JPH07293000A - Prestressing device - Google Patents

Abstract

PURPOSE:To repair and reinforce a bending crack by rotatably attaching a pair of tensioning members in both side positions across a portion to be prestressed, connecting the tensioning members to a connection, and exerting each tensioning member with a tensile force in the direction of its axis and toward the connection. CONSTITUTION:After a prestressing device 4A is attached to a member 100 to be repaired, locknuts 20, 21 are tightened to apply an axial tension P to tensioning members 17, 18. The magnitude of the axial tension P is adjusted by adjustment of the amount of tightening of each locknut 20, 21. The axial tension P is decomposed into a vertical force PV and a horizontal force PH at locking members 5, 12, and, since a bending crack C1 is prestressed by the horizontal force PH, the bending crack C1 is repairable using simple constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for introducing a prestressing force to a structural member such as a bridge girder or a beam of a building, and is particularly suitable for repairing cracks, fatigue damage, etc., and reinforcing for insufficient load bearing capacity. Prestressing device.

[0002]

2. Description of the Related Art In general, girders and beams such as roads and railway bridges may suffer cracking, fatigue damage, and insufficient load capacity due to deterioration over time and an increase in load.

[0003] Conventionally, as a method of repairing such a member by repairing the insufficient load capacity, a steel plate bonding method, a prestressing method, a cross-section increasing method, or an additional member method is known.

[0004]

However, the place where such repair work or reinforcement work is often restricted by traffic conditions, and the use of large-scale construction machines is restricted in the construction while allowing passage.

Further, for example, in the case of reinforcing by a steel plate bonding method, in order to carry out the reinforcing work while using the structure,
In addition to requiring large-scale temporary construction and large-scale construction machinery, the cost not only increases, but also work such as attaching a reinforcing steel material to an existing structure is subject to restrictions on working space and working time.

Therefore, it is an object of the present invention to provide a prestress introduction device capable of effectively repairing and increasing the yield strength with a simple structure.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 is such that one ends thereof are rotatably connected to each other to form a substantially V-shape or a substantially inverted V-shape, Each of the other end portions is connected to a pair of tension members rotatably attached to both sides of the member sandwiching the prestress introduction target portion, and a connecting portion of the pair of tension members, and the tension member is provided with the tension member in the axial direction. And a tension device that applies a tensile force toward the connecting portion side.

According to the second aspect of the present invention, one end portions are rotatably connected to each other to form a substantially V shape or a substantially inverted V shape, and each other end portion is a prestress introduction target portion in the member. And a pair of first tension members rotatably attached to both sides sandwiching each other, one end of which is rotatably connected to each other to form a substantially V-shape or a substantially inverted V-shape, and each of the other ends is the above-mentioned. A pair of second tension members rotatably attached to the member at an appropriate interval from the first tension member, and a tensile force between the connecting portions of the first tension member and the second tension member. And a tensioning device for applying.

[0009]

According to the first aspect of the present invention, by applying a tensile force to the connecting portion of the tension members by the tension device, the tension force in the axial direction acts on each tension member.

At this time, mutually opposite forces, that is, a compressive force to the prestressing target portion of the member, acts on the other end of each tendon, and this compressive force acts as a prestressing force, so that cracking or the like occurs. The prestress introduction site will be reinforced.

According to the invention described in claim 2, the first
By applying a tensile force by the tensioning device between the connecting portions of the tension member and the second tension member, a compressive force acts between the other ends of the first tension member and the other end of the second tension member. A tensile force opposite to the compressive force of the first tendon acts between the parts. As a result, the action of the compressive force of the first tension member on the prestressing target portion of the member acts so that the tensile force of the second tension member assists, and the prestress force can be effectively introduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described with reference to the drawings. First Embodiment FIGS. 1 and 2 show a first embodiment of the present invention.

The present embodiment discloses a prestress introducing device 4A capable of simultaneously repairing a bending crack C ₁ and an adhesive split crack C ₂ that have occurred in a member 100 to be repaired, such as a bridge girder using I type steel.

