JP2002004225A - Method and device for stretching erecting pc bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide technology having no need of using a sheath by solving the problem that the deterioration of the durability of a PC steel material is caused by water leaked into a gap part produced in the sheath in stretching erecting of a post tension system PC bridge. SOLUTION: The PC steel material is arranged in the form of a bridge body block, tightened by using a jack, concrete is placed, after the strength of concrete is expressed, the jack is loosed, and prestress is introduced into the concrete. It is repeated, and the PC bridge is right and left alternately extended and erected by a pretension system in the form of a cantilever.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for overhanging a PC bridge.

[0002]

2. Description of the Related Art A method of erection of a bridge constructed by dividing a bridge body from the top of a pier at intervals of 3 to 5 m in the direction of a bridge axis and projecting to the left and right is suitable for erection of a bridge having a long span and space conditions under a girder. It is widely used because it is not regulated.
In this method of overhanging the pier, the capital of the bridge pier, which is the base point (start point of overhang), is first constructed of reinforced concrete, and then the bridge block is cantilevered in a yajiro-bee-style while balancing the left and right from the capital. An overhang is erected, and the bridge is extended. In this case, the bridge block is constructed of post-tensioned prestressed concrete. The bridge block is cast in situ or as a precast concrete block previously manufactured in a manufacturing yard. In any case, the prestress of the bridge block is introduced by a post tension system.

[0003] This post-tension type prestressed concrete is formed by embedding a PC steel insertion duct (sheath) in concrete, and forming a PC in this sheath.
It pushes the steel material and strains it. After the introduction of the prestress, grout such as cement milk is injected into the sheath, and the PC steel is attached to the sheath. It is necessary that this grout completely fills the inside of the sheath to prevent intrusion of moisture at a later date. However, it has been pointed out that, in the past, a method for confirming the injection filling property has not been established, and unexpected vacancies were generated, causing corrosion of the PC steel material and the like, which sometimes caused a problem in the durability of the structure. . In addition, the post-tension method involves complicated operations such as sheath arrangement, fixing device attachment, and grouting.

[0004]

As described above, in the conventional overhanging construction of the PC bridge, the PC steel is tensioned by the post tension system. In that technology, after tensioning PC steel, P
The inside of the sheath that is the C steel material insertion hole is grouted with cement milk or the like. It is difficult to completely fill the inside of the sheath by this grouting, and voids are likely to occur. There is a problem that the durability of the PC steel material is degraded by water or the like that has entered the voids. As one measure to secure the durability of PC steel, it has been proposed to use a new material that is resistant to corrosion. However, the cost of the new material PC is high, and there are problems with the structure of the fixing part. Has not been adopted.

An object of the present invention is to develop and provide a method and apparatus for overhanging a PC bridge overcoming the above problems. The problem to be solved by the present invention is to provide a technique which does not require grouting without the use of a sheath in connection with the introduction of prestress when the bridge is overhanged.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is a method and an apparatus for overhanging a PC bridge over which the following technical means are taken. That is, according to the present invention, when the PC bridge is cantilevered, the formwork for one block of the bridge body is installed to protrude forward from the existing bridge body, and is placed in the formwork from the existing bridge body in the bridge axis direction. Tension is applied to the PC steel material arranged in the above, and then the one block of concrete is poured, and after the concrete is hardened, P
Prestress is introduced into concrete by releasing the tension of steel C. An overhanging method for a PC bridge is characterized by repeating the above steps to overhang a PC bridge.

The present invention relates to a method of constructing prestressed concrete on site by a pretensioning method that does not require a sheath, since the conventional post-tensioning method has a problem in grouting in the sheath. When constructing the bridge block in a cantilevered manner, place the PC steel in the formwork of the bridge block in advance, tension the PC steel using the jack, then cast concrete into the formwork, and wait a while. After the concrete has developed its strength, the jack is loosened and prestress is introduced into the concrete. By repeating this, the PC bridge is extended and extended alternately in a cantilever shape.
The method of the present invention can be used in combination with an external cable method or the like, and its application range is wide and is a very effective technique.

Further, in the present invention, a laterally tightened PC steel material is disposed in a mold, and after applying a tension to the laterally tightened PC steel material,
It is preferable to cast concrete. That is, the prestressing is introduced into the upper deck of the girder not only in the bridge axis direction but also in the direction perpendicular to the bridge axis (lateral direction) by the pretension method. Further, the upper floor slab, which is the base point of the cantilever overhanging construction, may be constructed of pretensioned prestressed concrete.

