JP2001098514A - Method for constructing arch rib of concrete arch bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve such a requirement that a concrete cross section and the quantity of reinforcing bars must be increased to resist the bending stress applied to arch ribs at an earthquake in the method for constructing the arch ribs by suspending arch-shaped steel pipes between both support points and placing lining concrete around the steel pipes. SOLUTION: Jacks 51 are provided between the apex junctions of steel pipes 11 suspended into an arch shape, lining concrete is placed, the jacks 51 are operated to apply the axial compressing force to the steel pipes 11 after the strength of the concrete appears, and splice plates 61 are permanently connected to construct the arch ribs of a concrete arch bridge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a concrete arch bridge, and more particularly, to an arch-shaped steel pipe, filling the steel pipe with concrete, and then winding the concrete on the steel pipe to form an arch rib. TECHNICAL FIELD The present invention relates to a method for constructing an arch rib of a composite arch bridge having a composite structure.

[0002]

2. Description of the Related Art Conventionally, a large number of arch-type bridges have been constructed from the viewpoint of having a structurally superior structural system and an excellent aesthetic appearance. In general, concrete arch bridges are constructed in such a way that the entire arch ribs are constructed using shoring, and then piers and bridges (stiffening girders) are constructed, and a method of overhanging erection that does not require shoring is used. There is. As shown in Japanese Patent Publication No. 60-15763, the present inventors erected a steel pipe in advance at the arch rib construction position, and filled the steel pipe with concrete to increase rigidity.
The arch ribs are pre-built by surrounding the steel pipe with cast concrete, and the arch ribs are used as supports to provide a method of constructing a concrete arch bridge in which a pier and a stiffening girder are constructed. This arch bridge construction method does not require any support such as temporary supports or framed scaffolds.

One example of the above construction method is shown in FIGS. FIG. 12 is an overall side view of an arch bridge 100, in which an arch rib 102 is constructed between arch abutments (bridges) 101 on both sides, and a pier 103 is erected on the arch rib 102.
FIG. 1 shows a view of erection of a stiffening girder (bridge) 104.
3 and 14 are views taken along the arrows HH and II in FIG. 10, respectively. The arch ribs 102 are steel pipes 105 that are initially bridged.
Built-in.

Further, the present applicant has disclosed Japanese Patent Publication No. Hei 5-46406 and Japanese Patent Laid-Open Publication No.
Japanese Patent No. 4847 and the like provide a method of erection of a steel pipe arch and a method of laying concrete.

[0005]

The arch rib construction method developed by the present inventors has many excellent advantages, but has the following problems. Originally the arch rib is a compression member in the completed structural system, but in the above arch rib construction method,
Bending acts on the arch rib during construction, and a bending moment remains on the arch rib even after completion. Therefore, it was necessary to increase the concrete section and the amount of rebar that resist bending stress. This is particularly noticeable when the length of the arch span is long.

[0006] The present invention solves the above problems and has been improved to reduce the bending moment remaining in the arch ribs.
Enables economical cross-sectional design, suppresses the increase in steel material,
It is an object of the present invention to provide a technology designed to improve seismic resistance by reducing the weight.

[0007]

According to the present invention, in constructing an arch rib of a concrete arch bridge, an arched steel pipe is bridged between both support points, concrete is filled in the steel pipe, and then the outer periphery of the steel pipe is surrounded. In a method of constructing an arch rib by casting a rolled concrete, a jack is interposed between the zenith joints of the steel pipe bridged in an arch shape, and the zenith joint is temporarily connected with an attachment plate, The rolled concrete is poured into the steel pipe in a stepwise manner from both support points toward the zenith, and after the winding to a certain position is completed and the strength of the concrete is developed, the zenith is connected while operating the jack. After loosening a bolt and introducing an axial compressive force to the arch rib, the connection bolt is tightened to fully connect the attachment plate, and the remaining rolled concrete is poured. It is a Achiribu construction method of that concrete arch bridge. The fixed position here refers to a position where the bending moment generated in the steel pipe by design is assumed to be excessive at the stage where concrete is wound up in a plurality of blocks stepwise from the support point toward the zenith. . This position depends on the design and is preferably determined strictly, but it may be conveniently located near the zenith.

The addition of the horizontal force (axial compression force) by the jack reduces the tensile stress of the arch rib due to the bending moment of the arch rib, which is increased by the rolled concrete and the subsequent load (especially the seismic load), and resists this tensile stress. It is intended to reduce the amount of steel material and concrete cross-section required for construction.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an arch rib construction method for a concrete arch bridge according to the present invention will be described in detail with reference to the drawings. This example is of the same type as the concrete arch bridge shown in FIGS. In this example, an example is described in which concrete is rolled up stepwise from a support point (arch abutment) toward the zenith and an axial compressive force is introduced while leaving a part of the zenith.

