JP3866998B2 - Steel / concrete composite floor slab - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a steel / concrete composite slab used for a bridge or other concrete structure.
[0002]
[Prior art]
As a floor slab such as a bridge, a steel-concrete composite slab (hereinafter simply referred to as “synthetic floor slab”) in which concrete is placed on a structural member in which reinforcing bars are arranged on an H-shaped steel or an I-shaped steel is known. FIG. 1 shows a typical type of such a synthetic floor slab, in which shape steels 2 made of I-shaped steel and H-shaped steel are arranged at regular intervals on an embedded formwork (bottom plate) 1 made of steel plates. It consists of a concrete member 6 placed in a structural member 5 in which a reinforcing bar 4 is arranged in a hole 3 opened in the shape steel 2.
[0003]
In addition to this, synthetic floor slabs are known that prestress structural steel, reinforcing bars, or cables to prevent the cracking of concrete. In order to reduce weight, expansion with iron powder mixed in The one using concrete is also known.
[0004]
[Problems to be solved by the invention]
The present invention does not prestress structural steel or reinforcing steel structural members, but prestresses concrete as it is manufactured, thereby preventing cracking of the concrete and improving the strength of the composite floor slab. The purpose is to provide.
[0005]
[Means for solving problems]
The composite floor slab of the invention according to claim 1 is a structural member formed by combining steel members made of steel plate, section steel, etc. in a vertical and horizontal manner on a floor slab made of steel plate, and fixing to the structural member. In a steel / concrete composite floor slab composed of expanded concrete that expands with hardening after being placed, at least one of the members in the longitudinal and transverse directions is formed by forming a web of H-shaped steel or I-shaped steel with a concave portion and a convex portion. It is formed by cutting into a sawtooth shape and dividing into two parts, and the convex part fits between the other members, and the concrete flows through the concave part when placing concrete .
[0006]
According to the composite floor slab of the present invention, since the steel members are used in the vertical and horizontal directions, the rigidity in the vertical and horizontal directions is increased, and the strength is improved. Therefore, the thickness of the floor slab can be reduced and the weight can be reduced. Moreover, since the member which forms the rectangular mesh of a structural member suppresses the expansion | swelling of the concrete which is going to expand with hardening, prestress is given to concrete.
[0007]
The structural members used in the present invention are usually provided with reinforcing bars, but in some cases, the reinforcing bars can be omitted. The expanded concrete is not particularly limited as long as it is a concrete that expands with hardening. As such a thing, the concrete which mixed iron powder etc. is mentioned, for example.
[0008]
The invention according to claim 2 is the invention according to claim 1 , wherein members having a constant sawtooth pitch are used, and each member is fixed on the bottom plate so as to deviate by an appropriate amount from an adjacent member having a sawtooth pitch in parallel. It is characterized by that.
According to the present invention, since the welded portions of the web and the bottom plate are scattered in the diagonal direction of the bottom plate, thermal strain generated during welding can be suppressed.
[0009]
The invention according to claim 3 is the invention according to claim 1 or 2 , wherein a through hole is formed in the other member.
According to the present invention, when concrete is placed, the concrete flows through the through holes, so that the concrete can be placed uniformly over the entire structural member.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A structural member A shown in FIG. 2 constitutes a composite floor slab according to the present invention, and a main member 12 arranged in a vertical direction on a bottom plate 11 and a main member 12 arranged in parallel to the main member 12. The member 13 is fixed in a lattice shape.
[0011]
The main member 12 has a T-shaped cross section, and a H-shaped steel web is cut into serrated irregularities and divided into two parts. As shown in FIG. 3, the convex parts 12a and the concave parts 12b are the same trapezoid and have a constant pitch. Is formed. Both the convex portion 12a and the concave portion 12b form a left-right symmetric trapezoid, but may be a left-right asymmetric trapezoid, or may have another shape such as a triangle or a quadrangle. In any case, the tip of the convex portion is fillet welded to the bottom plate 11 made of a steel plate, preferably butt-welded from one side grooved to the bottom plate 11 as shown in FIG. . Sufficient strength can be obtained only by performing welding from one side of the convex tip, and workability can be improved and productivity can be improved by performing welding only from one side. In the figure, 14 indicates a weld bead.
[0012]
