JP2025071528A - Beam structure - Google Patents

Abstract

[Problem] To reduce the number of supports supporting the beam-bottom formwork.
[Solution] The beam structure comprises a truss beam having a pair of upper chords lined up horizontally when viewed from the longitudinal direction, a lower chord arranged so that the pair of upper chords form the vertices of a triangle when viewed from the longitudinal direction, one diagonal member connecting one upper chord and the lower chord, and another diagonal member connecting the other upper chord and the lower chord, both ends of which are supported by a pair of structures, a plate-shaped beam bottom formwork arranged to straddle the pair of upper chords, and a concrete beam made of reinforced concrete formed using the beam bottom formwork.
[Selected Figure] Figure 1

Description

This disclosure relates to beam structures.

In the method of constructing a reinforced concrete building described in Patent Document 1, when constructing a reinforced concrete building of a rigid frame structure consisting of columns, beams, and floor slabs, beam reinforcing bar units assembled in a truss or lattice shape that has the strength to support at least the weight of the beam formwork and the concrete to be poured are arranged and fixed between the column reinforcing bars, and concrete is poured into the beam reinforcing bar unit section with the beam formwork held by the beam reinforcing bar unit.

Japanese Patent Application Publication No. 8-151684

When constructing a reinforced concrete structure, formwork for columns, beams, slabs, etc. is set up, and concrete is poured into the formwork. Here, the bottom formwork for the beams and the bottom formwork for the slab are supported by shoring.

In the past, in order to simplify the construction process, the bottom formwork of the slab between a pair of adjacent beam forms was replaced from plywood to deck material, reducing the number of supports supporting the bottom formwork of the slab. However, it was difficult to reduce the number of supports supporting the bottom formwork of the beams.

The objective of this disclosure is to reduce the number of supports that support the beam-bottom formwork.

The structure of the beam in the first aspect is characterized by comprising a truss beam having a pair of upper chords aligned horizontally when viewed from the longitudinal direction, a lower chord arranged so that the pair of upper chords form the vertices of a triangle when viewed from the longitudinal direction, a diagonal member connecting one of the upper chords to the lower chords, and another diagonal member connecting the other of the upper chords to the lower chords, both ends of which are supported by a pair of structures, a plate-shaped beam bottom formwork arranged to straddle the pair of upper chords, and a concrete beam made of reinforced concrete formed using the beam bottom formwork.

According to the above embodiment, the beam bottom formwork is positioned so as to straddle a pair of upper chord members that are arranged horizontally. In this way, the beam bottom formwork is supported by the pair of upper chord members, and the entire truss beam supports the weight of the concrete when it is poured. This makes it possible to reduce the number of supports that support the beam bottom formwork when constructing the concrete beam.

The beam structure according to the second aspect is the beam structure according to the first aspect, characterized in that the truss beams are provided with a deck plate that is spaced apart in the horizontal direction, straddles the upper chord members constituting a pair of adjacent truss beams, and has an end portion that faces the end portion of the beam bottom formwork in the horizontal direction.

According to the above embodiment, the deck plate is provided so as to straddle adjacent truss beams in the horizontal direction, and the end of the deck plate and the end of the beam bottom formwork face each other in the horizontal direction. Therefore, the floor slab formed using the deck plate as a formwork and the concrete beam formed using the beam bottom formwork as a formwork can be integrally formed.

The beam structure according to the third aspect is the beam structure according to the first aspect, characterized in that the upper chord is fitted with a stud that is embedded in the poured concrete.

According to the above embodiment, the upper chord is fitted with a stud that is embedded in the poured concrete. This improves the joint strength between the truss beam and the concrete beam. Furthermore, by integrating the truss beam and the concrete beam into a composite beam, the bearing strength of the beam can be improved compared to a single concrete beam.

This disclosure makes it possible to reduce the number of supports that support the beam-bottom formwork.

FIG. 2 is a front view showing a beam structure according to an embodiment of the present disclosure. FIG. 2 is a side view showing a truss beam constituting a beam structure according to an embodiment of the present disclosure. FIG. 2 is a perspective view showing a truss beam constituting a beam structure according to an embodiment of the present disclosure.

An example of a beam structure according to an embodiment of the present disclosure will be described with reference to Figures 1 to 3. Arrow H in each figure indicates the up-down direction, i.e., the vertical direction, arrow W in each figure indicates the width direction of the beam perpendicular to arrow H and the horizontal direction, and arrow D in each figure indicates the longitudinal direction of the beam perpendicular to arrows H and W and the horizontal direction.

