 deg. by the working of a central wind-shielding wall 6, an end-section wind-shielding wall 7 and an inspection-car rail 8. Accordingly, the pressure difference of the top face and underside of the box girder 2 is relaxed, self-excited aerodynamic force working to the box girder 2 can be reduced, and fluttering limit air velocity can be increased largely. Since the wide opening section is not required, pavement for a lane can be ensured sufficiently. Since wind velocity on the lane is reduced by the end-section wind- shielding wall 7, the traveling safety of a car can be ensured. Since the inspection-car rail 8 is used with an underside-side end-section wind-shielding wall in common, a structure is simplified so much, and a material for a bridge can be economized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bridge such as a long suspension bridge or a cable-stayed bridge, and more particularly to a bridge having a high flutter generation limit wind speed and excellent flutter resistance performance.

[0002]

2. Description of the Related Art For example, bridges such as long-sized suspension bridges and cable-stayed bridges have a low natural frequency of vertical bending and torsion, so that a wind speed at which a divergent vibration called flutter occurs (hereinafter referred to as a flutter generation limit wind speed). Tend to be lower. For this reason, as a cross-sectional shape of the bridge, a flat box-girder cross-sectional shape close to a flat blade having good dynamic aerodynamic characteristics is adopted. That is, the bridge has a box girder structure.

[0003]

However, even in the case of the bridge having a box girder structure having a flat box girder cross section, if the natural frequency is extremely low, the problem that the flutter occurrence limit wind speed is still low is still a problem. is there.

[0004] Therefore, for example, Japanese Patent Publication No. 3-65444.
A bridge described in Japanese Patent Application Laid-Open No. H11-280020 and a bridge described in Japanese Patent Application Laid-Open No. H11-280020 were previously filed.

In the former, a vertical opening is provided at the center of the box girder, and a vertical drift plate extending from the upper surface of the box girder to the lower surface of the box girder is provided through the center of the opening. . In the former, on the windward side, the flow of the wind is deflected by the deflector plate, and on the leeward side, the wind is prevented from adhering to the upper and lower surfaces of the box girder, and the self-excited aerodynamic force is suppressed. To increase the flutter occurrence limit wind speed.

In the latter, a wind shield wall having a structure through which wind passes is provided on the upper surface at the center of the box girder. In the latter case, the wind speed on the upper surface of the box girder is reduced in a state where a part of the flow of the wind passes through the wind shield wall, and the flutter occurrence limit wind speed is increased.

However, in the former, a relatively wide opening is required, so that pavement in a lane corresponding to the opening cannot be secured, and in the latter, the flutter occurrence limit wind speed is sufficiently high. There are issues such as not.

It is an object of the present invention to provide a bridge having a sufficiently high flutter generation limit wind speed and excellent flutter resistance performance.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, an opening is continuously or discretely formed in a central dividing portion of a box girder without invading a pavement portion. It is opened up and down, and on the top of the center of the box girder,
It is characterized in that a central wind shield wall is provided as a means for guiding air to the opening.

As a result, according to the first aspect of the present invention, the wind flowing on the upper surface and / or the lower surface of the box girder is guided to the opening by the central wind shield wall and escapes to the lower surface and / or the upper surface of the box girder. For this reason, the pressure difference between the upper surface and the lower surface of the box girder is reduced, the self-excited aerodynamic force acting on the box girder is reduced, and the limit wind speed at which flutter occurs is increased.

In particular, the invention according to claim 1 does not require a wide opening as compared with the conventional technique for preventing the wind from re-adhering to the upper and lower surfaces of the box girder. Therefore, the pavement for the lane can be sufficiently secured without invading the road. Further, the invention according to claim 1 can sufficiently increase the flutter occurrence limit wind speed, and is excellent in flutter resistance performance, as compared with the conventional technology of reducing the wind speed on the upper surface of the box girder.

According to a second aspect of the present invention, in the box girder, the opening is continuously or discretely opened in the vertical direction without invading the pavement portion. And a center wind shield wall and an end wind shield wall as wind guide means to the opening are provided on the upper surfaces of both ends, respectively.

