JPH0820916A - Construction method for subbase - Google Patents

Abstract

PURPOSE:To use a precast floor slab capable of being easily manufactured to provide a construction method for subbase for forming a curved part. CONSTITUTION:A reinforced concrete slab 34 is formed in the shape of a plane viewed rectangle, and a precast floor slab 31 for a curved part with the end of a skin plate 35 projected from the end 36 of the reinforced concrete slab 34 as an adjusting margin 39 is manufactured. The adjusting margin 39 of the precast floor slab 31 is so cut that length projected from the end face 37 of the reinforced concrete slab 34 becomes gradually short toward the end positioned to the inside of the curve from the end positioned to the outside thereof. The precast floor slab 31 is set adjacent to another precast floor slab 1, and it is connected thereto to form a subbase of the curved part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a roadbed, and more particularly to a method for constructing a roadbed that constitutes a curved portion.

[0002]

2. Description of the Related Art As one of the methods for constructing a roadbed in a bridge construction work, there is a method for constructing a roadbed by sequentially laying precast slabs manufactured in advance on a bridge girder. The structure of the precast floor slab applied to this construction method will be described with reference to FIG. FIG.
In FIG. 1, 1 is a precast floor slab, and a reinforced concrete slab 4 having a rectangular shape in plan view in which main rebars 2 and distribution rebars 3 are arranged in a grid pattern, and a skin plate 5 made of a thin steel plate attached to the lower surface thereof. It consists of and. The end portion 6 of the reinforced concrete slab 4 has a stepped shape including an upper end surface 7 and a lower end surface 8, and the force distribution reinforcing bar 3 projects from the upper end surface 7. The skin plate 5 is formed so that its end portion 9 projects from the lower end surface 8 of the reinforced concrete slab 4, and a gibber 10 is provided on the surface for the reinforced concrete slab 4, and this gibber 10 is embedded in the reinforced concrete slab 4. As a result, it is joined to the reinforced concrete plate 4.

The construction of a roadbed constructed using this precast floor slab 1 is shown in FIG. In FIG. 5, reference numerals 1 and 11 denote precast floor slabs adjacent to each other, which are placed on the same plane with the ends 6 and 16 of the reinforced concrete slabs 4 and 14 facing each other and a space 21 provided therebetween. ing. In the space 21, the distribution reinforcing bars 3 and 13 projecting from the upper end surfaces 7 and 17 of the reinforced concrete plates 4 and 14 are arranged in a wrapped state, and the wrapped distribution reinforcing bars 3 and 1 are further arranged.
A cast-in-place bar 22 is provided so as to be orthogonal to 3.
The lower end faces 8 and 18 are located closer to the upper end faces 7 and 17, and the end portions 9 and 19 of the skin plates 5 and 15 are closer to each other.
Form a gap 23 relative to a distance that is even shorter than the lower end faces 8 and 18. The back metal 2 is placed in this gap 23.
4 is welded and the lower part is closed by the backing metal 24, the precast floor slab 1, so that the wrapped reinforcing bars 3 and 13 and the cast-in-place bar 22 are embedded in the space 21.
Concrete 25 is cast up to the upper surface of 11.

By the way, the roadbed shown in FIG. 5 is a case where this roadbed is formed in a straight line shape, but when the roadbed is formed in a curved shape, the above-mentioned precast floor slab 1 having a rectangular shape in plan view is used. , 11 cannot be used as they are. Therefore, in order to form the curved portion of the roadbed by using the precast floor slab 1 having the above-mentioned basic structure, the following construction method is adopted. That is, as shown in FIG. 6, a precast floor slab 26 in which a dimension L between both ends gradually decreases from the outer side to the inner side in a predetermined curved portion is separately manufactured in a factory. Next, this precast floor slab is laid on the bridge girder on site and joined to the adjacent precast floor slab to form the curved portion of the roadbed.

[0005]

However, in the above-mentioned conventional construction method using a modified precast floor slab, all the joints can be constructed in the same manner, but it takes time to manufacture the modified precast floor slab. There was such a problem. That is, because the shape of the precast floor slab used for each curve part is different,
In the production of odd-shaped precast slabs, a large number of reinforced concrete slabs corresponding to them were required. Further, in the production in the factory using those form frames, the work was complicated and could not be performed efficiently.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for constructing a roadbed that forms a curved portion by using a precast floor slab that can be easily manufactured.

[0007]

In the roadbed construction method of the present invention, precast floor slabs provided with a reinforced concrete slab and a skin plate made of a thin steel plate attached to the lower surface of the reinforced concrete slab are adjacent to each other. Laying so as to provide a space between the end with the precast floor slab, with the end of the skin plate protruding from the end face of the reinforced concrete plate, the reinforcing bar is projected into the space from the end face of the reinforced concrete plate, further Concrete is cast in the space so as to bury the reinforcing bars, and the precast floor slab is a roadbed construction method that constitutes a curved portion of the roadbed, wherein the reinforced concrete slab is a plan view as the precast floor slab. The end portion of the skin plate protruding from the reinforced concrete plate is rectangular and the adjustment margin is set. Of the precast floor slab so that the projection length from the end face of the reinforced concrete slab becomes gradually shorter from the end located on the outer side of the curved portion to the end located on the inner side. It is characterized in that the precast floor slab, which is cut into pieces and the adjustment margin of the skin plate is cut, is laid next to another precast floor slab.

[0008]

According to the construction method of the present invention, the precast floor slabs manufactured for the curved portion have the same shape, and the adjustment margin of the skin plate arranged on one of the joint surfaces is adjusted on the spot. It is cut in consideration of the radius of curvature and then joined to the adjacent precast floor slab.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, 31 is a precast floor slab for a curved portion used in the construction method of the present invention, which is the same as the conventional precast floor slab 1 in which main reinforcing bars 32 and distribution reinforcing bars 33 are arranged in a grid pattern. It is composed of a reinforced concrete plate 34 having a shape and a skin plate 35 attached to the lower surface thereof. The end portion of the reinforced concrete slab 34 has a stepped shape including an upper end surface 37 and a lower end surface 38, and the distribution force reinforcing bar 33 projects from the upper end surface 37. The adjusting bar 39 provided on the power distribution reinforcing bar 33 and the skin plate 35 has a shape projecting more greatly at one end 36 of the reinforced concrete plate 34, and the dowel 40 welded to the skin plate 35 has The auxiliary rebar 41 is welded to prevent the adjustment margin 39 from being deformed. The auxiliary rebar 41 is provided in the same direction as the distribution rebar 33, and the reinforced concrete plate 3
It is embedded inside the No. 4 together with the dowel 40. Also,
The auxiliary rebar 41 is welded across the head of the dowel 40 to facilitate the placing of concrete on the overhanging skin plate 35.

FIG. 2 shows a subbase of a curved portion constructed by using the precast floor slab 31 for the curved portion. In the precast floor slab 31, the adjustment margin 39 of the skin plate 35 is cut in consideration of the radius of curvature of the curve, and the precast floor slab 1 is obliquely arranged and has a rectangular shape in plan view 1.
It is joined with. These precast floor slabs 1, 31
Is placed on the same plane with the ends 6 and 36 of the reinforced concrete plates 4 and 34 facing each other and a space 42 provided therebetween. Space 42 is precast floor slab 1,
Since 31 is diagonally arranged, it gradually narrows from the outside to the inside of the curve, and inside it, the distribution reinforcing bars 3 and 33 protruding from the end faces 7 and 37 of the upper steps of the reinforced concrete plates 4 and 34 are provided. Arranged in a wrapped state, a cast-in-place reinforcement bar 43 is provided so as to be orthogonal to the wrapped distribution reinforcing bars 3 and 33. A gap 44 between the end 9 of the skin plate 5 and the adjustment margin 39 formed in the lower part of the space 42
A backing metal 45 is welded to the. In the space 42 whose lower part is closed by the backing metal 45, the precast floor slab 1 is constructed so that the wrapped distribution reinforcing bars 3 and 33, the cast-in-place reinforcing bars 43 and the auxiliary reinforcing bars 41 welded to the dowel 40 are embedded. , 31 has concrete 46 placed therein.

A method of constructing the roadbed of the curved portion constructed as described above will be described. First, prior to on-site construction, a precast floor slab 31 for a curved part is manufactured in a factory. At that time, the frame of the reinforced concrete slab is the same as that of the precast floor slab 1 having a rectangular shape in plan view. As shown in FIG. 3, the adjustment margin 39 of the skin plate 35 of the precast floor slab 31 is cut on site in consideration of the radius of curvature of the curve. At this time, the distribution reinforcing bar 33 is also cut while leaving a length sufficient for the wrap length. Then, the precast floor slabs 1 and 31 are placed on a bridge girder (not shown) so that the end 9 of the skin plate 5 and the adjustment margin 39 of the skin plate 35 are aligned with each other, and the backing plate is closed so as to close the gap 44 between them. 45
Weld from below. Next, precast floor slab 1, 31
In the space 42 between them, the distribution reinforcing bars 3 and 33 are wrapped, and the cast-in-place reinforcing bars 43 are arranged above them. Finally, the space 42
Then, concrete 46 is cast to the upper surfaces of the precast floor slabs 1 and 31 so that the wrapped distribution reinforcing bars 3 and 33, the cast-in-place reinforcing bars 43, and the auxiliary reinforcing bars 41 welded to the dowel 40 are buried.

According to the above-mentioned construction method, the radius of curvature of the curve is set on-site so that the adjustment margin 39 of the precast floor slab 31 coincides with the end 9 of the precast floor slab 1 which is obliquely placed. The precast floor slabs 1, 31 are used after being cut and used according to
It is composed of concrete 46 cast in-situ in the space 42 provided between the. For this reason, there is no need for precast floor slabs with different shapes for each curve, and the precast floor slabs that are actually used for construction are the precast floor slab 1 with a rectangular shape in plan view that is used for the straight road portion and the curved roadbed. There can be two types of precast floor slabs 31 used. Further, since the reinforced concrete slabs 4 and 34 constituting these precast floor slabs 1 and 31 have the same shape, these precast floor slabs 1 and 31 are manufactured at the factory.
The same form can be used when manufacturing 31. That is, the frame can be standardized, and the work can be simplified and the productivity can be improved.

In this embodiment, one precast floor slab for the curved portion was used to construct the roadbed for the curved portion. However, a plurality of precast floor slabs for the curved portion were used for the roadbed for the curved portion. Can also be configured. That is, by using precast floor slabs for a plurality of curved parts in a row in the length direction of the roadbed, it is possible to form a long roadbed with a curved portion, and precast floor slabs for a plurality of curved parts are used for the roadbed. By using them side by side in the width direction, it is possible to form a curved portion of a wide roadbed. Further, in the present example, the roadbed of the curved portion was configured by using the precast floor slab having the adjustment margin only on one joint end, but the precast floor slab having the adjustment margin on both joint ends was used. It is also possible to construct a roadbed of curved parts.

[0014]

As described above, according to the construction method of the present invention, since the precast floor slab manufactured for the curved portion can be used to construct the roadbed for all curved portions, it is possible to use the conventional method. It is possible to eliminate the trouble of manufacturing a precast floor slab of a different shape for each curve. In addition, since the precast slab for this curved part has the same shape as the reinforced concrete slab used for the roadbed of the straight part, the work in the production of the precast slab by standardizing the frame Can be simplified and productivity can be improved.

[Brief description of drawings]

1 is a fragmentary perspective view of a precast floor slab for a curved portion used in a construction method of the present invention.

FIG. 2 is a fragmentary perspective view of a roadbed forming a curved portion showing an embodiment of the construction method of the present invention.

FIG. 3 is an explanatory view showing a cut portion of a precast floor slab for a curved portion in the construction method of the present invention.

FIG. 4 is a fragmentary perspective view showing a conventional precast floor slab for straight portions.

FIG. 5 is a fragmentary perspective view of a joint portion using a conventional precast floor slab for straight portions.

FIG. 6 is an explanatory view showing a conventional precast floor slab for a curved portion.

[Explanation of symbols]

 31 Precast floor slab for curved parts 33 Power distribution reinforcing bar 35 Skin plate 39 Adjusting margin 41 Auxiliary reinforcing bar 42 Space 46 Concrete

Claims (1)

[Claims] 1. A precast floor slab comprising a reinforced concrete slab and a skin plate made of a thin steel plate attached to the lower surface of the reinforced concrete slab so that a space is provided between the ends of adjacent precast slabs. Laid,
With the end portion of the skin plate protruding from the end surface of the reinforced concrete plate, the reinforcing bar is projected into the space from the end surface of the reinforced concrete plate, and concrete is placed in the space to bury the reinforcing bar, Each of the precast floor slabs is a method for constructing a roadbed that constitutes a curved portion of the roadbed, wherein the precast floor slab has a rectangular plan view of the reinforced concrete slab, and an end portion of the skin plate projected from the reinforced concrete slab Of the precast floor slab from the end located on the outside of the curved portion to the end located on the same side, the projection from the end surface of the reinforced concrete slab Cut the pre-cast floor slab that cuts the adjustment margin of this skin plate by cutting it so that the length gradually becomes shorter. A construction method of a roadbed that constitutes a curved portion, characterized by being installed next to the precast floor slab.