JP3069974B2 - Inflection point structure of PC steel on artificial ground - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a inflection point structure of PC steel in artificial ground by space truss, in particular, in an artificial soil in combination with the truss and PC steel, P
The present invention relates to an inflection point structure of a PC steel material provided at a joint between a lower chord material and an inclined member in order to introduce prestress into the artificial ground by using a C steel material.

[0002]

2. Description of the Related Art In recent years, with the soaring land prices and the shortage of construction land in cities, new ground has been placed above these areas in order to effectively utilize the space above roads, railroads, rivers, etc. and to utilize the city at a high level. There is growing interest in so-called artificial ground. Conventionally, as such artificial ground, P
A PC structure combining a C beam and a PC composite floor and a RC structure combining a RC frame and an RC floor are known, but in such a structure, it is necessary to provide an intermediate support for supporting the ground. Therefore, when constructing an artificial ground above a road, a railroad, or the like, it is difficult to adopt the intermediate strut because the intermediate strut becomes an obstacle to traffic or the like. On the other hand, various structures have been proposed that enable construction of a large-span artificial ground that does not require an intermediate support.For example, such a structure that applies bridge technology such as a truss structure or an arch structure,
A space truss structure to which the structure of a space truss roof is applied can be given. In the structure of the conventional artificial ground having a large span, the sectional force generated in the structure is mainly caused by its own weight, and it is not economical to enlarge the structure in order to increase the span. Therefore, in the case of a large-span artificial ground having a truss structure or an arch structure, a prestress is applied by using a PC steel material or the like to reduce the cross-sectional force generated in the structure to reduce the structure.

[0003]

However, in order to introduce prestress into such a conventional large-span artificial ground, in the case of the truss structure or arch structure, the prestress direction is determined by the truss structure or arch structure. Since it is limited to one direction in which it is erected, there is a problem that it is not possible to introduce a reasonable prestress into the structure of the artificial ground having a planar spread.

In addition, when PC steel is combined with the space truss, the arrangement and number of the PC steel are restricted by the strength of the members constituting the space truss or the structure of the space truss, and a large prestress is introduced. There was a problem that can not be.

[0005]

The present invention aims to provide an inflection point structure of PC steel to easily place the PC steel between predetermined upper chord member constituting the truss.

[0007]

Means for Solving the Problems In the present specification, an artificial
The ground is composed of upper and lower chords and an inclined member interposed between these joints, and a pyramidal unit frame composed of the upper and lower chords or the lower chord and the inclined member is vertically and horizontally connected and integrated. The constructed space truss, a floor member such as an RC slab attached above the upper chord material, and a predetermined upper chord material or a floor member attached to the upper chord material for introducing prestress to the space truss. An artificial ground made of a PC steel material, wherein the PC steel material is stretched at an inflection point at an arbitrary one of joints between a lower chord material and an inclined member located between the predetermined upper chord materials or floor members. numerous disposed possible and then by setting
Was.

Here, the end portion of the PC steel material to be stretched can be fixed to the upper chord material or the floor member, but may be fixed to a support structure separately provided with the artificial ground interposed therebetween.

The gist of the present invention is an inflection point structure for forming an inflection point of a PC steel material at a joint between the lower chord material and the inclined member of the artificial ground, wherein each end of the lower chord material and the inclined member is provided. A joint portion for integrally joining the portions, and an inflection portion provided with a fastening means for the PC steel material, which is rotatably attached to the joint portion around a vertical direction or a direction close to the joint. Inflection point structure of PC steel material.

Here, as the hooking means, an arc-shaped through-hole that curves downward is provided on a side surface of the inflection portion, and a PC steel material is inserted through the through-hole to cause the inflection portion to be bent. And a pair of locking members provided to face the outer peripheral surface of the PC steel member, each of which locks the other end of a PC steel material having one end fixed to each upper chord material.