As a result, according to the second aspect of the present invention, by the action of the central wind shield wall and the end wind shield wall, the wind flows on the upper and lower surfaces of the box girder in the case of the wind of the elevation angle +3 degrees (wind blowing up). The wind is guided to the opening and escapes to the lower and upper surfaces of the box girder. For this reason, the pressure difference between the upper surface and the lower surface of the box girder is reduced, the self-excited pneumatic force acting on the box girder can be reduced, and the flutter occurrence limit wind speed can be greatly increased.

In particular, the invention according to claim 2 has an effect that the wind speed on the upper surface of the box girder, that is, on the lane is reduced by the end windshield, so that the running safety of the vehicle can be secured. .

According to a third aspect of the present invention, the opening is formed vertically or continuously in the central divider band portion of the box girder without continuously or discretely invading the pavement portion. On the upper surface of both ends, a central wind shield wall and an end wind shield wall are provided as wind guide means to the opening, and an inspection car rail is laid on the lower surface of the box girder. Features.

As a result, according to the third aspect of the present invention, the wind in the range of the elevation angle ± 3 degrees (the wind blowing up against the horizontal wind) is formed by the action of the central windshield, the end windshield, and the inspection car rail. In this case, the wind flowing on the upper and lower surfaces of the box girder is guided to the opening and passes through the lower and upper surfaces of the box girder. For this reason, the pressure difference between the upper surface and the lower surface of the box girder is reduced, the self-excited pneumatic force acting on the box girder can be reduced, and the flutter occurrence limit wind speed can be greatly increased.

In particular, according to the third aspect of the present invention, since the inspection vehicle rail is also used as the lower end side windshield, the structure is simplified and the material of the bridge can be saved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Three embodiments of a bridge according to the present invention will be described below with reference to the accompanying drawings. In addition, this bridge is not limited by this embodiment.

(Embodiment 1) FIGS. 1 and 2 show Embodiment 1 of a bridge according to the present invention. In the figure,
Reference numeral 1 denotes a bridge such as a long suspension bridge or a cable-stayed bridge. In the drawings, a part is illustrated. The bridge 1 extends in a two-dot chain line direction.

The bridge 1 has a box girder structure. The cross section of the box girder 2 has, for example, a hexagonal flat box girder cross section. At both ends of the box girder 2, for example, a wind guide end 3 having a triangular cross section is provided.

At the center of the box girder 2, that is, only at the portion corresponding to the median strip, an air vent opening 4 is formed in the vertical direction. The opening 4 is provided continuously (or discretely) in the longitudinal direction of the bridge 1 without affecting the pavement portion. On the upper surface of the opening 4, a grating 5 is laid so as to be substantially flush with the upper surface of the box girder 2. The grating 5 may be laid on the lower surface of the opening 4 so as to be substantially flush with the lower surface of the box girder 2.

The box girder 2 blows wind into the opening 4.
There is provided an air guiding means for guiding the air to be removed. The wind guiding means includes a central wind shield wall 6 provided on a central upper surface of the box girder 2, an end wind shield wall 7 provided on both upper surfaces of the box girder 2, and a lower surface of the box girder 2. It consists of an inspection car rail 8 laid.

The central wind shield wall 6 is provided continuously (or discretely) in the longitudinal direction of the bridge 1 at the upper surface at the center of the box girder 2, that is, at the center of the upper grating 5 of the opening 4. Have been. This central windbreak wall 6 has a height of about 2
It is composed of an opening structure such as a punching plate of about 3 m.

The end windshields 7 are provided continuously (or discretely) in the longitudinal direction of the bridge 1 on the upper surface at both ends of the box girder 2, that is, at the portion corresponding to the balustrade of the bridge 1. Have been. The end windshield 7 has an opening structure such as a punching plate having a height of about 2 to 3 m, similarly to the central windshield 6. In addition, the end windshield 7
And the upper surface of the box girder 2 between the central windbreak wall 6 (upper grating 5) is a lane for traveling of the vehicle.

The inspection vehicle rails 8 are provided continuously on the lower surfaces of both ends of the box girder 2 in the longitudinal direction of the bridge 1. The inspection vehicle rail 8 is used for maintenance inspection and maintenance.

