JPS626050B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a prefabricated hinged arch culvert that is manufactured in sections as a reinforced concrete product and assembled on site.

Conventionally, practical culverts have been either circular, such as a hump pipe, or square, such as a box culvert, but when the load is large, such as when buried under a road, a large It has many disadvantages in terms of strength and economy, as it requires reinforcement of reinforced concrete, and it also has the disadvantage of being difficult to construct. There are also known prefabricated culverts, which are made by dividing the conventional culvert and making it easier to transport and handle. However, in many cases, mechanical consideration is not taken into the position of the divisions and the means of connection, leading to concerns about construction. In many cases, the structure was made more robust than necessary.

Therefore, the present invention has been pursued from a mechanical perspective and is the most stable, the manufacturing process is extremely easy, the formwork cost is low, it can be made with a large span as a secondary concrete product, and it is easy to transport and install. The present invention aims to provide a prefabricated hinged arch culvert.

The basic structure of the present invention is that the arch part can be manufactured separately from the foundation, and the arch part can be manufactured separately, which is extremely advantageous for formwork structure, reinforcement arrangement, concrete pouring, etc. This makes it easy to manufacture especially large-span arch culverts, and from a mechanical point of view, it is possible to construct statically fixed arches by connecting the divided parts with hinges. By providing the hinge at a position offset from the arch axis, it is possible to create a structure in which the axial force does not directly affect the hinge joint, and also to have a structure in which the divided parts are joined along the arch axis during assembly. This results in a prefabricated hinged arch culvert that is extremely stable in terms of strength.

The present invention will be explained in detail with reference to the embodiments shown below. Figures 1 and 2 are a front view and a plan view, respectively, showing an embodiment of a semicircular arch culvert, and the arch culvert main body 10 is divided into two pieces. The arch culvert consists of a single arch culvert 11, and the divided portions at the top 12 are connected by hinges at positions offset from the arch axis 10a, and the legs 13 are hinged on a foundation 20 having an L-shaped step 21. It is installed as a model. In the case of the embodiment, the left and right arch culvert units 11 are provided with protrusions 14 and recesses 15 alternately in the divided portions so that when the top portions 12 of the left and right arch culvert units 11 are combined, they interlock with each other along the arch axis 10a. In addition, the protruding part 14 is formed to protrude upward in a trapezoidal shape in order to provide a hinge connection shaft that is offset to the outside of the arch axis 10a passing through the center of the arch cross section, and extends through the center of the trapezoidal part. A connecting hole 16 is provided. This connecting hole 16
The left and right arch culvert units 11 are hingedly connected by inserting a connecting shaft 17 through them. Note that the configuration of this hinge connection portion is not limited to the embodiment, and for example, the hinge connection shaft is aligned with the arch axis 1.
This also includes a configuration provided inside 0a. The protruding part 14 and the recessed part 15 that engages with the protruding part 14 are configured such that when the arch is assembled, the distal end surfaces are joined with the connecting shaft 17 as a fulcrum, forming an arch shape along the arch axis 10a. . Further, in the case of the embodiment, a cushion mat 23 is provided between the protrusion 14 and the recess 15 that engage with each other. FIG. 3 is a perspective view showing the connecting portion when the arch is assembled in this embodiment. FIGS. 4 and 5 are a front view and a plan view showing the reinforcement structure inside the arch. The reinforcing bars 18 running on the inside and outside of the arch axis 10a reinforce the protrusion 14 and the leg 13 at both ends, and are provided in large numbers parallel to the width direction as shown in FIGS. 5a and 5b. Further, a large number of reinforcing bars 19 are also provided in a direction perpendicular to the reinforcing bars 18. Note that the connecting hole 16 of the hinge connecting portion can be provided by burying a metal pipe, etc., and the connecting shaft 1 is inserted into this metal pipe.
7 can be inserted therethrough.

In this way, the arch culvert bodies 10 combined at the hinge connection portion can be sequentially connected laterally on the foundation 20 to form an arch culvert of a predetermined length. in this case,
It is also possible to use a common connecting shaft 17.
11a is a joint provided on the side wall for filling with mortar etc. when connecting the arch culverts one after another; 22 is a bolt for fixing the leg portion 13 onto the foundation 20; In addition, in FIG. 1, 30 indicates the ground surface.