That is, as shown in FIGS. 1 and 2, the prestress introducing device 4A is provided with the web 2 of the member 100 to be repaired.
It has locking members 5 and 12 such as steel rods that can penetrate through.
A tension member 8 made of a metal wire rope or the like is connected to one end portion in the axial direction via a connecting portion 6 (hinge) that is rotatable in the circumferential direction of the locking member 5, and the shaft of the locking member 12 is similarly. A connecting portion 1 which is rotatable in the circumferential direction of the locking member 12 at one end in the direction
A tension member 15 such as a metal wire rope is connected via 3. The ends of the tension member 8 and the tension member 15 are rotatably connected to each other by a connecting portion 10 (hinge), and the tension member 8 and the tension member 15 are connected to each other in a substantially V shape. A pulling member 17 arranged vertically is connected to the connecting portion 10, a screw is formed at the other end of the pulling member 17, and the pulling member 17 is fastened by a tightening nut 20 to a bottom contact member 19 constituting a tensioning device. ing.

Similarly, a tension member 9 such as a metal wire rope is attached to the other axial end of the locking member 5 via a connecting portion 7 (hinge) which is rotatable in the circumferential direction of the locking member 5. Is connected to the other end of the locking member 12 in the axial direction.
A tension member 16 such as a metal wire rope is connected via a connecting portion 14 (hinge) that is rotatable in the circumferential direction.
The ends of the tension member 9 and the tension member 16 are rotatably connected to each other by a connecting portion 11 (hinge), and the tension member 9 and the tension member 16 are connected to each other in a substantially V shape. A vertically extending tension member 18 is connected to the connecting portion 11, and a screw is formed at the other end of the tension member 18, and a fastening nut 21 is used to fasten the bottom member 19 made of metal at the threaded portion. Has been done.

When the prestress introducing device 4A is attached to or attached to the repair target member 100, through holes for the locking members 5 and 12 are formed at positions extending over both sides of the bending crack C ₁ . 12 is penetrated, and the locking members 5, 1
The tensioning members 8, 15 and the tensioning members 9, 16 are attached to the respective ends of 2. At this time, the tension members 8 and 15, the tension member 17, and the tension members 9 and 16 and the tension member 18 are positioned on both surfaces of the web 2. Then, the tension member 1
7 and 18 are passed through the flange 3 and the bottom contact member 19 is applied to the lower surface of the flange 3, and then the tension members 17 and 18 are applied.
Are tightened by tightening nuts 20 and 21, respectively.

Next, the operation will be described. As mentioned above,
After attaching the prestress introduction device 4A to the repair target member 100, the tightening nuts 20 and 21 are tightened, and the tension member 1
Axial tension P is applied to 7 and 18. The magnitude of the axial tension P is adjusted by adjusting the tightening amount of the tightening nuts 20 and 21.

Axial tension P applied to the tension members 17 and 18
Are transmitted to the tensioning members 8 and 15 and the tensioning members 9 and 16, respectively, so that the locking members 5 and 12 are acted on by the force expressed by the following equation.

Vertical force P acting on the locking members 5 and 12
_V P _V = 1/2 · P (1) Horizontal force P _H P _H = P / 2 tan θ acting on the locking members 5 and 12 (2) where θ: line connecting the locking members 5 and 12 Minute and tension member 1
The angle at which the 7 (or 18) axis intersects.

In this way, the axial tension P is determined by the locking members 5, 12
In, the vertical force P _V and the horizontal force P _H are decomposed, and the bending crack C ₁ is prestressed by the horizontal force P _H, so that the bending crack C ₁ can be repaired with a simple configuration.

As can be seen from the equation (2), by making the crossing angle θ small, even if a small axial tension force is applied to the tension member 17, a large compression force acts between the locking members 5 and 12. be able to. As a result, it is possible to effectively repair and increase the yield strength with a simple structure without requiring a large-scale device.

Further, a bottom contact member 19 is attached to the lower surface of the flange 3 at the site where the adhesive split crack C ₂ occurs,
Since the flange 3 is tightened by the reaction force of the axial tension P by the tension member 17 and the tightening nut 20, the split of the web 2 and the flange 3 at the portion of the adhesive split crack C ₂ can be repaired at the same time, and the bending strength can be improved. It is also effective for enhancing

Further, when the prestress introducing device 4A is applied to a girder of a bridge, a floor of a building, etc., since the installation work of the prestress introducing device 4A is performed under the girder, etc. It does not interfere with traffic.

