JPH10159021A - Proof-stress reinforcing structure of bridge and bridge-fall preventive device and fixture for bridge-fall preventive device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a bridge fall from vibrations with an earthquake, etc., by arranging at least a pair or more of fixing members fixed to main girders respectively at two points separated in the main girder direction in the lateral direction on the underside sides of the main girders constituting an existing bridge and arranging a tensile member stretched between a pair of the fixing members. SOLUTION: Fixing members 52, 54 are fixed at two points separated in the direction of a plurality of main girders 16 respectively on the undersides of the main girders 16. A plurality of stretched tensile members 56 are disposed between a pair of the fixing member 52 and the fixing member 54. A wire or a steel bar, in which a small wire consisting of steel, etc., is intertwined, is used as the tensile member 56. Consequently, the main girders 16, tensile force working to the underside sides of the main girders by load by moving load such as a car passed on the bridge, is denied by compressive force worked to the underside sides of the main girders by the stretched tensile member 56. Accordingly, the proof stress of the bridge can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for reinforcing a bridge and a device for preventing a bridge from falling, and a fixing device therefor. More specifically, the present invention provides a structure for improving the maximum load that can be applied to a bridge, The present invention relates to a device for preventing a bridge from falling, and further relates to a reliable fixing device used for these devices.

[0002]

In recent years, with the rapid economic development, not only the traffic volume has increased, but also the size of individual vehicles has increased, and the loading load has also increased. On the other hand, there are a number of old bridges aged after construction, and there is a concern that the proof strength will decrease due to deterioration of materials. Even with relatively new bridges, many bridges have insufficient load-bearing capacity under the current conditions of use due to the revision of design standards and laws such as the Road Traffic Law.

[0003] As a countermeasure against a bridge having insufficient load-bearing capacity, a new solution is a fundamental solution. However, it is not only expensive but also requires long-term traffic interruption. Not preferred. For this reason, various methods have been proposed for reinforcing the load-bearing capacity without completely blocking traffic.

For example, a method of replacing a composite girder slab in a road bridge or the like (Japanese Patent Publication No. 3-5442) employs a method of replacing one half at a time on one side. First, a reinforcing steel wire is provided below a middle girder. And fix both ends of the steel wire near the girder end of the middle girder, and attach a supporting device that also supports the steel wire and receive the reaction force to the middle girder, and apply a reverse load to the middle girder in advance. A technique is disclosed in which this is reinforced to the same level as the outer girder which is a composite girder, and one side is replaced. However, since this method involves replacing a new bridge, the cost is high and cannot be applied to all existing bridges.

[0005] In addition, the reinforcement structure of an existing bridge and a method of constructing the same (Japanese Patent No. 2528081) are disclosed in Japanese Patent Application Laid-Open No. 2528081. Discloses a structure and a construction method in which a compressed PC steel material is arranged and pushed in and fixed, and further a tensile PC steel material is arranged and tensioned and fixed on the tension side in the longitudinal direction. Then, both the compressive and tensile prestresses introduced into the new ground cover are transmitted from the existing precast concrete girder adjacent to the ground cover to the entire bridge, and the prestress reinforces the existing bridge. However, when the width of the existing bridge is very narrow or the precast girder adjacent to the ground cover is considered to be effective, but when the width is wide, both prestressing of compression and tension is applied to the adjacent precast girder in order. There was a problem that it decreased as it was transmitted, had no effect on the entire bridge, and was not substantially uniform as a whole.

[0006] By the way, today, concrete bridges are not only constructed on rivers and the like, but the number of roads having a bridge structure is increasing due to the increase in the number of roads such as highways and taxiways. Not only in industry but also in life
It has become a lifeline. For this reason, even if a severe earthquake occurs, it is necessary to prevent the bridge from falling, and even if the bridge girder falls from the support part or the position of the bridge girder shifts, it can recover quickly. It is necessary to be.

Hitherto, an anchor bar has been used to prevent a bridge from falling due to displacement of a bridge girder with respect to an abutment or a pier due to vibration such as an earthquake. For example, as shown in FIG. 18, an anchor bar 14 is erected on a bridge seat 12 of an abutment 10, while a support 18 for mounting a main girder 16 on the bridge seat 12 is sandwiched between the anchor bars 14. It is arranged as if it were. Then, anchor cap 20 is attached to anchor bar 14.
After filling, anchor concrete 20 is poured into gaps formed between the main girders 16 respectively placed on the plurality of bearings 18, and anchor caps 20 are buried by the fill concrete 22. Keep it. Although the drop prevention device 24 using the anchor bar 14 has a certain effect, the anchor bar 14 is broken when a lateral displacement exceeding its shear stress occurs, and the bridge is dropped. Since the shear stress of the steel material constituting the anchor bar 14 is generally low, sufficient earthquake resistance cannot be obtained.

For this reason, a bridge prevention device 1 as shown in FIG. 19 is used together with or instead of the bridge prevention device 24 using the anchor bar 14. The bridge-preventing device 1 straddles the main girder 16 and uses the cross girder 2 provided at an appropriate place, and the cross girder 2 at the end of the main girder 16 and the parapet 30 of the abutment 10 are used. After the steel rod 3 is inserted through the through hole 32, concrete is poured into the through hole 32 and fixed. On the other hand, through hole 3
The ends of the steel rods 3 protruding from both ends are fixed via a support plate 4 or the like.

