JP2000337090A - Arched hollow structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arched hollow structure capable of having a predetermined strength and coping with even unbalanced load by reducing the thickness of each member. SOLUTION: In this arched culvert 25 having a pair of precast-concrete arched unit panels 1, 1 which form an arched channel 15 and having a lower construction 21 with the lower part of the arched channel 15 connected thereto, the pair of arched unit panels 1, 1 have their tops 6, 6 rigidly joined to each other and have their lower portions rigidly joined to the lower construction 21. When the arched channel 15 is exerted with load, positive and negative bending moments are produced on the arched unit panel 1, so that the maximum bending moment applied to the arched unit panel 1 becomes smaller than the maximum bending moment applied to a three-hinged structure. The arched culvert 25 is structurally advantageous also when unbalanced load is applied to the arched channel 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow structure having an arch shape.

[0002]

Conventionally, as an arch-shaped hollow structure, Japanese Utility Model Application Laid-Open No. 59-192911 discloses three types.
There is a precast concrete snow shelter in which a hinge arch type concrete block of unit length is connected and the block group is tensioned with a PC steel material (the scope of claims in the Japanese Utility Model Registration). This shelter is made of a highly reliable precast block member, mainly composed of a 3-hinge concrete arch that does not generate bending moment at the arch member end (Microfilm, page 2, lines 10-13)
Thus, there is known a structure in which a three-hinged arch-shaped structure is buried in the ground to form a passage as an arch culvert.

FIG. 14 is an explanatory view of an arch-shaped structure having a three-hinge structure, in which the joints at the tops of left and right precast plates 101, 101 are smoothened by hinges 102, and the lower portions of the precast plates 101, 101 are hinged. 103 and 103 are joined to the substructure 104. The arched hollow structure having such a three-hinged structure is a statically-determined structure. When an evenly distributed load P is applied to the arched hollow structure by earth and sand, and an equally distributed load Q is applied to the side surface thereof, the hinges 102 and 103 are used. Instead of generating a bending moment at a certain joint, the bending moment is maximized substantially at the center of each member, and the strength of the entire structure depends on the strength of the weakest member. Further, a biased load is applied to the structure, for example, the precast plate 10 on the left side in the figure.
When a load is applied to 1, the bending moment in the left precast plate 101 decreases, but the right precast plate 10
The bending moment at 1 is increased, and thus the three hinge structure has a disadvantage against an eccentric load.

Incidentally, it is known that the strength of the precast concrete member is increased by tensioning the precast concrete member by using a PC steel material. In the precast plate shown in FIG.
If the C steel material is arranged, the negative bending moment can be countered by the tensile force of the PC steel material. However, since the bending moment shown in FIG. 14 is applied after installation,
If tension is applied to the PC steel material during molding of the formwork, the precast plate 101 cannot be released smoothly, and if tension is applied after molding, the P
Problems such as warpage of the precast plate 101 due to the tension of the C steel material occur.

Accordingly, an object of the present invention is to provide an arch-shaped hollow structure capable of obtaining a predetermined strength with a reduced member thickness and capable of coping with an uneven load.

[0006]

According to a first aspect of the present invention, there is provided an arched hollow having a pair of precast concrete arched unit plates forming an arched structure and a substructure connecting a lower portion of the arched structure. In the structure, the tops of the pair of arched unit plates are rigidly joined to each other, and the lower portion of the arched unit plate is rigidly joined to the substructure.

According to the first aspect of the present invention, when the load is applied to the arch-shaped unit plate, positive and negative bending moments are generated by applying the load to the arch-shaped unit plate. The maximum bending moment is approximately one half of that of the 3-hinge structure, and the cross section of the member has been reduced.
It is structurally advantageous even when an eccentric load is applied to the arch structure.

According to a second aspect of the present invention, a lateral duct is formed at the top of the arch-shaped unit plate, and the tops of the pair of arch-shaped unit plates are abutted with each other. It is a PC steel rod joined by applying tension.