[0011]

In the artificial ground, any one or more joints between the lower chord member and the inclined member located between the predetermined upper chord members or between the floor members attached to the upper chord member or the floor member are provided. A plurality of PC steel materials can be installed as inflection points. Therefore, for example, by selecting upper and lower chord materials or the like on which a PC steel material is to be stretched, prestress can be introduced in a plurality of directions in accordance with the shape of the artificial ground having a planar spread. In addition, by using a plurality of inflection points, it is possible to easily arrange a plurality of PC steel materials between a pair of upper chord materials, thereby reducing a stress load per PC steel material and providing a large space to a space truss structure. Enables the introduction of prestress.

The inflection point structure of the PC steel material of the present invention facilitates positioning of the inflection portion in the direction of the stretched PC steel material by rotatably attaching the inflection portion to the joint. In addition, the arrangement of a plurality of PC steel materials between a pair of upper chord materials is facilitated.

[0013]

Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the artificial ground 10 includes a space truss 11, a PC cable 12 arranged vertically and horizontally on the space truss 11, and an RC slab mounted on the space truss 11 to form a flat surface. 13. The artificial ground 10 is, for example, mounted on a continuous underground wall or a foundation formed by a caisson method or the like constructed on both sides of an expressway to form a large span artificial ground.

The three-dimensional truss 11 is different from a general truss having a single structure and is constituted by a heavy structure to obtain balance and rigidity in the entire frame, and has a function of dispersing a load concentrated at one point. . That is, as shown in FIG. 2, the upper chord material 14 and the lower chord material 15 which are arranged in rows and columns in a grid pattern,
It is constituted by an inclined member 16 interposed between a joint 17 of the upper chord 14 and a joint 18 of the lower chord 15, and as a result, in the center of a square surrounded by four sides of the upper chord 14 in a plan view. The joint 18 of the lower chord material 15 is located, and four upper chord materials 1
4 and 4 inclined members 16 or 4 lower chords 15 and 4
A quadrangular pyramid-shaped unit frame is constituted by the inclined members 16, which are vertically and horizontally connected and integrated to constitute a three-dimensional truss 11 having a square shape when viewed in a plane (see FIGS. 3 to 6). In addition, each upper chord material 14, lower chord material 15, and inclined member 1
Numeral 6 supports the load by its axial force, and is constituted by a hollow pipe in order to reduce the weight of the member. However, H-shaped steel, box-shaped steel, or the like may be used.

The space truss 11 is located on the outer periphery of the space truss 11, and between each pair of opposed upper chord members 14 ',
Each of two PC cables 12 is connected to the upper chord 1
The RC slab 13 mounted on the 4 ′ is fixed vertically to the end face 13 ′ of the RC slab 13 (see FIG. 2) so that the RC slab 13 is stretched vertically and horizontally, thereby introducing prestress into the space truss 11. That is, as shown in FIG.
Of the joining points 18 of the lower chord material 15 located at the center of the square surrounded by the sides, the third one from the end is the inflection point 1
As 8 ', two PC cables 12 are provided for each pair of upper chords 14'. Here, each of the two PC cables 12 has one of two inflection points 18 'located between a pair of upper chord members 14' as an inflection point (FIG. 1).
), And are stretched in parallel without intersecting in a plane.
As shown in FIG. 3, the PC cable 12 is arranged vertically and horizontally over the entire space of the space truss 11, thereby rationally prestressing the artificial ground 10 in the vertical and horizontal directions according to the shape of the artificial ground 10 having a planar spread. Can be introduced. In the present embodiment, the PC cable 12 is fixed to the end face 13 'of the RC slab 13, but it can be fixed above the RC slab 13 by providing a fixing opening or the like. Further, a reinforcing member such as a fixing plate may be attached to the upper chord material 14 'to fix the PC cable 12 directly to the upper chord material 14'. Further, as shown in FIG. 11, if the PC cable 12 is fixed to the support structure 50 separately constructed with the artificial ground 10 interposed therebetween, a load for introducing prestress is not applied to the artificial ground. It is possible to find structural advantages.