In this bridge drop prevention device 1, since a tensile load mainly acts on the steel bar 3, the strength is greatly increased as compared with the anchor bar 14, and the earthquake resistance is also greatly improved. However, when an earthquake occurs, the vibration is immediately transmitted to the steel bar 3, and the steel bar 3 is broken before the load caused by the displacement of the main girder 16 acts on the anchor bar 14 because the steel bar 3 is less elongated. And the anchor bar 14
Was sometimes sheared. For this reason, there has been a problem that the fall prevention device 1 does not function as a fail-safe device with respect to the fall prevention device 24 using the anchor bar 14. Further, this fall prevention device 1 can be applied to a bridge provided with the cross beam 2, but cannot be applied to a floor slab bridge without the cross beam 2.

[0010] Next, the ends of the steel rods and cables used in the reinforcement structure for bridges and the bridge prevention device are fixed by a fixing device in order to apply tension. There are two types of fixing devices: a crimping type and a wedge type. However, the crimping type requires processing in a factory, and the length cannot be appropriately changed on site. For this reason, due to construction errors, the distance between the fixing device and the fixing device may be too long or short as a result, and it may be necessary to modify the bridge according to the length of the steel rod or the like. There was a problem. In addition, the wedge-type fixing device is preferable because the dimensions of the cable and the like can be appropriately changed at the construction site and can immediately cope with a dimensional error in the production of the bridge. However, the wedge-type fixing device may be loosened due to vibration or the like, so that it is necessary to pay attention to its use.

Therefore, the inventor of the present invention has intensively studied a method of almost uniformly reinforcing the strength of an existing bridge without interrupting traffic. In addition, 1 consisting of an anchor bar, etc.
After the secondary system bridge prevention device is activated, when the primary system bridge prevention device cannot stop the girder movement due to the earthquake, it suppresses the girder movement while allowing the girder to move a certain amount. The girder can be reliably stopped before the girder falls off the bridge seat and falls, and the moved girder is returned to its original position, and the activated fall prevention device is quickly restored to its original state. The inventors of the present invention have conducted intensive studies in order to provide an apparatus for preventing a bridge from falling, resulting in the present invention.

[0012]

SUMMARY OF THE INVENTION The gist of the bridge strength reinforcing structure according to the present invention is that the main girder constituting the existing bridge is provided at two points separated in the main girder direction on the lower side of the main girder. At least one pair of fixing members fixed to the spar are disposed in the lateral direction, and a tension member that is tensioned is disposed between the pair of fixing members.

[0013] In the reinforcing structure for a bridge according to the present invention, the fixing member may be a member crossing a main girder constituting an existing bridge, and the fixing member may be directly or indirectly fixed to each main girder. Is to be.

Further, in the reinforcing structure of a bridge according to the present invention, the main girder constituting the existing bridge is made of precast concrete, and the fixing members are individual main girder or joints between the main girder and the main girder. It is fixed to.

Further, in the bridge strength reinforcing structure according to the present invention, the fixing member is reinforced by a reinforcing member stretched between the fixing member and the upper end of the main girder.

Next, another point of the reinforcement structure of the bridge according to the present invention is that a cable is arranged between two points separated in the direction of the main girder on the lower surface side of the main girder constituting the existing bridge. At the same time, both ends of the cable are bent upward at the ends of the main girders to be tightened and tightened to the main girders, thereby compensating for the prestress of compression at the lower edge side of the main girders.

Further, in the bridge strength reinforcing structure according to the present invention, a main girder constituting the existing bridge is made of precast concrete, and the cable is disposed at a joint between the precast girder and the precast girder. Is to be.

The gist of the bridge fall prevention device according to the present invention is as follows. One end of a precast girder is disposed on an abutment, and a bridge fall prevention device provided on a parapet of the abutment and an end of the girder is provided. In the above, a through hole is provided in the ground on the stepping plate side at a position surrounding the parapet and the precast girder, a cable is inserted through the through hole, and the parapet and the precast girder are connected to prevent a bridge from falling. I did it.

Next, the gist of the fixing device according to the present invention is that the fixing device has an inner surface for holding the outer periphery of the end portion of the cable or the steel rod and a tapered outer surface, and is divided by the axial plane. A male cone, a female cone having at least a screw portion on an inner surface and an outer peripheral portion engaged with a tapered outer surface of the male cone, a female screw portion screwed to a screw portion of the female cone, and a male cone And a cap having a projection which is brought into contact with the end face of the female cone to push the male cone into the inner surface of the female cone.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a structure for reinforcing a bridge according to the present invention;

As shown in FIGS. 1, 2 and 3, in a concrete bridge having a relatively short span, both ends of a plurality of main girders 16 are provided at regular intervals on the bridge seat 12 of the abutment 10. Filling concrete 22 is cast between the main girders 16 which are placed on the bearing part 18 and are arranged side by side. A stepping plate 34 is formed on the abutment 10 on the side opposite to the bridge seat 12 with respect to the parapet 30, and a road surface layer 35 made of asphalt or the like is formed thereon by a known method. ing. The bearing 18 on which the main girder 16 is placed is constructed by laying a mortar 36 on the bridge seat 12 and then arranging a synthetic rubber shoe 38 thereon, as shown in FIG. Have been. Therefore, vibration transmitted to the abutment 10 through the main girder 16 is reduced, and conversely, vertical and horizontal vibrations caused by an earthquake or the like are reduced by the synthetic rubber shoe 38 and transmitted to the main girder 16. In addition,
The synthetic rubber shoe 38 is particularly preferably a laminate of a plurality of synthetic rubber layers and metal layers, but is not limited to this configuration.

