JP2004169309A - Bridge and its main tower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a main tower of a bridge, which can reduce not only the weight of a main tower body but also steel materials and working processes, even if assumed earthquakes are big. <P>SOLUTION: The main tower 15 of the bridge, which adopts a rigid frame type, is used for a suspension bridge, and equipped with a pair of tower columns 21 which are erected from a tower base part 20, and horizontal materials 22-26 which are arranged as rigid frame type supporting members between the tower columns 21 so as to couple the tower columns 21 together. A stiffening girder 27 for coupling the main towers 20 together and a road 27A, which is supported by the stiffening girder 27, are provided in a lowermost part between the tower columns 21. The horizontal member 23 is divided into one end 28 and the other end 29, and a main-tower surface direction absorption mechanism 30 is provided between both the ends 28 and 29. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to bridges such as suspension bridges and main towers used for these bridges.
[0002]
[Prior art]
The suspension bridge is, like the suspension bridge 1 shown in FIG. 9, an upright main tower 2, a cable 3 connecting the upper part of the main tower 2, a stiffening girder 4 connecting the lower part of the main tower 2, It comprises a cable 3 and a stiffener 4 for connecting the stiffening girder 4.
[0003]
The main towers of this suspension bridge are broadly classified into three types: truss type, ramen type, and truss / ramen combined type.
These types are selected in consideration of the structural environment such as earthquake resistance, but the shape of the main tower is also determined in consideration of economy, landscape, and the like (for example, see Non-Patent Document 1).
[0004]
FIGS. 10 and 11 show an example of a main tower of the above-mentioned conventional suspension bridge, which is a ramen type main tower.
In the main tower 2, the corners 8 of the tower 6 and the horizontal members 7 constituting the main tower 2 and the cross-sectional shape and size of the tower base 9 are determined based on the earthquake resistance to an earthquake.
The road 10 on which the vehicle passes extends along the stiffening girder 4.
[0005]
[Non-patent document 1]
Edited by Honshu-Shikoku Bridge Authority, "Design of Suspension Bridge", July 1990, Section 1.2.3 [0006]
[Problems to be solved by the invention]
However, since the conventional ramen-type main tower 2 employs a load-bearing structure, the sectional structure of the main tower becomes larger as the anticipated earthquake increases, resulting in a problem that the overall weight increases. In addition, the number of necessary steel materials and the welding process are also increased, resulting in a problem that the cost is increased.
[0007]
The present invention has been made in view of the above circumstances, and provides a main tower of a bridge that can reduce the weight of the main tower body and reduce the number of steel materials and work processes even when an anticipated earthquake is large. With the goal.
[0008]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems.
The invention according to claim 1 is a main tower of a bridge in which a pair of tower pillars is supported in a ramen form by a horizontal member, wherein the horizontal member is separated between one end and the other end. A main tower surface absorbing mechanism for absorbing energy for displacing the pair of columns relatively to each other.
[0009]
The main tower of this bridge has a main tower surface absorption mechanism that absorbs energy for displacing a pair of tower columns relatively to each other between one end and the other end where the horizontal member is divided. Therefore, the main tower surface direction absorbing mechanism can absorb seismic energy or the like applied in the direction in which the horizontal members of the main tower extend.
[0010]
The invention according to claim 2 is the main tower of the bridge according to claim 1, wherein the main tower surface direction absorbing mechanism connects a lower end of the other end to an upper end of the one end. A low-yield material having at least a portion having a lower yield stress than the horizontal material, the shaft member comprising: a member; and a shaft member connecting the lower end of the one end to the upper end of the other end. It is characterized by being formed by.
[0011]
In the main tower of this bridge, since the shaft member of the main tower surface absorption mechanism is formed at least in part of a low yield material having a lower yield stress than the horizontal material, the horizontal material of the main tower extends. Even if seismic energy or the like is applied in the direction, the low-yield material yields before the horizontal material yields. At this time, since the seismic energy and the like are absorbed, the load on the tower columns and the like can be reduced. In particular, since the shaft members are disposed at both ends of the horizontal member in a truss shape, seismic energy or the like that is obliquely applied to the extending direction of the horizontal member can be efficiently absorbed.