According to the structure of the second aspect, by applying a tension to the laterally straight PC steel rod, the joint can be firmly joined.

In the invention according to claim 3, the arch-shaped unit plate is tensioned by a PC steel material in a curved direction.

According to the structure of the third aspect, the strength is improved by the PC steel material in the bending direction. Also, only a negative bending moment is generated in the arch member of the three-hinged structure after installation, but the arch-shaped unit plate used for the indeterminate structure has positive and negative bending moments when subjected to a load after installation. Therefore, it is sufficient to arrange the PC steel material at almost the center of the thickness. Even if tension is given by the PC steel material at the time of manufacturing at the factory, the arch type unit plate may be transported or temporarily placed due to the tension. No deformation.

Further, in the invention according to claim 4, the PC steel rod is arranged on the tensile region side of the joint portion between the top portions.

According to the structure of the fourth aspect, since the PC steel bar resists the tensile force generated at the joint by the load after the installation, the joint can be firmly joined.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 12 show a first embodiment of the present invention. As shown in FIG. 1, a basic arch-shaped unit plate 1 made of precast concrete is made of high-strength concrete 2 and has an unpounded PC steel material in its bending direction. 3 and the PC steel material 3 is the arch-shaped unit plate 1
As shown in FIG. 5, an embedding fixing device 3A is fixed to the top side of the base plate, and the unpounded PC steel material 3 is tensioned to apply a tension, as shown in FIG. The image is fixed by the fixing device 3B. The basic arch-shaped unit plate 1 is bent in a fold line at bending positions 4 provided at substantially equal intervals, and has a large number of flat surfaces 5N and 5G on the inner surface and the outer surface. 5
.. Form a continuous bent surface as the inner angle θN of N, 5N, and a line connecting the inner surfaces at the bent position 4 in the basic arched unit plate 1 is an arc. The adjacent flat surfaces 5G on the outer surface of the basic arch-shaped unit plate 1 also form a continuous bent surface. In addition, the basic arched unit plate 1
The top portion 6 is formed with a thick portion 7 that makes the top portion 6 thicker than the lower portion, and an upper surface 7U of the thick portion 7 is formed to be nearly horizontal and flat. The arch-shaped unit plate 1 is formed so as to become gradually thicker toward the side. That is, as shown in FIG. 2, the thicknesses T1, T2, T3, and T4 at the bending position 4 are T1 <T2 <T3 <T.
4 in this example, T1 is 300 mm, T2
Is 330 mm, T3 is 360 mm, and T4 is 390 mm. The thickness of the joining surface 9 is equal to T4,
The thickness at the lower part of the bending position 4 in which 1 is described is equal to T1.
A duct 8 is formed at the top 6, and one end of the duct 8 is opened at the joining surface 9 of the top 6, and the other end is opened at a step 10 formed on the outer surface side at the end of the thick portion 7. ing. The duct 8 is arranged on the lower side of the joint surface 9 of the basic arched unit plate 1. Further, a plurality of ducts 11 in the longitudinal direction are formed in the basic arched unit plate 1. In addition, a reinforcing bar (not shown) is embedded in the basic arched unit plate 1.

Then, the joining surfaces 9, 9 at the tops of the pair of basic arched unit plates 1, 1 are abutted, and P
At the step 10, the anchor plate 13 is inserted at the end of the PC steel rod 12 to apply tension to the PC steel rod 12 and to form at the end of the PC steel rod 12. The nuts 14 are tightened and fixed to the threaded portions, so that the tops 6, 6 of the basic arched unit plates 1, 1 are rigidly joined to each other to form the arched structure 15. Further, the lateral tightening PC steel material 16 is inserted into the ducts 11 of the arched structures 15, 15...