A plurality of main girders 16 mounted in parallel with the abutment 10 are provided with a bridge prevention device to prevent the bridge from being easily dropped by an earthquake or the like. As one of the devices for preventing a bridge from falling, there is a device for preventing a bridge from falling by an anchor bar, which has been conventionally adopted and is effective.
The bridge prevention device using the anchor bar is configured such that, for example, when the bridge prevention device 24 is fixed, the bridge prevention device 24 on the opposite side is movable. That is,
The fixed-side bridge prevention device 24 is configured such that the anchor cap put on the anchor bar 14 is formed of a cylindrical member having an inner diameter slightly larger than the outer diameter of the anchor bar, and even if an offset occurs due to an earthquake or the like, the offset is prevented. It is configured not to grow. On the other hand, the movable-side fall prevention device 24 is configured such that the anchor cap put on the anchor bar is an elliptical or oval cylindrical member having a minor axis slightly larger than the outer diameter of the anchor bar and a comparatively long major axis,
The anchor cap is disposed such that the direction of the major axis is the direction of the main girder 16. Therefore, in the case where a displacement occurs due to vibrations such as an earthquake, the movable-side fall prevention device 24 is allowed within a certain range for movement in the direction of the main girder 16, but is limited to movement in a direction perpendicular to that. In contrast, movement is regulated. Therefore, abutment 10
If the relative movement amount of the main girder 16 and the main girder 16 is larger than the allowable amount, the anchor bar will be sheared.

In addition to the bridge prevention device using the anchor bar, a bridge prevention device is further provided. That is, the bridge-preventing devices 40 and 42 are disposed on both ends of the main girder 16 at all or every other or every other main girder 16 placed on the abutment 10. The bridge prevention devices 40, 42 correspond to the fixed side and the movable side of the above-described bridge prevention device 24, and if the bridge prevention device 40 is a fixed side, for example, The device 42 is set to be movable. The bridge-fall preventing devices 40 and 42 include a connecting member 44 made of a wire connecting the parapet 30 of the abutment 10 and the main girder 16.
And one end of the connecting member 44,
A supporting device 46 having an elastic plate capable of compressively elastically deforming when a tensile load is applied thereto, and a predetermined amount of shrinkage fixed to the other end of the connecting member 44 when a tensile load is applied to the connecting member 44. It comprises a biasing member for biasing the connecting member 44 in the axial direction, and a movable supporting device 48 provided with an elastic plate capable of compressive elastic deformation.

The connecting member 44 has a structure in which sleeves are attached to both ends of a wire, the periphery of the wire is covered by a flexible tube, and the inside of the tube is filled with oil such as grease. Have been. The wire may be, for example, a twisted PC steel wire, but in addition, a strand rope or a spiral rope may be used, and is not particularly limited.
In each case, a bundle of thin steel wires such as a twisted wire is used. By using a bundle of thin steel wires as wires,
Stronger against shear load and bending load than steel bar,
Moreover, since sufficient elasticity is obtained, even if the wire is pulled in the vertical or horizontal direction by an earthquake, the wire is not cut. Sleeves are attached to both ends of the wire by non-welding, particularly preferably by inserting the ends of the wire into holes formed in the sleeve and crushing (drawing) the sleeve.

The existing concrete bridge is provided with a load-bearing reinforcing structure 50 for reinforcing the load-bearing, so that the weight limitation of vehicles that can pass through the bridge is eased. The fixing members 52 and 54 are fixed to the lower surface side of the plurality of main girders 16 at two points separated in the main girder direction, respectively, and the tension reinforcing structure 50 is tensioned between the pair of fixing members 52 and 54. A plurality of tension members 56 are arranged and configured. Fixing member 5
2 and 54 are provided with members 58 such as grooved steel straddling all the main girders 16, and embedded bolts 60 erected on the concrete 22 between the main girders 16. Fixing members 62 which are firmly fixed and are fixed to both ends of the member 58 are fixed to the ends of the horizontal tightening bars which tighten the main girders 16 in the horizontal direction. Filling concrete 2
The reason why the embedded bolt 60 is erected on the main girder 2 is that a large number of piano wires for applying prestress to the main girder 16 are embedded on the lower surface side of the main girder 16, and the embedded bolt 60 is erected on the main girder 16. This is because it is not possible to make a hole to make the hole. Further, the fixing members 52 and 54 are provided with a lateral tightening member 64 along the longitudinal direction thereof.
2, 54 are firmly attached to the main girder 16.

As the tension member 56, a wire or a steel rod obtained by twisting a thin wire made of steel or the like is used, and the tension members 56 are attached to the fixing members 52 and 54 by fixing members 66 attached to both ends thereof. The fixing device 66 is configured such that a screw is formed in a sleeve that is pressed against the end of the tension member 56, and the nut is tightened to tighten and fix. Preferably, a plurality of tension members 56 are provided between the fixing member 52 and the fixing member 54.
6, and the tension is applied almost uniformly. Reference numeral 53 denotes the fixing member 5
It is a reinforcing material for preventing deformation of 2,54.

In the strength reinforcing structure 50, the tension member 56 is tensioned and disposed between the fixing members 52 and 54, so that the main girder 16 is interposed between the fixing members 52 and 54 and the concrete filling 22. A compressive force is applied to the lower edge side. As a result, the same effect as reinforcing the main girder 16 with prestress is obtained, and when the vehicle passes over the main girder 16, that is, over the concrete bridge, the main girder 16 is
Although a tensile force will act on the lower edge side, even when a heavy vehicle passes, the tensile force of the vehicle is canceled by the compressive force of the tension member 56,
As a result, the proof stress is improved. Therefore, the load that can be applied to the concrete bridge becomes larger than before the proof strength structure 50 is applied. In addition, in such a structure, since the weight of the load-bearing reinforcement structure 50 is relatively small,
The weight of the concrete bridge hardly changes and has no adverse effect.