Furthermore, since the structure of the prestressing device 4A is simple, mounting and prestressing can be easily carried out, and the device itself can be manufactured easily. In addition, since the pre-stress introduction device 4A itself can be configured in a relatively small size, temporary work such as large-scale scaffolding is not required, and installation work can be performed in a narrow space. Therefore, installation work efficiency and work time can be reduced. It is possible to shorten it.

The above effects are the same in the second and third embodiments described later. In the above description, the bending has been described the presence of cracks C ₁ and Bond Splitting cracks C ₂ assumes, cracks C ₁ bending site prestress introduced to Bond Splitting cracks C ₂ is deemed necessary, even if not occurred Member 1 to be repaired by mounting the device 4A
The method of use is not limited to the above-mentioned embodiment, since the reinforcement of 00 can be achieved.

Further, in the above description, since it is assumed that a bridge girder or the like is assumed, the tension member 17 is arranged in the vertical direction. However, depending on the installation mode of the prestress introducing device 4A, the direction of each element may be different. However, the names of the vertical force P _V and the horizontal force P _H are not limited to those directions, and the tension members 8 and 15 are made of metal wire. Although it is a rope, it is also possible to use a steel rod, a steel pipe, or the like. Second Embodiment FIG. 2 shows a second embodiment of the present invention.

In this embodiment, bending cracks C ₃ , C at a plurality of locations (two locations in the figure) of the web 2 of the member 100 to be repaired are used.
_A prestressing device 4B of a bi-prestressing method suitable for repairing when there are 4 is disclosed.

That is, as shown in FIGS. 3A and 3B, a compression member such as a metal pipe is connected to one end of a locking member 24 such as a steel rod penetrating the upper portion of the web 2 via a connecting portion 22. 6
7 is rotatably connected, and a compression member 68 such as a metal pipe is connected to one end of a locking member 29 that also penetrates the upper portion of the web 2 via a connecting portion 27. The distance between the locking member 24 and the connecting portion 27 is located outside the bending cracks C ₃ and C ₄ . Next, the tension members 67 and 68 are rotatably connected at the connecting portion 25. Tension members 67 and 68
And are connected in an inverted V shape.

Similarly, the other end of the locking member 24 is connected to the connecting portion 23.
A compression member (not shown) similar to the compression member 67 is rotatably connected to the other end of the locking member 29, and a compression member similar to the compression member 68 (FIG. (Not shown).

On the other hand, on the side of the bending crack C ₃ in the lower portion of the web 2, a tension member 6 such as a metal wire rope is connected to one end of a locking member 34 such as a steel rod via a connecting portion 33.
5 rotatably connected to each other, and also on the side of the bending crack C ₄ in the lower part of the web 2 as well, the locking member 3
A tension member 66, such as a metal wire rope, is rotatably connected to one end of 6 through a connecting portion 35. In this way
The tension members 65 and 66 are connected in an inverted V shape.

Similarly, the other end of the locking member 34 is connected to the connecting portion 33.
A tensioning member (not shown) similar to the tensioning member 65 is rotatably connected via the same, and is also connected to the other end of the locking member 36 at the side of the bending crack C ₄ in the lower portion of the web 2. A tension member (not shown) similar to the tension member 66 is rotatably connected via the portion 33.

As can be seen from FIG. 3 (b), a pulling member 37 such as a steel rod is attached to the connecting portion 25 and a pulling member such as a steel rod is attached to the connecting portion 30 in the vertical direction on one surface side of the web 2. The members 38 are rotatably connected to each other. The pulling members 37 and 38 are provided at their distal ends with mutually opposite screws, and are screwed into a tightening nut 39 such as a cap nut. Similarly, tensile members 40 and 41 such as steel rods are connected to the other surface side of the web 2 so that these tensile members 40 and 4
1 is also screwed into the tightening nut 42 with a reverse screw.

Next, the operation will be described. In the prestress introduction device 4B shown in FIG. 3, the tightening nut 39 is rotated to apply the axial tension P ₁ to the tension member 37, and the tension member 3
Axial tension P ₂ is applied to 8. Similarly, the tightening nut 42 is rotated to apply the axial tension P ₁ to the tension member 40 and the axial tension P ₂ to the tension member 41, respectively.