The apparatus of the present invention which can suitably carry out the above-mentioned method of the present invention comprises a formwork for one block which is mounted on an existing bridge body so as to be able to run in the bridge axis direction and is cantilevered. It is characterized by comprising an erecting work vehicle that extends and holds forward from the existing bridge body, and a tensioning unit that takes a reaction force to the existing bridge body and tensions the PC steel in the bridge axis direction extending from the existing bridge body. This is an overhanging device for the PC bridge. Further, it is preferable to provide a tensioning device mounted on the side surface of the mold to tension the laterally tightened PC steel material.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are diagrams illustrating an embodiment of an erection work vehicle and an erection work for extending and erection of a PC bridge by a pretension method according to an embodiment of the present invention. 1 is a side view, FIG. 2 is a view along arrow AA in FIG. 1, FIG. 3 is a front view in the traveling direction, and is a view along arrow BB in FIG.

1 to 3 show the construction of a bridge block 130 adjacent to an overhang portion (existing bridge body) 120 projecting from a column cap 110 on a pier 100. FIG. In this embodiment, an erection work vehicle 10 is used. Reinforcing bars and the like are assembled in a formwork 40 supported by the erection work vehicle 10, and PC steel materials are arranged (extended).
Then, concrete of the bridge block 130 to be extended is cast, and the cantilever of the bridge body is erected. Construction work vehicle 10
Is suspended by a suspending member 12 from a main beam 11 arranged on an existing bridge. Side truss frames 14 and 15 are provided on the lower beam 13 disposed at the lower end, and project to the front of the existing bridge to support the formwork 40. The front and rear lower beams 13 are connected by a lower connecting beam 16. The rear lower beam 13 is stiffened by a rear lower beam stiffener 17. The tail end of the side truss frame 14 is supported by the rear support device 20 on the lower surface of the floor slab of the existing bridge. The rear support device 20 has the traveling roller 21 attached to the roller bracket 23, so that the erection work vehicle 10 can easily move forward. In addition, since the jack 22 is provided, it is easy to adjust the supporting height. A form support beam 42 is suspended from the side truss frame 14 via jacks 41 and 43, and a form 40 is assembled thereon via a receiving member 45.

Tensioning unit 5 for tensioning PC steel 140
No. 0 includes rear anchor beams 51 and 52 disposed above and below the upper deck of the existing bridge 120. The tension rod 57 penetrating the existing bridge body passes through a through hole provided in the upper floor slab of the existing bridge body 120, and the upper and lower anchor beams 51,
52 are connected and fixed to form a reaction device against the tension caused by the PC steel 140. Upper and lower anchor beams 51, 52
, A reaction force beam 53 extends forward, and a jack 54 is attached to the tip thereof. The front frame 55 is a PC
The steel material 140 is temporarily fixed to the fixing frame 56, and the jack 54 acts on the front frame 55 to press the fixing frame 56, thereby applying tension to the PC steel material 140. The fixing frame 56 is supported via a jack 32 from the lateral beam 31 of the construction work vehicle 10. Tension unit 5
Numeral 0 is a structure that supports the reaction force of the tension of the PC steel material by itself, and introduces prestress into the bridge body by a pretension method.

After the PC steel is tensioned by the tensioning jack 54 of the tensioning unit 50, concrete is poured into the formwork. After the concrete reaches the desired strength, the tension jack 54 is loosened to introduce prestress into the concrete block. Thereafter, the erection work vehicle 10 and the tensioning unit 50 are advanced by one block length, and preparation for the construction of the next block is started. The above cycle is repeated to carry out cantilever extension of the bridge body. Note that, in the above case, the tension of the PC steel members 140 is simultaneously adjusted using the fixing frame 56, but the PC steel members may be tensioned one by one. In addition, although the suspension work vehicle uses a hanging type as a form in which a work space for a tension unit or the like can be effectively secured, it is needless to say that an overhead type mounted on a general bridge surface may be used.

Next, the construction of the column capital and the construction of the intermediate portion will be described below, including the means for supporting PC steel. FIG.
FIG. 4 is a construction explanatory diagram of a column capital part 110 on a pier 100. The bracket 70 is attached to the pier 100, and the lower part 111 of the capital 110 is constructed of reinforced concrete. At this time, the upper floor slab 112 is not constructed. A frame hill 71 is provided at each of two places on the bracket 70 in the bridge axis direction, and a reel 72 around which a PC steel material 140 is wound is mounted on one of them, and the PC steel material 140 is fed out to pass through the construction position of the upper floor slab 112 of the column capital 110. Is wound around the other reel 73. FIG.
Is a conceptual perspective view showing this, and the traveling direction of the PC steel material 140 is indicated by an arrow 74. FIG. 6 is a side view of FIG.

