JP3075997B2 - Falling bridge prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bridge prevention device for preventing a bridge girder from falling from a substructure such as a pier or an abutment in the event of a disaster such as an earthquake, and more particularly to a bridge prevention device. However, the present invention relates to a device having a damping function and a feature that horizontal force does not act due to expansion and contraction of a girder due to a temperature change.

[0002]

2. Description of the Related Art When a horizontal force acts on a pier or an abutment due to an earthquake or the like, not only the pier or the abutment is damaged, but also the bridge girder slips off the pier, that is, the bridge falls.
Conventionally, various devices have been proposed as a bridge prevention device. One of the devices is an actual bridge device proposed by the present applicant.
An apparatus described in Japanese Patent Publication No. 315 is known.

[0003] In this method, a dilatant fluid such as silicon putty (a modified product obtained by adding boron to methyl silicon rubber) is sealed in a cylinder, and a piston rod is connected to one of the structures such as a bridge girder. A cylinder is connected to another structure such as a bridge girder, a pier, or an abutment. A gap is provided between the piston and the peripheral wall of the cylinder so that the silicone putty can flow from one side of the piston to the other side.

According to this conventional apparatus, with respect to expansion and contraction of the bridge girder due to temperature change, the silicon putty slowly flows through the gap between the piston and the cylinder peripheral wall, so that the piston moves and the bridge girder moves. Follow the expansion and contraction. Also, with respect to an impact force such as an earthquake, the silicon putty operates as a rigid body without flowing, and functions as a fall prevention device by transmitting the impact force between structures.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to improve the above-mentioned conventional apparatus while making use of the advantages thereof, and has the following objects.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fall prevention device which can freely follow the expansion and contraction of a bridge girder due to a temperature change, and can resist an impact force such as an earthquake by an elastic body and exhibit a damping function. To provide.

[0007]

The present invention employs the following means to achieve the above object.

[0008] That is, the present invention is a fall prevention device for connecting two structures including a bridge girder in a bridge to prevent the bridge girder from falling, wherein the device is connected to one of the two structures and has an intermediate portion. A connecting rod provided with a piston, a first tubular member connected to the other of the two structures, the connecting rod being movably inserted, and a piston on the outer periphery of the connecting rod; Is accommodated from one side to the other side to allow movement of fluid, and a cylinder in which dilatant fluid is sealed as the fluid, and a second cylinder provided on the outer periphery of the connecting rod and provided integrally with the cylinder. Cylindrical member, the first cylindrical member and the second cylindrical member.
And a rubber-like elastic body fixed between the cylindrical member and the bridge member.

Further, according to the present invention, the first cylindrical member includes a small-diameter portion and a large-diameter portion smaller in diameter than the second cylindrical member, and the connecting rod is inserted through the small-diameter portion, and The rubber-like elastic body is fixed between a portion and the second tubular member.

Further, the present invention is characterized in that an end of the connecting rod projects from the small-diameter portion to the large-diameter portion, and the protruding end is provided with an engaging portion capable of engaging with the small-diameter portion. In the fall prevention device.

According to the present invention, when the bridge girder expands and contracts due to a temperature change, the piston moves due to the slow flow of the dyrant fluid from one side of the piston to the other side, whereby the connecting rod is moved to the first position. It moves relative to the tubular member and follows the expansion and contraction of the bridge girder without resistance.

[0012] Also, with respect to an impact force such as an earthquake, the dierant fluid operates as a rigid body without flowing. As a result, the impact force acting on the connecting rod or the first cylindrical member is transmitted between the connecting rod and the first cylindrical member via the second cylindrical member and the rubber elastic body integrated with the cylinder. It is transmitted to each other, that is, the impact force is transmitted between the two structures. At this time, the rubber-like elastic body resists due to elastic shear deformation, makes the vibration cycle of the impact force longer, and transmits it between the first tubular member and the second tubular member. Absorbs and attenuates horizontal forces.