The bridge 1 according to the first embodiment is configured as described above, and its operation will be described below.

First, by the action of the central wind shield wall 6, the end wind shield wall 7, and the inspection car rail 8, the elevation angle of horizontal wind is ± 3.
In the case of a wind in the range of degrees (the wind of elevation + degree is a wind that blows up, while the wind of elevation -degree is a wind that blows down), the wind ( 2 (indicated by a dotted arrow in FIG. 2) is guided to the opening 4 and passes through the lower surface of the box girder 2. On the other hand, wind (indicated by a solid line → mark in FIG. 2) flowing on the lower surface of the box girder 2 is guided to the opening 4 and escapes to the upper surface of the box girder 2. Therefore, the pressure difference between the upper surface and the lower surface of the box girder 2 is reduced, and the self-excited pneumatic force acting on the box girder 2 can be reduced.

As described above, the bridge 1 according to the first embodiment can greatly increase the flutter occurrence limit wind speed in the case of winds within the range of the elevation angle ± 3 degrees. For example, an experimental result has been obtained in which a flutter limit wind speed is about 80 m / s or more for a suspension bridge having a central span of 2800 m.

The bridge 1 according to the first embodiment
Since the wind speed on the upper surface of the box girder 2, that is, on the lane is reduced by the end windshield 7, there is an effect that the traveling safety of the vehicle can be ensured.

Further, the bridge 1 according to the first embodiment
Since the inspection vehicle rail 8 is also used as a lower surface side end windshield, the structure is simplified and the material of the bridge can be saved. The first embodiment shown in FIGS. 1 and 2
Corresponds to claim 3.

Furthermore, the bridge 1 according to the first embodiment does not require a wide opening as compared with the conventional technique for preventing wind from adhering to the upper and lower surfaces of the box girder.
Therefore, the opening 4 does not affect the pavement,
The pavement for the lane can be sufficiently secured. That is, since the opening 4 is limited only to the median strip, it is possible to secure pavement in all lanes.
In addition, the bridge 1 according to the first embodiment can sufficiently increase the flutter occurrence limit wind speed and is excellent in flutter resistance performance, as compared with the conventional technology of reducing the wind speed on the upper surface of the box girder.

(Modification of First Embodiment) FIG. 3 is an explanatory diagram showing a modification of the first embodiment. In the drawing, the same reference numerals as those in FIGS. 1 and 2 denote the same components. This modification is shown in FIG.
2 and a lower surface side central windshield 9 at the center lower surface of the box girder 2, that is, at the center of the lower grating 5 of the opening 4, continuously in the longitudinal direction of the bridge 1 (see FIG. 2). Or (discretely). The lower-side central wind shield wall 9 has an opening structure such as a punching plate having a height of about 2 to 3 m.

FIG. 4 is an explanatory view showing a modification of the first embodiment. In the drawing, the same reference numerals as those in FIGS. 1 and 2 denote the same components. This modification is different from the bridge 1 shown in FIGS. 1 and 2 in that a lower end side wind shield wall 10 is provided on the lower surface of both ends of the box girder 2 continuously (or discretely) in the longitudinal direction of the bridge 1. ). The lower-side end windshield 10 is formed of an opening structure such as a punching plate having a height of about 2 to 3 m, like the lower-side central windshield 9.

FIG. 5 is an explanatory view showing a modification of the first embodiment. In the drawing, the same reference numerals as those in FIGS. 1 and 2 denote the same components. This modified example is different from the bridge 1 shown in FIGS. 1 and 2 in that the lower surface side central windshield 9 is provided at the center lower surface of the box girder 2, that is, the center of the lower grating 5 of the opening 4.
In addition, the lower surface side end windshield 10 is provided on the lower surface at both ends of the box girder 2.
, Respectively, continuously in the longitudinal direction of the bridge 1 (or
(Discretely).

The modifications shown in FIGS. 3 to 5 can achieve substantially the same functions and effects as those of the first embodiment shown in FIGS.

(Embodiment 2) FIG. 6 is an explanatory view showing Embodiment 2. In the drawing, the same reference numerals as those in FIGS. 1 and 2 denote the same components. Bridge 100 in Embodiment 2
Is obtained by removing the inspection car rail 8 from the bridge 1 shown in FIGS. 1 and 2.

