JPH11117231A - Protective device for tensing transverse prestressing pc steel in pc bridge girder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective device capable of controlling the run-out of transverse prestressing PC steel toward the side in a PC bridge girder, when the transverse prestressing PC steel is tensed, even in the case the PC steel is broken. SOLUTION: In the structure in which both end parts of transverse prestressing PC steel penetrating through a plurality of main girders for connecting them in the transverse direction are fixed to both end parts of the PC bridge girders, pretective sheet fitting frames 12 are detachably provided on the uper surface of the PC bridge girder 2. Then, protective sheets 11 are fitted to the fitting frames 12 in the positions distant from a prscribed distance from both ends of the PC bridge girder 2, and also they are positioned so that the axial extended line of the PC steel 6 intersects the sheet surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a bridge girder into which PC steel is introduced (hereinafter referred to as a PC girder). The present invention relates to a protection device for preventing lateral tension of a PC steel material in order to prevent it from being pulled out.

[0002]

2. Description of the Related Art In a post-tension type simple girder bridge, which is one of the PC structures, a PC main girder manufactured by a post-tension type is built on a pier (and an abutment) near a bridge. . In this case, the PC steel material and the rebar are arranged in the longitudinal direction of the PC main girder, and in the horizontal assembling process, the plurality of main girders arranged side by side are also tightened by the PC steel material and tightly integrated.

[0003]

When the main girder is laterally tightened with a PC steel material, the PC steel material for the horizontal tightening is broken due to the strong tensile force (for example, about 50 tons), and the cutting line is cut off. May jump out to the side with intense momentum. PC bridges are often constructed as viaducts that span a wide road, or under conditions where a railway is running below, in which case the cut line of the broken PC steel falls down and the road There was a danger of hitting people, cars and trains passing by and damaging them.

[0004] It is an object of the present invention to provide a protection device for lateral tightening of PC steel in a PC bridge girder which has solved the above-mentioned problems.

[0005]

In order to achieve the above-mentioned object, in the PC bridge girder according to the present invention, a PC steel horizontal tightening and protection device is provided. In the structure in which both ends of the laterally tightened PC steel material are fixed to both sides of the PC bridge girder, a protective sheet mounting frame is detachably provided on the upper surface of the PC bridge girder. The protective sheet is attached at a position separated by a distance from the above and at such a position that the axial extension of the PC steel material intersects the sheet surface.

The protective sheet mounting frame comprises a horizontal rectangular frame provided on the upper surface of the PC bridge girder and a vertical rectangular frame provided on the horizontal rectangular frame.
It is composed by stacking multiple sheets of arad fiber alone,
It is preferable to attach the peripheral portion of the protective sheet to the vertical rectangular frame.

According to the present invention, when the PC steel for lateral tightening in the PC bridge girder is tensioned by a tension jack with a large tensile force, the PC steel is broken and cut.
When the steel protrudes to the side of the PC bridge girder, the PC steel hits the protective sheet of the protective device and is smoothly received, the protruding can be controlled, and the PC steel can be reliably received on the work scaffold. There is no danger of falling on trains and railways.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a state where a PC steel material for lateral tightening of a post-tension type simple girder bridge (PC bridge) is tensioned, FIG. 2 (A) is an enlarged plan view of a protective sheet mounting frame,
FIG. 3A is a view of the right front part of FIG.
FIG. 4B is a right side view showing the vertical rectangular frame of FIG.
FIG. 3 is a perspective view of a protective sheet.

In FIG. 1, a PC bridge girder 2 is constructed by arranging a plurality of main girder 1 side by side, and the upper part 3 is a pavement surface. Floor slab concrete 4 is cast in the upper gap between the main girders 1. Horizontal girder concrete is also cast in the lower gap between the main girders 1, but is not shown. Further, a PC steel material and a reinforcing bar extending in the longitudinal direction of the bridge are provided on each main girder 1, but these are also not shown. The main girder 1a located on both sides of the PC bridge girder 2 is provided with ground covering reinforcing bars 5 at predetermined intervals in the bridge longitudinal direction.

In FIG. 1, in order to connect a plurality of main girders 1, the main girders 1 are penetrated in the lateral direction and PC steel members 6 for lateral tightening are used.
The tip (left end) of this PC steel material 6 is
The first fixing member 7 protrudes outside the main girder 1a on one side.
The base end (right end) is the main girder 1 on the other side.
A second fixing device 8 is provided at the protruding base end, and a PC steel material end is connected to a tension rod of a tension jack 9 disposed outside the main girder.

Accordingly, a reaction force is applied to the main girder 1a on the right side in the figure, and the tension jack 9 is driven to tension the PC steel material 6 for lateral tightening by the tension rod, and in this state, the second fixing device 8 is tightened. Then, grout is filled in the sheath on the outer periphery of the PC steel material 6 for lateral tightening. Then, even after the tension jack 9 is removed due to the hardening of the grout, the main girder 1 can be laterally tightened and connected firmly.

