JPH0358402B2 - - Google Patents

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention is directed to a multi-span simple steel girder bridge in which intermediate expansion and contraction devices are removed to form one continuous composite deck between abutments. Concerning the construction method of continuous deck slabs between abutments using simple steel girders.

"Prior art" Conventionally, in elevated bridges that form the road surface for vehicles to travel on, when this is a simple girder, that is, the fourth
As shown in the figure, when the main girder 3 supported by a plurality of piers 2 constructed at regular intervals between the abutments 1 and 1 is a simple girder with a plurality of independent girders as shown in the figure, between the abutments 1 and 1, Expanding and retracting devices 5 are provided in all spaces between adjacent concrete slabs 4 constructed thereon, that is, for each span. This is to absorb the expansion and contraction of the steel girder due to temperature changes.

"Problems to be Solved by the Invention" In such a so-called multi-span simple steel girder bridge, as described above, the expansion and contraction devices 5 are provided for each span. In addition, this expansion and contraction device has often been damaged in the past, posing problems in the maintenance and management of bridges.

Therefore, the present invention seeks to provide a method for constructing continuous deck slabs between abutments using multi-span simple steel girders, which can improve vehicle running performance, prevent noise, reduce construction costs, and reduce maintenance. It is something.

"Means for Solving the Problem" In the method of constructing a steel girder bridge having one or more piers for supporting a main girder between abutments, the main girder is constructed as a simple girder. On top of that, concrete precast composite deck slabs each having a steel bottom formwork with a welding allowance for connection are successively laid, and after the bottom formwork of each of these slabs is welded and connected, each slab is Concrete is poured into the joints between the abutments to form one continuous composite deck slab between the abutments.

Here, when attaching each precast composite deck slab, the deck slab positioned on the pier should be placed so that it overlaps both of the main girders adjacent in the bridge axis direction, that is,
It is preferable to lay the cable so that it straddles the adjacent main girders.

``Example'' The examples shown in Figures 1 to 3 show construction examples for a four-span case with three piers 2 between the abutments 1 and 1, and as is clear from these figures. The deck slab 10 is formed as a continuous composite deck slab over multiple spans, that is, over four spans, and the main girder 3 is constructed as a simple girder like the conventional example shown in Fig. 4. .

Next, an example of a method for constructing the synthetic floor slab 10 will be described.

For example, as shown in FIG. 2, a large number of reinforcing steel materials such as dowels 12, main bars 13, distribution bars 14, etc. are arranged on a bottom formwork 11 made of a steel plate that also serves as a strength member, and concrete 15 is poured. A so-called concrete precast composite deck slab 10' is prepared in which a connecting welding margin 11a is formed to wrap around the formwork 11, and this is sequentially laid on the main girder 3, and each of these precast The welding margins 11a of the bottom forms 11 in the composite floor slab 10' are welded and connected to each other. At this time, some of the precast composite deck slabs 10', that is, the composite deck slabs 10' located on the piers 2, overlap (straddle) both of the main girders 3, 3 adjacent to each other in the bridge axis direction. At the same time, this composite floor slab 10'
The bottom formwork 11 is fixed with bolts 16 to the upper flanges 3a, 3a of both main girders 3, 3 adjacent to each other in the bridge axis direction.

Next, each precast composite floor slab 1 that was laid
By pouring joint concrete 17 at the joints for connection between 0' and hardening it, and applying paving 18 with asphalt or the like on each composite deck slab 10', the bridge abutment 1, as shown in FIG. One continuous composite deck slab 10 is formed in one span, that is, in four spans.

The composite floor slab 10 formed in this way is a uniform continuous floor slab with no expansion and contraction device between the abutments 1 and 1, so there are various problems caused by the presence of the expansion and contraction device as in the past. The cause of this is fundamentally eliminated.