The lower part of the arched structure 15 is a substructure.
The substructure 21 in this example is made of reinforced concrete made of cast-in-place concrete, and has a flat plate portion 22 having a substantially constant thickness and cradle portions 23 provided on both sides of the flat plate portion 22.
23, and the upper part of the cradle part 23 has the arched structure.
A recess 24 into which the lower part of the 15 is inserted is formed. And
Insert the lower part of the arched structure 15 into the recess 24,
And the arched structure 15 is rigidly joined to the substructure 21. An arch culvert 25 as a hollow structure is formed by the substructure 21 connecting the arched structure 15 and a lower portion of the arched structure 15. In the figure, 26 is a road surface provided on the substructure 21 and 27 is a sidewalk. Then, in the arched structure 15 using the basic arched unit plate 1, the arched unit plates 1 on both sides at the joint surfaces 9, 9.
The inner angle θ of the top formed by the inner surfaces 5N, 5N is equal to the other inner angle θN, the radius R of the arched structure 15 is, for example, 6 meters, the inner space width H is 12 meters, and the pedestal portion is formed.
The width, which is the inside dimension of 23, 23, is 11.1 meters.

When the arched culvert 25 thus formed is buried, a load is applied. This will be described with reference to the drawing of FIG. 4. FIG. 4 shows that an evenly distributed load P is applied to the arched culvert 25 formed from the basic arched unit plate 1 by earth and sand, and an equally distributed load Q is applied to a side surface thereof. When these loads P and Q are applied, a bending moment M is generated in the arched culvert 25 as shown in FIG. In this specification, a positive bending moment M is a moment in a direction in which the member is concaved,
The negative bending moment M is a moment in a direction that makes the member convex. In this manner, by forming the arch-shaped culvert 25 as an indeterminate structure having three rigid members, positive and negative bending moments M are generated in the arch-shaped unit plate 1, and negative bending moments such as three hinges are generated. Unlike the case where only the bending occurs, the maximum value of the bending moment M generated in the arch-shaped unit plate 1 can be reduced. Also, a positive bending moment M is generated at the top of the arched structure 15, and a tensile force is generated at the lower part of the top 6, that is, a force is generated in the direction of opening the lower part of the joint surfaces 9, 9, but PC steel is used. Since the rod 12 is arranged below the joint surface 9, it is possible to effectively resist the tensile force.

When a partial load is applied to the arched structure 15, for example, when a load larger than one arched unit plate 1 is applied to one arched unit plate 1, the other arched unit plate 1 becomes negative. However, in the case of three rigid bodies, the positive and negative bending moments M are generated by the equally distributed load as shown in FIG. The bending moment M generated by the three hinges is small, which is structurally advantageous against an eccentric load.

As described above, in the present embodiment, a pair of precast concrete arch-shaped unit plates 1 and 1 forming the arched structure 15 and a substructure connecting the lower part of the arched structure 15 are provided. 21), the tops 6, 6 of a pair of arched unit plates 1, 1
6 While rigidly joining each other,
1 is rigidly joined to the substructure 21, so that when a load is applied to the arch-shaped unit plate 1 by using an indeterminate structure, positive and negative bending moments M are generated in the arch-shaped unit plate 1. The maximum bending moment applied to the arch-shaped unit plate 1 is approximately one half of that of the three-hinged structure, the cross section of the member is reduced, and the structural advantage is obtained even when an eccentric load is applied to the arched structure 15, It has excellent resistance to earthquakes and the like.

Further, as described above, in this embodiment, claim 2
In response to the above, a horizontal duct 8 is formed on the top 6 of the arch-shaped unit plate 1 so that the joining surfaces 9, 9 of the tops 6, 6 of the pair of arch-shaped unit plates 1, 1 abut each other. Since the straight PC steel rods 12 inserted into the ducts 8 and 8 are joined by applying tension, the tension is applied to the straight PC steel rods 12 in the lateral direction to fix them. The parts can be firmly joined.

