JP2005030153A - Beam with attached steel plates - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a beam with less cracking but large bending rigidity given by a steel plate attached on the lower surface of the beam, with both upper and lower surfaces of the concrete beam covered with the steel plates along the longitudinal direction of the beam. <P>SOLUTION: In this beam, two sheets of steel plates 2 and 3 having a width and a length capable of covering both upper and lower surfaces of the concrete beam 1 along the longitudinal direction are arranged at intervals so that the flat surfaces thereof face each other. These steel plates are integrally connected through girths 4 installed along the longitudinal direction, concrete is deposited between the steel plates, and the steel plates 2 and 3 are stuck on both upper and lower surfaces of the concrete beam. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a composite girder having a composite structure of steel and concrete that is provided on both the upper and lower surfaces of a concrete girder so as to be coated with steel plates along the length direction of the girder.

  Conventionally, as a general composite girder combining steel and concrete, a composite girder in which concrete is provided on both sides of a web in an H-shaped steel is widely known.

  The steel is not an H-shaped steel, but a truss in which angle-shaped steels arranged in parallel are connected by diagonal members, and this angle-shaped steel and the truss are used as a steel frame and the concrete is coated on the outside. Steel concrete girders are also known.

Japanese Patent Laid-Open No. 11-210093 Japanese Utility Model Publication No. 52-37459

  In the girder structure in which concrete is provided on both sides of the web of H-shaped steel, when placing concrete on both sides of the web, first, the concrete is placed with the H-shaped frame tilted sideways so that one side of the web is the bottom. Once the concrete placed on this surface has hardened, the H formwork will be tilted sideways to the opposite side, and the concrete will be placed on the opposite side. It takes a lot of time to set up, and there is a problem that a large support is required for the formwork support equipment.

  Moreover, in the composite girder using the H-shaped steel manufactured in this way, the concrete is divided into left and right by the H-shaped steel web, so that the cross section of the concrete is up and down in appearance. Although it is the same as the width of the flange, in reality, there is only half the thickness divided on both sides of the web, which has the problem of low torsional rigidity.

  On the other hand, in a girder that uses a truss-shaped steel frame formed by connecting diagonal members between a pair of parallel angle irons instead of H-shaped steel, if flat steel plates are used as upper and lower flanges, Since it is necessary to provide connecting projections for connecting diagonal materials, it is common to use angle steel that can be used as connecting projection pieces for connecting diagonal materials, instead of flat steel plates. However, when angle steel is used for the upper and lower members connecting the truss diagonal members, there is a problem in that the angle steel cannot be bent like a camber.

  In addition, like the bridge girder shown in Patent Document 2, when a truss-like steel frame with diagonal members connected between the vertical sides of the upper and lower angle steels is used as the girder, the mold is formed between the horizontal sides of the upper and lower angle steels. It is necessary to attach a frame plate and pour concrete into the form plate from above. For this reason, the upper angle steel has a structure in which concrete filling holes are provided over the entire length by partially interspersing the angle steel provided with the projections for connecting diagonal members. This girder has a problem that it can only be used for a bridge girder when floor slab concrete is integrally formed above.

  As a means for solving the problems of the conventionally known girders using the truss as a steel frame, the upper and lower surfaces of the concrete girders are respectively made of steel plates along the length direction of the girders. Covered and provided in the cross section of a concrete girder, it acts as a connecting material that connects the upper and lower steel plates together rather than as a steel frame, and is cheaper and cracked by the steel plates attached to the underside of the girder. The purpose is to provide a girder beam with little bending rigidity.

  As a concrete means for the steel sheet affixing girder according to the present invention, two steel sheets having a width and a length capable of covering both the upper and lower surfaces of the concrete girder along the length direction so that the planes face each other. Arranged at intervals, the two steel plates are connected together by a connecting material provided along the length direction, and the upper steel plate is provided with a stopper, and concrete is placed between the two steel plates. Thus, steel plates are bonded to both the upper and lower surfaces.

  As a standard girder shape, two steel plates are arranged in parallel so that both end portions and the central portion are equally spaced, and these steel plates are integrally connected by a truss-like connecting material. It is preferable.