[0012]
According to a third aspect of the present invention, in the main tower of the bridge according to the first or second aspect, the main tower surface direction absorbing mechanism includes a thin plate member that connects the one end to the other end. It is characterized by having been done.
[0013]
In the main tower of this bridge, the main tower surface absorption mechanism is composed of a thin plate member connecting one end to the other end. Even if a load is applied, the thin plate member yields before the horizontal member yields. At this time, seismic energy and the like are absorbed, and the load on the tower columns and the like can be reduced.
[0014]
The invention according to claim 4 is the main tower of the bridge according to claim 3, wherein the thin plate member is provided with a rib-like stiffening portion.
[0015]
In the main tower of this bridge, the thin plate member is provided with a rib-like stiffening portion, so that the stiffening portion can increase the yield stress of the thin plate member to a predetermined level.
[0016]
The invention according to claim 5 is the main tower of the bridge according to any one of claims 1 to 4, wherein the pair of tower columns includes a plurality of the horizontal members, and the main tower surface direction absorbing mechanism. Is provided on the second horizontal member from the upper end of the column.
[0017]
In the main tower of this bridge, the main tower surface absorption mechanism is provided on the second horizontal member from the upper end of the tower post, so compared to the case where it is at the upper end of the tower post, transportation and construction of the main tower The main tower surface absorption mechanism is not damaged, and seismic energy or the like can be efficiently absorbed in a place having a large swing similarly to the upper end of the tower column.
[0018]
The invention according to claim 6 is a main tower of a bridge in which a pair of towers is supported in a ramen form by horizontal members, wherein the towers have a height at a position displaced in a bridge axis direction from a center axis thereof. A rod provided in the direction, and a bridge axis direction absorbing mechanism that is connected between one end and the other end where the rod is divided and absorbs energy that displaces both ends relatively to each other. It is characterized by having.
[0019]
The main tower of this bridge has a bridge axial absorption mechanism that absorbs energy that displaces both ends of the rod relatively to each other. , The seismic energy or the like is absorbed by the bridge axial absorption mechanism, and the load on the tower columns and the like can be reduced.
[0020]
The invention according to claim 7 is the main tower of the bridge according to claim 6, wherein the bridge axial absorption mechanism is an oil damper.
[0021]
In the main tower of this bridge, since the bridge axial absorption mechanism is an oil damper, the displacement of both ends of the rod and its vibration can be attenuated by the viscosity of the oil damper.
[0022]
The invention according to claim 8 is the main tower of the bridge according to claim 6 or 7, wherein the bridge axial absorption mechanism is provided at each of the cross-sectional corners of the tower column. I do.
[0023]
In the main tower of this bridge, the bridge axial absorption mechanism is installed at the position that causes the maximum displacement of the column at the four corners of the column cross section, so that seismic energy etc. can be efficiently absorbed. Can be.
[0024]
According to a ninth aspect of the present invention, there is provided the bridge according to any one of the first to eighth aspects.
[0025]
In this bridge, the main tower is provided with an absorption mechanism for absorbing seismic energy and the like, so that even if the bridge becomes a long bridge, the size and weight of the main tower can be suppressed.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
1 to 3 show a first embodiment of the present invention.
[0027]
The main tower 15 of the bridge shown in FIG. 1 is used for a suspension bridge, adopts a ramen type, and uses a ramen type to connect a pair of towers 21 erected from a tower base 20 and the towers 21. And horizontal members 22 to 26 disposed between the tower columns 21 as support members. A stiffening girder 27 connecting between the main towers 20 and a road 27A supported by the stiffening girder 27 are provided at the lowermost part between the tower columns 21.