In the concrete bridge having the above structure, when vibrated by an earthquake, not only the movable side bridge prevention device 42 but also the fixed side bridge prevention device 40 is allowed to move to a certain extent. Therefore, in the case of a slight displacement due to a relatively small earthquake, etc., the bridge prevention device by the anchor bar 14 operates, so that an excessive force is not always applied to the bridge prevention devices 40 and 42. . Therefore, the fall prevention devices 40 and 42 are always secured as the last safety valve associated with a large earthquake. As a result, the abutment 1
When the anchor bar 14 is sheared by vibrating and moving the bridge girder 0 and the bridge girder, the connecting members 44 of the bridge-fall prevention devices 40 and 42 connect the main girder 16 and the parapet 30 with each other. It does not lead to a bridge.

Further, when a large and heavy truck passes through this concrete bridge, the strength reinforcing structure 50 is provided at the center on the lower surface side of the main girder 16 on which the maximum bending moment acts. Proof stress will be greatly improved. Therefore, it becomes possible for a heavy truck to pass more safely than before. Further, since the bending strength of the concrete bridge is reduced by the strength reinforcing structure 50, the amplitude of the vertical vibration generated when a heavy truck passes is reduced, and the vibration can be damped faster. And deterioration can be prevented.

Although one embodiment of the bridge strength reinforcement structure and the construction method according to the present invention has been described above, the present invention is not limited to the above-described embodiment. In the following description, the same reference numerals are given to the same portions in the drawings, and the description is omitted in principle.

For example, as shown in FIG. 4 and FIG. 5, the strength reinforcing structure 68 is not only fixed by embedded bolts or the like buried in the interposed concrete 22, but also at appropriate places of the fixing members 52, 54. You may make it fix by the diagonal member 70 which is a reinforcement member provided. That is, the diagonal member 70 firmly fixes the fixing member 52 and the fixing member 54 pulled by the tensioned tension member 56 to the main girder 16, and also fixes the respective fixing members 52 and 54 and the main girder 16. In order to apply a prestress to the main girder 16 between the upper end of the main girder 16 and the upper part of the main girder 16, the diagonal concrete 22 is disposed obliquely in the space between the fixing members 52 and 54 and the upper end of the main girder 16. Is done. The method of applying the diagonal members 70 is as follows. The diagonal material is obliquely applied to a portion of the concrete 22 between the main girder 16 and the main girder 16 at an appropriate position in consideration of the balance on which the load acts. A hole is made, and a load receiving portion 72 is provided on the upper end side of the bridge through which the hole has penetrated. Then, the diagonal member 70 is inserted into the hole between the load receiving portion 72 and the fixing member 52 or 54, and the diagonal member 70 is fixed by applying tension to the diagonal member 70.

With this configuration, the fixing members 52 and 54 are firmly fixed to the main girder 16 via the filling concrete 22 by the diagonal members 70 and the buried bolts, and the tension members 56 are provided.
The fixing members 52 and 54 do not fall off the bridge due to the tension of the bridge. The main girder 16 between the fixing members 52 and 54 by the tension member 56 and the main girder 1 between the fixing members 52 and 54 and the upper end of the main girder 16 by the diagonal member 70.
Since a compressive force is further applied to the portion 6, the weight of the vehicle passing over the bridge can be made larger than before. Further, by disposing the diagonal member 70, it is possible to increase the tension applied to the tension member 56.

Next, as shown in FIGS. 6 and 7, a tension member 76 may be used as the strength-reinforcing structure 74 so as to be stretched over substantially the entire length of the main girder 16 so as to be disposed in the space between the concrete 22. good. The tension member 76 is disposed in a substantially horizontal direction on the filling concrete 22 corresponding to the center of the lower surface of the main girder 16. At both ends of the main girder 16, the filling concrete 22 is connected to the lower surface center. A hole is formed in an oblique direction connecting the upper end side, and the hole is provided in the hole. Both ends of the tension member 76 are fixed by applying tension to the load receiving portion 72 provided in the filling concrete 22 portion, and concentrated stress acts on the bending member 76 at the bent portion of the tension member 76. A direction changing member 78 having a smooth curved surface is provided so as to prevent cutting.
After the tension member 76 is disposed in the 22 pieces of the filling concrete, concrete, resin, or the like is injected into the oblique hole, and the surface of the tension member 76 disposed on the bottom side of the bridge has concrete. The tension member 76 is
Is preferably fixed integrally with the filling concrete 22 and the main girder 16.

The tension member 7 in the strength reinforcing structure 74
6 is most preferably a wire obtained by twisting a thin steel wire, but a steel rod can also be used, and there is no particular limitation. In addition, the oblique holes provided in the 22 parts of the filling concrete are formed by a boring device or the like, and construction work such as formation of the load receiving portion 72 and disposition of the tension member 76 is performed by partially stopping the traffic on the road. be able to.

The strength reinforcing structure 7 constructed as described above
According to 4, it is possible to apply as much tension as possible to the tension member 76, and a compressive force as a reaction of the tension is efficiently transmitted to the lower surface side of the main girder 16 via the filling concrete 22; The strength of the main girder 16, that is, the bridge, is improved. Further, since the tension member 76 is buried in the concrete 22 between the main girders 16 and does not protrude to the outside, the height under the girders does not change,
It does not hinder the passage of the road passing under the bridge provided with the load-bearing reinforcement structure 74.

