JP2821546B2 - Truss composite beam structure - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a truss beam structure which is particularly effective when used for a structure having a long span.

[Prior Art] Conventionally, a truss structure is usually used for a roof and a floor of a long-span structure. In this truss structure, two or more truss beams in which a chord material and a lattice material are assembled into a truss material are arranged in parallel with each other. By laying roof materials such as deck plates and corrugated slate on these truss beams, a roof can be formed, and by laying a composite floor of PC board called half PC board and cast-in-place concrete, etc. , Can form a floor. This structure has the advantage of being able to freely construct an indoor space that suits the purpose, and has the advantage that it can easily accommodate expansion, and is widely used for structures such as long bridges, event halls, and production facilities. Have been.

Incidentally, in the truss structure described above, a structure for introducing prestress into the truss has been recently developed. This structure is a structure in which PC steel is arranged on the lower chord of a truss beam that is composed of upper chord, lower chord and lattice material in a truss shape, and the PC steel is integrally attached to the lower chord, or The steel pipe or the PC steel stranded wire is penetrated into a sheath pipe provided so as to penetrate in the axial direction. The PC steel is tensioned by applying a tensile force in the axial direction, and both ends of the PC steel are fixed to both ends of the lower chord while maintaining the prestress.

In the above truss beam structure, a load applied to the entire truss generates a compressive force in the axial direction of the upper chord member and a tensile force in the axial direction of the lower chord member. Here, if a pre-stress is applied to the lower chord material in advance to give an appropriate compressive force to the PC steel material, the tensile force generated in the lower chord material can be reduced and canceled. Therefore, the bending generated in the truss beam is eliminated. Also, since the stress of each member can be reduced by the stress borne by the PC steel material, the amount of members used can be reduced compared to the conventional one, and the entire structure can be lightened to some extent. Can be.

[Problem to be Solved by the Invention] The truss beam structure described above can not only prevent the truss beam from being greatly bent, but also realize an economical frame by reducing its own weight. However, this truss beam has room for improvement in the following points, for example. That is, (a) Since the entire truss beam is made of steel, local buckling of the truss member may occur due to external stress, and in particular, local buckling may occur due to thermal stress such as solar radiation. .

(B) For the same reason as described above, structural damping is small due to external vibration such as an earthquake, and the vibration of the structure cannot be reduced.

(C) If the structure constructed with the above-mentioned truss beam structure becomes extremely long, the ratio of the weight of the truss structure to the total weight of the structure increases, and the entire structure is further reduced in weight. Has limitations.

The main use of the above truss beams is as a structural material for roofs and floors. When roof materials such as deck plates and corrugated slate are laid on the above truss beams, a roof can be formed,
A floor can be formed by laying floor materials such as PC boards. Although the above-mentioned roofing material and flooring material seem at first glance to be structural materials, they do not have any function as structural materials that bear some of the stress generated in the truss beams. Therefore, the structure of the truss beam itself must be strengthened to the extent that the weight of the roofing material and the flooring material increases, which is uneconomical. Further, conventionally, it is structurally difficult to reduce the above-mentioned roofing material and flooring material, which has been a major obstacle in pushing down the weight of the entire structure.

An object of the present invention is to provide a structure of a truss beam that can effectively solve the above problems and reduce the weight of the entire structure.

[Means for Solving the Problems] The truss composite beam structure of the present invention provides a truss beam and a concrete beam by forming a concrete beam integrally with the upper chord member on a steel truss beam. And a prestress is introduced into the lower chord of the truss beam by a PC steel material integrally provided with the lower chord.

[Operation] The concrete beam formed on the upper chord of the truss beam so as to be integral with the upper chord resists the compressive force generated in the axial direction of the upper chord, and causes local buckling of the upper chord. And attenuates vibrations caused by external vibrations. In addition, the prestress introduced by the PC steel material reduces the tensile force generated in the axial direction of the lower chord material, and alleviates or cancels it.

Embodiment FIGS. 1 to 3 are views showing a first embodiment of the present invention, and are views showing a structure A constructed using a truss composite beam 1 according to the present invention.

