JPH05339912A - Joint structure for precast block for bridge - Google Patents

Abstract

PURPOSE:To reduce the necessary amount of prestress as well as raise the reliability of joint structures between blocks. CONSTITUTION:A box-like male coupler 20 whose upside is opened and the front side is projected is buried in the front sides of the upper and lower flanges of a precast block 10, and a female coupler 30 to be connected with the male coupler 20 is buried in the back side. In the joint between the blocks 10, 10 the female coupler 30 on newly set block side is connected with the male coupler 20 on the existing block side and the blocks 10 are connected by a coupling bolt 24 thrust through a bolt hole 21. The tensile force of the bolt 24 is transmitted to the blocks 10, 10 by anchoring bars fixed to both the couplers 20 and 30 through the couplers 20 and 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure for a bridge precast block constructed by a precast block method.

[0002]

2. Description of the Related Art The bridge superstructure employs a precast block method applicable to long and large spans and capable of shortening the construction period. The construction method is
In a factory or on-site production yard, concrete blocks that are divided into sizes according to the capacity of the transportation / erection machine are manufactured, and the blocks are erected on site and joined by reinforcing bars or integrated by prestressing. is there.

In order to take advantage of the advantage of the seam structure in the precast block method, the blocks are adhered to each other with an epoxy resin or the like, and usually the reinforcing bars are not continuous. Therefore, it is a design condition that a PC steel material that connects the blocks to each other is arranged and prestressed so that tensile stress is not generated in the concrete of the block joint when a design load is applied.

The above-mentioned design conditions are severer than those of the cast-in-place method, and as a result of the required amount of prestress being increased, the amount of PC steel is also increased, which is one of the causes of impairing the economical efficiency of the precast block method. There is.

Further, when joining the precast block, it is necessary to apply an appropriate compressive force between the joints while the epoxy resin cures. Conventionally, a temporary tension force is applied by using a temporary PC steel material. After curing the epoxy resin,
C steel material had been removed.

[0006]

It is an object of the present invention to provide a highly reliable joint structure for precast blocks for bridges with respect to the joint structure between precast blocks, reduce the amount of prestress required, and carry out an economical precast block construction method. Is to establish.

[0007]

According to the present invention, in a structure in which a bridge precast block having a guide key for positioning is joined to a joint end, the guide key is a box-shaped joint member having an open top. It is characterized in that the male and female joint members are connected by joint bolts on the fitting surface.

[0008]

[Operation] If the male joint member on the existing block side is fitted with the female joint member on the new block side and both precast blocks are joined by joint bolts, the tensile force transmitting capacity of the joint bolts is arranged in the block body. The tensile force of the joint bolt is transmitted to the main body of the precast block via the male and female joint members by making the tensile force transmission capability of the reinforcing bar equal to that of the rebar. Further, when the blocks are joined by an adhesive, the joint bolt plays a role of giving a necessary compressive force while the adhesive cures.

[0009]

EXAMPLES The present invention will be described in detail below with reference to examples. First, a conventional example will be described with reference to FIG. FIG. 4 is a front view of a typical bridge precast block 10,
The block 10 has a box-shaped cross section including an upper flange (slab) 11, a lower flange 12 and a web 13.

A large number of shear keys 15 are provided on the front surface of the web 13 in order to secure the shearing force of the concrete at the seam, and new blocks are installed on the front surfaces of the upper and lower flanges 11 and 12. A plurality of guide keys 16 are provided in a protruding manner for positioning when attracting and joining the existing block. The above configuration is the same as that of the precast block 10 according to the present invention shown in FIG. 1, and in the present invention, the guide key 16 further has a function as a joint member.

