JPH0971904A - Preventive method of concrete slab bridge from falling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a bridge body from falling even when the lower structure of a bridge pier or the like deforms and the slab end is dislocated from the support seat, and prevent the secondary disaster of the falling bridge, in a concrete slab bridge having a slab construction like a cast-in-place hollow slab bridge or a prestressed concrete hollow girder bridge. SOLUTION: A bridge body 2 is inserted in the axial direction of a concrete slab bridge and PC cables 5 are stretched between both abutments. The PC cables 5 are stretched in such an extent of tension that the slack is eliminated. Both ends of PC cable are anchored in the parapets 3, 3 of the abutments 1, 1 respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing a concrete slab bridge from falling.

[0002]

2. Description of the Related Art When a lower structure such as a bridge pier is displaced due to an earthquake or the like, there is a problem that the bridge body falls. For girder type bridges in concrete bridges, the problem of preventing bridge collapse is solved by connecting the abutment fulcrum cross girder and abutment parapet or by connecting both girders of the pier fulcrum with PC steel rods or the like. be able to. However, in a concrete slab bridge with a slab structure, the anchor bar is only embedded in the abutment and / or the pier fulcrum part from the structure, and if the displacement of the pier becomes large, the anchor bar will break or the concrete of the girder, abutment, and pier will fall off. There was a risk that the bridge would fall.

[0003]

DISCLOSURE OF THE INVENTION The present invention is to develop and provide a method for preventing collapse of a concrete slab bridge by solving the above problems peculiar to the concrete slab bridge. The present invention prevents the bridge body from falling even if the concrete slab bridge with a slab structure, such as a cast-in-place hollow slab bridge or a PC hollow girder bridge, does not drop even if the substructure such as a pier is displaced and the slab end comes off the bearing seat. The purpose is to prevent the occurrence of secondary disasters and minimize damage.

[0004]

The present invention has been made to solve the above-mentioned problems, and a PC cable is stretched between both abutments by penetrating the bridge body in the bridge axis direction of a concrete slab bridge. However, it is a method of preventing collapse of concrete slab bridges, characterized in that the ends of the PC cables are fixed to the parapets of both abutments, respectively.

In this case, the PC cable may be made a PC cable which does not adhere to the bridge over the entire length and insulated from the bridge so as to be displaceable with each other, or the fixed end of the PC cable at the bridge. In the vicinity of the support, the PC cable may be attached to the bridge body to prevent the anchor bar from breaking.

[0006]

1 is a side view of a concrete slab bridge according to an embodiment of the present invention showing a method of preventing the bridge from falling.
The bridge 2 consists of an abutment 1 and a movable support, respectively.
The bearings 16 and 16 of FIG. 1 are fixed to the fixed bearing end 7 by the anchor bar 8 against expansion and contraction of the bridge 2.

A PC cable 5 for preventing falling bridges is stretched through the bridge body 2 erected between the abutments 1 and 1, and the fixing tools 4 and 4 are provided behind the parapets 3 and 3 of the abutments 1 and 1, respectively. Both ends of the PC cable 5 are fixed. PC stretched
The tension of the cable 5 should be such that the slack is removed.
Make sure not to restrain the normal displacement of the bridge body 2. In the example of FIG. 1, the fixed bearing end 7 of the PC cable 5 for preventing bridge collapse
The vicinity is integrally attached to the bridge 2. In the other portion, the PC cable 5 is housed in the sheath 6, and the bridge body 2 and the PC cable 5 are insulated. In this way, unnecessary stress is not generated in both the bridge body 2 and the PC cable 5 without being restricted by the expansion and contraction of the concrete bridge body 2.

2 and 3 are sectional views of the embodiment shown in FIG. 1, showing different bridge bodies. Figure 2 is a cast-in-place Hollow Slab bridge 10 with a PC cable 5
Are provided in the concrete section. FIG. 3 shows a case of a bridge body in which a precast prestressed concrete hollow girder 11 is erected, and the PC cable 5 for preventing bridge collapse is arranged in cast-in-place concrete 13.

FIG. 4 is a detailed view of the fixed bearing end 7 of the bridge body 2, in which a cushion packing 15 is sandwiched between the bridge body 2 and the parapet 3.
Penetrate the parapet 3 and attach it to the back of the parapet with the fixing tool 4
An end portion of the C cable 5 is fixed, and a cap 14 is provided to prevent the fixing tool 4 from rusting. The fixing tool 4 may be a fixing tool composed of a wedge and a sleeve. A steel sleeve is crimped to the end of the PC cable and a male screw is engraved on the outer circumference of the sleeve.
It may be a screw-type fixing device in which a nut is screwed and fixed.

FIG. 5 is a detailed view of the movable bearing end 9. As in FIG. 4, a cushion packing 15 is provided between the bridge body 2 and the parapet 3. The PC cable 5 is housed in the sheath 6. The fixing tool 4 and the cap 14 are similar to those described in FIG. The method of the present invention can also be applied to the case of a slab bridge spanning several spans by stretching a PC cable over several spans. Further, as a means for insulating the bridge body 2 and the PC cable 5, a PC cable coated with a polyethylene pipe or the like by applying grease or asphalt can be used.

[0011]

As compared with the conventional anchor bar method, the method of the present invention can effectively prevent the collapse of the concrete slab bridge even if the substructure of the concrete slab is largely displaced, and the secondary disaster caused by the collapse of the bridge. Can be prevented.

[Brief description of drawings]

FIG. 1 is a side view of a concrete slab bridge according to an embodiment.

FIG. 2 is a cross-sectional view of a cast-in-place hollow slab bridge.

FIG. 3 is a cross-sectional view of a bridge body using a prestressed concrete hollow girder.

FIG. 4 is a detailed side view showing the fixed bearing end of the embodiment.

FIG. 5 is a detailed side view showing the movable bearing end of the embodiment.

[Explanation of symbols]

1 Abutment 2 Bridge 3 Parapet 4 Fixing tool 5 Cable 6 Sheath 7 Fixed bearing end 8 Anchor bar 9 Movable bearing end 10 Hollow slab 11 Prestressed concrete hollow girder 13 Cast-in-place concrete 14 Rustproof cap 15 Buffer packing 16 Bearing

Claims (3)

[Claims] 1. A PC cable is stretched between both abutments, passing through the bridge in the axial direction of the concrete slab bridge,
A method for preventing the collapse of concrete slab bridges by fixing the ends of the cables to the parapets of both abutments. 2. The method for preventing collapse of a concrete slab bridge according to claim 1, wherein the PC cable is a PC cable that does not adhere to the bridge over the entire length. 3. The method for preventing collapse of a concrete slab bridge according to claim 1, wherein the PC cable is a PC cable attached to the bridge body near the fixed-end bearing of the bridge body.