JPH08232213A - Method and equipment for reinforcing existing bridge - Google Patents

Abstract

PURPOSE: To correctly execute the reinforcement of an existing concrete girder from the lower part of the girder, and to dispense with the traffic restriction or a large scale civil construction. CONSTITUTION: One end 5 of a strip-shaped tension member 4 is fixed to a side 3 of a skeleton 2 of a bridge girder 1 by a fixing tool 6, and a frame 21 of a tracting equipment 20 is fixed to the other end 9 of the bridge girder 1 by bolts and nuts 10. In the tracting equipment 20 fitted symmetrical to the right and left of the skeleton 2, a roll 22 for reversing the tracting direction is fixed in the frame 21, and a roll 25 for traction which is fitted to a movable frame 24 is provided. The reaction force of a jack 26 is supported by the frame 21 to tract the movable frame 24, and when the strip-shaped tension member 4 reaches the preset tension, the end part of the strip-shaped tension member 4 is fixed by a fixing device 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing an existing bridge and a device therefor.

[0002]

2. Description of the Related Art Due to the recent revision of the Road Traffic Law, due to an increase in truck loads and the like, a situation has arisen in which repairs are required to increase the strength of the frame and piers of existing bridge girders. For steel bridges and the like, reinforcement by addition of steel may be considered, but for concrete bridge girders, such reinforcement is not easy. There is also a means of providing an external cable and assisting to pull near the lower surface of the frame of the bridge girder, but there are problems such as the fixing part structure of the cable, the bending up structure of the cable, and the problem of anticorrosion of the cable.

[0003]

The present invention has been developed in view of such circumstances, and (a) it can be easily fixed to the frame or pier of a concrete bridge girder. (B) tension pulling of a reinforcing member. (C) No need for work on both sides of the bridge in the longitudinal direction (d) No problem such as corrosion (e) Work can be performed symmetrically on the left and right sides of the bridge girder (f) Portable It can be used for many bridge girders easily and repeatedly using the equipment. (G) It is used for the reinforcement method of existing concrete bridge girders and its construction to avoid problems such as avoiding obstacles and not causing deterioration of landscape. The purpose is to provide a device.

[0004]

According to the present invention, one end of a band-shaped tension member is fixed to both sides of a skeleton near one end of a concrete bridge girder, and both sides of the skeleton near the other end of the bridge girder are respectively fixed. The reinforcing method of an existing bridge is characterized in that the other end of the strip-shaped tension member is simultaneously pulled, and the other end of the pulled strip-shaped tension member is fixed to the vicinity of the other end of both side surfaces of the body.

Further, one end of the band-shaped tension member is fixed to the side surface of the upper or lower end of the concrete pier, the other end of the band-shaped tension member is pulled at the other end of the pier, and the other end of the pulled band-shaped tension member is pulled. A method for reinforcing an existing bridge, characterized in that it is fixed near the other end of the pier. Furthermore, a strip-shaped tension member is spirally wound around the outer surface of the concrete pier, and one end of the strip-shaped tension member is fixed to the pier outer surface. It is a method of reinforcing existing bridges, which is characterized by fixing to the outer surface of the pier and introducing hoop stress to the pier.

An apparatus of the present invention capable of suitably carrying out the above method is a frame mounted inside the end of a concrete bridge girder in the longitudinal direction of the girder, and a roll mounted on the frame and inverting the direction of the strip tension member. A reinforcing device for an existing bridge, characterized in that the frame is provided with a towing device for supporting a reaction force and towing a belt-shaped tension member. Further, it is preferable that the frame of this device can be attached to the outer surface of the pier so that it can be used for enhancing axial stress and hoop stress of the pier.

[0007]

The function of the existing concrete bridge girder of the present invention is as follows.
A band-shaped tension member is used instead of an external cable. As the belt-shaped tension member, FRP (fiber reinforced plastic) obtained by molding fibers such as polyamide fiber and carbon fiber into a belt shape is used. The required tensile strength depends on the fiber type,
Any thickness can be obtained depending on the thickness and width of the strip.

When reinforcing the existing concrete bridge girder, both ends of the strip-shaped tension member are fixed near the end of the frame. The bending moment due to the load on the bridge girder is minimized at both ends of the bridge girder, and is large at the center, so reinforcement is rational. In addition, since belt-shaped tension members are attached to both side surfaces of the frame of the concrete bridge girder and pulling and tensioning at the same time, bilateral symmetry is prevented and an unbalanced load is not generated.

The tension of the strip tension member introduces stress into the concrete. The magnitude of this stress can be determined according to the concrete bridge girder to be reinforced. The belt-shaped tension member can effectively reinforce the side surface of the existing concrete bridge at a position where it does not interfere. Moreover, since it is attached to the side surface of the frame of the bridge girder, it does not damage the landscape.