FIG. 9 is a side view of the arch rib 10 according to the construction method of the present invention, and FIG. 10 is a sectional view taken along the line GG of FIG.
As shown in FIG. 10, a plurality of rows (three rows in this example) of steel pipes 1
9, as shown in FIG. 9, a bridge abutment (arch abutment) 21 is bridged between the abutments 21, the concrete 12 is filled in the steel pipe 11, and the steel pipe 11 is surrounded with a rolled concrete 13 to cast the arch rib 10. Construct (see FIG. 10). Thereafter, the pier 31 and the stiffening girder 41 are erected to construct the arch bridge (see FIG. 9). The arch rib 10 has concrete 1 inside.
A connecting member 14 for connecting a plurality of rows (three rows) of steel pipes 11 filled with 2
And the periphery thereof is wrapped with a wrapping concrete 13.

FIG. 11 shows an example of a method for erection of a steel pipe having an arch rib. FIG. 11 is an explanatory diagram of a erection method called a lowering method. In FIG. 11, three arc-shaped steel pipe blocks 15 are joined by three to form a steel pipe block assembly 16.
Are shown. This steel pipe block assembly 16 is hinged on each arch abutment (abutment) 21 so as to be tiltable in the arch axis direction, an anchor 32 is provided behind the abutment 21, and a PC strand 33 or the like is fed out with a jack or the like, and the steel pipe block is drawn out. Tilt the assembly 16 to the arch axis. The steel pipe block assembly 16 similarly tilted from the opposite shore is connected to the arch top part (crown part) 35. The lowering method shown in FIG. 11 is an example, and the construction of the steel pipe of the arch rib may be bridged by another known method. Further, it is preferable that the concrete is laid by the method proposed by the present applicant.

According to the present invention, a jack is interposed at the zenith joint of the steel pipe spanned like an arch in the above-described arch rib construction method. FIG. 1 is a plan view of the zenith joint (crown). Jack 51 between the opposed steel pipes 11
And the steel pipes 11 are temporarily connected to each other by the attachment plate 61. The attachment plate 61 is provided with a long slot 63 in the axial direction of the steel pipe (in the direction of the arrow 52) and is connected by bolts 62.

FIG. 2 is a view taken in the direction of arrows AA in FIG. 1 and is a detailed view of a steel pipe connecting portion at a zenith joint (crown portion). Steel pipe 11
Are temporarily connected by an attachment plate 61. The attachment plate 61 has a long hole, and can be fixed by adjusting the dimension in the arch axis direction.
The inside of the steel pipe 11 is filled with concrete. FIG. 3 is a view taken in the direction of arrows BB in FIG. 1, and a jack 51 is inserted between the ends of the steel pipe 11. FIG. 4 is a sectional view taken along the line CC of FIG.
In the sectional view taken in the direction of the arrow, the jack 51 is inserted between the end faces of the steel pipe 11, the joint bolt 62 is loosened, and the gap between the end faces of the steel pipe 11 is expanded.

Next, the construction method of the present invention will be described according to the procedure.

A) A steel pipe block 15 manufactured in a factory is carried into a site, one end is fixed to an arch abutment 21 by a hinge as shown in FIG. 11, and the steel pipe block 15 is connected to connect a steel pipe block assembly 16 for a half arch. Is assembled into a pillar shape. Anchor 32 is attached to the front and rear of the arch bat 21, and the steel pipe block assembly 1 is connected to the PC strand 33 or the like.
6 Support. Similarly, a half-arch steel pipe block assembly 16 is assembled on the abutment on the opposite shore. At this time, the steel pipes in a plurality of rows may be assembled while being connected by a connecting member in a horizontal manner, or may be connected later.

B) Anchor 3 behind arch abutment 21
The PC strand 33 from 2 is loosened while being held by a jack or the like, and the semi-arched steel pipe block assembly 16 is loosened.
Is tilted toward the opposite shore until the predetermined arch axis is reached. Also tilt from the opposite shore, and the arch zenith joint 35
Then, the steel pipe block assembly 16 tilted from both banks is temporarily joined by the attachment plate. Although the steps a) and b) described above are performed by the lowering method, other methods may be used.

C) In a steel pipe erected from both banks,
The concrete is filled except for a part of the steel pipe connection at the zenith. Concrete filling is performed from the left bank and the right bank while maintaining the balance.

D) When the concrete inside the steel pipe has hardened, the concrete is wound around the steel pipe except for the closed top part. Concrete wrapping may be performed by a known method.

E) Prior to the construction of the concrete at the zenith-closed part, a jack is inserted between the steel pipe end faces or between the wrapped concrete end faces, and while the jack is being operated, the bolts for the temporary joining are gradually loosened to apply an axial compressive force to the arch ribs. Introduce.
The axial compression force may be set to a value corresponding to the axial force corresponding to the bending moment when the entire arch rib is supported on the shoring, but may be a smaller value.
The jack may be attached to one end of the opposite end surface before the temporary bonding of the zenith.

F) When a predetermined axial compression force is introduced, the loosened temporary joining bolts are tightened and fully tightened.

G) Next, the remaining closed part (zenith joint part)
Pour concrete in.

H) Thereafter, the pier and the stiffening girder are constructed, and the concrete arch bridge is completed.