[0028]
In FIG. 1, the horizontal member 23 is disposed second from the upper end of the tower column 21 and is divided into one end 28 and the other end 29, and a gap between the two in the main tower surface direction is provided. A main tower surface absorption mechanism 30 functioning as a vibration device is provided.
As shown in FIGS. 2 and 3, the main tower surface absorption mechanism 30 includes a front gusset 33 provided at a front upper corner 31 of one end 28 and a front lower corner 32 of the other end 29. And a front shaft member 34 for connecting the front gussets. Also, a rear gusset 37 disposed at the rear lower corner 35 of the one end 28 and the rear upper corner 36 of the other end, and a rear shaft member 38 connecting the rear gussets are formed. Have.
[0029]
The front shaft member 34 includes a front shaft portion 39 that forms a central portion, and a plastic deformation portion (low-yield material) 40 that connects the front gusset 33 and an end of the front shaft portion 39, respectively.
Similarly, the rear shaft member 38 includes a rear shaft portion 41 and a plastic deformation portion 40. The members are set so that the compressive yield stress of the plastic deformation portion 40 is smaller than the compressive yield stress of the horizontal members 22 to 25 and the front shaft portion 39 and the rear shaft portion 41.
[0030]
In order to hide the front shaft member 34 and the rear shaft member 38 from the outside, the shielding plate 42 is bolted between the walls of the one end 28 and the other end 29 to such an extent that the seismic isolation effect is not affected. It is bolted so that it is restricted to each end only in the direction.
[0031]
Next, a seismic isolation method for the main tower during an earthquake will be described. The main tower surface seismic isolation device 30 functions when a load is applied to the main tower 15 in the width direction of the road 27A when the earthquake occurs.
That is, the seismic energy or the like propagating from the extending direction of the horizontal member 23 in order to displace the pair of tower columns 21 relatively to each other, is in a plastically deformed portion 40 acts as a compressive force in the axial direction. If the value of the compressive stress caused by this force exceeds the compressive yield stress of the plastically deformable portion 40, the plastically deformable portion 40 yields, so that a part of the seismic energy applied in the width direction of the road 27A is absorbed. That is, the load applied to the other members is reduced.
[0032]
Further, since the front shaft member 34 and the rear shaft member 38 are disposed so as to extend in directions different from each other in a truss-like manner, an earthquake is applied obliquely to the direction in which the horizontal members extend. Energy and the like are also branched in the direction in which each shaft member extends, and are efficiently absorbed.
[0033]
According to the main tower of this bridge, since the shape of the horizontal members and the pillars, which are the main tower constituent members, can be determined based on the load after compression yielding of the plastic deformation portion 40, the main tower and the like can be maintained while maintaining the earthquake resistance. Weight can be reduced.
[0034]
Next, a second embodiment according to the present invention will be described with reference to FIGS. In the following description, the same reference numerals are given to the components described in the first embodiment, and description thereof will be omitted.
[0035]
The difference between the second embodiment and the first embodiment is that the first embodiment employs a main tower direction absorption mechanism using a front shaft member 34 and a rear shaft member 38. In the second embodiment, the thin plate member shown in FIGS.
That is, the main tower surface absorption mechanism 43 shown in FIGS. 5 and 6 includes a shear panel (thin plate member) 45 that connects between the center of one end 28 and the center of the other end 29. .
[0036]
In the above-mentioned shear panel 45, a convex rib (stiffening part) 47 has a certain length dimension and a certain width dimension on one side of the plate part 46, and keeps a certain distance from the adjacent rib 47. Are arranged in such a manner.
Note that, in order to hide the shear panel 45 from the exterior, between the walls of the one end 28 and the other end 29, the shielding plate 42 is connected to each end only in the bolt direction so as not to affect the seismic isolation effect. It is bolted to be restrained.
[0037]
Next, a seismic isolation method at the time of an earthquake in the present embodiment will be described. As in the first embodiment, the main tower surface absorption mechanism 43 functions when a load in the main tower direction is applied to the main tower 15 when an earthquake occurs.