[0013] Here, the dirant fluid is a kind of non-Newtonian fluid, and is a pure viscous fluid in which the apparent viscosity increases as the shear rate increases. Therefore,
In the case of a slow motion such as expansion and contraction of a bridge girder due to a temperature change, the shear rate is small and the fluidity is exhibited. In the case of an impact force, the shear rate is large and the body operates as a rigid body without flowing. As the diluent fluid, silicon putty or the like, which is a modified body obtained by adding boron to methyl silicon rubber, can be used as in the conventional case.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall front view showing an embodiment of the present invention. This embodiment is an example in which the present invention is applied to a simple girder bridge having two or more spans. In this simple girder bridge, the respective ends of the bridge girders 2 and 2 are placed facing each other with an interval above the pier 1 as a lower structure. Then, one bridge girder 2 is supported on the fixed pier F and the other bridge girder 2 is supported on the pier 1 via the movable support M.
Expansion and contraction of the bridge girder 2 due to a temperature change or the like is absorbed by the gap between the bridge girder 2 and 2.

The bridge prevention device 3 is provided between the bridge girders 2 and 2 and connects them. FIG. 2 is a horizontal sectional view showing the details of the fall prevention device 3, and FIG. 3 is a sectional view taken along line AA of FIG. The falling bridge prevention device 3 includes a connecting rod 5 having a piston 4 provided at an intermediate portion, and a first cylindrical member 6. A connecting plate 8 having a pin hole 7 at one end of the connecting rod 5
Is provided. This connecting plate 8 is used as one bridge girder 2
The connecting rod 5 is connected to one bridge girder 2 by being pivotally supported via a pin 10 to a bracket 9 fixed to the bracket 9.

The first cylindrical member 6 comprises a small diameter portion 6a and a large diameter portion 6b screwed to the small diameter portion 6a. The connecting rod 5 is movably inserted into the small diameter portion 6a, and the other end is connected to the small diameter portion 6a. It protrudes into the large diameter portion 6b. A nut 24, which is an engaging portion, is screwed to the projecting end of the connecting rod 5, and the nut 24 can be engaged with the end surface of the small diameter portion 6a. The large-diameter portion 6b is provided with a connection plate 12 having a pin hole 11. The first tubular member 6 is connected to the other bridge girder 2 by pivotally supporting the connection plate 12 via a pin 14 to a bracket 13 fixed to the other bridge girder 2.

A cylinder 15 is provided on the outer periphery of the connecting rod 5 so as to accommodate the piston 4. A second cylindrical member 17 is provided on the outer periphery of the connecting rod 5,
The second cylindrical member 17 and the cylinder 15 are connected to a bolt 18
, And the inside of the cylinder 15 is sealed by an end wall 19 of the second tubular member 17. These cylinder 15 and second cylindrical member 17 and connecting rod 5
And bearings 16 are interposed between them.

The inside of the cylinder 15 contains a dierant fluid 2
0 is enclosed. As the diluent fluid, a silicon putty, which is a modified product obtained by adding boron to a methyl silicone rubber as in the prior art, is used. A gap 21 is formed between the inner wall of the cylinder 15 and the piston 4, and the dierant fluid 20 can flow from one side of the piston 4 to the other side. An orifice may be provided in the piston 4 instead of or in addition to the gap 21.

Between the small diameter portion 6a of the first cylindrical member 6 and the second cylindrical member 17, a cylindrical rubber-like elastic body 22 made of high-damping rubber is fixed. More specifically, the rubber-like elastic body 22 is vulcanized and bonded between the mounting ring 23 and the small-diameter portion 6a, and is mounted on the second cylindrical member 17 via the mounting ring 23 screwed to the second cylindrical member 17. It is fixed to the shape member 17.
The rubber-like elastic body 22 is vulcanized and formed on the outer periphery of the small diameter portion 6a, and then contracted by drawing the mounting ring 23 to give a residual stress in the radial direction.