As shown in the above example, the tension member 7
6 may be inserted into and fixed to a hole provided diagonally above the end of the main girder 16. However, due to the structure of the bridge or its surroundings, diagonal holes are formed on both sides. If it is not possible, as shown in FIG.
It is also possible to fix the one end of 6 to the fixing member 80 to form the strength reinforcing structure 82. The fixing member 80 may be simply fixed to the filling concrete 22 with an embedding bolt or the like (not shown), but as shown in FIG.
A reinforcing member 84 is inserted into a vertically opened hole in the concrete filling 22, and the fixing member 8 is fixed by the reinforcing member 84.
0 may be firmly fastened to the upper part of the main girder 16.

By the way, the above-described proof reinforcement structures 74, 82
In the case where the end of the main girder 16 is compressed diagonally or vertically by a strong force by the tension member 76 or the reinforcing members 70 and 84, if the main girder 16 is formed of a hollow slab bridge, The main girder 16 may be crushed in the hollow portion. Therefore, as shown in FIG. 9, a hole 88 is formed in the upper part of the main girder 16 so as to communicate with the hollow portion 86, and concrete 90 or the like is hit at least at a location where there is a risk of being crushed by the tension member 76 or the reinforcing members 70 and 84. It is preferable to set up. By placing the concrete 90 in the hollow portion 86, the compression resistance of the main girder 16 is increased, and the tension that can be applied to the tension member 76 or the reinforcement members 70, 84 and the tension member 76 can be set large. As a result, the bearing capacity of the bridge will be further improved.

The structure of the main girder to which the above-mentioned various strength reinforcing structures can be applied is not limited to the hollow box type slab bridge. For example, as shown in FIG. The precast girder 94 may be a precast girder 94 having a shape, or a precast girder 96 having a solid I shape as shown in FIG.
The tension member 76 is placed and fixed at the place where the concrete filling 22 between the precast girders 94 and 96 is cast. In each case, the precast girder 9 attempts to return the tension of the tension member 76 to the original state.
The compression force acting on the precast girders 94,96
The tension member 76 is preferably buried by concrete 98 so that it is efficiently transmitted to

Meanwhile, the tension member 76 is disposed under strong tension on the lower surface side of the place where the concrete filling 22 between the precast girder 94, 96 as the main girder and the precast girder 94, 96 is cast. You. For this reason, there is a possibility that the filling concrete 22 is broken and lifted by the tension of the tension member 76. Therefore, as shown in FIG. 10, the I-type steel 97 and the waste material of the railroad rail are buried in the place where the filling concrete 22 is cast, to prevent the filling concrete 22 from breaking and floating. preferable. In addition, by adopting such a configuration,
When a bending moment acts on the precast girders 94 and 96 by a load, the proof strength is further improved by the embedded I-beam 97 and the like. In addition, what is buried in the place where the concrete filling 22 is cast is not limited to the I-shaped steel 97 or the like, and steel materials having various shapes such as an L-shaped steel and a T-shaped steel can be used. The thing of the shape which raises a coefficient is preferable.

The compressive force acting on the main girder (precast girder) by the tension applied to the tension member 76 is equal to the tension member 7.
Even if it is not possible to embed 6, since a compressive force is applied to the main girder (precast girder) from the place where both ends of the tension member 76 are fixed,
There is no particular problem. However, when a moving load acts on the bridge, it is most preferable that a compressive force acts at a position where the maximum bending moment acts on the main girder (precast girder). Therefore, by directly covering the steel surface of the tension member 76 with concrete, the tension member 76 and the concrete may be brought into close contact with each other, but for example, as shown in FIG. It is more preferable that the pressure ring 100 is pressed and that the convex ring 100 enhances adhesion and responsiveness to the concrete in which the tension member 76 is embedded.
The shape, material, and the like of the convex ring 100 are not particularly limited, and the intervals at which they are disposed are not particularly limited.

Next, the tension member 7 in the above-described embodiment is used.
The fixing device provided at the end portion such as 6 has a sleeve press-fitted, and a nut is screwed into a male screw formed on the sleeve, thereby fixing the tension member 76 and applying a tension. Was composed. It is not necessary to provide the fixing device having such a configuration at both ends of the tension member 76, and a wedge-type fixing device may be used at one or both ends. The wedge-type fixing device removes the divided wedges from the tension member 76.
The end of the tension member 76 is pinched by being inserted into the tapered surface between the grip and the grip. In addition to such fixing devices, it is also possible to use various fixing devices such as a fixing device using a male cone and a female cone, a fixing device using a wedge, an anchor head, a trumpet sheath, and the like. Absent. In any case, a fixing tool that can hold a wire composed of a plurality of fine wires for a long period of time and does not cause a situation such as cutting is used. However, in these fixing devices, wedges emerge due to vibration or the like, and the tension members 7
6 may become loose.

For this reason, in order to prevent the fixing device from loosening due to vibration or the like, it is possible to use a wedge-type fixing device 102 as shown in FIG. 12, for example. The wedge-type fixing device 102 includes an inner surface 104 that sandwiches the outer periphery of the end portion of the tension member 76 formed of a cable or a steel bar, and a tapered outer surface 106, and a male cone 108 divided by an axial plane thereof. And an inner surface 110 engaged with the tapered outer surface 106 of the male cone 108, and a female cone 114 having at least a screw portion 112 on the outer peripheral portion.
And a female screw portion 116 screwed to the screw portion 112 of the female cone 114, and the male cone 108 brought into contact with the end surface of the male cone 108 to connect the male cone 108 to the inner surface 11 of the female cone 114.
And a cap 120 provided with a convex portion 118 that is pushed to zero.