That is, the upper surface at the center of the box girder 2 (the opening 4
At the center of the upper grating 5), a central wind shield wall 6 is provided continuously (or discretely) in the longitudinal direction of the bridge 100. Further, on the upper surfaces of both ends of the box girder 2 (portions corresponding to the balustrades of the bridge 1), end wind shield walls 7 are provided continuously (or discretely) in the longitudinal direction of the bridge 100. The central wind shield wall 6 and the end wind shield walls 7 are formed of an opening structure such as a punching plate having a height of about 2 to 3 m.

The bridge 100 according to the second embodiment includes:
With the above configuration, the operation will be described below.

First, due to the action of the central wind shield wall 6 and the end wind shield wall 7, as shown in FIG. 6, in the case of the wind (wind blowing up) W of the elevation angle + 3 ° θ with respect to the horizontal line HH. The wind (indicated by a dotted arrow in FIG. 6) flowing on the upper surface of the box girder 2 is guided to the opening 4 and escapes to the lower surface of the box girder 2. On the other hand, box girder 2
(Indicated by the solid line → mark in FIG. 6) flowing through the lower surface of the box girder is led to the opening 4 and escapes to the upper surface of the box girder 2. Therefore, the pressure difference between the upper surface and the lower surface of the box girder 2 is reduced, and the self-excited pneumatic force acting on the box girder 2 can be reduced.

As described above, in the case of the bridge 100 in the second embodiment, the wind speed at which flutter occurs is greatly increased when the wind is at an elevation of +3 degrees. For example, an experimental result has been obtained in which a flutter limit wind speed is about 80 m / s or more for a suspension bridge having a central span of 2800 m. Also,
An experimental result of about 60 m / s or more has been obtained in the case of a wind having an elevation angle of ± 3 degrees excluding the elevation angle of +3 degrees.

Further, the bridge 10 according to the second embodiment
0 is the upper surface of the box girder 2 due to the end windshield 7, that is,
Since the wind speed on the lane is reduced, there is an effect that the traveling safety of the vehicle can be ensured. Note that the second embodiment
Corresponds to claim 2.

Further, the bridge 1 according to the second embodiment
00 does not require a wide opening as compared to the prior art which prevents wind from re-adhering to the upper and lower surfaces of the box girder.
Therefore, the opening 4 does not affect the pavement,
The pavement for the lane can be sufficiently secured. That is, since the opening 4 is limited only to the median strip, it is possible to secure pavement in all lanes.
Further, the bridge 100 according to the second embodiment can sufficiently increase the flutter occurrence limit wind speed, and is excellent in flutter resistance performance, as compared with the conventional technology of reducing the wind speed on the upper surface of the box girder.

(Modification of Second Embodiment) FIG. 7 is an explanatory diagram showing a modification of the second embodiment. In the drawing, the same reference numerals as those in FIG. 6 indicate the same components. This modified example is different from the bridge 100 shown in FIG. 6 in that the lower surface side central windshield 9 is provided at the center lower surface of the box girder 2, that is, the center of the lower grating 5 of the opening 4.
Are provided continuously (or discretely) in the longitudinal direction of the bridge 100. The lower-side central wind shield wall 9 has an opening structure such as a punching plate having a height of about 2 to 3 m.

FIG. 8 is an explanatory view showing a modification of the second embodiment. In the drawing, the same reference numerals as those in FIG. 6 indicate the same components. This modification is different from the bridge 100 shown in FIG.
On the lower surface at both ends of the box girder 2, a lower-side end windshield 10 is provided,
00 are provided continuously (or discretely) in the longitudinal direction. This lower surface side end windshield 10 is
Like the lower surface side central wind shield wall 9, it is constituted by an opening structure such as a punching plate having a height of about 2 to 3 m.