  In addition, a camber is provided on the upper steel plate of the two steel plates, and the steel plates are arranged so that the interval between the central portions of these steel plates is larger than the interval between the two end portions. It is good also as a structure connected integrally.

  Furthermore, as a steel plate affixed on both the upper and lower surfaces of a concrete girder, it is preferable to make it the structure which made the board width of the upper steel plate shorter than the board width of a lower steel plate among two steel plates.

  According to the steel plate affixing girder of the present invention, first, steel plates are coated on the upper and lower surfaces of the concrete girder along the length direction of the girder. As a result, it is possible to manufacture a girder with a small bending crack and a large bending rigidity at a low cost.

  In addition, since the steel plate affixing girders are connected to the upper and lower steel plates by connecting members in the middle part, compared to the conventional H-shaped steel girders, there is no web, so the steel member is greatly reduced in weight. As it is possible, the concrete provided between the upper and lower concrete is not divided by the intermediate web as in the case of H-section steel, so it is twisted compared to the H-section steel girder with web A concrete section with high rigidity can be obtained.

  The diagonal material provided in the cross section of the concrete girder has an emphasis on the function as a connecting material that connects the upper and lower steel plates together rather than the mechanism as a steel frame, and the length, angle, etc. of the diagonal material should be selected as appropriate. Thus, it is possible to obtain a cross-section girder having different girder heights at the center and both ends according to the application.

  The two steel plates bonded to the upper and lower surfaces of the concrete girder may have the same plate width on both the upper and lower surfaces, but the width of the upper steel plate is slightly shorter than the width of the lower steel plate. It is preferable to keep it. In this way, when the plate width of the upper steel plate is somewhat reduced, when the mold plate is provided on both sides while maintaining the plate width of the lower steel plate, the upper end of the mold plate and the lower upper surface of the mold plate A concrete filling hole is provided between the side of the steel plate and the concrete placement work can be performed efficiently.

  Next, the construction of one preferred embodiment of the steel sheet affixing girder according to the present invention will be described with reference to an example shown in the drawings. As shown in FIG. 1, this steel aggregating girder is basically a concrete girder. Two steel plates 2 and 3 having a width and a length capable of covering both the upper and lower surfaces along the length direction are attached to the upper and lower surfaces of 1.

  As shown in FIG. 2, the two steel plates 2 and 3 basically have the same plate width on both the upper and lower surfaces. Preferably, the upper steel plate 2 is a plate as shown in FIG. A material whose width is somewhat shorter than the plate width of the lower steel plate 3 is used. The concrete girder 1 is reinforced by reinforcing bars 8.

  The two steel plates 2 and 3 are integrally arranged via a connecting material 4 provided along the length direction on the inner center line in a state where the two steel plates 2 and 3 are arranged at intervals so that the planes face each other. It is connected. This connecting member 4 is assembled in a truss shape by connecting the end of the diagonal member 6 to the connecting projection 5 provided on the inner center line of the steel plates 2 and 3, but rather than the mechanism as a steel frame, The function is significant as a connecting material for integrally connecting the upper and lower steel plates 2 and 3, and the length and angle of the diagonal member 6 are appropriately set according to conditions such as the purpose and scale of the girder.

  As a standard girder shape including the two steel plates 2 and 3, as shown in FIGS. 1 and 4, the two steel plates 2 and 3 are arranged so that both end portions and the central portion are equally spaced. It is preferable that the steel plates 2 and 3 are integrally connected to each other by the connecting material 4 in parallel.

  Further, as the shape of the girder, the steel plate 2 that can be bent freely is provided on the upper surface of the girder, so that the central portion swells upward in the upper steel plate 2 as shown in FIG. And a structure in which the central portions of the upper and lower steel plates 2 and 3 are arranged so as to be larger than the intervals between both ends, and these steel plates 2 and 3 are integrally connected by a truss-like connecting material 4. It is good. In the girder shown in FIG. 5, the lower steel plate 3 is horizontal, but the lower steel plate 3 may also be provided with a camber as shown in FIG. 6.

  As shown in FIGS. 5 and 6, the upper steel plate 2 is provided with a gibber 7 for improving the adhesion to concrete. However, as shown in FIG. 7, the plate width of the upper steel plate 2 is shortened. In the case of the spar, it is possible to drop the both side ridges 17a of the dowel 17 bent in an inverted U shape so as to contact both sides of the upper steel plate 2 from above and attach the both side ridges 17a to the reinforcing bars 8. it can.