(Overall composition)
As shown in Fig. 1, the composite beam 12 having the beam structure 10 of this embodiment includes a truss beam 20, a plate-shaped beam bottom formwork 40 placed on the truss beam 20, and a concrete beam 50. As shown in Figs. 1 and 2, a plurality of composite beams 12 are provided at intervals in the width direction of the beam (hereinafter referred to as "width direction"). The truss beams 20 constituting the composite beam 12 are exposed to the indoor space 100.

[Truss beam 20]
1 and 2, the truss beam 20 comprises a pair of upper chord members 22 aligned in the width direction and extending in the longitudinal direction, and a lower chord member 32 arranged so as to form the apex of a triangle with the pair of upper chord members 22 when viewed in the longitudinal direction. The width direction is an example of the lateral direction.

Furthermore, the truss beam 20 includes a diagonal member 42 that connects one upper chord member 22 and the lower chord member 32, a diagonal member 52 that connects the other upper chord member 22 and the lower chord member 32, and a connecting member (not shown) that connects the pair of upper chord members 22. For ease of explanation below, the upper chord member 22 located on one side in the width direction (right side in FIG. 1) will be referred to as upper chord member 22a as one upper chord member 22, and the upper chord member 22 located on the other side in the width direction (left side in FIG. 1) will be referred to as upper chord member 22b as the other upper chord member 22. Note that when there is no particular distinction between the upper chord members 22a and 22b, the final alphabet will be omitted.

-Upper chord 22-
1, the upper chord member 22 includes a pair of L-shaped angle members 24, which are arranged so that the plate surfaces of the pair of angle members 24 overlap and the upwardly facing surfaces of the pair of angle members 24 are on the same plane. Both ends of the upper chord member 22 are attached to columns 110 (see FIG. 3). The columns 110 are an example of a structure.

For ease of explanation, the angle iron 24 located at the center of the composite beam 12 in the width direction will be referred to as angle iron 24a, and the angle iron 24 located on the outer side of the composite beam 12 in the width direction relative to angle iron 24a will be referred to as angle iron 24b.

Angle iron 24a and angle iron 24b are fixed together by a fixing member (not shown). In addition, headed studs 26 are attached by welding to the upward-facing surface of angle iron 24a, and multiple headed studs 26 are provided at intervals in the longitudinal direction. Headed studs 26 are an example of a stud.

-Lower chord 32-
As shown in Fig. 1, the lower chord member 32 includes a pair of L-shaped angle members 34 and a connecting member 38 that connects the pair of angle members 34. The pair of angle members 34 are arranged so that the plate surfaces of the pair of angle members 34 face each other with a gap therebetween, and the lower surfaces of the pair of angle members 34 facing downward are on the same plane. Both ends of the lower chord member 32 are separated from the column 110 (see Fig. 3) in the longitudinal direction.

The pair of angle members 34 each have a plate portion 36 that faces each other with a gap between them, and the connecting members 38 are hung across the upper portions of the pair of plate portions 36 and are provided at intervals in the longitudinal direction.

A light 70 extending in the longitudinal direction is disposed between the pair of plate sections 36 and below the connecting member 38, and this light 70 is fixed to the lower chord member 32 by a fixing member (not shown).

-Diagonal member 42 connecting upper chord member 22a and lower chord member 32-
The diagonal members 42 are formed using metal rods with a circular cross section, and are divided into diagonal members 42a that are inclined to one side in the vertical direction and diagonal members 42b that are inclined to the other side in the vertical direction, as shown in Fig. 2. The adjacent diagonal members 42a and 42b are arranged so as to form a V shape with an open upper portion or a V shape with an open lower portion. The diagonal member 42 is an example of one diagonal member.

The upper ends of the diagonal members 42a and 42b are attached by welding to the angle member 24a that constitutes the upper chord member 22a. The lower ends of the diagonal members 42a and 42b are attached by welding to the angle member 34 on the upper chord member 22a side that constitutes the lower chord member 32.

-Diagonal member 52 connecting upper chord member 22b and lower chord member 32-
The diagonal members 52 are formed using metal rods with a circular cross section, and are divided into diagonal members 52a that are inclined to one side in the vertical direction and diagonal members 52b that are inclined to the other side in the vertical direction, as shown in Fig. 2. The adjacent diagonal members 52a and 52b are arranged so as to form a V shape with an open upper portion or a V shape with an open lower portion. The diagonal member 52 is an example of another diagonal member.

The upper ends of the diagonal members 52a and 52b are attached by welding to the angle member 24a that constitutes the upper chord member 22b. The lower ends of the diagonal members 52a and 52b are attached by welding to the angle member 34 on the upper chord member 22b side that constitutes the lower chord member 32.