FIG. 5 shows another embodiment corresponding to FIG. 1. In FIG. 1, a jack 51 is interposed between steel pipe end faces, whereas a jack 51 is provided between opposed steel pipe concrete end faces between adjacent steel pipes 11. With the steel pipe joint bolts 62
This is a method of loosening and pushing apart between the end faces to apply an axial compressive force to the arch rib.

FIG. 6 is a view taken along the line DD in FIG. 5, and FIG. 7 is a view taken along the line EE in FIG.
It is an arrangement view inserted between end faces.

FIG. 8 is a diagram of a jack 51 suitably used in the present invention. The jack 51 is formed of a thin iron plate in a bag shape called a flat jack, and a pressurized fluid is injected into the inside of the jack 51 from the injection hole 70 to inflate the bag, thereby obtaining a head. It is of a structure that obtains the lift. The injection fluid may be either non-hardening or hardening. In general, however, it is often the case that a hardening fluid such as cement milk or synthetic resin mortar is injected and buried as it is after use. FIG. 8 (a) is a cross-sectional view of the jack, in which a pressure plate 71 is sandwiched on the thickened working surface of the jack and inserted between the structures, and the injection hole 70
More pressure fluid is injected. FIG. 8B shows a pressure fluid 72.
FIG. 8 (a) shows the state after the implantation of FIG.
(B) It is possible to obtain a head up to W. FIG.
(C) is a circular jack 5 viewed from the arrow FF in FIG.
1 is shown.

In this embodiment, a circular jack is illustrated, but a square or rectangular jack is also commercially available and may be used properly. Further, there is a similar one called a bag jack formed in a bag shape with synthetic rubber reinforced with steel fiber, but it can be suitably used similarly.

In this embodiment, an example is described in which concrete is laid stepwise from a support point (arch abutment) toward the zenith and an axial compressive force is introduced while leaving a part of the zenith. It is sufficient to introduce an axial compressive force at a point in time when it is assumed that the bending moment generated in the steel pipe by design will be excessively large at the stage where concrete is divided into a plurality of blocks in a stepwise manner from the support point toward the zenith, and is assumed to be excessive. Therefore, in some cases, the jack may be operated a plurality of times for each stage. In that case, it is preferable to use non-hardening water or oil as the pressure fluid to be injected into the jack.

In the above embodiment, the lowering method is adopted for erection of the steel pipe. However, the present invention is not limited to this, and a known method such as a method using a cable crane or a method using a pillon and hanging diagonally with a wire rope is used. It is possible to do.

[0029]

According to the present invention, when constructing an arch rib of a concrete arch bridge, a jack is interposed at a zenith joint and operated to introduce an axial compressive force to the arch rib.
It has become possible to reduce the bending moment generated in the arch rib laying process and to improve the sectional force of the arch rib. In particular, in the case of an arch rib having a long span, it is possible to suppress an increase in the amount of concrete and the amount of reinforcing steel, and to reduce the weight,
The effects contributing to the improvement of economic efficiency are enormous.

[Brief description of the drawings]

FIG. 1 is a plan view of a zenith joint of an embodiment.

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 a view taken in the direction of arrows CC in FIG. 3;

FIG. 5 is a plan view of a zenith joint of another embodiment.

FIG. 6 is a view as seen from the direction of the arrow DD in FIG. 5;

FIG. 7 is a view as seen in the direction of arrows EE in FIG. 6;

FIG. 8 is a diagram illustrating the operation of the jack.

FIG. 9 is a side view of the arch rib.

FIG. 10 is a view taken in the direction of arrows GG in FIG. 9;

FIG. 11 is an explanatory view of a method of erection of an arch rib steel pipe.

FIG. 12 is an overall side view of an arch bridge.

FIG. 13 is a view taken in the direction of arrows HH in FIG. 12;

FIG. 14 is a view taken along the arrow II in FIG. 12;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Arch rib 11 Steel pipe 12 Concrete 13 Rolled concrete 14 Connecting material (joint) 15 Steel pipe block 16 Steel pipe block assembly 21 Abutment (Arch abut) 31 Pier 32 Anchor 33 PC strand 34 Arch axis 35 Arch zenith joint (Crown part) 41 Supplement Rigid girder 51 Jack 61 Abutment plate 62 Bolt 63 Elongated hole 70 Injection hole 71 Support plate 72 Pressure fluid 100 Arch bridge 101 Arch butt (Abutment) 102 Arch rib 103 Bridge pier 104 Stiffening girder (bridge body)

Claims (1)

[Claims] 1. A method of constructing an arch rib by bridging an arched steel pipe between both support points, filling the inside of the steel pipe with concrete, and then surrounding the outer circumference of the steel pipe and pouring concrete into the steel pipe. A jack is interposed between the zenith joints of the arched steel pipe and the zenith joint is temporarily connected by an attachment plate, and the steel pipe is wound in a stepwise manner from both support points toward the zenith. Pile concrete is poured, winding up to a certain position is completed, and after the strength of the concrete is developed, the zenith connection bolt is loosened while operating the jack and an axial compression force is introduced into the arch rib, and then the connection is made. Tighten the bolt and fully connect the contact plate,
A method of constructing an arch rib of a concrete arch bridge, which comprises placing remaining rolled concrete.