JP2012202069A - Sheath and bridge fall prevention device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheath usable regardless of a drawing direction of a PC steel wire from a wall surface of a bridge girder or a bridge abutment.SOLUTION: A sheath 1 includes a trunk part 3 and a head part 2. The head part 2 is provided with a bellows part 21 having a contraction margin gradually increased from an upper edge side to a lower edge side holding an axial center of the head part 2 therebetween. When the bellows part 21 is shortened, rear end opening of the head part 2 is inclined to the axial center of the sheath 1. The trunk part 3 comprises step parts 31 and 32 whose inner diameter is reduced stepwisely from a rear end side to a front end side. The sheath 1 is buried inside a structure 5 in the state that the bellows part 21 is not shortened when a wall surface 5A of the structure 5 is orthogonal to the drawing direction of the PC steel wire, and is buried inside the structure 5 in the state that the bellows part 21 is shortened when the wall surface 5A of the structure 5 is not orthogonal to the drawing direction of the PC steel wire.

Description

  The present invention relates to a sheath used for a falling bridge prevention device.

  As shown in Patent Document 1 below, there is a fallen bridge prevention device in which a bridge girder is connected to an abutment or another bridge girder with a PC steel wire. In this falling bridge prevention device, a sheath is embedded in a wall surface from which a PC steel wire of the bridge girder or the abutment is drawn, and the PC steel wire is drawn out from the bridge girder or the abutment through the sheath.

  In this kind of falling bridge prevention device, the end of the bridge girder or the abutment wall surface side has a trumpet shape in order to prevent the PC steel wire that is bent as the bridge girder or the abutment moves from interfering with the wall surface of the bridge girder or abutment An expanded sheath is used.

Japanese Patent Laid-Open No. 11-323832

  For bridges such as slanted bridges and curved bridges where the bridge axis and support line are not perpendicular, the PC steel wire is drawn diagonally with respect to the wall of the bridge girder or abutment. I could not.

  The object of the present invention has been made in view of such problems, and provides a sheath that can be used regardless of the direction in which a PC steel wire is drawn from the wall surface of a bridge girder or an abutment, and a method for preventing a falling bridge using the sheath. It is to be.

In order to achieve such an object, a sheath of the present invention is a sheath including a trunk portion and a head portion that extends from one end of the trunk portion, and has an opening end of the head portion. A bellows portion that is inclined and contracted with respect to the axial center of the sheath is provided.
Further, the present invention is characterized in that the bellows portion has a shrinkage margin that gradually increases from one edge side to the other edge side across the axis of the head.
In addition, the present invention is characterized in that the body portion includes a step portion having an inner diameter reduced in a stepped manner from the one end side to the other end side.
Moreover, this invention is equipped with the adjustment cylinder accommodated in the said trunk | drum, and the support part which supports the said adjustment cylinder in the said trunk | drum.
Further, the falling bridge prevention device of the present invention is a bridge girder falling prevention device for connecting a bridge girder to a bridge abutment or other bridge girder with a linear member housed in a sheath, and inserting the linear member through the sheath. Features.

  According to the present invention, since the bellows portion is contracted and the opening end of the head is inclined with respect to the axial center of the sheath, the sheath can be used regardless of the direction in which the PC steel wire is drawn from the wall surface of the bridge girder or the abutment. it can.

It is a side view which shows the sheath of the 1st Embodiment of this invention, (a) has shown the state which the bellows part has not shrunk | reduced, and (b) has shown the shrunk state. It is a side view which shows the state which cut | disconnected the trunk | drum of the sheath shown in FIG. It is a side view which shows the sheath of the 2nd Embodiment of this invention, (a) has shown the state which the bellows part has not shrunk, and (b) has shown the shrunk state. It is a figure which shows the adjustment cylinder accommodated in the trunk | drum of a sheath, (a) is a top view, (b) is a longitudinal cross-sectional view. It is a longitudinal cross-sectional view which shows the state by which the steel wire from which thickness differs was penetrated by the trunk | drum.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
The vertical and forward / backward directions used in the following description are shown in the drawings used for the description. The top, bottom, front and back are described for explanation, and needless to say, the actual arrangement may be different.

  As shown in FIG. 1, the sheath 1 is embedded in the structure 5 of an abutment or a bridge girder, and the steel wire 6 is penetrated inside.

  The sheath 1 includes a cylindrical body portion 3 and a head portion 2 extending in a trumpet shape from the rear end of the body portion 3 and is formed of a flexible material such as resin. ing. The body 3 has a large-diameter portion 33, a medium-diameter portion 32 that has a cylindrical shape that is smaller than the large-diameter portion 33 and extends forward from the large-diameter portion 33, and a cylinder that has an outer shape smaller than the medium-diameter portion 32. And a small-diameter portion 31 extending forward from the medium-diameter portion 32.