Therefore, by utilizing the fixing device 102, a predetermined tension is applied to the tension member 76 to thereby obtain a plurality of divided wedge-shaped male cones 108.
Bites into the tapered inner surface 110 of the female cone 114, and the tension member 76 is firmly tightened. Then, the cap 120 is screwed into the male cone 1 by the convex portion 118.
By pressing the end face 08, it is possible to prevent the male cone 108 from coming out due to vibration or the like, and to use it stably for a long period of time.

When the fixing member 102 is disposed at both ends of the tension member 76, at least one end of the tension member 76 is fixed by the fixing member 102, and then the female cone 114 is passed through the other end of the tension member 76. The male cone 108, which is divided while the other end of the female 76 is tensioned by using a hydraulic cylinder or the like, is used to form the tapered inner surface 11 of the female cone 114.
0, and the tension member 76 is fixed by the male cone 108 and the female cone 114. Thereafter, after the tension member 76 extending from the male cone 76 is cut at an appropriate position, the cap 120 is screwed into the screw portion 112 of the female cone 114 so that the male cone 108 does not come off from the female cone 114. . By such an operation, the fixing device 102 is firmly attached to the tension member 76, and the fixing device 102 does not loosen.

As described above, a typical example of the load-bearing reinforcement structure and the construction method according to the present invention has been described.
In particular, it is also possible to adopt another strength reinforcing structure and a construction method corresponding to the structure of the main girder (precast girder), and there is no particular limitation. For example, it is also possible to appropriately combine and configure each element in the above-described various types of strength reinforcing structures, and various construction methods can be adopted accordingly.

Further, the above-described strength reinforcing structure is not limited to concrete bridges, but can be applied to steel bridges. When applied to a steel bridge, the fixing member does not need to be large enough to cross the bridge, and is used by welding or screwing an individual fixing member to a part of the steel material constituting the main girder. That is, in the case of a steel bridge, the fixing member of the load-bearing reinforcement structure is directly fixed to the main girder constituting the steel bridge.

The embodiments of the load-bearing reinforcement structure, the method of construction thereof, and the fixing tool used therein according to the present invention have been described above. Next, the embodiment of the device for preventing a bridge from falling and the method of constructing the same according to the present invention will be described. explain.

First, as shown in FIG. 13 and FIG. 14, the bridge fall prevention device 122 is provided with one end of the precast girder 124 on the abutment 10 and the parapet 30 of the abutment 10 and the girder 1 are connected.
24, a through hole 126 is provided in the ground on the side of the stepping plate 34 at a position surrounding the parapet 30 and the precast girder 124, and the cable 1 is provided in the through hole 126.
28, and the parapet 30 and the precast girder 1
24 to prevent the bridge from falling. More specifically, a through hole 126 is provided at an appropriate position at the end of the precast girder 124 so as to allow at least two cables 128 to enter therein by a boring device or the like substantially in parallel with the end surface.

Next, in the case of a newly constructed bridge, a pipe or the like is arranged on the ground on the side of the stepping plate 34 so that the cable 128 can be arranged in an arc shape and buried with concrete. A pipe or the like is arranged and buried so that the cable 128 can be arranged in an arc shape in the portion and the ground cover 130, and the pipe forms a through hole 126, and is formed so that concentrated stress does not act on the cable 128. You.
The parapet 3 at the place where the cable 128 is provided
It is also possible to form the zero part by bending it into an arc shape.
On the other hand, in the case of an existing bridge, a through hole 126 is formed in the ground on the side of the stepping plate 34 in a direction along the parapet 30 by boring or the like.
The through-hole 126 is formed by bending as much as possible so that concentrated stress does not occur in the cable 128 when the cable 128 is inserted.

After the cable 128 is inserted through the through hole 126 configured as described above and the parapet 30 is wound about one and a half turns, the cable 128 is arranged.
Fixing devices 132 are attached to both ends of the cable 128. The anchor 132 is attached to the cable 128 such that when the bridge (precast girder 124) is moved by an earthquake, the precast girder 124 is allowed to move by a certain amount.

Therefore, when the bridge is moved by a large earthquake, the cable 128 moves by an extended amount,
As the extension of the cable 128 stops, the movement of the bridge is stopped, and the bridge is prevented from being dropped. Cable 128
Wire diameter, that is, the wire diameter and number of thin steel wires that compose it,
The number and arrangement position of the cables 128 should be set based on the total weight of the bridge and the like. It is also possible to use another type of bridge prevention device together with the bridge prevention device 122, and there is no particular limitation.

This fall prevention device 122 can be applied not only between a bridge and an abutment, but also for prevention of a fall between bridges continuously arranged on a pier.
That is, as shown in FIG. 13, a plurality of precast girders 124 and a plurality of precast girders 124 connected on the pier 134 are provided with through holes 126 at their respective ends in the same manner as described above. A cable 128 is inserted into the through-holes 126 so as to be wound around at least one and a half turns. Fixing tools (not shown) are attached to both ends of the cable 128, and fixed in the same manner as described above to prevent the bridge from falling. It constitutes. Also in this configuration, when a large earthquake occurs, the cable 12
The precast girder 124 and the precast girder 124 connected by 8 do not largely separate from the pier and do not fall.