  The girders are formed by pouring concrete 9 between two steel plates 2 and 3 as shown in FIGS. In this case, when the upper and lower steel plates 2 and 3 have the same width, the two steel plates 2 connected by the connecting material 4 on the mold plate 10 as shown in FIG. , 3 are placed sideways, and concrete 9 is poured from above into the height of the side edges 2a, 3a of the steel plates 2, 3.

  On the other hand, among the upper and lower two steel plates 2 and 3, when the upper steel plate 2 has a short plate width, a plurality of sets of upper and lower steel plates 2 and 3 are grouped as shown in FIG. The mold plates 11 are arranged on both surfaces of each of the upper and lower steel plates 2 and 3 while maintaining the width of the lower steel plate 3 while being parallel to each other in such a direction as to be on the lower side.

  As a result, a filling hole 12 for the concrete 9 is provided between the upper end 11a of the mold plate 11 and the side 2a of the upper steel plate 2 having a short plate width. The concrete plate 9 is filled with the concrete 9 from the filling hole 12. By doing so, a plurality of concrete girders can be formed efficiently at the same time, and if the respective girders are separated by peeling the form plate 11 after the concrete is hardened, the girders can be easily obtained at the construction site.

  The steel plate girder of the present invention has a structure in which a steel plate that is strong against tension is affixed to the lower surface of a concrete girder that is weak to tension. As shown in Fig. 10, in the case of a small span bridge with a span of about 20 to 25m, install both ends of this girder directly on both abutments and provide RC floor slabs on it. Therefore, it has the advantage that an economical bridge can be constructed with a short construction period.

The partially notched perspective view which shows the structure of 1 Example of the steel plate sticking girder which concerns on this invention. The cross-sectional view of the girder used as the basic form of the steel plate pasting girder concerning the present invention. FIG. 2 is a cross-sectional view of the cross-section of the steel plate pasting girder shown in FIG. 1. Sectional drawing along the length direction of the steel plate sticking girder shown in FIG. Sectional drawing along the length direction of the girder of the Example which made the space | interval of the upper and lower steel plates the shape where the center part was high and both ends were low. Sectional drawing along the length direction of the girder of the Example which gave the curvature to the upper and lower steel plates. FIG. 4 is a cross-sectional view of a state where a gibber is attached on the upper steel plate of the girder shown in FIG. Sectional drawing which shows the method at the time of concrete placement of the girder shown in FIG. Sectional drawing which shows the method at the time of concrete placement of the girder shown in FIG. The perspective view which shows the structure of the bridge using the steel plate sticking girder of this invention.

Explanation of symbols

1: Concrete girder,
2: Upper steel plate,
2a: upper steel plate side,
3: Lower steel plate,
3a: lower steel plate side,
4: Tie,
5: Connecting projection,
6: Diagonal,
7: Giver,
8: Rebar,
9: Concrete,
10: Formwork plate,
11: Formwork plate,
11a: upper end of the mold plate,
12: Concrete filling hole,
17: Giver,
17a: Giber both ends

Claims (4)

  Two steel plates having a width and a length capable of covering both the upper and lower surfaces of the concrete girder along the length direction are arranged at intervals so that the planes face each other. It is integrally connected by a connecting material provided along the direction, and the upper steel plate is provided with a stopper, and concrete is placed between both steel plates, and the steel plates are bonded to both the upper and lower surfaces. Steel plate girder.   The steel plate pasting girder according to claim 1, wherein the two steel plates are arranged in parallel and are integrally connected by a truss-like connecting material, and both end portions and the central portion of the girder are formed to have equal girder heights.   A camber is provided on the upper steel plate, or both the upper and lower steel plates of the two steel plates, and these steel plates are connected together by a truss-like connecting material, so that the girder height at the center of the girder is higher than the girder height at both ends. The steel plate affixing girder according to claim 1 formed so as to be larger.   The steel plate pasting girder according to claim 1, wherein the upper steel plate width of the two steel plates is shorter than the lower steel plate width.

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