There are two methods for reinforcing the piers of concrete bridges: introducing stress in the axial direction of the piers and introducing hoop stress as reinforcement against shearing of the piers. The former will reinforce the bridge girders in the vertical direction.
That is, belt-shaped tension members are simultaneously attached to a plurality of planes symmetrical with respect to the axial center of the bridge pier, and the tension members are tensioned and fixed. It is as if the horizontal reinforcement of the bridge girder is carried out in the vertical direction. For example, one end of the band-shaped tension member is fixed to the upper end of the bridge pier, and the tension device is fixed to the foundation of the lower end to tighten and fix it.

Regarding the hoop stress, a band-shaped tension member is helically wound around the outer surface of the concrete pier to introduce the stress. The stress is introduced by repeatedly applying tension and fixing at an appropriate length along the longitudinal direction of the belt-shaped tension member wound in a spiral state so as to reach the entire outer surface of the pier. This appropriate length depends on the cross-sectional shape of the pier. For example, when the cross section is surrounded by a continuous curve of circular, oval, elliptical or similar smooth arcs, the belt-shaped tension members are sequentially pulled and fixed every 0.5 to 2 turns. Often,
When the cross section is rectangular, trapezoidal, polygonal, etc., it is advisable to repeat the tension fixing for each side.

The device of the present invention is a device for easily tightening and fixing the band-shaped tension member, and has a frame attached to the end of the concrete bridge girder inward in the girder longitudinal direction. A roll that reverses the direction of the belt-shaped tension member and a traction device that easily pulls the reversed tension member are provided in this frame. This towing device includes a towing roll around which a tension member reversed by a reversing roll is wound, and a jack for towing the towing roll. The towing roll has a mechanism that rotates to wind around the end of the tension member several times to endure pulling and to prevent rotation when towing with a jack. The jack exerts a reaction force on the frame, and the frame is fixed to the inner surface of the span at the end of the bridge girder. Therefore, tension consolidation can work within the span of the bridge. No special preparatory work or equipment layout is required for the extension outside the span of the bridge, so reinforcement can be performed quickly and labor-savingly. By mounting this device on both the left and right sides of the frame of the bridge girder and synchronizing the left and right simultaneously to pull and tension the belt-like member, stress can be introduced to the bridge girder without imbalance.

[0013]

Embodiments of the present invention will be described in detail with reference to the drawings. Figure 1 shows the sides 3 and 3 of the frame 2 of the concrete bridge girder 1.
It is a top view of the process of attaching the belt-shaped tension member 4 to FIG. Figure 2
FIG. 3 is a side view of FIG. 1. FR on side 3 of frame 2 of bridge girder 1
One end 5 of the band-shaped tension member 4 made of P is fixed with a fixture 6. The fixture 6 is composed of a holding plate 7 and a bolt nut 8. The fixture 6 fixes together the band-shaped tension members 4 arranged on the side surfaces 3 and 3 of the body 2 by means of bolts and nuts 8 which are inserted across the body 2.

The frame 21 of the traction device 20 is fixed to the other end 9 of the bridge girder 1 with bolts and nuts 10. The tow devices 20 are symmetrically attached to the left and right of the body 2. The traction device 20 has a frame 21 in which a traction direction reversing roll 22 is fixedly mounted in a fixed bearing 23.
And a towing roll 25 supported by the movable frame 24.
It has. The movable frame 24 is a rod 27 of a jack 26.
It is connected to. The jack 26 pulls the movable frame 24 while the reaction force is supported by the frame 21. The reaction force of the jack 26 is supported by the concrete at the other end 9 of the bridge girder 1 via the frame 21.

The band-shaped tension member 4 is wound around the pulling direction reversing roll 22 and then around the pulling roll 25. The tow roll 25 rotates freely when the belt-shaped tension member 4 is wound, and moves toward the jack 26 without rotating when the jack 26 pulls the movable frame 24.
The band-shaped tension member 4 is pulled. An example of a mechanism for preventing this rotation is shown in FIGS. FIG. 6 shows a ratchet 41 and a ratchet wheel 42 for preventing rotation of the tow roll 25.
And FIG. 7 is a side view thereof. Further, FIG. 8 shows a shaft recess 45 and a mechanism or the like in which the recess 45 enters the groove 46 to prevent rotation when the jack is pulled. FIG. 9A shows a recess 45 of the tow roll shaft. When the jack 26 pulls the tow roll 25, the recess 45 is fitted into the groove 46 and rotation of the roll 25 is prevented. Of course, in addition to this, for example, a reverse rotation preventing mechanism such as a coaster, a mechanism for attaching and detaching a fixed element such as a key and a cotter, a clutch mechanism such as a dog clutch, a friction clutch, and a cam may be used. It may be driven by an automatic device or the like.

Next, the construction for reinforcing the bridge girder by the method of the present invention will be described. The band-shaped tension member 4 fixed to one end side of the body 2 is fixed to both side surfaces by through bolt nuts 8 provided by sewing the body 2, and is extended to the other end side along the side surface 3 of the body 2 and the pulling direction is reversed. Is wound around the towing roll 25 via the towing roll 22 and
Is towed by jack 26. Left and right jacks 26, 2
6 are synchronized and pull with the same pulling force.