Next, the above-mentioned bridge fall prevention devices 122 and 130 are described.
Can be applied to various floor slab bridges (slab bridges). In addition, as shown in FIG. 15 and FIG.
3 can also be applied. That is, a bridge is formed by arranging a plurality of precast T-beams 133 side by side, and a through hole 136 is provided at a position close to a horizontal beam 134 formed at an end of the plurality of T-beams 133. On the other hand, as shown in FIG. 16, a curved through hole 138 is formed in the ground on the side of the
Is provided. The curved through hole 138 can be formed by curving a part of the parapet 30 or by arranging a pipe with a curve and embedding it with concrete or earth and sand. Further, the through holes 136 of the T-spar 133 and the through holes 138 on the side of the
A curved through hole 142 is also formed in the parapet 30 part and the ground cover 140 part connecting
The cable 144 is inserted through the cables 138 and 142, and both ends of the cable 144 are fixed with the fixing tools 146, respectively, to constitute the fall prevention device 148.

In this embodiment, a similar effect can be obtained. Further, as shown in the figure, the bridge-fall preventing device 148 can be provided in two or three or more stages. In the case of a bridge composed of T-beams 133, it is not necessary to connect all of the T-beams 133 constituting the bridge together with a cable 144, and connect one or more units of the T-beam 133 with a cable 144. There is no particular limitation, for example.

It should be noted that the above-described bridge fall prevention devices 122 and 13 are provided.
0,148 can be applied not only to a newly built bridge, but also to an existing bridge. In addition, this fall bridge prevention device 12
Nos. 2,130,148 can be applied to steel bridges in addition to concrete bridges. However, when applied to a steel bridge, it is preferable to arrange the cables 128 and 144 and to arrange a guide member for preventing concentrated stress from acting on the cables 128 and 144.

Also, the above-mentioned bridge fall prevention devices 122 and 13 are provided.
At 0,148, the fixing devices 132, 142 attached to both ends of the cables 128, 144 preferably have a screw structure. However, when the amount of elongation of the cables 128 and 144 cannot be secured, as shown in FIG. 17, the cables 128 and 144 are fixed to one ends of the cables 128 and 144, and are set in advance when a tensile load is applied to the cables 128 and 144. Urging means 150 for urging the cables 128 and 144 in the axial direction with an amount of contraction, an elastic plate 152 capable of compressive elastic deformation, and a cap for ensuring the deformation behavior of the urging means 150 and the elastic plate 152 154 may be used at both ends of the cables 128 and 144. By using such a fixing device 156, it is possible to secure a preset elongation, that is, a moving amount of the precast girder 124.

The typical embodiments of the reinforcement structure for bridges and the device for preventing falling of bridges according to the present invention, the method of constructing them, and the fixing tools used in these devices have been described with reference to the drawings. Needless to say, the present invention is not limited to the illustrated embodiment.

For example, in the above-described drawings, the shape and structure of the abutment and the pier are substantially single, but it is needless to say that these shapes and structures have no relation in the application of the present invention. Further, the structure of the bearing portion is not limited to the above-described example, and although not illustrated one by one, it is needless to say that any of them is included in the scope of the present invention. In addition, the present invention is not limited to the primary-type bridge-fall prevention device, and the present invention is not limited to the anchor bar type, and various improvements, modifications, and modifications are made based on the knowledge of those skilled in the art without departing from the gist of the present invention. It can be implemented in.

[0059]

In the structure for reinforcing the strength of a bridge according to the present invention, the tension member is arranged on the lower surface side of the main girder constituting the existing bridge while being tensioned. The tensile force acting on the lower surface side of the main girder due to the load caused by the moving load of the moving vehicle or the like is canceled by the compressive force applied to the lower surface side of the main girder by the tensioned tension member. As a result, the strength of the bridge is increased as compared with the related art. In addition, since the strength reinforcing structure is achieved by the tension member and the weight of the bridge itself is not particularly increased, the strength can be surely increased without a decrease in the strength due to its own weight.

Next, a bridge fall prevention device according to the present invention is intended to be a device capable of at least preventing a bridge fall after a so-called primary-system bridge fall prevention device such as an anchor bar is destroyed by a large earthquake or the like. Parapets and bridges on the abutment, so that the relative movement between the abutment / pier and the bridge girder coming from the vibration caused by the large earthquake can be stopped slightly, at least within the range where the bridge is not dropped. A cable is wound between the bridges to form a bridge fall prevention device. Therefore, as long as the cable is not cut, the bridge is prevented from being dropped. Further, the bridge fall prevention device according to the present invention can be applied to any bridge, particularly if it is mainly a bridge made of precast girder, and versatility can be obtained.
It can be applied to existing bridges, and can prevent bridges from falling. Furthermore, the bridge prevention device of the present invention is easy to maintain due to its structure, and after a disaster occurs,
When repairing a bridge, it can be performed from the top of the bridge, and the work can be performed safely and quickly.

Next, in the fixing device according to the present invention, a cap for preventing the male cone from being loosened by further pressing the male cone against the female cone is provided on the conventional fixing device including only the male cone and the female cone. The male cone does not loosen due to vibrations transmitted by vehicles passing through the bridge, eliminating the need for maintenance and maintenance of fixing tools. Can be fixed, and the reliability is high.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing one embodiment of a bridge strength reinforcing structure according to the present invention, wherein FIG. 1 (a) is a fragmentary sectional view and FIG. 1 (b) is an enlarged sectional view of a principal part. .

FIG. 2 is an explanatory bottom view of a bridge to which the bridge strength reinforcement structure shown in FIG. 1 is applied.

FIG. 3 is an explanatory view of a bridge to which the reinforcement structure of the bridge shown in FIG. 1 is applied, wherein FIG.
(b) is an enlarged bottom view of a principal part of the load-bearing reinforcement structure.

FIG. 4 is a fragmentary cross-sectional view showing another embodiment of the reinforcing structure for a bridge according to the present invention.