At the time of the above-mentioned construction work, the PC steel material 6 for lateral tightening is tens of tons (for example, 50 tons) by the tension jack 9.
When tensioned by such a high tensile force, the PC steel material 6 may be cut in the middle. At that time, the cut PC steel material 6 may jump out of the main girders 1a on both sides with great force and fall downward.

As a protective measure against this, in the present invention, a pop-out protective device 10 is provided on both sides of the PC bridge girder 2. The protection device 10 is provided with a protection sheet 11 and
And a protective sheet mounting frame 12.

The protective sheet mounting frame 12 is formed by assembling a plurality of frame members each having a predetermined size into a rectangular shape and welding them. That is, the protective sheet mounting frame 12 is composed of a horizontal rectangular frame 13 and a vertical rectangular frame 15 welded by the welding portion 14 so as to be vertically downward from the outer end 13 a of the horizontal rectangular frame 13.
And lower ends of both sides of the vertical rectangular frame 15 and the horizontal rectangular frame 1
Of the inclined reinforcing frame 1 welded at the welded portion 14 to the side of the frame 3
6, and the rectangular protective sheet 11 is developed and attached to the vertical rectangular frame 15.

The horizontal rectangular frame 13 is disposed on the upper surface of the PC bridge girder 2 and is temporarily fixed, and the vertical rectangular frame 15 is located on a side of the PC bridge girder 2 at a fixed distance from a side end thereof. .
The means for temporarily fixing the horizontal rectangular frame 13 to the upper surface of the PC bridge girder 2 is not limited, but in the example shown in FIGS.
3, a long side frame 13b made of an angle material and a distal end connection frame 13c also made of an angle material are assembled into a substantially U-shape by welding, and the base end of the long side frame 13b (the left end in FIG. 2). A mounting plate 18 having two guide long holes 17 is welded to the lower surface of the portion (1). 2 above
Fixing bolts 19 are inserted and planted in the floor slab concrete 4 that fills the gap between the PC main girders 1 corresponding to the three guide slots 17.

Therefore, the horizontal rectangular frame 13 of the protective sheet mounting frame 12 is installed on the upper surface of the PC bridge girder 2 in the arrangement of FIG. Fixing bolt 1 from above 18
By fastening the fastening nut 23 to the base 9, the base end of the horizontal rectangular frame 13 can be detachably fixed to the upper surface of the PC main girder 1.

On the other hand, as shown in FIG. 3, a plurality of bolt holes 24 are formed at predetermined intervals in each of four sides of the vertical rectangular frame 15 in order to mount the protective sheet 11 thereon. As shown in FIG. 4, the protective sheet 11 is formed by stacking a plurality (for example, two or three) of a single sheet 11a in which a plurality of fasteners 25 with bolt holes are provided at predetermined intervals on four sides. You. Each sheet unit 11a has an aramid fiber sandwiched between two facing materials made of a soft synthetic resin sheet, leather, or the like, and a core material 26 is interposed at four edges.
A stopper 25 with a bolt hole is attached via the core 26. The size of the protective sheet 11 is, for example, about 1.3 m to about 2.0 m on one side.

The protective sheet 11 has a strength capable of reliably receiving the weight of the broken PC steel material 6 for lateral tightening when the PC steel material 6 protrudes with violent momentum, has a low manufacturing cost, and has a low construction cost. The above condition is satisfied by stacking a plurality of rectangular single sheets 11a made of the aramid fiber and having a core material 26 interposed therebetween at the edges. 2 above
One to three sheets 11a are superimposed on each other with the bolts 25 having fittings in alignment with each other, and the peripheral edge of the protective sheet 11 is
Along with the side frame, the bolt 30 is inserted through the bolt 25 of the protection sheet 11 and the bolt hole 24 of the vertical rectangular frame 15, and nuts are fastened to the four sides of the protection sheet 11. It can be firmly fixed to the vertical rectangular frame 15 by being stretched.

As is apparent from FIG. 1, the protective sheet mounting frames 12 are symmetrically disposed on both sides of the PC bridge girder 2 and at this time, are disposed outside the PC bridge girder 2 at regular intervals. The protection sheet 11 is disposed such that the axial extension of the laterally tightened PC steel material 6 intersects at the center thereof.

Therefore, if the PC steel 6 is cut and jumps out to the side when the PC steel 6 is tensed, the cut PC steel 6 hits the protective sheet 11 with violent force,
Moreover, it does not repel like a metal plate, but its momentum is smoothly reduced and it falls down. A work scaffold 27 extending in the longitudinal direction of the bridge is provided below the protection sheet 11, and the cut PC steel material 6 that falls against the protection sheet 11 at a reduced speed is used for the work scaffold 27. It is received and does not fall down.