FIGS. 7 to 9 show the method of constructing the upper column slab 112. FIG. 7 is a side view, and FIGS.
FIG. 4 is a view as viewed from an arrow C and a view as viewed from an arrow D-D. Tension unit 80
Are provided above and below the position where the upper floor slab 112 is to be constructed on the column capital 110, and are provided with upper and lower compression main beams 81 and 82 which protrude to both sides in the bridge axis direction.
(FIG. 8) and end cross beams 84 and 85 (FIG. 9). At the end cross beams 84, 85 at both ends of the main beams 81, 82,
A number of vertical auxiliary members 86 are stretched over the vertical auxiliary members 8.
6 is provided with a fixing plate 87 made of a PC steel material 140. FIG. 10 is a detailed view of the fixing plate 87, and FIGS. 11 and 12 are views taken along arrows EE and FF of FIG. 10, respectively. The fixing plate 86 is engaged with the end cross beams 84 and 85, and supports the fixing portion 91 via a tension jack 92. Fixing unit 91
Is provided with a seat for the fixing grip 93 for fixing the PC steel 140.

The construction of the column capital is as follows. As shown in FIG. 4, a bracket 70 is installed on the upper end side surface of the pier 100. Abdomen and lower floor slab of column capital 110 (lower part 11
Perform 1). Next, as shown in FIG.
A PC steel member 140 is disposed so as to pass through the inside, and a tension unit for the capital is attached to the position of the upper floor slab 112. Assemble the formwork and steel of the upper floor slab 112. The PC steel 140 is tensioned and fixed to the fixing plate 87. The concrete of the upper floor slab 112 is cast. After hardening concrete, PC steel 1
When the tension of 40 is released, prestress is introduced into the upper floor slab 112. Dismantle the formwork and dismantle the capital cap tension unit.

Next, the construction of the overhang bridge body is performed. Construction of the overhang is performed by installing the construction work vehicle, installing the reaction force receiving beam, installing the tension unit, assembling the formwork and reinforcing bars, then tensioning the PC steel, placing concrete, and then hardening the concrete. The pre-stress is introduced into the concrete by releasing the tension of the concrete, and then the process of dismantling the formwork, the construction work vehicle and the movement of the tensioning unit is followed. 13 is a side view of a construction example of the overhang bridge body of the present invention, FIG. 14 is a view as seen from the direction of arrows EE in FIG. 13, and FIG. 15 is a view as seen from the direction of arrows FF in FIG. The construction work vehicle 10 and the tensioning unit 50 shown in FIG. 13 are the same as those shown in FIG. The PC steel material 140 gives prestress to the concrete in the existing bridge body 120, and its extension is fixed to the fixing frame 56 of the tensioning unit 50, and the PC block 140 in the upper floor slab of the bridge body block 130 before the concrete is cast. The part is nervous. PC steel 140 is further extended to P
The guide is guided by a guide plate 171 attached to the C steel support guide rail 170. The PC steel support guide rail 170 changes its direction vertically downward from the front of the erection work vehicle 10, bends horizontally rearward, and is supported by the horizontal beam 13 of the erection work vehicle 10.

FIG. 16 is a side view showing the support of the PC steel material 140, and FIG. 17 is a front view of FIG. 16 and 17
The illustration of the erection work vehicle 10 is omitted in FIG. Existing bridge 1
A cable reel 164 is suspended below the existing bridge body 120 via a frame 163 from a cable truck 160 traveling on the cable carrier 20. The cable reel 164 holds the PC steel material 140. The PC steel material 140 unwound from the cable reel 164 is guided by a large number of guide plates 171 attached to the guide rails 170, and is supplied to the upper floor slab around the tip of the bridge block 130 to be overhanged. After that, concrete is prestressed in the upper deck of the pre-constructed bridge. FIG. 17 is a front view of FIG.
2 shows a cable truck 160 traveling by 2
The state where the cable reel 164 is supported by the suspension frames 163 suspended from both ends of the beam 161 of the cable carriage 160 is shown. By using such a dedicated cable reel, the present invention can be easily and rationally implemented.

FIG. 18 is a side view of the tensioning unit 150, FIG. 19 is a view taken in the direction of arrows HH in FIG. 18, and FIG. 20 is JJ in FIG.
FIG. 21 is a view taken in the direction of the arrow K in FIG. 18, and FIG. 22 is a view taken in the direction of the arrow L in FIG. The tensioning unit 150 is basically the same as the tensioning unit 50 shown in FIG.