  The head 2 is aligned with the trunk 3 at the axis. The head portion 2 is provided with a bellows portion 21 that shrinks the rear end opening portion of the head portion 2 whose diameter is enlarged with respect to the axis of the sheath 1. The bellows portion 21 has a gradually increasing shrinkage from the upper edge side to the lower edge side. A locking portion 22 is formed at the rear end opening of the head 2. The locking portion 22 extends outward from the rear end opening of the head 2 and is formed over the entire circumference of the rear end opening.

  As shown in FIG. 1 (a), when the wall surface 5A of the structure 5 is orthogonal to the direction in which the steel wire 6 is drawn, the head portion 2 has the locking portion 22 at the rear end opening. It extends in the radial direction of the portion 2 (a direction orthogonal to the axis of the sheath 1), and is embedded in the structure 5 in a state where the bellows portion 21 is not contracted. On the other hand, as shown in FIG. 1B, when the wall surface 5A ′ of the structure 5 ′ is not orthogonal to the direction in which the steel wire 6 is drawn, the locking portion 22 moves the rear end opening to the head. 2 extending obliquely with respect to the radial direction of 2 and embedded in the structure 5 ′ with the bellows portion 21 contracted. A cylindrical sheath 7 is embedded on the side of the structure 5 opposite to the wall surface 5A. The steel wire 6 is inserted through the sheath 1 and the sheath 7 and penetrates the structure 5. A rear end portion of the sheath 7 is inserted into the trunk portion 3.

  As shown in FIG. 2A, when the steel wire 61 having a small outer diameter is inserted, the trunk portion 3 is embedded in the structure 5 with the small diameter portion 31 to the large diameter portion 33 provided. The 2B, when a steel wire 62 having an outer diameter larger than the steel wire 61 is inserted, the small-diameter portion 31 is cut from the medium-diameter portion 32, and the medium-diameter portion 32 and the large-diameter portion. It is embedded in the structure 5 with the portion 33 provided. Further, as shown in FIG. 2C, when a steel wire 63 having an outer diameter larger than the steel wire 62 is inserted, up to the stepped portion 32 is cut and only the large-diameter portion 33 is provided. Embedded in the structure 5.

  According to this embodiment, the shrinkage allowance of the bellows portion 21 gradually increases from the upper edge side to the lower edge side across the axis of the head 2, and when the bellows portion 21 shrinks, the head 2. Since the rear end opening is inclined with respect to the radial direction of the head 2, even if the wall surface 5 A ′ of the structure 5 ′ is not orthogonal to the drawing direction of the steel wire 6, it is within the structure 5 ′. The steel wire 6 can be inserted. Moreover, it is possible to draw out the steel wire 6 at various angles with respect to the wall surface 5A ′ by shrinking only a part of the bellows part 21 instead of the entire bellows part 21 or adjusting the shrinkage amount. Accordingly, the sheath 1 can be used regardless of the direction in which the PC steel wire is drawn from the bridge girder or the abutment wall surfaces 5A, 5A '.

  Further, according to the present embodiment, by using the sheath 1 by cutting the small diameter portion 31 and the medium diameter portion 32 as a boundary, not only the steel wire 61 that matches the inner diameter of the small diameter portion 31 but also the medium diameter portion 32. A steel wire 62 that matches the inner diameter and a steel wire 63 that matches the inner diameter of the large-diameter portion 33 can also be inserted into the sheath 1.

Next, a second embodiment of the present invention will be described with reference to the drawings.
3A and 3B are side views showing the sheath 1A of the present embodiment, where FIG. 3A shows a state where the bellows portion 21 is not contracted, and FIG. 3B shows a contracted state.

  The sheath 1A shown in FIG. 3 is embedded in the structure 5 and penetrates the steel wire 6 in the same manner as the sheath 1 of the first embodiment, and includes a cylindrical trunk portion 3A and a trunk portion 3A. And a head portion 2A extending in a trumpet shape from the rear end. In addition, an adjustment cylinder 4 (see FIG. 4), which will be described later, formed of a flexible material such as resin is accommodated in the body portion 3A.

  Similarly to the head 2 of the first embodiment, the head 2A includes the bellows portion 21A and the locking portion 22A, and the drawing direction of the steel wire 6 is orthogonal to the wall surface 5A of the structure 5 3A, when the bellows portion 21A is not contracted and embedded in the structure 5, and the drawing direction of the steel wire 6 is not perpendicular to the wall surface 5A ′ of the structure 5 ′. As shown in FIG. 3B, the bellows portion 21A is embedded in the structure 5 ′ in a contracted state.