The above device for preventing a bridge from falling works as follows.
In normal times when an impact force such as seismic force does not act on the pier 1, the bridge girder 2 expands and contracts due to a temperature change. At this time, the piston 4 moves due to the slow flow of the dierant fluid 20 from one side of the piston 4 to the other side. I do. Accordingly, the connecting rod 5 moves with respect to the first tubular member 6 and follows the expansion and contraction of the bridge girder 2. That is, in this case, almost no load is transmitted between the connecting rod 5 and the first cylindrical member 6.

On the other hand, when an impact force such as an earthquake acts on the pier 1, the pier 1 vibrates as shown by arrows in FIG.
The impact force is applied to. In response to this impact force, the dierant fluid 20 operates as a rigid body without flowing. As a result, the impact force acting on the connecting rod 5 or the first cylindrical member 6 is applied to the connecting rod 5 and the first cylindrical member 6 via the second cylindrical member 17 and the rubber elastic body 22 integrated with the cylinder 15. Are transmitted to each other between the tubular members 6, that is, the impact force is transmitted between the bridge girders 2.

At this time, the rubber-like elastic body 22 resists due to the elastic shear deformation, and the vibration period of the impact force is lengthened and transmitted between the first tubular member 6 and the second tubular member 17. At the same time, it absorbs the energy of the impact force and rapidly attenuates the horizontal force. The amplitude is the nut 24 and the first cylindrical member 6
If the distance is greater than or equal to the distance between the small diameter portion 6a, the nut 24 is engaged with the end face of the small diameter portion 6a, and ultimately, the bridge girder 2 is prevented from falling.

The above embodiment is merely an example, and the present invention can be variously modified. For example, in the above embodiment, the fall prevention device is installed between two bridge girders, but may be installed between a bridge girder and a pier or abutment.

[0024]

As described above, according to the present invention, the bridge girder can freely follow the expansion and contraction of the bridge girder due to the temperature change, and can resist the impact force of an earthquake or the like by elasticity and exhibit a damping function. Thus, the impact force can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall front view showing an embodiment of the present invention.

FIG. 2 is a horizontal cross-sectional view showing a bridge fall prevention device.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Bridge pier 2 ... Bridge girder 3 ... Bridge prevention device 4 ... Piston 5 ... Connecting rod 6 ... First cylindrical member 6a ... Small diameter part 6b ... Large diameter part 15 ... Cylinder 17 ... Second cylindrical member 20 ... Dilant fluid 21: gap 22: rubber-like elastic body 24: nut

Claims (3)

(57) [Claims] An apparatus for preventing two bridges including a bridge girder from being connected to each other in a bridge to prevent the bridge girder from falling, wherein a piston is connected to one of the two structures and an intermediate part has a piston. A connecting rod provided, a first cylindrical member connected to the other of the two structures and through which the connecting rod is movably inserted, and an outer periphery of the connecting rod, wherein the piston is one of A cylinder which is accommodated to allow movement of fluid from one side to the other side, and in which a dilatant fluid is sealed as the fluid; and a second cylindrical member provided on the outer periphery of the connecting rod and provided integrally with the cylinder. A fall prevention device, comprising: a member; and a rubber-like elastic body fixed between the first tubular member and the second tubular member. 2. The first cylindrical member includes a small-diameter portion and a large-diameter portion smaller in diameter than the second cylindrical member, and the connecting rod is inserted through the small-diameter portion, and the small-diameter portion and the small-diameter portion are connected to each other. The fall prevention device according to claim 1, wherein the rubber-like elastic body is fixed between the second tubular member and the second tubular member. 3. An end of the connecting rod protrudes from the small-diameter portion to the large-diameter portion, and the protruding end is provided with an engaging portion capable of engaging with the small-diameter portion. Item 2
The described bridge fall prevention device.