JPS63151758A - Method of introducing prestressed force to torus beam - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATION The present invention relates to a method for introducing prestressing forces into a truss beam in response to moments generated in the chord members by the self-weight of the truss beam.

``Prior Art'' A conventional method for introducing prestress force into a truss beam is to provide a fixing section at the end of a string, passing through the fixing section, and disposing a PCA material along the chord. The PCj 141 is fixed to the fixing section in a state where a prestress force is applied to the PCj 141.

Therefore, by introducing compressive force into the chord material using the PC steel material, it is possible to reduce the tensile force that normally occurs in the lower chord material or the upper chord material due to a vertical load, and to reduce the cross-sectional area of the chord material.

``Problems to be Solved by the Invention'' However, in the conventional method of introducing stress force into a truss beam, the bending moment generated in the chord members of the truss beam due to the vertical load and the beam back of the chord members are Due to the relationship between The compressive force is not commensurate with the tensile force, and
Since the cross-sectional shape of the string material is unified at the largest part, there is a problem that it is unreasonable and uneconomical.

The present invention has been made in view of the above problems, and
The purpose of this invention is to provide a method of introducing prestress force into prestressing steel materials, which allows truss beams to be set up rationally and economically.

"Means for Solving the Problems" In order to solve the above problems, the present invention arranges PCjlQ materials along at least one chord material of a truss beam consisting of an upper chord material, a lower chord material, and a lattice material. At the same time, after fixing the girder beams through which the prestressed steel material is inserted at predetermined intervals along the chords, the vertical direction applied to the truss beams is According to the shape of the moment generated in the chord material by the load and the tensile force generated in the chord material by the beam back of the chord material, a prestress force commensurate with the tensile force is introduced into the PCm material. It is characterized in that it is sequentially fixed to the girders using fixing means.

"Embodiment" Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 5. Figures 1 to 5 are for explaining the present invention in detail. Figure 1 (a) is a diagram showing the entire truss beam, and Figure 1 (b) is a diagram showing the chord members of the truss beam due to their own weight. The bending moment diagrams generated in FIGS. 2 to 5 are enlarged views of the chord members in FIG. 1, and show that prestress force is introduced by the method of the present invention.

In these figures, reference numeral 1 indicates a truss beam, and this truss beam 1 is composed of an upper chord member 2, a lower chord member 3, and a lattice member 4. The truss beam I is shown in FIG. 1(b).
A bending moment due to a vertical load is acting as shown in .

Next, a method of introducing prestress force into this truss beam by the method of the present invention will be explained.

First, as shown in FIG. 2, a 20w4 material 5 is disposed on the lower chord member 3 of the truss beam I in the direction in which it extends along the lower chord member 3, and as shown in FIG. This PC
Girder beams 6.degree. 6 passing through the steel material 5 are fixed to the center portion of the lower chord member 3 at a predetermined interval. Next, as shown in FIG. 4, a prestress corresponding to the tensile force generated in the lower chord member 3 is applied depending on the shape of the bending moment generated in the lower chord member 3 due to the vertical load applied to the truss beam 1 and the back of the beam. With the force introduced into the prestressing steel 5, it is fixed to the girder 6.6 with nuts (ie fixing means) 7,7.

Furthermore, a girder 6.6 fixed to the center of the lower chord member 3
P on both sides at a predetermined interval toward the end of the lower chord member 3.
After fixing the girder beams 6a, 6a through which the Cjliil material 5 is inserted, a bending moment generated due to the load applied in the vertical direction to that part (between the girder frame 6 and the girder frame 6a) and the back of the beam is generated in the lower chord member 3. A prestress force corresponding to a predetermined amount of tensile force is introduced into the PCl4 material 5, and in this state, the PC steel material 5 is attached to the girder 6 by nuts 7a, 7a.
a, 6 fixed at a.

Thereafter, following the same procedure, a prestress force is applied to the lower chord member 3 from the center to both ends commensurate with the bending moment of that part caused by the load applied in the vertical direction and the tensile force determined by the beam back. We will introduce it.

Therefore, according to the method of introducing prestress force into a truss beam of the present invention, a prestress force commensurate with the bending moment generated by the load applied in the vertical direction to each part of the lower chord member 3 and the tensile force generated by the beam back can be applied. It will be introduced. In other words, a compressive force commensurate with the tensile force generated in each part of the lower chord member 3 is introduced, and the shape of the truss beam 1, the cross-sectional shape of the lower chord member 3, the material of the PC steel, etc. are selected accordingly. The material and shape can be set rationally and economically.

In addition, in the above embodiment, a method of introducing prestress force to the lower chord member 3 was shown, but the method is not limited to this, and it may be introduced to only the upper chord member 2 or to both the upper chord member 2 and the lower chord member 3. You can also do this.

In addition, in the above embodiment 4, the moment generated in the truss beam l due to a vertical load forms a chevron-shaped curve that increases toward the center, as shown in Fig. 1(b). Because of this, a large prestress force is introduced in the central part, but it is not limited to this, and a bending moment of any size may occur at any location, or the height of the beam at that part may be affected. Depending on the situation, a prestress force commensurate with the tensile force generated in each part may be introduced.

"Effects of the Invention" As explained above, in the method of introducing prestress force into a truss beam of the present invention, the PC
After arranging the steel members and fixing the girder beams through which the 20W4 material is inserted at predetermined intervals along the chord members, the truss beams are installed between each girder beam from the center of the chord members toward both ends. Introducing a prestress force commensurate with the tensile force into the PC material according to the shape of the moment generated in the chord material due to the vertical load applied to it and the tensile force generated in the chord material by the beam back of the chord material. In this state, they are fixed to the girders one by one using a fixing means, so that a compressive force commensurate with the tensile force generated in each part of the chord material is introduced. The shape of the truss beam, the cross-sectional shape of the chord material, the material of the PC steel, etc. can be selected accordingly, and the material and shape can be set rationally and economically.

[Brief explanation of the drawing]

1 to 5 show one embodiment of the present invention, FIG. 1(a) is a side view showing the entire truss beam, and FIG. 1(b) is the truss beam of FIG. 1(a). Figures 2 to 5 are enlarged views of the lower chord of the truss beam in Figure 1, and Figure 2 shows the state in which 20W4 members are installed. Figure 3 is a side view of the lower chord member showing a state in which the girder beam is fixed at the center, and Figure 4 is a side view of the lower chord member showing the state in which the girder beam is fixed at the center. Fig. 5 is a side view of the lower chord member showing the fixed state, and Fig. 5 is a side view showing the state where the lower chord member is fixed to the girder beam with girder beams provided on both sides and a predetermined prestress force introduced into the PC1i material. be.

Claims (1)

[Claims] PC steel members were arranged along at least one chord member of a truss beam consisting of an upper chord member, a lower chord member, and a lattice member, and girder beams through which the PC steel members were inserted were fixed at predetermined intervals along the chord members. Then, between each girder beam from the center of the chord toward both ends, the moment generated in the chord due to the vertical load applied to the truss beam and the shape of the moment generated in the chord and the beam back of the chord. Depending on the tensile force, PC
A method for introducing a prestress force into a truss beam, characterized in that a prestress force commensurate with the tensile force is introduced into the steel material, and then the steel material is sequentially fixed to the girder beam using fixing means.