FIG. 9 is an explanatory view showing a modification of the second embodiment. In the drawing, the same reference numerals as those in FIG. 6 indicate the same components. This modification is different from the bridge 100 shown in FIG.
A lower surface side central windshield 9 is provided at the center lower surface of the box girder 2, that is, a center of the lower grating 5 of the opening 4, and a lower surface side end windshield 10 is provided at the lower surfaces at both ends of the box girder 2, respectively. Bridge 1
00 are provided continuously (or discretely) in the longitudinal direction.

The modified examples shown in FIGS. 7 to 9 can achieve substantially the same functions and effects as those of the second embodiment shown in FIG.

(Third Embodiment) FIG. 10 is an explanatory diagram showing a third embodiment. In the drawing, the same reference numerals as those in FIGS. 1, 2 and 6 denote the same components. The bridge 101 in the third embodiment is different from the bridge 1 shown in FIGS.
The end windshield 7 and the inspection car rail 8 are deleted, or the end windshield 7 is removed from the bridge 100 shown in FIG.

That is, the upper surface at the center of the box girder 2 (the opening 4
In the center of the upper grating 5, a central wind shield wall 6 is provided continuously (or discretely) in the longitudinal direction of the bridge 101. This central windbreak wall 6 has a height of about 2 to 3 m.
And a punching plate. In addition,
In FIG. 10, reference numeral 11 denotes a balustrade provided on the upper surface of both ends of the box girder 2 instead of the end windshield 7.

The bridge 101 in the third embodiment is
With the above configuration, the operation will be described below.

As shown in FIG. 10, the wind (indicated by the dotted arrow in FIG. 10) flowing through the upper surface of the box girder 2 is guided to the opening 4 by the action of the central wind shield wall 6, as shown in FIG. Exit.
In some cases, wind (indicated by a solid arrow in FIG. 10) flowing on the lower surface of the box girder 2 may be guided to the opening 4 and escape to the upper surface of the box girder 2.

For this reason, the pressure difference between the upper surface and the lower surface of the box girder 2 is reduced, the self-excited aerodynamic force acting on the box girder 2 can be reduced, and the limit wind speed at which flutter occurs can be increased. . For example, an experimental result of about 60 m / s or more has been obtained in the case of a wind with an elevation angle of ± 3 degrees.

In the third embodiment, the opening 4 is formed at the center of the box girder 2, and the central wind-shield wall 6 is formed by the box girder 2.
Since it is provided on the upper surface at the center of the vehicle, it is possible to provide a bridge having a simple structure, a sufficiently high flutter occurrence limit wind speed, and excellent flutter resistance performance. The third embodiment shown in FIG. 10 corresponds to claim 1.

Further, the bridge 1 according to the third embodiment
01 does not require a wide opening, as compared to conventional techniques that prevent wind from re-adhering to the upper and lower surfaces of the box girder.
Therefore, the opening 4 does not affect the pavement,
The pavement for the lane can be sufficiently secured. That is, since the opening 4 is limited only to the median strip, it is possible to secure pavement in all lanes.
Further, the bridge 101 according to the third embodiment can sufficiently increase the flutter occurrence limit wind speed and is excellent in the flutter resistance performance as compared with the conventional technology of reducing the wind speed on the upper surface of the box girder.

(Modification of Third Embodiment) FIG. 11 is an explanatory diagram showing a modification of the third embodiment. In the figure, the same reference numerals as those in FIG. This modified example is different from the bridge 101 shown in FIG. 10 in that the lower surface side central windshield 9 is provided in the center lower surface of the box girder 2, that is, in the center of the lower grating 5 of the opening 4 in the longitudinal direction of the bridge 101. It is provided continuously (or discretely). The lower-side central wind shield wall 9 has an opening structure such as a punching plate having a height of about 2 to 3 m.

FIG. 12 is an explanatory view showing a modification of the third embodiment. In the figure, the same reference numerals as those in FIG. This modification is different from the bridge 101 shown in FIG.
The bridge 101 is provided continuously (or discretely) in the longitudinal direction. The lower-side end windshield 10 has a height of about 2 in the same manner as the lower-side central windshield 9.
It is composed of an opening structure such as a punching plate of about 3 m.

