JPS5851083B2 - Construction method for connecting girders using prestressed steel girders - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for constructing a prestressed steel girder when constructing a bridge using a prestressed steel girder, commonly called a prestressed steel girder, and particularly to a method for constructing a connecting girder using the prestressed steel girder. It is.

As a bridge construction girder, a forward deflection load is applied to the steel girder in advance, concrete is placed around the lower flange that will be the tension side, and the forward deflection load is released after the concrete hardens. A prestressed steel girder commonly referred to as a pre-beam is already known (Japanese Patent Publication No. 33-10424), which introduces prestress stress into the lower flange concrete by the restoring force of the steel girder.

A girder in which such a prestressed steel girder is erected on site and then web concrete and slab concrete are placed to completely cover the steel girder with concrete is called a pre-beam composite girder.

This pre-beam composite girder has a high bending stiffness because the lower flange concrete and deck concrete are attached to the steel girder, and the girder height can be lower than that of a normal composite girder. This is extremely advantageous for construction of bridges that are subject to production limits.

Additionally, since the steel girder itself is not exposed, it has the advantage of not requiring maintenance such as painting, not generating noise, and being fire resistant.

The pre-beam composite girder has such advantages because the steel girder as a component is formed with prestressed concrete added to the lower flange in advance, so it is difficult to connect the steel girders together. Due to problems with the processing structure, etc., it has traditionally been used for simply supported type bridges.

However, if the problems with the prestressed steel girder connection structure are solved and it becomes possible to apply the pre-beam composite girder to a connected girder type, the advantages of the original pre-beam composite girder of 55 tlr6 will be improved in terms of earthquake resistance, vehicle running properties, etc. It can be connected to a bridge of the connecting girder type which is advantageous in terms of this, and the range of use of the pre-beam composite girder can be further expanded.

The present invention was developed based on the above-mentioned purpose, and the girder ends of a plurality of prestressed steel girders are connected by a structure that is different from each other and supported by a final single intermediate support. In this state, first concrete slabs were poured in the span area that remained near the intermediate supporting point, and the dominant dead load was borne by the simple girder system, and then the exposed parts of the left and right steel girders were connected using bolts, etc. By pouring concrete for the connecting section and connecting the boundary surface of the lower flange concrete section with adhesive, small dead loads such as ground cover, handrails, pavement, etc. and live loads of vehicles, etc. can be continuously reduced. The object of the present invention is to provide a method for constructing a connecting girder using prestressed steel girders, which is characterized by being supported by a girder system.

Next, the construction method according to the present invention will be described in detail with reference to illustrated embodiments. FIG. 11, and b indicates the left end of the other steel girder 12.

The girder end of the steel girder 11 is cut out in an L shape so as to include the upper 7 langes 31 at a portion approximately half the height of the web 21, and a web 2. Inner vertical end plate perpendicular to 4. The horizontal end plate 4□ and the vertical end plate 43 are welded together.

Further, a stiffening plate 6 is provided between the middle part of the horizontal end plate 42 and the lower flange 51, and the center part of the horizontal end plate 42 at the position where the stiffening plate 6□ is provided is A support pin 7 is provided protrudingly.

On the other hand, the girder end of the steel girder 12 is cut out in an inverted shape so as to include the lower 7 langes 5□ at a portion about the height of half of the web 22.
The web 22 is located between the notch and the end surface of the web 2□.
An inner vertical end plate 401 and a horizontal end plate 402 perpendicular to
and the vertical end plate 403 are welded together, and a stiffening plate 6 is welded between the intermediate part of the horizontal end plate 402 and the upper 7 langes 3□.
2 is provided.

Although these steel girders 11.1□ are not shown, concrete 8□8□ is placed on the lower flanges 5□ and 5□, which are on the tensile side, when a forward bending load is applied. By releasing the front deflection load after curing, prestress stress is applied to the lower flange concrete 8□, 82.

The erection of the prestressed steel girders described above is carried out in the order shown in FIGS. 2a to 2e.

That is, as shown in FIG. 2A, after the intermediate fulcrum front 10 is installed at a predetermined position, the front prestressed steel girder 1□ is erected by one shoe 9□ and the intermediate fulcrum front 10.

At this stage of erection, the web 21 is attached to the prestressed steel girder 11.
As shown in FIG. 1, web concrete 111 is provided on both sides of the concrete bar 111 except for the ends.
．． This may be done simultaneously with the pouring of 132.

After the prestressed steel girder 1□ is erected by the shoes 9□ and 10, this steel girder 1. One prestressed steel girder 1 □ is constructed between the support pin 7 of the girder cutout end 4 and the other foot 92 in the girder.

This steel girder 12 is constructed so that the horizontal end surface 40□ of the girder notch end 40 shown in FIG.

Further, in this Q steel girder 12, concrete 112 is placed in advance on the web 22 except for the end portion 40, similar to the steel girder 1□.

Next, as shown in FIG.
At the same time, both steel girders 11. 12
Floor slab concrete 1 is placed on the upper flange 3□, 32 of the part where the intermediate fulcrum part with the girder notch end 4, 40 is left.
31.132 was poured, and this concrete floor slab 13□
, 132 and the prestressed steel girders 1□ and 12 to form a pre-beam composite girder in the span.

At this time, care is taken to connect both steel girders i, i2 with bolts 12 so as not to restrict the deflection angle of both steel girders due to support of bearing pins 7.

At this point, the dead load on both steel girders 18, 1□ is being borne by the simple girder system.