  The adjustment cylinder 4 shown in FIG. 4 has a cylindrical shape with an outer diameter slightly smaller than the inner diameter of the body portion 3A, and is formed slightly longer than the body portion 3A. As shown in FIG. 5, on the inner peripheral surface of the rear end portion of the body portion 3A, the rearward movement of the adjustment cylinder body 4 is restricted, and the support section 34 that supports the adjustment cylinder body 4 in the body portion 3A. Is formed. The support portion 34 has a rectangular cross-sectional shape, is formed over the entire circumference of the body portion 3A, and has an annular shape.

  When the steel wire 64 having a small outer diameter is inserted, the trunk portion 3A is embedded in the structure 5 with the adjustment cylinder 4 housed in the trunk portion 3A, as shown in FIG. The Moreover, when the steel wire 65 whose outer diameter is larger than the steel wire 64 is inserted, as shown in FIG.5 (b), the structure 5 in the state which has not accommodated the adjustment cylinder 4 in the trunk | drum 3A. Buried in The rear end portion of the sheath 7 is inserted into the trunk portion 3 </ b> A or the adjustment cylinder 4.

  According to this embodiment, the shrinkage allowance of the bellows portion 21A is gradually increased from the upper edge side to the lower edge side across the axis of the head portion 2A, and when the bellows portion 21A is shortened, the head portion 2A. Since the opening end of the first member is inclined with respect to the axis of the sheath 1A, the same effect as the sheath 1 of the first embodiment can be obtained.

  Moreover, according to this embodiment, the adjustment cylinder 4 is accommodated in the trunk portion 3A, and the adjustment cylinder 4 is supported in the trunk portion 3A by the support portion 34, thereby matching the inner diameter of the barrel portion 3A. Not only the wire 64 but also a steel wire 65 matching the inner diameter of the adjusting cylinder 4 can be inserted into the sheath 1A.

  In each of the above-described embodiments, the case has been described in which the constriction margin of the bellows portions 21 and 21A is gradually increased from the upper edge side to the lower edge side, but the rear end of the heads 2 and 2A is the axis of the sheath 1 and 1A. On the other hand, the configuration of the bellows portions 21 and 21A is arbitrary as long as it can be tilted and contracted.

  Moreover, although each said embodiment demonstrated the case where the latching | locking parts 22 and 22A were formed in cyclic | annular form at the rear end of the heads 2 and 2A, the shape of the latching | locking parts 22 and 22A is arbitrary, It may be formed only at a part of the rear end of the portions 2 and 2A. Further, the locking portions 22 and 22A may not be provided.

  Moreover, although the case where the trunk | drum 3 was provided with the small diameter part 31, the medium diameter part 32, and the large diameter part 33 was demonstrated in the said 1st Embodiment, the quantity of a level | step difference part is arbitrary. Further, the small diameter part 31, the medium diameter part 32, and the large diameter part 33 may be formed so that the inner diameters are reduced stepwise from the front end side to the rear end side, and the outer diameters may be formed to be equal in size. .

  Moreover, although the said 2nd Embodiment demonstrated the case where the one adjustment cylinder 4 suitable for the thickness of the steel wire 64 was used, it is steel from the some adjustment cylinder 4 from which the magnitude | size of an internal diameter differs. It is good also as a structure which selects and uses the adjustment cylinder 4 suitable for the thickness of the line 6. FIG. Moreover, the support part 34 does not need to be formed over the perimeter of 3 A of trunk | drums, The shape is arbitrary.

  Moreover, although each said embodiment demonstrated the case where the sheath 7 was embed | buried to the wall surface of the front side of structure 5 'on the opposite side to wall surface 5A', the wall surface of the front side is with respect to the drawing-out direction of the steel wire 6. Therefore, the sheath 1, 1A may be used on the front side of the structure 5 ′.

1, 1A Sheath 2, 2A Head 21, 21A Bellows 22, 22A Locking 3, 3A Body 31 Small diameter (step)
32 Medium diameter part (step part)
33 Large diameter part (step part)
34 Supporting part 4 Adjustment cylinder 5, 5 'Structure 5A, 5A' Wall surface 6, 61-65 Steel wire 7 Sheath

Claims (5)

A sheath including a trunk portion and a head portion extending from one end of the trunk portion.
A sheath having an accordion portion that contracts by tilting an opening end of the head with respect to an axis of the sheath.   The sheath according to claim 1, wherein the bellows portion has a shrinkage margin that gradually increases from one edge side to the other edge side across the axis of the head.   The sheath according to claim 1 or 2, wherein the body portion includes a step portion having an inner diameter that is reduced in a stepped manner from the one end side to the other end side. An adjustment cylinder housed in the body,
The sheath according to any one of claims 1 to 3, further comprising a support portion that supports the adjustment cylinder body in the body portion. A falling bridge prevention device for connecting a bridge girder with an abutment or another bridge girder with a linear member inserted through a sheath,
A fallen bridge prevention device, wherein the linear member is inserted through the sheath according to any one of claims 1 to 4.

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