Axial tension P applied to the tension members 37 and 38
₁ and P ₂ are transmitted to the respectively transmitted tension members 65 and 66 and tension members 67 and 68, and as a result, the following forces act on the locking members 24, 29, 34 and 36.

The vertical force acting on the locking member 24 and the _{29 P V1 P V1 = 1/} 2 · P 1 ... (3) horizontal force acting on the locking member 24 and the _{29 P H1 P H1 = P 1} / 2tanθ 1 (4) where θ ₁ is the angle at which the line segment connecting the locking members 24 and 29 and the axis of the tension member 37 (or 40) intersect.
The horizontal force P _H1 acts as a tensile force.

The vertical force P _V2 P _V2 = 1/2 · P ₂ (5) acting on the locking members 34 and 36 (5) The horizontal force P _H2 P _H2 = P ₂ / P acting on the locking members 34 and 36 ₂ tan θ ₂ (6) where θ ₂ is the angle at which the line segment connecting the locking members 34 and 36 and the axis of the tension member 38 (or 41) intersect.
The horizontal force P _H2 acts as a compressive force.

In this way, the tightening nuts 39 and 42
Applied axial tension P₁, P₂Are the locking members 24, 29
The vertical force P is applied to the locking members 34 and 36._V1And horizontal force
P_H1And the vertical force P_V2And horizontal force P_H2Each smell
Bending crack C ₃And C_FourAgainst and water
Flatness P_H1, P_H2Pre-stress (compression force) introduced by
Bending crack C₃And C_FourIn each
And they are in close contact and can repair each crack.
Maintain the soundness of the repair target member 100 with a simple configuration.
It is also effective in increasing bending strength.Third embodiment FIG. 4 shows a third embodiment of the present invention.

In the present embodiment, the prestress introducing device 4C generates, for example, a horizontal member P _H which acts to bring the crack faces of the bending crack C ₄ generated in the concrete repair target member 100 into close contact with each other. This is an example in which the repair target member 100 is repaired by applying stress.

That is, as shown in FIGS. 4A and 4B, a steel locking bar 58 penetrating in the transverse direction of the repair target member 101 is provided on the upper side of the web 43 of the repair target member 101. . Both ends of the locking bar 58 are suspended from the lower surface of the girder 75, the suspension members 70 and 73 and the fixing nut 7.
1, 74 are suspended and supported.

On the other hand, on the lower surface of the flange 44, the web 4
3 and the member 44 to be repaired at the positions (2 places) where the bending shear crack C ₅ generated between the flange 44 is sandwiched.
Bottom support members 49 and 54 extending in the transverse direction are additionally provided.

A pulling member 57 made of a steel rod or the like fastened by a fixing nut 59 is hung at one end of the locking bar 58, and the pulling member 57 has an inverted V-shape via a connecting portion 56. Tensioning member 50 made of metal wire rope,
55 is rotatably connected. The end of the tension member 50 is rotatably connected to the connecting portion 46 of the fixing bolt 47 fixed to the one end of the bottom contact member 49 by the fixing nut 48. An end portion of the tension member 55 is rotatably connected to a connecting portion 51 of a fixing bolt 52 fixed by a fixing nut 53 to one end portion of the bottom contact member 54.

At the end portion of the locking bar 58, the tension members 69, 63 and the other tension member (not shown) have an inverted V-shape between the locking bar 58 and the bottom contact member 54 in the same structure as described above. The pre-stress introduction device 4C is formed.

In the above construction, the fixing nuts 59, 7
Axial tension P is applied to the tension members 57 and 69 by tightening 2
Is applied, and the axial tension P is applied to the vertical force P _V and the horizontal force P _{H at the} connecting portions 46, 51, 62 and the connecting portion (not shown).
Is decomposed into. At this time, since the horizontal force P _H acts in the direction shown in FIG. 4A, it acts as a compressive force on the bending shear crack C ₅ .

The vertical force P _V and the horizontal force P _{H at the} connecting portions 46, 51, 62 and the connecting portion (not shown) are expressed as follows. To _{P V = 1/2 · P} ... (7) P H = P / 2tanθ ... (8) where, theta: tensile segment connecting connecting portions 46 and 51 (or connecting portions 62 and the not shown coupling portion) member 57 (or 6
This is the angle at which the axis of 9) intersects.