By the way, when implementing the present invention, the main girder will be designed as a simple girder, but in order to make the deck 10 continuous over multiple spans, there will be a slight negative bend on the intermediate fulcrum P. A moment is generated. Therefore, this negative bending moment is borne by the bottom formwork 11, which also serves as a strength member, and exerts the effect of minimizing the tensile force acting on the concrete 15 in the bridge axis direction.

Here, if the above-mentioned negative bending moment is large, as shown in FIG. , it is desirable to form the thick portion 11b which is sufficiently thicker than other portions.

Furthermore, if necessary, as shown in FIG.
9 and 19, respectively, and also provide a pair of thin partition members 20, 20 on the joint line of both partition plates 19, 19 to divide the pavement 18 into two in the bridge axis direction. suitable. In the figure, reference numeral 19a indicates anchor bars of the partition plate 19.

If the above-mentioned measures are implemented, a structure can be obtained in which cracks in the bridge axis direction of the concrete 15 on the intermediate supporting point P can be reliably prevented due to the action of the thick wall portion 11b in any of the structures. In particular, in the configuration shown in FIG.
are separated on the pier 2 by the partition plate 19 and the partition material 20, and are connected only at the thick wall portion 11b, so the tension in the transverse axis direction that acts on the slab itself due to various causes such as earthquakes, etc. The force does not act on the concrete layer 15, the pavement 18, etc., but only on the thick wall portion 11b, and as a result, the crack prevention effect described above becomes even more reliable.

In addition, according to the method of the embodiment, the bridge body and the substructure become one continuous structure, so in consideration of horizontal force due to earthquakes, etc., the main girder 3 on the bridge pier 2, for example, as shown in the illustrated example, Measures such as fixing one of the three to the pier 2 and making the other movable, or having the horizontal force taken at one place and making all the others movable, are possible depending on the weather conditions at the construction site. It is desirable to apply this method based on the results of three-dimensional analysis including the following.

"Effects of the Invention" As explained above, according to the present invention, precast composite deck slabs are connected in series to form a continuous, uniform composite deck slab over multiple spans, so that it is possible to By removing the expansion and contraction devices for each span that were required in steel girder bridges, construction efficiency and cost savings can be improved.Moreover, by removing the expansion and contraction devices in this way, vehicle running performance has been improved. It has excellent advantages, such as improving bridge construction and noise prevention, and is also preferable from the viewpoint of bridge maintenance and management.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a schematic side view, FIG. 2 is an enlarged view of the part shown in FIG. 1, and FIG. 3 is another embodiment. FIG. 2 is an enlarged view similar to that shown in FIG. 2, and FIG. 4 is a schematic side view showing a conventional example. 1... Bridge abutment, 2... Pier, 3... Main girder, 3a...
...Top flange, 10... Floor slab, 10'... Precast composite floor slab, 11... Bottom formwork, 11a...
Welding allowance, 11b...thick part, 15...concrete (concrete layer), 17...joint concrete, 19...steel partition plate.

Claims (1)

[Claims] 1. A method of constructing a steel girder bridge having one or more piers for supporting a main girder between the abutments, wherein the main girder is constructed as a simple girder, and connecting After sequentially laying concrete precast composite deck slabs equipped with steel plate bottom formwork with a welding allowance of A method for constructing a continuous deck slab between abutments using a multi-span simple steel girder, characterized by pouring concrete between the abutments to form one continuous composite deck slab between the abutments. 2 A part of each of the precast composite deck slabs is laid so as to overlap both of the main girders adjacent in the bridge axis direction, and the bottom formwork of this precast composite deck slab is laid over the main girders adjacent to each other in the bridge axis direction. Claim 1 characterized in that it is fixed to both main girders.
Construction method described in section. 3. The bottom formwork of the precast composite deck slab, which is laid overlapping both of the main girders adjacent to each other in the axial direction of the bridge, is formed so that at least the part that spans between the adjacent main girders is thicker than the other parts. 3. The construction method according to claim 2, wherein the thick portion is provided with a partition plate that divides the concrete layer on the bottom formwork into two in the bridge axis direction.