FIGS. 4 to 6 show other examples of the arrangement of the PC cable 12 on the space truss 11. FIG. FIG. 4 shows that all the joints 18 between the lower chord member 15 and the inclined member 16 between the pair of upper chord members 14 ′ located on the outer periphery are used as inflection points 18 ′, and one inflection point 18 ′ is provided. PC cable 12
In other words, the eight PC cables 12 per one pair of upper chord members 14 ′ are obliquely stretched in parallel so as not to intersect with each other when viewed in a plane. By arranging a large number of PC cables 12 on the space truss 11 in this way, the load imposed on each PC cable 12 can be reduced, and the stress generated in the fixing portion can be reduced. Prestress can be introduced. FIG.
The direction of the PC cable 12, which is stretched obliquely when viewed in a plane, is changed every other according to the order of the inflection points 18 'where the pair of upper chords 14' is attached, and is stretched in parallel. FIG. 6 shows eight PC cables 12 extending obliquely in parallel between each pair of upper chords 14 ′. The direction of 12 is alternately arranged every other pair. According to such a configuration, the prestress can be introduced in a well-balanced manner without generating an unbalanced load on the artificial ground 10. The PC cable 12 to be stretched
The number, arrangement, position of the inflection point 18 ′, etc. are design items, and are arbitrary in consideration of the size of the span of the artificial ground 10, the design load placed on the artificial ground, the fixing force of the PC cable 12, and the like. Is set to In this embodiment, the PC
Although the cable 12 is described as being stretched between the upper chords 14 ′ located on the outer periphery, the cable 12 is not limited to this as long as it is between the paired upper chords 14, and the predetermined upper chord 14
Alternatively, a part of the artificial ground 10 can be intensively strengthened by selecting the RC slab 13. Furthermore, PC cable 1
2 is installed as an out-cable so that re-tensioning and maintenance such as replacement can be performed easily,
At the time of replacement, even if one PC cable 12 is detached, the load to be supported by the other PC cable 12 can be supplemented, so that the replacement can be performed easily and safely without requiring reinforcement work or the like.

On the other hand, in order to bend the PC cable 12 at the inflection point 18 ', for example, an inflection point structure 20 as shown in FIG. 7 is used. That is, the inflection point structure 20
Is composed of a joint 21 for integrally joining the respective ends of the lower chord material 15 and the inclined member 16 and a bent portion 22 attached to the upper surface of the joined member 21. The PC cable 12 is connected to the bent portion 22. An arc-shaped through-hole 23 that is bent downward and that is inserted and bent is provided. In FIG. 7, the two through holes 23 are arranged side by side for positioning the two PC cables 12 shown in FIG. 3 so that they do not intersect when two PC cables 12 are arranged in parallel. 3 is provided so as to use one joint point 18 as an inflection point 18 ″ in both the vertical and horizontal directions, as indicated by 18 ″ in FIG. is there. FIG. 8 shows another example of the inflection point structure 20. That is, the joint 2
A pair of rings 24 for locking the PC cable 12 are provided on the outer peripheral surface of the inflection portion 22 integrated with the backing member 1 and one end thereof is fixed to the upper chord material 14 '. The other end of the PC cable 12 is locked by a hook 25 or the like, so that the pair of PC cables 12 is continuous via the inflection portion 22.

FIGS. 9A to 9C show an embodiment of an inflection point structure of PC steel according to another invention of the present application. That is, the inflection point structure 30 is constituted by the joint portion 31 and the inflection portion 32, and the inflection portion 32 is rotatably mounted on the upper surface of the joint portion 31. According to such a configuration, since the positioning of the through hole 33 of the inflection portion 32 in a predetermined direction can be easily performed, when a large number of PC cables 12 are stretched, the work is facilitated. In addition,
(A) is a rotating mechanism with a so-called saucer type structure,
(B) shows a rotating mechanism having a so-called internal joint type structure, and (c) shows a rotating mechanism having a so-called cover type structure. Further, FIG.
(C) shows another embodiment of the inflection point structure according to the present invention. The inflection point structure 40 is configured such that an inflection portion 42 continuously provided above a joining portion 41 is constituted by two-stage inflection members 43 and 44, each of which is rotatably attached to the joining portion 41. With this, one joint point 18 can be used as an inflection point 18 ″ in both the vertical and horizontal directions,
In particular, in the arrangements and the like shown in FIGS. 4 to 6, when a large number of PC cables 12 are stretched, the installation is facilitated.