When the belt-shaped tension member 4 is pulled until it reaches a predetermined tension, the fixing device 30 fixes the end portion of the belt-shaped tension member 4. The fixing device 30 includes a holding plate 31 and a bolt nut 32, and the bolt nut 32 penetrates the body 2 to fix the left and right band-shaped tension members of the body together. FIG. 3 shows the frames 2, 2 of the concrete bridge girders 1a, 1b, 1c, ...
The process of sequentially attaching the belt-shaped tension members to 2, ... is shown, and when the construction of the bridge girder 1a is completed, the second traction device 20 is transferred to the bridge girder 1b, and the bridge girders 1b are sequentially installed.

FIG. 4 shows the reinforcement in the longitudinal direction of the pier. One end of the strip-shaped tension member 4 is driven into the side surface of the upper end of the concrete pier and fixed with a fixture 5 using an anchor, and the other end of the strip-shaped tension member is pulled at the lower end of the pier,
It shows a method of reinforcing an existing bridge by fixing the other end of the pulled band-shaped tension member near the other end of the pier. FIG. 5 (a),
(B) is a spirally wound tension member covering the outer surface of a concrete pier in a spiral shape, one end of which is fixed to the outer surface of the pier, and the tension member is pulled once every one to two turns, and the pulled tension member The method of reinforcing the existing bridge by fixing the tension member to the outer surface of the pier and introducing hoop stress to the pier is shown.

[0019]

According to the present invention, an existing concrete bridge girder can be easily reinforced, and since the reinforcing material is attached to both side surfaces of the skeleton, it does not project and does not damage the landscape, Reinforcement is carried out accurately. In addition, the reinforcement work can be performed from below the girder, and does not require special traffic interruptions or major civil engineering work.

The device of the present invention can easily tension the band-shaped tension member for each digit. In addition, it becomes possible to easily perform reinforcement in the longitudinal direction of the column, reinforcement in the hoop stress direction, and the like.

[Brief description of drawings]

FIG. 1 is a plan view illustrating a method for reinforcing an existing concrete bridge according to an embodiment.

FIG. 2 is a side view illustrating a method of reinforcing an existing concrete bridge according to an embodiment.

FIG. 3 is a plan view illustrating a method for reinforcing an existing concrete bridge according to an embodiment.

FIG. 4 is a vertical cross-sectional view illustrating a method for reinforcing an existing concrete pier according to an embodiment.

5 (a) is a transverse sectional view and FIG. 5 (b) is a side view for explaining a method of reinforcing an existing concrete pier in the example.

FIG. 6 is an explanatory diagram of a rotation preventing mechanism of a tow roll.

FIG. 7 is an explanatory diagram of a rotation preventing mechanism of a tow roll.

FIG. 8 is an explanatory diagram of a rotation blocking mechanism of a tow roll.

FIG. 9 is an explanatory diagram of a rotation blocking mechanism of a tow roll.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Bridge girder 2 Body 3 Side surface 4 Tension member 5 End part 6 Fixing tool 7 Holding plate 8 Bolt nut 9 Other end 10 Bolt nut 20 Traction device 21 Frame 22 Inversion roll 23 Fixed bearing 24 Movable frame 25 Traction roll 26 Jack 27 Rod 30 Fixing device 31 Holding plate 32 Bolt nut 41 Ratchet 42 Ratchet wheel 45 Recess 46 Groove

Claims (5)

[Claims] 1. A concrete bridge girder has one end of a strip-shaped tension member fixed to both side surfaces of a skeleton in the vicinity of one end thereof, and the other end of the strip-shaped tension member in each side of the skeleton near the other end of the bridge girder. A method for reinforcing an existing bridge, which comprises: simultaneously pulling and fixing the other end of the pulled band-shaped tension member to the vicinity of the other end of each side surface of the body. 2. One end of a strip-shaped tension member is fixed to a side surface of an upper end or a lower end of a concrete pier, the other end of the strip-shaped tension member is pulled at the other end of the pier, and the other end of the pulled tension member is stretched. A method of reinforcing an existing bridge, characterized in that the end is fixed near the other end of the pier. 3. A strip-shaped tension member is spirally wound around the outer surface of a concrete bridge pier, and one end of the strip-shaped tension member is fixed to the outer surface of the pier. A reinforcement method for an existing bridge, characterized in that a strip-shaped tension member is fixed to the outer surface of the pier and hoop stress is introduced into the pier. 4. A frame attached to the inside of a girder longitudinal direction at the end of a concrete bridge girder, a roll attached to the frame for reversing the direction of the band-shaped tension member, and a pulling force of the frame-shaped tension member for supporting a reaction force. A reinforced device for an existing bridge, comprising: 5. The reinforcement device for an existing bridge according to claim 4, wherein the frame includes a fixing portion that is fixed to the outer surface of the concrete pier.