FIG. 5 is an explanatory bottom view of the reinforcement structure of the bridge shown in FIG. 4;

FIGS. 6A and 6B are explanatory views showing still another embodiment of the reinforcement structure of the bridge according to the present invention, wherein FIG. 6A is a fragmentary cross-sectional view of a main part, and FIG. FIG.

FIG. 7 is an explanatory bottom view of the reinforcement structure of the bridge shown in FIG. 6;

FIG. 8 is a fragmentary sectional view showing still another embodiment of the reinforcement structure for a bridge according to the present invention.

FIG. 9 is an explanatory cross-sectional view of a main part showing another embodiment of the bridge strength reinforcement structure according to the present invention.

FIGS. 10 (a) and 10 (b) are cross-sectional explanatory views showing another embodiment of the reinforcing structure for a bridge according to the present invention.

FIG. 11 is an explanatory view of a principal part showing another embodiment of the tension member used in the bridge strength reinforcement structure according to the present invention.

FIG. 12 is an explanatory view showing an embodiment of a fixing device used in a bridge strength reinforcing structure and a bridge fall prevention device according to the present invention, wherein FIG. 12 (a) is a front sectional explanatory view, and FIG. It is a side view with cap removed.

FIG. 13 is an explanatory view showing an embodiment of a bridge fall prevention device according to the present invention, wherein FIG. 13 (a) is a front explanatory view and FIG.
(b) is an explanatory plan view.

14 is a fragmentary explanatory diagram of the bridge falling prevention device shown in FIG. 13;

FIG. 15 is an explanatory view showing another embodiment of the bridge fall prevention device according to the present invention, wherein FIG. 15 (a) is an explanatory front sectional view and FIG. 15 (b) is an explanatory side view. .

FIG. 16 is a fragmentary explanatory diagram of the bridge falling prevention device shown in FIG. 15;

FIG. 17 is an enlarged cross-sectional explanatory view showing another embodiment of the fixing device used in the bridge fall prevention device according to the present invention.

FIGS. 18 (a) and (b) are cross-sectional views of a main part showing the operation of a conventionally used anchor bar type fall prevention device together with its operation.

19A and 19B are explanatory views showing a conventionally-provided bridge fall prevention device, wherein FIG. 19A is an enlarged sectional view of a main part, and FIG. 19B is a side view of the main part.

[Explanation of symbols]

 10: Abutment 12: Bridge seat 14: Anchor bar 16: Main girder (girder) 18: Bearing 22: Filling concrete 24: Falling prevention device (primary system) 30: Parapet 34: Stepping plate 40, 42, 122, 148: Falling bridge prevention device 44: Connecting member 50, 68, 74, 82: Strength reinforcing structure 52, 54, 80: Fixing member 56, 76: Tension member 60: Embedded bolt 66, 102, 132, 146, 156: Fixing tool 70: Diagonal member (reinforcing member) 72: Load receiving portion 78: Direction changing member 84: Reinforcing member 86, 92: Hollow portion 94, 96, 124: Precast girder (main girder) 108: Male cone 114: Female cone 120: Caps 126, 136, 138, 142: Through holes 128, 144: Cable 130: Ground cover 133: T girder

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[Procedure amendment]

[Submission date] December 18, 1996

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 10

FIG. 2

FIG. 3

FIG. 4

FIG. 11

FIG. 5

FIG. 6

FIG. 8

FIG. 14

FIG. 7

FIG. 9

FIG.

FIG. 13

FIG.

FIG. 16

FIG.

FIG.

FIG.

Claims (8)

[Claims] 1. The underside of a main girder constituting an existing bridge,
At least one pair of fixing members fixed to the main girder are provided at two points separated in the main girder direction in the horizontal direction, and a tension member tensioned between the pair of fixing members is provided. A reinforcement structure for bridges, characterized by being installed. 2. The fixing device according to claim 1, wherein the fixing member comprises a member crossing a main girder constituting an existing bridge, and the fixing member is fixed directly or indirectly to each main girder. Strength reinforcement structure of the bridge to be described. 3. The main girder forming the existing bridge is made of precast concrete, and the fixing members are fixed to individual main girder or joints between the main girder. The structural strength reinforcement structure of a bridge according to claim 1 or 2. 4. The reinforcing structure according to claim 3, wherein the fixing member is reinforced by a reinforcing member stretched between the fixing member and an upper end of the main girder. Strength reinforcement structure for bridges. 5. The underside of a main girder constituting an existing bridge,
A cable is disposed between two points separated in the direction of the main girder, and both ends of the cable are bent upward at the ends of the main girder, respectively, and tightened tightly to the main girder, and compressed on the lower edge side of the main girder. Strengthening structure for bridges characterized by supplementing the pre-stress of the bridge. 6. The girder of claim 5, wherein a main girder constituting the existing bridge is made of precast concrete, and the cable is disposed at a joint between the precast girder. Strengthening structure of bridges that do. 7. An apparatus for preventing falling of a bridge provided at one end of a precast girder on an abutment and provided on a parapet of the abutment and an end of the girder. A bridge fall prevention device, wherein a through hole is provided in the girder, and a cable is inserted through the through hole to connect the parapet and the precast girder to prevent the bridge from falling. 8. A male cone having an inner surface sandwiching an outer periphery of an end portion of a cable or a steel rod and a tapered outer surface, and being engaged with a male cone divided by the axial plane and a tapered outer surface of the male cone. A female cone having at least a threaded portion on the inner surface and the outer peripheral portion to be mated, a female threaded portion screwed into the threaded portion of the female cone, and And a cap having a convex portion to be pressed into the inner surface of the fixing device.