[0020]

As described above, the artificial ground is composed of a three-dimensional truss composed of an upper chord, a lower chord, and an inclined member, a floor member, and a space between predetermined upper chord members or a floor member mounted above the same.
P where the joint between the lower chord and the inclined member is stretched as an inflection point
Since it is made of C steel, by arranging PC steel in at least two directions on the space truss, it is possible to introduce a reasonable prestress in conformity with the shape of the artificial ground having a planar spread. A large prestress is introduced by arranging a large number of PC steel materials using the inflection point of (1) to reduce the weight of the artificial ground, thereby making it possible to easily construct a large-diameter artificial ground.

Further, the inflection point structure of the PC steel material provided at the joint portion between the lower chord material and the inclined member according to the present invention is a joint portion for integrally joining each end portion of the lower chord material and the inclined member, and the joint portion. The inflection portion is rotatably mounted on the tongue, and the inflection portion is easily positioned. By using the inflection portion, a plurality of PC steel materials to be stretched between predetermined upper chord materials can be easily arranged. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an artificial ground .

FIG. 2 is a cutaway sectional view of the artificial ground .

FIG. 3 is a plan view showing an example of the arrangement of PC steel materials on a space truss.

FIG. 4 is a plan view showing an example of disposing PC steel materials on a space truss.

FIG. 5 is a plan view showing an example of disposing PC steel materials on a space truss.

FIG. 6 is a plan view showing an example of arrangement of PC steel materials on a space truss.

FIG. 7 is a perspective view showing an example of an inflection point structure for attaching a PC steel material.

FIG. 8 is a perspective view showing another example of the inflection point structure.

FIGS. 9A to 9C are perspective views showing an embodiment of an inflection point structure of a PC steel material according to the present invention.

FIGS. 10A to 10C are perspective views showing another embodiment of the inflection point structure of the PC steel material of the present invention.

FIG. 11 is an explanatory view showing a situation in which a PC steel material is fixed on a support structure provided separately from the artificial ground.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Norihiko Kunimine 2-5-8 Kitaaoyama, Minato-ku, Tokyo Inside (72) Inventor Izumi Maekawa 2-5-8 Kitaaoyama, Minato-ku Tokyo (72) Inventor Motoyoshi Osumi 2-5-8 Kitaaoyama, Minato-ku, Tokyo Hazumi Co., Ltd. (56) References JP-A-2-54038 (JP, A) JP-A-62-178647 (JP, A) JP-A-58-181907 (JP, A) JP-A-3-151403 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E04H 1/00 E04C 5/00-5 / 20 E01D 7/00 E01D 9/04 E04B 1/19 E04B 1/342

Claims (2)

(57) [Claims] 1. A three-dimensional truss in which upper and lower chord members and each end of an inclined member interposed therebetween are joined to each other to form a unit frame, which is vertically and horizontally connected integrally, and an upper part of the upper chord member. In the artificial ground consisting of the floor member attached to the floor, a PC steel material is stretched between predetermined upper chord members or between the floor members attached thereto, and provided at the joint between the lower chord member and the inclined member to introduce prestress. a inflection point structure, a joining portion for joining the ends of the lower chord member and the inclined member integrally substantially vertical
An inflection point structure for a PC steel material, comprising: an inflection portion rotatably attached to the joint portion about a direction, the inflection portion including a means for attaching the PC steel material. 2. The inflection portion comprises a two-stage inflection member,
Each inflection member is substantially vertical with respect to the axis.
It is characterized by being provided rotatable with respect to the joint.
An inflection point structure of the PC steel material according to claim 1.