JPS62228567A - Method for introducing prestress into truss 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 Field J The present invention relates to a method for introducing prestress into truss wires, and particularly relates to a truss unit constructed from a truss unit assembled into a truss shape using lower chord materials, lower chord materials, and lattice materials. This is about how to introduce prestress into beams.

Conventionally, in the case of truss beams, which have been adopted as a frame type for the roofs of long-span structures, the amount of deflection increases as the length increases, and the ratio of the weight of the truss head to the overall weight of the structure increases. The problem was that it was uneconomical. Therefore, in order to solve these problems, the applicant of the present invention proposed a truss beam incorporating prestress in Japanese Patent Application No. 175997/1982. In other words, the prestress is created by integrally arranging the PC steel material in the span direction of a truss beam made up of the upper chord material, the lower chord material, and the lattice material, and tensioning and fixing the PC'iA shrine at both ends of the beam. This is to be introduced.

``Problems to be Solved by the Invention'' The above-mentioned truss beam not only prevents large deflections from occurring in the truss beam, but also reduces its own weight and realizes an economical frame. However, even with this truss beam, there was still room for consideration, such as the following points.

Due to demand or transportation reasons, it is necessary to unitize the truss beams, making it difficult to arrange the prestressing steel.
The efficiency of prestress introduction work is reduced.

■Prestress decreases due to damage to PC steel, etc., which affects the entire truss beam. In particular, if the I) C steel material breaks, the prestress introduced into the truss beam will be lost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for introducing prestress into a truss beam, which can effectively solve the above problems.

"Means for Solving the Problems" The present invention provides a method for connecting a plurality of truss units assembled in a truss shape by upper chord members, lower chord members, and radius members along the longitudinal direction of the chord members, and connecting adjacent truss units to each other along the longitudinal direction of the chord members. PC spanning units
'g4 materials are arranged, and this P C1,il 4
The feature is that prestress is introduced into each truss unit by applying tensile force to the truss unit.

"Function" In the method for introducing prestress having the above configuration, the prestress can be introduced into the truss unit 1η by disposing the PCj1444 at the same time as the assembly of the truss unit, and the prestress can be introduced into the truss unit 1η by is fixed in a tensioned state for each I/Las unit, so the pc
(a) Even if a part of the truss is cut off, the damage will only be done partially, so the entire truss beam will not be affected, and prestress loss can be minimized.

"Example" FIG. 1 shows a truss beam A constructed by implementing an example of the present invention.
- The truss unit 5 is constructed of an upper chord member 1 and a lower chord member 2 made of section steel, and a radius member 3 and left and right belly members 4 that connect these. ) is constructed by joining a plurality of them along the longitudinal direction (horizontal direction in Fig. 1). A bearing plate 6 which is molded to each other is provided at both ends of the lower chord (second), and each lower chord member 2 is provided with a PC that passes through the bearing plate 6 and straddles the adjacent truss unit 5. Steel members 7 are integrally attached with their positions shifted up and down.

This PCf! In the illustrated example, A material 7 has screws 7 on both ends.
The PCj14 bar with a is applied and the nut 8 is placed on the bearing plate 6 of the truss unit 5 under tension.
It is fixed through. As a result, this truss beam A is
Compressive force is applied in advance by the PCA material 7, and prestress is introduced. Note that as the PCA material 7, a PC steel stranded wire or the like may be used instead of the PC steel rod.

Next, regarding the implementation of the method of the present invention, the truss beam Δ
Explain the process of assembling.

To assemble the truss beam Δ, a plurality of ready-made truss units 5 are delivered to the site, and as shown in FIG. , the lower chord members 2.2 and the belly members 4, 4 are matched, the truss unit 5 is joined, and the PC steel member 7 is inserted into the truss unit 5 at the left end (the left end in FIG. 2) with the bearing plate 6 passed through. A tensile force is applied to the PC steel material 7 by fixing it thereon by means of a tool 8. By this operation, prestress is introduced into the first truss unit 5 located at the left end of the truss beam A in such a manner that adjacent truss units 5 are connected by the PC steel material 7.

Then, the above-mentioned operations (i.e., joining of the truss unit 5, arrangement and tensioning operation of the PC steel material 7) are performed on the truss unit 5.
The process was repeated for each of the second and subsequent truss units 5 to be joined to the right side of the beam, and as the truss units 5 were connected, the prestress shown in Fig. 1 was introduced) - Lath beam A was completed. do.