That is, the seismic energy or the like propagated from the extending direction of the horizontal member 23 acts on the shear panel 45 from one end 28 and the other end 29 as a compressive force in a panel in-plane direction. When this load exceeds the buckling stress of the shear panel 45, the shear panel 45 undergoes buckling deformation. Due to this buckling, part of the seismic energy and the like applied in the width direction of the road 27A is converted into energy that yields the shear panel 45 and absorbed, and the load applied to other members is reduced.
[0038]
Further, since the ribs 47 are formed on the shear panel 45, the buckling stress can be set to a predetermined level higher than the case where the ribs 47 are not provided, and energy lower than the estimated seismic energy or the like is applied. Not to buckle.
[0039]
According to the main tower of this bridge, the shape of the horizontal member, the pillar, and the like, which are the main tower constituent members, can be determined based on the post-buckling load of the shear panel 45. Weight can be reduced.
[0040]
Next, a third embodiment according to the present invention will be described with reference to FIGS. In the following description, the components described in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0041]
The difference between the third embodiment and the first and second embodiments is that, in the first and second embodiments, the horizontal member 23 is provided with the main tower surface absorption mechanism, whereas the third embodiment is different from the third embodiment. This embodiment is different from the first embodiment in that a bridge axial absorption mechanism is employed in the tower 21.
[0042]
The bridge-axis seismic isolation device 50 shown in FIG. 7 includes an upper end 51 of the tower 21 and a lower end of the tower base 20 at four corners inside the cross section which is displaced in the bridge axis direction from the center axis of the tower 21. A rod 53 that connects the portion 52 in the height direction is provided. Further, in the bridge axial seismic isolation device 50, a portion between a rod upper end cross-section (one end) 54 and a rod lower end cross-section (the other end) 55 formed by dividing the rod 53 in the middle is provided. And an oil damper 56 for absorbing energy for displacing both ends relatively to each other.
[0043]
The rods 53 are disposed so as to penetrate through the front-side penetration portion 57 and the rear-side penetration portion 58 that are vertically provided at four corners of the cross section of the tower column 21 of the main tower 15. I have.
These rods 53 are made of a rigid steel material.
[0044]
Next, a seismic isolation method at the time of an earthquake in the present embodiment will be described. The bridge axis direction absorbing mechanism 50 functions when a load is applied to the main tower 15 in the bridge axis direction, which is the extending direction of the road 27A, when an earthquake occurs.
That is, when the shaking in the bridge axis direction propagates to the tower column 21 via the tower base 20, displacement occurs in the bridge axis direction. At this time, the rod 53 disposed in the front side penetrating portion 57 tends to vertically separate the rod upper end cross-section 54 and the rod lower end cross-section 55 connected by the oil damper 56. At the same time, the rod 53 disposed in the rear side penetrating portion 58 tries to approach the upper end cross-sectional portion 54 and the lower end cross-sectional portion 55 connected by the oil damper 56 in the vertical direction, so that these situations alternate. appear.
[0045]
At this time, since the displacement and vibration of the rod 53 that is going to be separated or approached by the oil damper 56 are attenuated, a part of the seismic energy or the like applied in the bridge axis direction is absorbed by the oil damper 56. That is, the load on the other members is reduced.
[0046]
According to the main tower of this bridge, by estimating the damping capacity of the oil damper 56 in advance, it is possible to determine the shape of the horizontal members, the tower columns, etc., which are the main tower constituent members. Weight can be reduced.
[0047]
Note that the main tower surface seismic isolation device shown in the first embodiment or the second embodiment and the bridge axis seismic isolation device shown in the third embodiment may be used in combination. .
In addition, the suspension bridge is an end having a configuration for supporting the cable on the main tower, but is particularly effective for a bridge having a configuration for supporting the cable on the main tower. May be used as the main tower.
[0048]
【The invention's effect】
The present invention described above has the following effects.