As described above, according to the present embodiment, claim 3
In response to the above, the arched unit plate 1 is connected to the PC in the bending direction.
Because it is more strained by steel material 3, PC in the bending direction
Although the strength can be improved by the steel material 3 and only a negative bending moment is generated in the arch member of the 3-hinge structure after installation, the arch-shaped unit plate 1 used for the indefinitely fixed structure has When a load is applied after the installation, positive and negative bending moments M are generated. Therefore, the PC steel material 3 may be disposed substantially at the center of the thickness. Due to the tension, the arch-shaped unit plate 1 is not deformed during transportation or temporary placement.

Furthermore, in this embodiment, since the PC steel rods 12 are arranged on the tensile region side of the joints between the tops according to the fourth aspect, the joints are formed by the load after installation. When the PC steel bar 12 resists the tensile force generated at the joint, the joint can be firmly joined.

Next, a modified example of the arched unit plate will be described with reference to FIGS. 7 to 12. In order to make the width smaller than that of the arched culvert 25, the top 6 of the basic arched unit plate 1 will be described. The shortened arch-shaped unit plates 1A, 1B, 1C are formed. These arch-shaped unit plates 1A, 1B, and 1C are different from the basic arch-shaped unit plate 1 in the length of the top portion 6 in the width direction, and respective joining surfaces 9A, 9B, and 9C are formed in parallel with the joining surface 9. ing. In addition, the step part 10 is an arch-shaped unit plate 1, 1A.
The arched unit plates 1B and 1C are provided with a step 10A longer than the step 10 in the width direction. The relative height positions of the ducts 8 of the arched unit plates 1 and 1A are the same, and the ducts 8 of the arched unit plates 1B and 1C are identical.
Are the same relative height position. Then, the arched structure formed by the arched unit plates 1A, 1B, 1C is used.
The inner angles θA, θB, θC of the tops of 15A, 15B, 15C and the arched structure 15 formed by the basic arched unit plate 1
Is related to the top interior angle θ, θ>θA>θB> θC.

As described above, the length of the top 6 in the width direction was changed, and the thickness TS of the joint surface and the center position of the duct 8 were set as shown in Table 1 below. As shown in FIG. 3, in Table 1, Gt and Nt indicate the center positions of the duct 8 from the inner and outer surfaces, respectively. Also, arched structures 15A, 15B, 15 formed by the respective arched unit plates 1A, 1B, 1C.
The inner space widths Ha, Hb, Hc of C are 11 meters, 10 meters, and 9 meters.

[0025]

[Table 1]

As shown in Table 1 above, at the joint surfaces, the PC steel bars 12 are connected to the joint surfaces 9, 9 at the arched structures 15, 15A, 15B.
On the inner surface side of A and 9B, the arched structure 15C, the PC steel rod 12 was on the outer surface side of the joining surface 9C. Then, similarly to the arched structure 15, in the arched structures 15A and 15B, when a load is applied at the time of installation, a force is applied in a direction to open the lower part of the joint surfaces 9, 9A and 9B, and on the other hand, on the inner surface side The top portion can be firmly joined by the resistance of the PC steel rod 12 thus formed. On the other hand, in the arched structure 15C, the inside angle θC of the top becomes small,
Since the top 6 has a pointed shape, when the loads P and Q shown in FIG. 14 are applied, a negative bending moment is generated at the top 6, a tensile force is generated at the top of the top 6, and the joining surfaces 9 C, 9 C
A force in the direction of opening the upper part of the joint is generated, but since the PC steel rod 12 is arranged on the upper side of the joint surface 9C, it is possible to effectively resist the tensile force.

FIG. 13 shows a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. Structure
An enclosing block 31 is erected on one side of the top 6 of the fifteen, and the mountain side of the enclosing block 31 is backfilled to form an inclined surface 32.

By backfilling one side of the arched structure 15 in this way, even if an eccentric load is applied to the arched structure 15, the arched culvert 25 is a statically indeterminate structure with three rigid joints. A high strength can be obtained with respect to the load, and the same actions and effects as those of the first embodiment can be obtained according to the first to fourth aspects.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. For example, in the embodiment, the example in which the substructure is formed by cast-in-place concrete is shown, but a part or all of the substructure may be made of precast concrete. Further, the PC steel material in the bending direction may be tensioned by a pretension method. Further, in the embodiment, the arch-shaped unit plate whose plane is continuously bent is shown, but the inner surface of the arch-shaped unit plate may be formed in an arc.