The tensioning unit 150 includes rear anchor beams 151 and 152 attached to a tension rod 157 penetrating the upper deck of the existing bridge 120.
Reaction force beam 1 from upper and lower anchor beams 151 and 152
53 is extended and the end cross beams 158, 159
The front cross beams 158 and 159 are provided with a front frame 155, a jack 154, and a fixing frame 156. The jack 154 acts on the front frame 155 and presses the fixing frame 156 to apply tension to the PC steel 140, and at this time, the reaction force beam 153 supports the reaction force of the tension. Normally, dozens of PC steels are arranged, so that the front frame can collectively tighten the PC steels so that the PC steels can be efficiently tensioned and released.
Configure so that tension can be released. In addition, since the middle portion of the PC steel material is sequentially tightened, a long chuck is used to prevent damage to the PC steel material due to the tension. In addition, it is necessary to consider the return of the PC steel material due to the lack of adhesion at the time of introducing the prestress. Since the method of the present invention basically has no fixing device, there is a possibility that the adhesion may be cut off. This is not a problem with strand material, but if there is a fear of becoming a problem, attach a crimp grip or the like.

The bridge block 130 is prestressed by a pretension method. Further, as shown in FIG. 19, the bridge block 130 is applied to the upper floor slab of the bridge block 130 by applying tension to the laterally tightened PC steel 142 stretched between members 141 attached to both ends of the cross beam. A lateral tightening prestress can be applied.

FIGS. 21 and 22 show the rear anchor beam 15.
This shows the relationship between the tension rods 1 and 152 and the tension rod 157. The tension rod 157 is a through bolt penetrating the existing upper floor slab, and is tightened between the upper and lower anchor beams 151 and 152 by a jack 180.

In the above description, the means for feeding the PC steel drum by suspending it on or from the bridge body and supplying the same is described. However, the support and handling of the PC steel material are not limited thereto. As shown in FIG. 23, the messenger wire 190 is stretched in the bridge axis direction,
The PC steel 140 may be hung from the messenger wire, or a drum may be provided on the ground and a guideway may be provided to guide the PC steel 140 depending on the bridge construction conditions. further,
The PC steel material may be connected by a coupler or the like at an appropriate length, and the ends may be fixed at the appropriate lengths and another PC steel material may be overlapped and mechanically continuous, or the cable may be U-shaped. It can be designed according to the actual situation, for example, by being bent into concrete and buried in concrete to form a fixing end.

[0024]

According to the present invention, the prestressing of the PC bridge to be overhanged is replaced with the conventional post tension system.
The pretension method is used. The prestress is introduced in the main direction of the erection, the horizontal direction of the floor slab, and the center of the span during the overhang.

According to the present invention, the grouting after tensioning of the PC steel due to the introduction of the conventional post-tension type prestress is not required, and the PC steel is completely buried in the concrete. Therefore, since no grouting defect is generated, a problem such as corrosion of the PC steel due to incomplete filling does not occur, and a highly reliable bridge body can be constructed. In addition, complicated operations such as sheath arrangement, fixing tool attachment, grouting, and the like associated with the post-tension method are not required.

Further, in the conventional overhanging work, the overhang work of the bridge body is performed at the same time on the left and right sides, but in the present invention, the overhang work can be performed separately on the left and right sides. Therefore, although the construction period of one cycle is almost the same, it is possible to eliminate the waste of labor that occurs during concrete curing.

Further, according to the present invention, since the reinforcing steel in the bridge axis direction arranged in the upper floor slab can be replaced with a PC steel material, there is an effect that the amount of reinforcing steel can be reduced or omitted.

[Brief description of the drawings]

FIG. 1 is a side view of an embodiment of the present invention.

FIG. 2 is a view taken along the line AA of FIG. 1;

FIG. 3 is a view taken in the direction of arrows BB in FIG. 1;

FIG. 4 is an explanatory diagram of construction of a column capital on a pier.

FIG. 5 is a conceptual perspective view showing construction of a column capital.

FIG. 6 is a side view of FIG. 4;

FIG. 7 is a side view.

FIG. 8 is a view as viewed in the direction of the arrows CC.

FIG. 9 is a view as seen in the direction of arrows D-D.

FIG. 10 is a detailed view of a fixing plate.

FIG. 11 is a view of the fixing plate as seen from an arrow EE.

FIG. 12 is a view of the fixing plate viewed from an arrow FF.

FIG. 13 is a side view of a construction example of the present invention.

FIG. 14 is a view as seen from the direction of arrows EE in FIG. 13;

FIG. 15 is a view as viewed in the direction of arrows FF in FIG. 13;

FIG. 16 is a side view of an example of supporting a PC steel material in a working example of the present invention.

