JPS6327493B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-point hinge prefabricated box culvert.

In conventional one-piece box culverts, the same reverse bending moment of positive and negative occurs in all frames due to the load, which not only makes it difficult to arrange the correct reinforcement that requires a certain strength, but also increases the amount of reinforcement. However, it had the disadvantage of increasing the overall size, and there were problems with workability, construction efficiency, and economic efficiency.

Therefore, the present invention aims to provide a three-point hinged prefabricated box culvert that is dynamically the most stable by connecting the top frame and the left and right side frames with a hinge at two points, and connecting the bottom frame with a hinge at the center. to do,
Bending moment and shearing force act on the top frame due to the load, but the bending moment and shearing force act on the side frame and bottom frame very little, and only axial force acts mainly, making it ideal for a reinforced concrete structure that is resistant to compression. Since it is made up of three parts, it can be divided into parts and produced in a factory, making it possible to manufacture high-quality products.It is also easy to transport and erect, which reduces construction costs and shortens the construction period. ,
Furthermore, the present invention aims to provide an unprecedented and innovative box culvert whose side frame can be designed in accordance with the shape of the seawall waterway to which it is attached.

The present invention will be explained in detail with reference to the embodiments shown below. In FIGS. 1 and 2, 1 indicates an upper frame;
Reference numerals 2 and 3 indicate left and right side frames, and 4 and 5 indicate left and right bottom frames, and the left side frame 2 and the bottom frame 4, and the right side frame 3 and the bottom frame 5 are each integrally constructed. The side parts 12 and 13 of the upper frame 1 also form part of the side frames 2 and 3 of the box culvert as a whole, but here they are constructed integrally with the upper frame 1. The hinge frame parts 2 of the side frames 2 and 3 are attached to both sides 12 and 13 of the upper frame 1.
Hinge frame part 1 that faces 1 and 31 and interlocks with each other
1 are provided, and a hinge shaft 6 passing through these,
It is hinged at 7. In addition, the left and right bottom frames 4,
5 face each other at mutually interlocking hinge frame portions 41 and 51, and are hingedly connected at a hinge shaft 8. side frame 2,
3 is formed to be inclined in the direction in which the bottom frames 4 and 5 can be sandwiched in accordance with the shape of the installation revetment waterway to be constructed, but depending on the shape of the waterway, it may be vertical like a conventional box culvert. Also good. Further, the hinge shafts 6, 7, and 8 are provided offset to the outside of the thickness of each frame, and are configured so as not to directly receive the axial pressure generated on each frame. In FIG. 2, the broken line 9 and black dots 10 in the right half indicate the reinforcing bar arrangement state.

Figure 3 shows a model of the prefabricated box culvert structure with three-point hinges, and the thickness t of each frame is 0.5.
m, the width a of the axis of the upper frame 1 is 7 m, both sides 12,1
The height b from the axis of frame 3 is 1.25 m, the height c from the axis of side frames 2 and 3 is 2 m, and the width d of bottom frames 4 and 5 is 3.5 m.
6, 7, and 8 indicate three-point hinge connections. In addition, as shown in Fig. 4, the upper frame 1 is
1.25t/m uniformly distributed load w and concentrated load p in the center
is applied, and when earth pressure H is gradually applied to both sides from 2.71 t/m to the upper frame 0 t/m, the moment M
As shown in the left half of the center line 0-0 in Figure 5a, it is 10.4t・m at both ends of the upper frame 1, and the maximum at the center.
A moment of 11.5t・m is generated, and the hinge connection part 6,
The moment of the side frame and bottom frame below 7 is a maximum of 1.4 t・m, which is an almost negligible value. In addition, the shear force S is as shown in the shear force diagram in the right half of Fig. 5a,
A maximum of 8.3t is generated from the center of the upper frame 1 to both sides, and a maximum of 8.1t is generated on both sides, but the shearing force S of the side frame and bottom frame is a maximum of 3.2t, which is an extremely small value.
In addition, as shown in the axial force diagram in Figure 5b, the axial force N is 8.1t on the horizontal part of the upper frame 1 and 8.3t on both ends.
A maximum axial force of 9.5t will be generated on the side frames 2 and 3 and 5.2t on the bottom frame.

The box culvert of the present invention having the above-mentioned configuration is installed on the seawall G as shown in
is constructed inside and is constructed as a bridge on top of the upper frame 1, but since it can be divided into three parts, the upper frame 1, the left and right side frames, and the bottom frame at the three hinge parts, it is easy to work. A high-quality reinforced concrete product can be obtained through factory production, transportation can be divided into parts to reduce bulk, and erection can be done by engaging the hinge parts and using the hinge shafts 6, 7,
8 can be inserted and assembled, saving labor costs.
Not only does it have the effect of shortening the construction period, but
Due to the load, no moment or shear force is applied to the side frame and bottom frame, and only axial force acts mainly on the side frame and bottom frame, so it has the effect of providing a box culvert that is ideal for a reinforced concrete structure that is resistant to compression. Since the frame can be bent and designed in advance into a trapezoidal shape or other shape to match the shape of the installed revetment waterway, it has the effect of being able to be installed without major construction or changes to the waterway, and is useful in practical use. There are so many things to do.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of a prefabricated box culvert according to the present invention, Fig. 2 is a front view showing the reinforcement arrangement in the right half of the box culvert, and Fig. 3 is an explanation showing a structural model of the embodiment. Figure 4 is an explanatory diagram showing the load state in one usage mode of the structural model, and Figures 5a and 5b are explanatory diagrams showing the moment diagram, shear force diagram, and axial force diagram when receiving the load. It is a diagram. 1: Top frame, 2, 3: Side frame, 4, 5: Bottom frame, 6,
7, 8: Hinge series, 11, 21, 31, 41, 5
1: Hinge frame.

Claims (1)

[Scope of Claims] 1. An assembly type box culvert with a three-point hinge, in which the top frame and the side frames are hingedly connected at two points on the left and right, and the bottom frame is hingedly connected at one point in the center. 2. The prefabricated box culvert according to claim 1, in which the three-point hinge connection shaft is set at a position offset from the axis on which the axial force of the frame body acts. 3 In a prefabricated box culvert with a three-point hinge, in which the top frame and the side frames are hinged at two points on the left and right, and the bottom frame is hinged at one point in the center, the lower part of the two-point hinge connection on the left and right An assembly type box culvert with three-point hinges, in which the side frames are bent in a direction that allows the bottom frame to be sandwiched, and the overall structure is in the form of a trapezoid. 4. The prefabricated box culvert according to claim 3, wherein the three-point hinge connection shaft is set at a position offset from the axis on which the axial force of the frame body acts.