FIG. 13 is an explanatory view showing a modification of the third embodiment. In the figure, the same reference numerals as those in FIG. This modification is different from the bridge 101 shown in FIG. 10 in that a lower surface side central windshield 9 is provided at the center lower surface of the box girder 2, that is, at the center of the lower grating 5 of the opening 4. On the lower surfaces at both ends, lower surface side end windshield walls 10 are provided continuously (or discretely) in the longitudinal direction of the bridge 101, respectively.

The modifications shown in FIGS. 11 to 13 can achieve substantially the same functions and effects as those of the third embodiment shown in FIG.

(Modifications of Central Windshield and Lower Surface Side Central Windshield) FIGS. 14 and 15 are partial perspective views showing modifications of the central windshield and the lower surface side central windshield. FIG.
The center wind shield wall and the lower face side center wind shield wall 13 shown in FIG. 1 are in the form of folded plates obtained by bending a punching plate into a trapezoidal shape. The center wind shield wall and the lower face side center wind shield wall 14 shown in FIG. 15 are formed in a slate shape by bending a punching plate into an S-shape. The central wind shield wall and the lower central wind shield walls 13 and 14 serve as guides for guiding the wind to the opening 4 as indicated by arrows in FIGS. 14 and 15. As a result, the wind removal effect increases.

The central wind shield wall 6, the end wind shield wall 7, the lower center wind shield wall 9, the lower end wind shield wall 10, the folded and slate-shaped central wind shield walls and the lower central shield wall. Wind wall 13, 1
Reference numeral 4 denotes a punching plate, but is not limited to the punching plate. For example, a plate without an opening may be used.

[0060]

As is apparent from the above description, in the bridge according to the present invention (claim 1), the wind flowing on the upper surface and / or the lower surface of the box girder is guided to the opening by the central wind shield wall. Exit to the lower and / or upper surface. For this reason, the pressure difference between the upper surface and the lower surface of the box girder is reduced, the self-excited aerodynamic force acting on the box girder is reduced, and the limit wind speed at which flutter occurs is increased.

In particular, a bridge according to the present invention (Claim 1)
Does not require a wide opening compared to conventional techniques that prevent wind from re-adhering to the top and bottom surfaces of the box girder,
The opening does not affect the pavement, and the pavement for the lane can be sufficiently secured. Further, the invention according to claim 1 can sufficiently increase the flutter occurrence limit wind speed, and is excellent in flutter resistance performance, as compared with the conventional technology of reducing the wind speed on the upper surface of the box girder.

A bridge according to the present invention (Claim 2)
Is an elevation angle of +3 due to the action of the central windshield and the end windshield.
In the case of a moderate wind (wind blowing up), wind flowing on the upper and lower surfaces of the box girder is guided to the opening and escapes to the lower and upper surfaces of the box girder. For this reason, the pressure difference between the upper surface and the lower surface of the box girder is reduced, the self-excited pneumatic force acting on the box girder can be reduced, and the flutter occurrence limit wind speed can be greatly increased.

In particular, a bridge according to the present invention (Claim 2)
Since the wind speed on the upper surface of the box girder, that is, on the lane, is reduced by the end windshield, the traveling safety of the vehicle can be ensured.

A bridge according to the present invention (Claim 3)
Is a box girder in the case of winds of up to ± 3 degrees (wind up and down against horizontal wind) due to the action of the central wind shield, the end wind shield, and the inspection car rail. The wind flowing on the upper surface and the lower surface of the box girder is guided to the opening and passes through the lower surface and the upper surface of the box girder. For this reason, the pressure difference between the upper surface and the lower surface of the box girder is reduced, the self-excited pneumatic force acting on the box girder can be reduced, and the flutter occurrence limit wind speed can be greatly increased.

In particular, a bridge according to the present invention (Claim 3)
Since the inspection vehicle rail is also used as a lower surface side end windshield, the structure becomes simpler and the material of the bridge can be saved.

[Brief description of the drawings]

FIG. 1 is a partial perspective view showing Embodiment 1 of a bridge according to the present invention.

FIG. 2 is an explanatory diagram showing a flow state of a wind.

FIG. 3 is a modified example of the first embodiment and is an explanatory diagram illustrating a flow state of wind.

FIG. 4 is a modified example of the first embodiment and is an explanatory diagram illustrating a flow state of wind.