17 is a view as viewed in the direction of arrows GG in FIG. 16;

FIG. 18 is a mounting side view of the tension unit.

FIG. 19 is a view as viewed in the direction of arrows HH in FIG. 18;

20 is a view taken in the direction of arrows JJ in FIG. 18;

21 is a view as viewed in the direction of the arrow K in FIG. 18;

FIG. 22 is a view taken in the direction of the arrow L in FIG. 18;

FIG. 23 is an explanatory view in which a PC steel material is suspended by a messenger wire. .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Erecting work vehicle 11 Main beam 12 Suspension member 13 Lower beam 14, 15 Side truss frame 16 Lower connecting beam 17 Rear lower beam stiffener 20 Rear support device 21 Running roller 22 Jack 23 Roller bracket 31 Lateral beam 32 Jack 40 Formwork 41, 43 jack 42 formwork supporting beam 45 receiving member 50 tension unit 51, 52 anchor beam 53 reaction force beam 54 jack 55 front frame 56 fixing frame 57 tension rod 70 bracket 71 framework stand 72 reel 73 reel 74 arrow 80 tension unit 81 , 82 Main beam 83 Intermediate cross beam 84, 85 End cross beam 86 Vertical auxiliary member 87 Fixing plate 91 Fixing section 92 Tension jack 100 Bridge pier 110 Column cap 111 Lower part 112 Upper floor slab 120 Overhang (Existing bridge) 130 Bridge block 140 PC steel 141 Member 142 Lateral tightening PC steel 150 Tension unit 151, 152 Anchor beam 153 Reaction beam 154 Jack 155 Front frame 156 Fixing frame 157 Tension rod 158, 159 End cross beam 160 Reel Dolly 162 Wheel 163 Hanging frame 170 PC steel support guide rail 171 Guide plate

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[Procedure amendment]

[Submission date] July 10, 2000 (2007.1.
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

Next, the construction of the overhang bridge body is performed. Construction of the overhang is performed by installing the construction work vehicle, installing the reaction force receiving beam, installing the tension unit, assembling the formwork and reinforcing bars, then tensioning the PC steel, placing concrete, and then hardening the concrete. The pre-stress is introduced into the concrete by releasing the tension of the concrete, and then the process of dismantling the formwork, the construction work vehicle and the movement of the tensioning unit is followed . FIG. 13 is a side view of a construction example of the overhang bridge body of the present invention, FIG. 14 is a view taken along the line EE of FIG.
5 is a view as viewed from the direction of arrows FF in FIG. The construction work vehicle 10 and the tensioning unit 50 shown in FIG. 13 are the same as those shown in FIG. The PC steel material 140 gives prestress to the concrete in the existing bridge body 120, and its extension is fixed to the fixing frame 56 of the tensioning unit 50, and the PC block 140 in the upper floor slab of the bridge body block 130 before the concrete is cast. The part is nervous. PC steel 140 is further extended to PC
Guide plate 1 mounted on steel support guide rail 170
Guided by 71. PC steel support guide rail 1
Numeral 70 changes the direction from the front of the erection work vehicle 10 vertically downward, bends horizontally rearward, and the horizontal portion is supported by the horizontal beam 13 of the erection work vehicle 10.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

[Procedure amendment 4]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 13

[Procedure amendment 5]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG.

[Procedure amendment 6]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG.

Claims (5)

[Claims] 1. When constructing a PC bridge over a cantilever,
A PC in which a formwork for one block of a bridge body is installed so as to protrude forward from the existing bridge body, and is arranged in the formwork from the existing bridge body in the bridge axis direction.
A tension is applied to the steel material, and then the one-block concrete is poured, and after the concrete is hardened, the tension of the PC steel material is released to introduce prestress into the concrete, and the above steps are repeated to cantilever the PC bridge. An overhanging method for a PC bridge, which comprises overhanging the bridge. 2. A laterally tightened PC steel material is provided in the formwork,
2. The method of claim 1, wherein concrete is cast after applying tension to the laterally tightened PC steel. 3. The method of claim 1, wherein the column cap on the pier is constructed by a pretension method. 4. An installation work vehicle that is mounted on an existing bridge body so as to be able to travel in the direction of the bridge axis, and that holds a formwork of one block to be cantilevered and extended forward from the existing bridge body. An overhanging apparatus for a PC bridge, comprising: a tensioning unit that takes a reaction force to the bridge body and tensions a PC steel member extending in a bridge axis direction from an existing bridge body. 5. A laterally tightened P which is mounted on a side surface of a formwork.
The overhanging device for a PC bridge according to claim 4, further comprising a tensioning device for tensioning the C steel material.