[Beam bottom formwork 40]
1, the beam-bottom formwork 40 is placed so as to straddle a pair of upper chord members 22 spaced apart in the width direction. Specifically, it is disposed so as to straddle the angle member 24a constituting the upper chord member 22a and the angle member 24a constituting the upper chord member 22b.

[Concrete beam 50]
The concrete beam 50 is made of reinforced concrete, and is placed in the attic space 120 as shown in Fig. 1, and placed on the beam-bottom formwork 40 to have a rectangular cross section. The concrete beam 50 is constructed using the beam-bottom formwork 40. The headed studs 26 are embedded inside the concrete beam 50. In this way, the headed studs 26 function as shear connectors that connect the concrete beam 50 and the truss beam 20.

〔others〕
1, the deck plate 130 is provided so as to straddle adjacent truss beams 20 in the width direction. Specifically, one end of the deck plate 130 is placed on the angle material 24b of the truss beam 20 arranged on one side in the width direction and faces an end of the beam-bottom formwork 40 in the width direction. The other end of the deck plate 130 is placed on the angle material 24b of the truss beam 20 arranged on the other side in the width direction and faces an end face of the beam-bottom formwork 40 in the width direction.

In addition, a floor slab 132 made of reinforced concrete is placed on the deck plate 130, which is formed using the deck plate 130 as a formwork. The floor slab 132 is sandwiched between a pair of concrete beams 50, and the thickness of the floor slab 132 is made thinner than the thickness (height) of the concrete beams 50. The floor slab 132 is formed integrally with the concrete beams 50.

(summary)
As described above, in the beam structure 10, the beam bottom formwork 40 is disposed so as to straddle a pair of upper chord members 22 spaced apart in the width direction. The beam bottom formwork 40 is supported by the pair of upper chord members 22. Since the entire truss beam 20 can support the weight of the concrete when poured, the number of supports supporting the beam bottom formwork 40 when constructing the concrete beam 50 can be reduced.

In addition, in the beam structure 10, a deck plate 130 is provided so as to straddle adjacent truss beams 20 in the width direction, and the end face of the deck plate 130 and the end face of the beam bottom formwork 40 face each other in the width direction. Therefore, the floor slab 132 formed using the deck plate 130 as a formwork and the concrete beam 50 formed using the beam bottom formwork 40 as a formwork can be integrally formed.

In addition, in the beam structure 10, headed studs 26 that are embedded in the poured concrete are attached to the upper chord 22. This improves the joint strength between the truss beam 20 and the concrete beam 50. Furthermore, by forming a composite beam in which the truss beam 20 and the concrete beam 50 are integrated, the bearing strength of the beam can be improved compared to a single concrete beam.

In addition, in the beam structure 10, the light 70 extending in the depth direction is placed between a pair of angle bars 34. This allows the light 70 to be protected by the pair of angle bars 34.

Although the present disclosure has been described in detail with respect to a specific embodiment, it will be apparent to those skilled in the art that the present disclosure is not limited to the embodiment, and various other embodiments are possible within the scope of the present disclosure. For example, in the above embodiment, the lower chord 32 is formed by two angle members 34, but the lower chord may be formed by one member such as an angle member, or may be formed by three or more members such as an angle member.

In addition, in the above embodiment, both ends of the upper chord 22 were attached to the columns 110, but this is not limited to the columns 110, and the upper chord 22 may be attached to any structure.

10 Beam structure 20 Truss beam 22 Upper chord 22a Upper chord 22b Upper chord 26 Headed stud (an example of a stud)
32 Lower chord member 40 Beam bottom formwork 42 Diagonal member (an example of one diagonal member)
42a: diagonal member 42b: diagonal member 50: concrete beam 52: diagonal member (an example of another diagonal member)
52a Diagonal member 52b Diagonal member 110 Pillar (an example of a structure)
130 Deck plate

Claims (3)

A truss beam having a pair of upper chords aligned horizontally when viewed from the longitudinal direction, a lower chord arranged so that the pair of upper chords form the vertices of a triangle when viewed from the longitudinal direction, one diagonal member connecting one of the upper chords and the lower chord, and another diagonal member connecting the other upper chord and the lower chord, both ends of which are supported by a pair of structures;
A plate-shaped beam bottom formwork arranged to straddle the pair of upper chord members;
A concrete beam made of reinforced concrete formed using the beam bottom formwork;
A beam structure comprising: The truss beams are provided in a plurality of spaces in the lateral direction,
A deck plate is provided that spans the upper chord members constituting a pair of adjacent truss beams and has an end portion facing an end portion of the beam bottom formwork in the lateral direction.
The beam structure of claim 1 . The upper chord is fitted with a stud that is embedded in poured concrete.
The beam structure of claim 1 .