[0045] Thus, according to this embodiment, bending shear for cracking prestressing compressive force by the horizontal force P _H with respect to C ₅ are introduced, bending shear cracks C ₅ is in close contact flange 44 and The web 43 can be repaired.

In this embodiment, as in the other embodiments, the member to be repaired 1 when the bending shear crack C ₅ does not exist.
01 can be used as a reinforcing device.

[0047]

As described above, according to the first aspect of the present invention, the tensioning device applies a tensile force to the pair of tension members to attach each of the pair of tension members to the member (locking portion). Since inward horizontal forces can be generated on each other, it is possible to repair and reinforce bending cracks with a simple device configuration.

According to the second aspect of the present invention, the tensioning device simultaneously applies a tensile force to the first and second tension members to attach each of the first and second tension members to the member. Since the inward horizontal forces can be generated in each of the (locking portions), a prestress of double the size of the invention of claim 1 is introduced to the bending crack with a simple structure. It is possible to repair and reinforce.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a prestress introduction device of the present invention.

2A and 2B show a first embodiment of the prestressing apparatus of the present invention, in which FIG. 2A is a front view and FIG. 2B is A in FIG.
FIG.

FIG. 3 shows a second embodiment of the prestressing apparatus of the present invention, (a) being a front view and (b) being a B in (a) figure.
It is a -B sectional view.

FIG. 4 shows a third embodiment of the prestressing apparatus of the present invention, (a) is a front view and (b) is a C in FIG.
FIG.

[Explanation of symbols]

_{C 1, C 3, C 4} ... flexural crack C ₂ ... Bond Splitting cracking C ₅ ... bending shear crack P, P _1, P ₂ ... axial pull _{P H, P H1, P H2} ... horizontal force P _V, P _V1, P _V2 ... Vertical force 1 ... Flange 2 ... Web 3 ... Flange 4A, 4B, 4C ... Pre-stress introduction device 5 ... Locking member 6, 7 ... Connection part 8, 9 ... Tension member 10, 11 ... Connection part 12 ... Engagement Stop member 13, 14 ... Connection part 15, 16 ... Tension member 17, 18 ... Tensile member 19 ... Bottom support member 20, 21 ... Tightening nut 22, 23 ... Connection part 24 ... Locking member 25, 26, 27, 28 ... connecting part 29 ... locking member 30, 31, 32, 33 ... connecting part 34 ... locking member 35 ... connecting part 36 ... locking member 37, 38 ... tension member 39 ... tightening nut 40, 41 ... tension member 42 … Tightening nut 43… Web 44… Flange 46… Stationary Part 47 ... Fixing bolt 48 ... Fixing nut 49 ... Bottom contact member 50 ... Tension member 51 ... Connecting part 52 ... Fixing bolt 53 ... Fixing nut 54 ... Bottom contact member 55 ... Tension member 56 ... Connecting part 57 ... Tension member 58 ... Engagement Stop bar 59 ... Fixing nut 60 ... Fixing bolt 61 ... Fixing nut 62 ... Connecting part 63 ... Tensile member 64 ... Connecting part 65, 66, 67, 68 ... Tensile member 69 ... Tensile member 70 ... Suspension member 71, 72 ... Fixing Nut 73 ... Suspension material 74 ... Fixing nut 75 ... Girder 100, 101 ... Repair target member

Claims (2)

[Claims] 1. One end of each member is rotatably connected to each other to form a substantially V-shape or a substantially inverted V-shape, and each of the other ends is rotatable to both side positions sandwiching a prestress introduction target portion of a member. A pair of tension members attached to the tension member, and a tension device that is connected to the connection portion of the pair of tension members and applies a tensile force to the tension member toward the connection portion in the axial direction. Prestressing device. 2. One end of each member is rotatably connected to each other to form a substantially V-shape or a substantially inverted V-shape, and each of the other ends is rotatable to both positions sandwiching a prestress introduction target portion of a member. And a pair of first tension members attached to each other, and one end portions of which are rotatably connected to each other to form a substantially V shape or a substantially inverted V shape, and each other end portion is between the first tension member. A pair of second tension members rotatably attached to the member at appropriate intervals, the first tension member and the second tension member.
A prestressing device comprising: a tensioning device that applies a tensile force between the connecting portions of the tensioning member.