When the structure A is described in detail, the structure A is divided into structures 2 and 2 which are erected in parallel to each other to form an outer wall.
A plurality of truss composite beams 1 extending in the X direction (inter-beam direction) in the figure are bridged, and a half PC board is interposed between the truss composite beams 1,1,1.
It has a configuration in which 3 and 3 are bridged.

The structure 2 has a configuration in which a plurality of columns 2a, 2a, 2a and a plurality of wall members 2b, 2b,... Are provided between the columns 2a, 2a, 2a.

A plurality of truss composite beams 1,1,1
Are stretched in parallel with each other with both ends fixed to the columns 2a, 2a, 2a of the structures 2, 2. A half PC plate 3 is stretched between the truss composite beams 1,1,1. Both ends of the half PC plate 3 are fixed to the truss composite beams 1 and 1 to form a roof B of the structure A.

The truss composite beam 1 used for the above-mentioned structure A will be described with reference to FIGS. The truss composite beam 1 is composed of an upper chord member 4 and a lower chord member 5 whose main parts are made of an H-shaped steel, and a lattice member 6 made of an H-shaped steel for connecting these members, in a truss structure. On the upper surface 7 of the upper chord material 4, a plurality of studs 8, 8,. A concrete beam 9 is formed integrally with the upper chord 4 so as to include these studs 8, 8, ... and extend along the longitudinal direction of the upper surface 7 of the upper chord 4. In the concrete beam 9, a reinforcing bar 10 is embedded and disposed so as to extend in the longitudinal direction.

That is, the truss composite beam 1 has a plurality of structures obtained by combining a steel truss beam and a concrete beam 9.

On the other hand, on both side surfaces of the lower chord material 5, the lower chord material 5 is integrally formed.
PC steel materials 11 and 11 are provided.
11 introduces prestress.

In order to introduce the prestress into the PC steel materials 11, 11, the assembly of the truss composite beam 1 is completed, the concrete beam 9 is formed, the half PC plates 3, 3 are laid, and the finishing required for the structure A is completed. After the materials and other equipment are installed,
The PC steel 11 is strained. The PC steel material 11 is tensioned by applying a tensile force in the axial direction, and a prestress is introduced. Both ends are fixed to both ends of the lower chord material 5. In this way, prestress is introduced into the truss composite beam 1.

Here, the operation of the truss composite beam 1 will be described. As shown in this embodiment, when a prestress is applied by the PC steel materials 11 and 11 to give an appropriate compressive force to the lower chord material 5, the upper chord material 4 is pushed up through the lattice material 6 and the generated compression is generated. At the same time as the force is reduced and canceled, the tensile force generated in the lower chord material 5 is also reduced and canceled.

On the other hand, the concrete beam 9 formed integrally with the upper chord 4 of the truss composite beam 1 is
This counteracts the compression force generated by this bending moment due to the load applied from above to vertically below, and reduces or cancels this compression force. Therefore, truss composite beam 1
Can be reduced.

Here, since the concrete beam 9 is formed integrally with the upper chord member 4 of the truss composite beam 1, local buckling of the truss member against external stress can be prevented. Concrete beam 9 with high thermal insulation against stress
Can prevent local buckling due to thermal stress. Moreover, since the concrete beam 9 has a function of increasing the structural damping against external vibration such as an earthquake, the vibration of the entire structure can be reduced. When a large force is applied to the structure, the concrete beam 9
Can be expected, so that the proof stress of the entire structure can be increased. In addition, since a part of the stress generated in the truss composite beam 1 can be borne by the concrete beam 9, the concrete beam 9 can be used as a structural member.

Therefore, since it is possible to withstand a larger load as compared with the conventional truss beam, it is possible to easily construct a long structure such as an oblique bridge, artificial ground, etc. Since the amount can be reduced, the entire structure can be reduced in weight.

Next, FIG. 4 to FIG. 6 are views showing an embodiment in which the truss composite beam 1 shown in the first embodiment is applied to various structures. In addition, the configuration and operation of the truss composite beam 1 itself,
The effects are exactly the same as those described in the first embodiment, and the description is omitted here.