Since the main tower of the bridge of the present invention is provided with the main tower surface direction absorbing mechanism on the horizontal member, it is possible to reduce the number of components such as the main tower while maintaining the earthquake resistance, thereby reducing the weight and the process. The number can be reduced.
[0049]
The main tower of the bridge of the present invention is provided with a bridge axial absorption mechanism in the height direction of the main tower, so that the overall weight can be reduced without increasing the size of the main tower and the like even under the same environmental conditions. In addition, the number of components and the number of steps can be reduced.
[0050]
Since the bridge of the present invention includes the main tower of the bridge of the present invention, the weight of the main tower can be reduced even for a long bridge, and the cost and labor required for construction can be reduced.
[Brief description of the drawings]
FIG. 1 is a front view of a main tower of a bridge provided with a main tower direction absorbing mechanism according to a first embodiment of the present invention.
FIG. 2 is a sectional view taken along the line II-II in FIG.
FIG. 3 is a view taken along line III-III in FIG. 2;
FIG. 4 is a front view of a main tower of a bridge provided with a main tower direction absorbing mechanism according to a second embodiment of the present invention.
FIG. 5 is a sectional view taken along line IV-IV of section A in FIG. 4;
FIG. 6 is a view taken in the direction of arrows VV in FIG. 5;
FIG. 7 is a side view of a main tower of a bridge provided with a bridge axial absorption mechanism according to a third embodiment of the present invention.
FIG. 8 is a sectional view of a main tower of a bridge provided with a bridge axial absorption mechanism according to a third embodiment of the present invention.
FIG. 9 is a schematic diagram of a suspension bridge on which a main tower of a conventional bridge is provided.
FIG. 10 is a front view of a main tower of a conventional bridge.
FIG. 11 is a side view of a main tower of a conventional bridge.
[Explanation of symbols]
2, 15 Main tower 7, 22 to 26 of bridge Horizontal member 28 One end 29 The other end 30, 43 Main tower surface direction absorbing mechanism 34 Front shaft member (shaft member)
38 Rear shaft member (shaft member)
40 plastic deformation part (low yielding material)
45 shear panel (thin plate member)
50 Bridge axis direction absorption mechanism 53 Rod 56 Oil damper

Claims (9)

A pair of towers is the main tower of the bridge supported by horizontal members in a ramen style,
A main tower surface direction absorbing mechanism for absorbing energy for displacing the pair of tower columns relatively to each other is provided between one end and the other end where the horizontal member is divided. And the main tower of the bridge. The main tower direction absorption mechanism includes a shaft member that connects the upper end of the one end to the lower end of the other end, and a shaft that connects the lower end of the one end to the upper end of the other end. The main tower of a bridge according to claim 1, wherein at least a part of the shaft members is formed to have a lower yield stress than the horizontal member. The main tower of a bridge according to claim 1 or 2, wherein the main tower surface direction absorbing mechanism is constituted by a thin plate member connecting the one end to the other end. The main tower of a bridge according to claim 3, wherein the thin plate member is provided with a rib-shaped stiffening portion. The pair of towers are provided with a plurality of the horizontal members, and the main tower surface direction absorbing mechanism is provided on the second horizontal member from an upper end of the tower columns. 4. The main tower of the bridge according to any one of 4. A pair of towers is the main tower of the bridge supported by horizontal members in a ramen style,
The tower post is connected between a rod provided in a height direction at a position displaced in a bridge axis direction from a center axis thereof, and one end portion and the other end portion of the rod divided. A bridge main tower, comprising: a bridge axial absorption mechanism that absorbs energy for displacing both ends relatively to each other. The main tower of a bridge according to claim 6, wherein the bridge axial absorption mechanism is an oil damper. The main tower of a bridge according to claim 6 or 7, wherein the bridge axial absorption mechanism is provided at each of the cross-sectional corners of the tower column. A bridge comprising the main tower of the bridge according to claim 1.

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