Next, in this state, as shown in Fig. 3, both steel girders 11°1
In addition to final tightening of the bolts 12, the vertical end plates 41 and 403 and 43 and 40□ are connected by the bolts 14, and the upper flanges 3m and 3□ are connected to the rising connecting plate 15. ．． ．． Bolt 16 inserted between 15□
Connect more firmly so that both steel girders 18, 12 are continuous.

After the two steel girders 12 are connected, as shown in FIG. 2d, concrete 113 is poured into the web of the intermediate fulcrum portion of both steel girders 11 and 12, and slab concrete 133 is poured into the upper flange.

Although not shown in the drawings, at this stage concrete is also placed on the transverse girders above the intermediate supports that connect the main girders.

After that, the left and right side girders 10, 1□ lower flange concrete 5
Adhesive 17 is injected into the interface between □ and 5□, and after the adhesive 17 hardens, the girder is erected as a continuous girder. From then on, as shown in Figure 2 e, the girder is constructed as a continuous girder. It supports the dead load afterward or the live load of vehicles, etc.

The construction method according to the present invention includes the above steps and has the following advantages.

In other words, when constructing Gohan's connecting girders, at the stage when the left and right girders are initially constructed as a simple girder system, the connecting ends of the left and right girders are supported separately by two basses, and after connecting the two girders, the connecting ends of the left and right girders are supported separately. It is necessary to remove the bass and replace it with one intermediate fulcrum.

On the other hand, in the construction method of the present invention, the connecting ends of each steel girder have an L-shaped notch on one side and an inverted-shaped notch on the other. steel girder 1
1 is supported by one intermediate fulcrum part 10, and the other steel girder 1□ having the inverted-shaped notch end 40 supports the intermediate fulcrum part 1
Since the inverted-shaped notched end 40 is to be constructed on the L-shaped notched end 4 of the existing girder 11 supported by the support pin 7, an intermediate part supporting the connecting part of the two steel girders is installed. Since only one fulcrum part 10 is sufficient and it can be installed from the beginning, there is no need for any complicated work such as relocating the shoe, and a significant improvement in work efficiency can be expected.

Moreover, both steel girders are 11. For the load before connection of 12,
On the other hand, the steel girder 11 generates a deflection angle around the intermediate fulcrum part 10, and the other steel girder 12 generates a deflection angle around the bearing pin 7. At the stage of temporary erection, it is difficult to construct a structure that restrains these deflection angles, for example. Therefore, the dominant dead load is borne by the simple girder system, which has the advantage of faithfully maintaining the function of the simple girder system when constructing the connected girder.

In addition, since the connection between the two steel girders 1□ and 1□ is made by bolt connection at the girder notch end 4°40, girder manufacturing errors, girder erection errors can be easily absorbed, and the erection and connection work is extremely easy. Bolt connections include horizontal end faces 4□, 40□ with bolts 12, vertical end faces 4□, 403 and 43
．． 4 (connection to L by bolts 14), it can sufficiently cope with bending and shearing force of the steel girder due to dead load and live load that act after the connection is constructed.

Further up 7 lunges 3□. The bolt 16 connecting 32 is
Together with the rising connecting plates 15□ and 152, it functions to transmit 7 lances and prevent slipping of the concrete floor slab 133.

In addition, in this construction method, multiple steel girders are connected to each other to form a connected girder, so the dominant dead load at the stage of erection is borne by the simple girder system, and after the connection, the ground covering, parapet, pavement, etc. By using a continuous girder system to support relatively small dead loads and live loads such as It can reduce the tensile stress of the slab and the associated cracking of the slab concrete.

In addition, while taking advantage of the advantages of pre-beam composite girders, such as low noise, ease of maintenance, and anti-gradation, the continuous girder system improves earthquake resistance and vehicle running performance, and has a good moment balance, making it simple. It has advantages such as being more economical than digits.

[Brief explanation of the drawing]

Figures 1 a and b are perspective views showing the structure of the girder end of a prestressed steel girder used in the erection method according to the present invention, Figures 2 a to e are side views illustrating the addition process, and Figure 3 is a 4 is a sectional view taken along the line ■-■ in FIG. 2a, FIG. 5 is a sectional view taken along the line V-V in FIG. 2C, and FIG. It is a sectional view taken along the line Vl-Vl in Figure d. In the figure, 11.12...Prestressed steel girder, 2□
, 22... Web, 30, 31... Upper flange, 4
, 40... Girder notch end, 51.5□... Lower flange, 7... Support pin, 8□, 8□... Lower flange prestressed concrete, 10... Intermediate fulcrum part, 11
1,122. 113...web concrete, 12, 14, 16.
...Bolt, 13. ．． 13□, 133...floor slab concrete, 11...adhesive.

Claims (1)

[Claims] 1. A prestressed steel girder having an L-shaped notch at the end of the girder;
A prestressed steel girder having an inverted-shaped notch at the end of the girder is erected on an intermediate support with the hooks of the notch being different,
Concrete slabs, etc., are poured into the spans of both steel girders, leaving the areas near the intermediate supports, and the spans are made into composite girders made of prestressed steel girders.Then, the notches on the left and right steel girders above the intermediate supports are constructed. After connecting the steel girders with bolts, etc., and placing the remaining concrete at the intermediate fulcrum, adhesive is injected into the concrete interface between the lower flange of both the left and right girders at the intermediate fulcrum. A method for constructing connected girders using prestressed steel girders, which is characterized by the ability to receive loads such as dead loads and live loads as continuous girders.