[0030]

According to the first aspect of the present invention, there is provided an arched hollow structure comprising a pair of precast concrete arched unit plates forming an arched structure and a substructure connecting a lower portion of the arched structure. The tops of the pair of arched unit plates are rigidly joined to each other, and the lower part of the arched unit plate is rigidly joined to the substructure, so that a predetermined strength can be obtained by suppressing the member thickness. Thus, it is possible to provide an arch-shaped hollow structure capable of coping with an uneven load.

According to a second aspect of the present invention, a lateral duct is formed at the top of the arch-shaped unit plate, and the tops of the pair of arch-shaped unit plates are abutted with each other and a straight line is inserted through each duct. Since the PC steel rods are joined by applying tension thereto, a predetermined strength can be obtained by suppressing the member thickness, and an arch-shaped hollow structure capable of coping with uneven loads can be provided.

Further, according to the third aspect of the present invention, the arch-shaped unit plate is tensioned by a PC steel material in a curved direction, so that a predetermined strength can be obtained by suppressing the thickness of the member, and it can cope with an uneven load. Can be provided.

Further, the invention according to claim 4 is characterized in that the PC steel bar is arranged on the tensile region side of the joint portion between the top portions, and it is possible to obtain a predetermined strength by suppressing the thickness of the member.
An arch-shaped hollow structure capable of coping with an uneven load can be provided.

[Brief description of the drawings]

FIG. 1 is a front view of a hollow structure having an inner space width H showing a first embodiment of the present invention.

FIG. 2 is a plan view of the arched structure;

FIG. 3 is a cross-sectional view of the top of the arched structure.

FIG. 4 is a moment diagram of the same.

FIG. 5 is a cross-sectional view of the top of the arched unit plate.

FIG. 6 is a cross-sectional view of a lower portion of the arch-shaped unit plate.

FIG. 7 is a front view of the hollow structure whose inner space width is Ha.

FIG. 8 is a cross-sectional view of the top of the arched structure.

FIG. 9 is a front view of the hollow structure whose inner space width is Hb.

FIG. 10 is a cross-sectional view of the top of the arched structure.

FIG. 11 is a front view of the hollow structure whose inner space width is Hc.

FIG. 12 is a cross-sectional view of the top of the arched structure.

FIG. 13 is a sectional view of a hollow structure showing a second embodiment of the present invention.

FIG. 14 is a moment diagram of an arched structure having a three hinge structure.

[Explanation of symbols]

 1, 1A, 1B, 1C Arched unit plate 8 Duct 12 PC steel bar 15, 15A, 15B, 15C Arched structure 21 Substructure

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akira Sato 1-8-23 Bentenbashi-dori, Niigata City, Niigata Familiar F-Term (reference) 2D055 BB02 CA08 EB01 GC06

Claims (4)

[Claims] 1. An arched hollow structure comprising: a pair of precast concrete arched unit plates forming an arched structure; and a substructure connecting a lower portion of the arched structure, wherein the pair of arched unit plates is provided. Characterized in that the tops of the arched unit plate are rigidly joined to each other and the lower part of the arched unit plate is rigidly joined to the substructure. 2. A horizontal duct is formed at the top of the arched unit plate, and the tops of the pair of arched unit plates are abutted with each other, and a linear P is inserted through each duct.
The arch-shaped hollow structure according to claim 1, wherein the C steel rod is joined by applying tension thereto. 3. The arch-shaped hollow structure according to claim 1, wherein said arch-shaped unit plate is tensioned by a PC steel material in a curved direction. 4. The arch-shaped hollow structure according to claim 2, wherein said PC steel bar is arranged on a tensile region side of a joint portion between said top portions.