The member 13 is formed by forming a large number of through-holes 15 in a narrow steel plate, and is similarly fixed to the bottom plate 11 by fillet welding, preferably with the tip being grooved and butt-welded to the bottom plate 11 from one side. Assembly of the main member 12 and the member 13 to the bottom plate 11 is performed as follows. First, the member 13 is placed sideways on the bottom plate 11 and fixed in the vertical direction of the bottom plate 11 at the same pitch as the pitch of the convex portions 12a. Next, the main member 12 is vertically oriented, and is fixed on the floor slab 11 at a constant pitch in the lateral direction so that the convex portions 12 a are fitted between the members 13.
[0013]
In the illustrated example, the member 13 is attached to the center of the recess 12b and has a gap with the recess ceiling, but may be close to one side of the recess 12b or be in contact with the recess ceiling. Also good. After fixing the main member 12, the reinforcing bars 15 are arranged on the main member 12 so as to be orthogonal to the main member 12.
[0014]
As described above, the main member 12 and the member 13 are assembled vertically and horizontally on the bottom plate 11, and the concrete mixed with iron powder is placed on the structural member A obtained by arranging the reinforcing bars 18. The cast concrete flows to the corners of the structural member A through the trapezoidal concave portions between the convex portions of the main member and the through holes 15 of the member 13, and the edge cutting of the concrete is also eliminated.
[0015]
As the concrete hardens, it tends to expand due to the corrosion of the iron powder. However, the front, rear, left and right are restrained by the main member 12 and the member 13, and as shown in FIG. Since it is suppressed by the flange 12c of the member 12, the expansion is suppressed and prestress is applied. In the figure, 16 indicates concrete.
[0016]
In the above embodiment, the through hole 15 is provided only in the member 13, but in another embodiment, the through hole is also formed in the convex portion 12 a of the main member 12. As a result, the fluidity of the concrete is further improved, and the edge cutting of the concrete is eliminated and the strength is further improved. A structural member B shown in FIG. 5 is obtained by forming a through hole 17 in the flange 12b of the main member 12 in the structural member A shown in FIG.
[0017]
【The invention's effect】
According to the composite floor slab of the invention according to claim 1, the bottom plate is used as a substitute for the formwork, the members made of steel plate, shape steel, etc. are arranged vertically and horizontally, and by forming a lattice shape, the rigidity in the vertical and horizontal directions is increased. It is possible to obtain a composite floor slab with the same strength, which is thin and light weight, and because the expansion is suppressed by the surrounding members and bottom plate when the concrete is hardened, prestress is given. Can prevent cracking of concrete and greatly extend the life of floor slabs. By cutting and splitting an existing shape steel web into two parts, the web can have one member with a similar shape simultaneously with one shape steel. Two effects , such as being able to be obtained with good productivity and low cost, are achieved.
[0018]
According to the invention concerning Claim 2 , since the welding location to a baseplate can be shifted diagonally, the thermal distortion at the time of welding can be suppressed.
In the invention according to the third aspect , the concrete can be filled with the concrete at the time of placing the concrete, and the concrete can be resisted to the shearing force by filling the concrete into the hole of the steel plate. As a result, the strength of the floor slab is improved.
[Brief description of the drawings]
FIG. 1 is a perspective view in which a part of a conventional composite floor slab mounted on a girder is cut out.
FIG. 2 is a perspective view of a structural member of a composite floor slab according to the present invention.
FIG. 3 is a cross-sectional view of a structural member.
FIG. 4 is a cross-sectional view of a synthetic floor slab.
FIG. 5 is a cross-sectional view of another embodiment of a structural member.
[Explanation of symbols]
11 .. Base plate 12. Main member 12a. Convex portion 12b. Concave portion 12c. Flange 13. Member 14. Welded beads 15, 17. Through hole 16. Concrete.

Claims (3)

A structural member formed by combining steel members made of steel plates, shaped steels, etc., vertically and horizontally on a bottom plate made of a steel plate and fixed in a lattice shape, and expanded concrete that expands with hardening after being placed on the structural member In the steel / concrete composite floor slab, at least one of the longitudinal and lateral members is obtained by cutting a web of H-shaped steel or I-shaped steel into a sawtooth shape of a concave portion and a convex portion and dividing it into two. A steel / concrete composite floor slab formed, wherein a convex portion is fitted between the other members, and the concrete flows through the concave portion when the concrete is placed . Using certain member pitch sawtooth, steel-concrete composite slab according to claim 1 wherein the saw tooth pitch of each member on the bottom plate, characterized in that the fixed as displaced an appropriate amount and the adjacent member parallel . Claim 1 or 2 steel-concrete composite slab as claimed, characterized in that the formation of the through hole on the other member.

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