The introduction of prestressing of the truss A is achieved by integrally disposing the PC steel material 7 while joining the truss unit 5, and I)C1
Truss unit due to tension of t7! - Since it is carried out every 5, it is easy to arrange the I) Cjii material 7, simplifying the tension introduction work and improving its workability.

In addition, since the prestress is introduced into each truss unit 5, the prestress can be easily changed according to the stress state of the truss ff1A. , it is possible to obtain an economical frame by eliminating the need to introduce excessive prestress.

Furthermore, in the method of the present invention, the fixing of the P (J21 material 7) is
Since this is done by screwing the nut 8 onto the male thread 7a of the jlJ material 7, there is no set loss during tension fixing and there is no slip after fixing, so prestress can be reliably introduced.

In addition, in the operation of the above-mentioned embodiment, the method of introducing prestress to the truss beam A is to join the truss units 5 sequentially from the left side, arrange the PC scrap material 7, and perform this I)c M4
A tensile force is applied to U 7 to introduce prestress to form the 3-rotated ball 11i3, but the present invention is not limited to this, but the truss units 5 can be combined and joined as needed. Then, in each case, place the C steel material 7, tension the PC steel material 7, and introduce prestress.

In the no-truss beam A constructed as described above, P(,
We decided to adjust the prestress by the A21 material 7, which would not only reduce the deflection of the L/Rath A, but also allow the PC steel +4'7 to bear part of the tensile load applied to the lower chord material 2. The strength of the lower string 142 can be reduced accordingly.

In addition, in the serious crime example, the method of the present invention was applied to L/Las A made up of the upper chord I and the lower chord 2 made of II section steel, but the upper chord I or the lower chord 2 was made of steel pipe or other Of course, the method of the present invention may be applied to a truss beam made of shaped steel material.

Next, another embodiment of the method of the present invention will be described with reference to FIG. In the case of this embodiment, basically, the truss units 5 are molded together from the left side and joined 7 in sequence in the same way as in the previous embodiment, and each truss unit 5 is attached to P(J4 A method has been implemented in which H7 is placed, tensioned, and prestressed.

However, in the non-embodiment, after tensioning the PCI material 7 placed on the lower chord +A2 of the truss unit 5, the nuts 8 on the outer periphery of the PC steel material 7 placed on both left and right sides of the bearing plate 6 are tightened, and this PCJliii material 7 is attached to the bearing plate. 6 from both sides, and then connect the PC steel material 7 of the pond to this PC steel material 7 via a cover (connector) 10, and then connect the PC steel material 7 of this l)c KJ41.
Remove the bearing plate 6 at the right end of the truss unit 5 in the same process.
The biggest characteristic is that it has become established in the world.

In addition, in this example, the fixing process is carried out while connecting the PC steel materials 7 one after another with the turntables 10. The height of the lower chord member 2 can be made smaller than that of the previous model.

"Effects of the Invention" As explained above, the present invention connects a plurality of truss units assembled into a truss shape by upper chord members, lower chord members, and radii (E) along the longitudinal direction of the serious chord members, and Matching I・
In order to introduce prestress into each truss unit by placing a PC+14 +4 that spans the truss unit and sequentially applying a tensile force to this PC514R, prestress is introduced in the truss unit :Di. This makes it possible to improve the workability of prestress introduction work.

Also, since the serious PCJlW material is fixed in a tensioned state for each truss unit, if a part of the r'cv4 material were to be cut off, it would be a problem. However, since only a partial response is required, the loss of prestress can be kept to a minimum without affecting the entire lath frame.

[Brief explanation of drawings]

The figures are shown for detailed explanation of the invention, so the first
The figure is a side view of Nonitoranu 粱 which has been introduced using the method of the present invention, and the second figure is a truss uni...! Fig. 3 is a side view of the truss unit A... river/rust beam, I...'' second string (I, 2... Lower chord (O, 3...
Latisse, 4... Belly material, 5...
...Truss unit, 6 ... ... Support r■
- J et al., 7.
・ ... PC Steel +, ( , 7a...Owaji, 8...Natsu.

Claims (1)

[Claims] A method for introducing prestress into a truss beam formed by joining a plurality of truss units assembled in a truss shape with upper chord members, lower chord members, and lattice members along the longitudinal direction of the chord members, the method comprising: A method for introducing prestress into a truss beam, characterized in that prestress is introduced for each truss unit by respectively arranging PC steel materials that span adjacent truss units and sequentially applying tensile force to the PC steel materials.