The working scaffold 27 is attached by a known means, and the inner end thereof is attached to the main girder 1a on both sides by an anchor bolt (not shown) via a reinforcing frame 28. The upper end of the inclined support frame 29 rising from the outer end of the work scaffold 27 is supported on the upper surface of the PC bridge girder 2 by an upper horizontal support frame and an upper vertical support frame (not shown).

The work procedure of the present invention will be described.
The tension jack 9 is attached to one side of the PC bridge girder 2 and then the protective device 10 is attached to the PC bridge girder 2 (at this time, the working scaffold is already provided). Subsequently, a tensioning operation of the laterally tightened PC steel material 6 is performed. Next, the protective device 10 is removed from the PC bridge girder 2. Subsequently, the tension jack 9 is removed from one side of the PC bridge girder 2 and moved to the next position. The anchor bolt 19 is cut in a later step.

By sequentially repeating the above operations (1) to (4), the laterally tightened PC steel material 6 introduced at predetermined intervals in the longitudinal direction of the PC bridge girder 2 can be sequentially and skillfully and safely tensioned.

FIG. 5 shows the protective sheet mounting frame 12.
2 shows a horizontal rectangular frame 13d according to another example of the above and a fixing means therefor. The horizontal rectangular frame 13d in FIG. 5 is configured by assembling angle materials into a flat rectangular shape. Then, the horizontal rectangular frame 13d is arranged on the upper surface of the PC bridge girder 2 as shown in FIG.
b, a pressing rod 20 composed of two single tubes for holding b is provided,
The upper part of the fixing bolt 19 is raised through the two pressing rods 20, the pressing rods 20 are pressed by the holding metal 21, and the fixing bolts 19 are inserted into the bolt holes 22 of the holding metal 21, and the anchoring is performed from above the holding metal 21. By fastening the fastening nut 23 to the screw portion of the bolt 19, the base end of the horizontal rectangular frame 13d can be detachably fixed to the upper surface of the PC main girder 1.

[0025]

As described above, according to the present invention,
When the PC steel for lateral tightening in the PC bridge girder is tensioned with a large tensile force by a tension jack, the PC steel is broken if the cut PC steel protrudes to the side of the PC bridge girder. It is received smoothly by hitting the protective sheet in the device, its protrusion is controlled, and it is slowed down and received on the lower work scaffold, so that the cutting line of the broken PC steel material falls down as before, There is an excellent effect that the danger of hitting a person, a car, or a train passing on the road and damaging them can be reliably eliminated and the configuration is simple.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention and showing a state in which a laterally tightened PC steel material is tensioned in a PC bridge girder.

FIG. 2A is an enlarged plan view of a protective sheet mounting frame.
FIG. 2B is an enlarged sectional view taken along line CC of FIG.

FIG. 3 (A) is a front view of the right side of FIG. 2 (A),
FIG. 4B is a right side view showing the vertical rectangular frame of FIG.

FIG. 4 is a perspective view of a protective sheet.

5A is a plan view of a protective sheet mounting frame according to another embodiment of the present invention, and FIG. 5B is an enlarged cross-sectional view taken along line DD of FIG. 5A.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main girder 2 PC bridge girder 3 Upper part 4 Floor slab concrete 5 Ground covering steel 6 PC steel for side tightening 7 1st fixing device 8 2nd fixing device 9 Tension jack 10 Protrusion protection device 11 Protective sheet 12 Protective sheet mounting frame 13 Horizontal short Formwork 14 Welded part 15 Vertical short formwork 16 Inclined reinforcing frame 17 Guide long hole 18 Mounting plate 19 Fixing bolt 20 Pressing rod 21 Pressing fitting 22 Bolthole 23 Fastening nut 24 Bolthole 25 Bolthole stop fitting 26 Core material 27 Scaffolding for work 28 Reinforcement frame 29 Inclined support frame 30 Bolt

Claims (2)

[Claims] In order to connect a plurality of main girders in a horizontal direction, in a structure in which both ends of a laterally tightened PC steel material penetrating the main girders are fixed to both side parts of the PC bridge girders, an upper surface of the PC bridge girders is provided. A protective sheet mounting frame is provided detachably on the protective sheet, and the protective sheet is positioned on the mounting frame at a predetermined distance from both sides of the PC bridge girder and such that the axial extension line of the PC steel crosses the sheet surface. A protective device for tensioning laterally tightened PC steel in a PC bridge girder, characterized in that it is equipped with: 2. The protective sheet mounting frame comprises a horizontal rectangular frame provided on the upper surface of a PC bridge girder and a vertical rectangular frame provided on the horizontal rectangular frame. The protective sheet is a single sheet made of aramid fiber. The protective device for lateral tightening and tightening of PC steel beams in a PC bridge girder according to claim 1, wherein a plurality of the protective sheets are stacked, and a peripheral portion of the protective sheet is attached to the vertical rectangular frame.