FIG. 2 is a perspective view of the male joint member 20. The male joint member 20 is formed in a box shape having an open upper portion and a convex front portion. Bolt through holes 21, 21 are formed in a horizontal position on the side wall of the front portion of the male joint member 20, and a large number of anchor ribs 22 project outward from the other side walls. As shown in FIG. 1, the male joint member 20 is embedded on the front side of the upper and lower flanges 11 and 12 of the precast block 10, and the female joint member 30 corresponding to the male joint member 20 is embedded on the rear side.

FIG. 3 shows the precast blocks 10, 10.
It is a top view which expanded and showed the principal part in the joining part of.
The female joint member 30 on the new block side is fitted to the male joint member 20 on the existing block side, and both precast blocks 10 are joined by the joint bolts 24 inserted through the bolt through holes 21.
10 are joined. The tensile force transmitting capacity of the joint bolt 24 is made equal to the tensile force transmitting capacity of the reinforcing bar arranged in the precast block body, so that the joint bolt 24
Is a substitute for the above-mentioned reinforcing bar that transmits tensile force.

That is, the tensile force of the joint bolt 24 is transmitted to the main body of the precast block 10 via the male and female joint members 20 and 30 by the anchor ribs 22 fixed to the joint members. Further, the joint bolt 24 plays a role of giving a necessary compressive force while the epoxy resin is cured.

Next, a construction method using the precast block 10 will be described with reference to FIG. In the figure, an erection girder 34 is bridged between the piers 32, 32, and the block 10 carried by a truck is hung on a moving carriage 36 to move forward in the erection girder 34 (step (2)). After 10 is hung on the erection girder 34, prestressing is applied to integrate them (step (3)). Step (4) shows a situation in which the shoe is replaced with a girder to advance the erection girder 34 and move to the next span.

In the steps from (2) to (3), the work of drawing the new block to the existing block is performed. Conventionally, in the pulling work, a concrete projection, a temporary bracket, a beam, or the like is mounted in a block, and the above-mentioned temporary PC steel material is fixed and pulled to this.

On the other hand, in the present invention, the joint member 20,
30 can be used as a fixing unit for the above-mentioned attraction. Therefore, it is not necessary to separately use the fixing means such as the concrete projection, the temporary bracket, and the beam as described above.

Conventionally, since two roles of the pulling work and the temporary tensioning work until the epoxy curing are required, PC steel is used for this pulling work, but in the present invention, the epoxy curing is used. Tension force up to joint bolt 24
Since it is given in the above, the role of the attracting material is only one of the attracting work. Therefore, it is sufficient to use a normal chain block, a lever block, or the like for pulling, and the chain block ends may be fixed to the existing and new joint members 20 and 30.

[0018]

According to the joint structure of the precast block for a bridge according to the present invention, the precast blocks are connected to each other by a joint bolt capable of transmitting a tensile stress equivalent to that of a reinforcing bar, and the joint member is connected for block joining. Since it is also used as the guide key, the reliability of joining the precast blocks to each other is increased, and the required amount of prestress is reduced, so that the amount of main PC cable can be reduced.

Further, it becomes possible to omit the PC steel material which is temporarily installed to give a necessary compressive force while the adhesive is being hardened. Further, the PC steel material for pulling the block and the fixing member (projections, brackets, beams, etc.) can be omitted, which is economical.

[Brief description of drawings]

FIG. 1 is a front view of a precast block according to the present invention.

FIG. 2 is a perspective view of a male joint member 20.

FIG. 3 is an enlarged plan view of an essential part of a joint portion of a precast block.

FIG. 4 is a front view showing a conventional example of a precast block.

FIG. 5 is an explanatory view of a precast block installation process.

[Explanation of symbols]

 10 Precast Block 16 Guide Key 20 Male Joint Member 24 Joint Bolt 30 Female Joint Member

Claims (1)

[Claims] 1. In a structure for joining a bridge precast block having a guide key for positioning at a joint end, the guide key is formed by a pair of male and female joint members having an open top and a box shape, A joint structure for a precast block for a bridge, wherein the male and female joint members are connected by joint bolts on a fitting surface.