First, FIG. 4 shows a long bridge according to a second embodiment of the present invention.
FIG. The long bridge 12 is a fulcrum on both sides of the river
This long bridge 12 has two truss composite beams 1 arranged so as to be parallel to each other, and both ends of these truss composite beams 1 are fixed to fulcrums 13, 14, A half PC board or the like is bridged between the composite beams 1 and 1 to add the necessary strength as a bridge. In this way, it is possible to economically construct the long bridge 12 with its own weight reduced.

Next, FIG. 5 is a view showing a long suspension bridge 15 according to a third embodiment of the present invention. The long suspension bridge 15 is different from the long bridge 16 constructed in the same manner as the second embodiment in that the fulcrum points 17 and 1 on both banks of the river are provided.
Erect a support 19 vertically on one fulcrum 18 of 8
The wires 21, 21,... Are suspended from the tip 20 of the wire 9 and are fixed to the bridge girder 22. In this manner, an economical construction of the long suspension bridge 15 with its own weight reduced as in the second embodiment becomes possible.

Next, FIG. 6 is a view showing an artificial ground 23 according to a fourth embodiment of the present invention. The artificial ground 23 includes structures 25, 25 erected in parallel with each other on the ground 24, as in the first embodiment.
In the figure, a plurality of truss composite beams 1 extending in the X direction (inter-beam direction) are bridged, and a half PC plate (not shown) is bridged between the truss composite beams 1 and 1. The lower side of the artificial ground 23 can be used for a parking lot or the like, and the upper side can be used to construct a building 26 such as an office or a work place. In this way, it is possible to economically construct an artificial ground with reduced self-weight.

Further, a plurality of the truss composite beams 1 can be continuously provided in the girder direction (the Y direction in FIG. 3) to form a long structure. The truss composite beam 1 can be connected not only in the girder direction but also in various directions to construct a three-dimensional truss structure.

[Effects of the Invention] The present invention forms a truss composite beam composed of the truss beam and the concrete beam by forming a concrete beam integrally with the upper chord material on the steel chord truss beam. In addition, since the prestress is introduced into the lower chord material of the truss beam by the PC steel material integrally provided with the lower chord material, the following excellent effects can be obtained.

(A) Local buckling of the truss member can be prevented against external stress, and since the concrete member with high heat insulating properties bears against thermal stress such as solar radiation, local buckling due to thermal stress can be prevented. it can.

(B) Structural damping can be increased with respect to external vibration such as an earthquake, and vibration of a structure can be reduced.

(C) Since it can withstand a larger load than conventional truss beams, it is possible to easily construct an oblique bridge, artificial ground, and the like.

(D) Since the concrete beams are integrated, the number of steel members of the upper chord material can be reduced, the weight can be reduced, and the cost can be reduced.

As described above, various points are improved, and excellent effects can be expected.

[Brief description of the drawings]

1 to 3 are views showing a first embodiment of the present invention. FIG. 1 is a side view of a truss composite beam, and FIG. 2 is a cross-sectional view taken along the line II-II of FIG. FIG. 3 is an overall perspective view of a structure constructed using truss composite beams. FIGS. 4 to 6 show the truss composite beam 1 shown in the first embodiment.
FIG. 4 is a view showing an embodiment in which a structure is added, FIG. 4 is a schematic view showing a state where a long bridge, which is a second embodiment of the present invention, is constructed, and FIG. 5 is a third embodiment. FIG. 6 is a schematic view showing a state in which a certain large suspension bridge is constructed, and FIG. 6 is a schematic view showing a state in which an artificial ground of the fourth embodiment is constructed. A ... structure, 1 ... truss composite beam, 2 ... structure, 3
... Half PC board, 4 ... Upper chord material, 5 ... Lower chord material, 6 ...
Lattice, 8 …… Stud, 9 …… Concrete beam, 11
…… PC steel.

Claims (1)

(57) [Claims] 1. A truss composite beam composed of the truss beam and the concrete beam is formed on the steel chord truss beam by forming a concrete beam integrally with the upper chord material. A truss composite beam structure characterized in that a prestress is introduced into the lower chord of the truss beam by using a PC steel material integrally provided with the lower chord.