FIG. 5 is a modified example of the first embodiment and is an explanatory diagram illustrating a flow state of wind.

FIG. 6 is a second embodiment of the bridge according to the present invention, and is an explanatory view showing a wind flow state.

FIG. 7 is a modified example of the second embodiment, and is an explanatory diagram illustrating a flow state of wind.

FIG. 8 is a modified example of the second embodiment, and is an explanatory diagram showing a flow state of wind.

FIG. 9 is a modified example of the second embodiment, and is an explanatory diagram illustrating a flow state of wind.

FIG. 10 is a third embodiment of the bridge according to the present invention and is an explanatory diagram showing a wind flow state.

FIG. 11 is a modified example of the third embodiment, and is an explanatory diagram showing a flow state of wind.

FIG. 12 is a modified example of the third embodiment, and is an explanatory diagram illustrating a flow state of wind.

FIG. 13 is a modified example of the third embodiment and is an explanatory diagram illustrating a flow state of wind.

FIG. 14 is a partial perspective view showing a folded plate-shaped air guiding means.

FIG. 15 is a partial perspective view showing a slate-shaped air guiding means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 100, 101 Bridge 2 Box girder 3 Wind guide end 4 Opening 5 Grating 6 Central wind shield 7 End wind shield 8 Inspection car rail 9 Lower face side central wind shield 10 Lower face side edge wind shield 11 Railing 13 Folded plate-shaped wind guide 14 Slate-shaped wind guide

Continued on the front page (71) Applicant 000173810 Civil Engineering Research Center 1-6-4 Taito, Taito-ku, Tokyo (71) Applicant 000000099 Ishikawajima-Harima Heavy Industries Co., Ltd. 2-2-1 Otemachi, Chiyoda-ku, Tokyo (71 ) Applicant 000000974 Kawasaki Heavy Industries, Ltd. 3-1-1, Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo (71) Heavy Machinery Co., Ltd. 9-11-11 Kita-Shinagawa, Shinagawa-ku, Tokyo (71) Applicant 000004123 Nippon Kokan Co., Ltd. 1-1-2 Marunouchi, Chiyoda-ku, Tokyo (71) Applicant 000005119 Hitachi Zosen Corporation Osaka Prefecture 1-7-89 Minami Kohoku, Suminoe-ku, Osaka (71) Applicant 000005902 Mitsui Engineering & Shipbuilding Co., Ltd. 5-6-1, Tsukiji, Chuo-ku, Tokyo (72) Inventor Shinsuke 5-717-1 Fukahoricho, Nagasaki-shi (72) Honda, Mitsubishi Heavy Industries, Ltd. Hiroshi 5-7-17-1 Fukabori-cho, Nagasaki-shi Mitsubishi Heavy Industries, Ltd.Nagasaki Research Laboratory (72) Inventor Ichiro Masuda 4-2-2, Kannonshinmachi, Nishi-ku, Hiroshima-shi Mitsubishi Heavy Industries, Ltd.Hiroshima Works (72) Inventor Nakajima Yukihiro 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City Mitsubishi Heavy Industries, Ltd. Hiroshima Works F-term (reference) 2D059 AA08 BB06 BB08 EE00 GG06 GG08

Claims (3)

[Claims] 1. A bridge having a box girder structure, wherein an opening is continuously or discretely opened in a median strip portion of the box girder without vertically invading a pavement portion. A bridge, wherein a central wind shield wall is provided on a central upper surface of the girder as a means for guiding air to the opening. 2. A bridge having a box girder structure, wherein an opening is continuously or discretely opened in a central divider portion of the box girder without invading a pavement portion. A bridge, wherein a central wind shield wall and an end wind shield wall are provided on a central upper surface and upper surfaces of both ends of the girder as wind guiding means to the opening, respectively. 3. A bridge having a box girder structure, wherein an opening is continuously or discretely opened in a vertical direction in a center divider portion of the box girder without invading a pavement portion. A central windshield and an end windshield are provided on the upper surface of the center and both ends of the girder as wind guiding means to the opening, respectively, and an inspection car rail is laid on the lower surface of the box girder. A bridge, characterized in that: