JPH04202907A - Bridge upper structure - Google Patents

Abstract

PURPOSE:To simplify a construction process, decrease the welding residual stress and improve the fatigue strength and to improve the appearance by connecting plural steel members to each other by cross girders to form a main girder and fixing a reinforced concrete floor plate on the main girder. CONSTITUTION:The upper edges of a pair of steel materials 11 having a U-shaped section are butted, welded and joined 12 to form one steel member 10 where upper and lower flange members 111 and right and left web portions 112 are connected to each other. Subsequently, plural brace blocks 130 are welded to the upper flange portion 110. A reinforced concrete floor plate 51 is combined with the main girder 52a through the brace blocks 130. Thus, a construction process can be simplified, the welding residual stress of a main girder can be decreased and further fatigue strength and the appearance can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial field of application The present invention relates to a bridge pier consisting of a pedestal erected on a footing that is not supported by a pile foundation, etc., and a beam installed horizontally on the pedestal. This relates to the bridge superstructure placed on the bridge.

(B) Prior Art Conventional bridge piers mainly include T-shaped piers and gate-shaped piers.6 For convenience of explanation, the T-shaped piers will be explained as an example. In the case of a T-shaped pier as a bridge substructure, as shown in Figure 7, a beam (overhang beam) 4 overhangs from a pedestal 3 built on a footing 2 supported by a pile foundation 1. , the load of #5 bridge as a superstructure can be supported.

Next, @v#5 as a superstructure is shown in Fig. 8(A).

, (B), it is made up of a reinforced concrete floor slab (RC floor slab) 51 and a main girder 52. The main girder 52 has an I-shaped cross section, as shown in FIG. 8 (^) and FIG. 9 (^), and a box-shaped cross section, as shown in FIG. 8 (B) and FIG. 9 (8). There are some cross sections. Each of these main girders 52 is composed of a web 521, a flange 522, and an auxiliary member 523. Usually, these steel materials are joined by welding.

In this way, if a member having the cross section shown in FIG. 9 is manufactured by welding flat steel plates, it will require only one step and will be complicated, and the manufacturing period will be long, resulting in poor economic efficiency. Furthermore, due to the structural characteristics, residual stress due to welding causes a deterioration in proof strength and a decrease in fatigue strength due to the use of thin plates. Also, its cross-sectional shape is shown in Figure 3 (B).
A square or T-shape as shown in Fig. 8fA) is inferior in appearance.

(c) Problems to be Solved by the Invention The problems to be solved by the present invention are to obtain a bridge superstructure that saves manufacturing labor, reduces welding residual stress, improves fatigue strength, and improves aesthetics. be.

(D) Means for Solving Section U The bridge superstructure of the present invention consists of a pedestal erected on a footing supported by a pile foundation, etc., and a pier consisting of a beam installed horizontally on the pedestal. In the bridge superstructure that is placed on the
A main girder is constructed by interconnecting steel members whose upper and lower flange portions and left and right web portions are an integral member with a plurality of cross beams, and a plurality of dowels are attached to the upper flange portions of the steel members. The above-mentioned problem has been solved by a means characterized in that a reinforced concrete slab is fixed to the main girder by passing the dowel and concrete over the main girder.

It is also possible to provide voids in the concrete above the crossbeams.

(E) Function The bridge superstructure of the present invention is produced by pressing a steel plate with a UO press machine or the like to form a pair of U-shaped steel plates in which the web and the lower flange are integrated, and then pressing the upper edges of the plates against each other. A steel member is used in which the upper and lower flange portions and the left and right web portions are joined together by welding to form a continuous integral member. This steel member reduces the weld length and shortens the manufacturing time. The web thickness and flange thickness are the same, and no local buckling occurs.
By increasing the thickness, the yield strength in the plastic region is also improved.

By making the cross-sectional shape of the bridge steel member into an oval curved shape, the aesthetic appearance is also improved. This is because, compared to the conventional square cross-sectional shape, the oval shape maintains the continuity of the surface, giving a sense of visual security.

Additionally, a dowel is welded to the upper flange to strengthen the bond with the concrete. Weight reduction can also be achieved by appropriately creating voids within the concrete.

The circular side surfaces of the main girder improve shear strength and create a stable structure. Furthermore, by integrating the main girder with the reinforced concrete deck slab (RC deck slab), it becomes a steel/concrete composite structure, and the compressive force is received by the reinforced concrete deck slab, and the tensile force is received by the steel members, which improves the strength. This will be further improved.

(F) Embodiment An embodiment of the bridge superstructure of the present invention will be described with reference to FIGS. 1 to 6.

As shown in FIG. 1, the li%i beam upper ellipse of the present invention 5
Structure, pile foundation, etc. 1 supports a footing 2 with a pedestal 3
The bridge superstructure 5a, which is placed on a pier consisting of a beam 4 erected and horizontally installed on a pedestal 3, has a plurality of steel members 10 (as best shown in FIG. 3). In the illustrated example, the main girder 52a is formed into an ellipse by being connected to each other by the cross beams 20, and @
A plurality of dowels 13 are attached to the upper flange portion 111 of the manufactured member 10.
0 is welded, and a dowel 130 is placed on the main girder 52a to synthesize the reinforced concrete slab 51.

The lower flange 111 of the steel member 10 is placed on the beam 4 of the pier using the support 30 and fixed.

In addition to the T-shaped piers shown in Figure 1, the piers are gate-shaped (as shown in Figure 2).
A) It may be a t-type or an overhanging gate type (B).

As shown in FIG. 3, the giA member 10 is made by welding (12
), upper and lower flange portions 111 and left and right web portions 112
or continuous with each other as an integral member.

In FIG. 3(^), the left and right web portions 112 are formed into an arc shape, and in FIG. R) is attached. The width of the flange portion 111 is preferably 1 to 3 times the girder height of the web portion 112.

As shown in FIG. 4, the U-shaped cross-section steel plate 11 is formed into a U-shape by pressing down the steel plate 15 with a U press 16, and later welded together to form a web portion 112 and a flange portion 111 that are continuous and integral with each other. It is considered to be a member of

This member thus obtained (FIGS. 3A and 3B) can have high strength in the plastic region, as shown in the conceptual diagram of load-displacement shown in FIG. In the case of the conventional box-shaped cross-sectional member shown in FIG. 9 [B], since a thin plate is generally used, the local buckling strength of pressure al III and the shearing strength of the web portion are severe, but as shown in FIG. In the case of the wedge-shaped cross-section members (8) and (8), by using a thick plate, the U-shaped cross-section member has better toughness against the applied load than the box-shaped cross-section member shown in FIG. 9 (8). 6. The joint portion between the web portion and the flange portion has a continuous curved shape, which improves stability and aesthetic appearance.

As shown in FIG. 5(^), the bridge superstructure of the present invention does not necessarily require voids in the concrete 140, but as shown in FIG. 5(B) and FIG. A void 150 may be provided in the concrete 140 above the concrete 20. Furthermore, as an alternative, a space 160 corresponding to the void may be formed by extending the crossbeam 20 twice as shown in Fig. 5 fc). good. The void is effective in eliminating the weight of the main girder 52a.

The dowel 130 strengthens the connection between the steel member 10 and the RC deck slab 51 through the concrete 140.

(g) Effects According to the present invention, by using bridge steel members for a part of the main girder of the superstructure, the construction process can be omitted, welding residual stress in the main girder can be reduced, and fatigue strength can be improved. , it is possible to improve the aesthetic appearance. Therefore, the structure is advantageous in terms of economy, safety, and aesthetics.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a bridge on which the bridge superstructure of the present invention is mounted. FIG. 2 is a cross-sectional view of another bridge to which the present invention can be applied. FIG. 3 is a cross-sectional view of a steel member used in the present invention, and FIG. 4 is an explanatory diagram of the manufacturing process of the @-made member shown in FIG. FIG. 5 is a partial cross-sectional view of various modifications of a part of the structure of the present invention. Fig. 6 is a graph showing the effect of the structure of the present invention, Fig. 7 is a cross-sectional view of a conventional bridge, Fig. 8 is a cross-sectional view of a conventional bridge superstructure, and Fig. 9 (8), +8) is a graph showing the effect of the structure of the present invention. Figure 8 (^), fB) ノ'rXA
- A cross-sectional view seen from the rXA line O and the rXB-rXB line. 1: Pile foundation 2: Footing 3: Pillar
4: Overhang beam 5, g4 bridge (superstructure)
10:@ made member 11, U-shaped cross section steel material 5a:
Bridge superstructure 111: Flange part 112: Web part 12+1 joint 20: Cross beam 30: Support 130 Nijibel 51: Reinforced concrete slab 150: Void Fig. 2 (A) (B) Fig. 3 Fig. 5 70 10' Figure 8 IXA -' Figure 9 2z

Claims (1)

[Scope of Claims] 1. In a bridge superstructure that is placed on a pier consisting of a pedestal erected on a footing supported by a pile foundation or the like and a beam installed horizontally on the pedestal, 1. The upper edges of the pair of U-shaped steel members are butted against each other and welded together, and the upper and lower flanges and left and right web parts are continuous with each other and are made into an integral member.Multiple steel members are interconnected with cross beams to form the main body. A bridge superstructure comprising a girder, a plurality of dowels fixed to the upper flange portion of the steel member, and a reinforced concrete deck slab fixed to the main girder by passing the dowels and concrete over the main girder. . 2. The bridge superstructure according to claim 1, wherein voids are provided in the concrete above the cross beam.