The semicircular arch culvert having the above configuration can be dynamically analyzed as a three-hinge arch (statically determined arch) as shown in FIG. P
is the uniformly distributed load due to earth and sand applied to the top surface of the arch, Q
is a uniformly distributed load applied to the side surface of the arch, H is a horizontal reaction force at the arch legs, V _A and V _B are vertical reaction forces, R is the arch radius, and point C is the hinge connection at the top of the arch.
Now, with reference to FIG. 7, the bending moment M _E , the axial force N _E , and the shear force S _E at an arbitrary point E (x, y) between the members AC with the arch leg A as the origin are determined as follows. x=R(1-cosθ) y=Rsinθ V _A = V _B = PR Since bending moment at point C = 0, H=R/2(P-Q) Bending moment M at point _E is, M _E =PRx- R/2(P-Q)y-Q/2y ² -P/2x ² The axial force N _E at point E is: N _E =-(V _A -Px) cosθ-(H+Qy) sinθ Shear force S at point E _E becomes S _E = (VA _- Px) sin θ - (H + Qy) cos θ.

Here, as an example, when P = 7.70t/m ² Q = 2.00t/m ² R = 0.55m, the moment M between arches AC, the axial force N,
To illustrate the distribution of shear force S, moment M
is as shown in Fig. 8a, shear force S is shown in Fig. 8b, and axial force N is shown in Fig. 8c. At this time, the absolute value of the moment is the maximum at 2.16t・m when θ = 30°, the shear force is the maximum at 2.69t at point A, the axial force is 2.67t at point C, and the maximum is 2.69t at point A.
The total weight is 4.24 tons, and both of these values can be adequately supported by the reinforced concrete arch. Furthermore, when used in tunnels to protect against snow or landslides, an unbalanced load will act on one side of the arch, as shown in FIG. 9. Here, T is the own weight, P is the vertical equally distributed load other than the own weight and the own weight applied to the left half of the arch, Q is the average horizontal earth pressure,
H _A and H _B are the horizontal reaction forces at points A and B of the arch legs, and V
_A and _VB are the vertical reaction forces, R is the arch radius, and point C is the top of the hinged arch.

From the above conditions, the vertical reaction force V A at point A of the leg is _{V A =} (3PR + TR - QR) / 4 ... (1) The vertical reaction force V _B at point B of the leg is V _B = (PR + 3TR + QR) / 4 ...(2) Also, the horizontal reaction force H _A at point A is H _A = (-PR-TR + 3QR) / 4 ... (3) The horizontal reaction force H _B at point B is H _B = (PR + TR + QR) /4 ...(4) It is expressed as.

When the coordinates are set as shown in FIGS. 9 and 10, x, x', y, y' are expressed by the following equations.

x=R(1-cosθ)...(5) x'=R(1-cosθ')...(6) y=Rsinθ...(7) y'=Rsinθ'...(8) Any AC member The bending moment M _E , axial force N _E , and shearing force S _E generated at point E are as follows: M _E =V _A x+HA _y −Px ² /2−Qy ² /2…(9) N _E =−( V _A −Tx) cosθ+(H _A −Qy) sinθ
...(10) S _E = (V _A - Px) sin θ + (H _A - Qy) cos θ
…Since it can be expressed as (11), these equations (9), (10), and (11) can be expressed as (1)
By substituting (3), (5), and (7), each value can be found.

Similarly, the bending moment M _F , axial force N _F , and shear force S _F generated at any point F of the BC member are as follows: M _F =V _B x'-H _B y'-T(x') ² / 2...(12) N _F =-(V _B -Tx')cosθ'-H _B sinθ'
...(13) S _F =-(V _B -Tx') sinθ' + H _B cosθ'
......(14), so these equations (12), (13), and (14) can be expressed as
By substituting (2), (4), (6), and (8), each value can be found.

As described above, according to the present invention, by providing the hinge connection portion at the top of the reinforced concrete arch culvert, the structure can not only be made dynamically very stable as a statically determined arch, but also Since the arch part can be manufactured in parts, only the inner part needs to be used as formwork, which is extremely advantageous in terms of transportation and concrete pouring. moreover,
Since the hinge is connected at a position offset from the arch axis, it is possible to obtain a strong arch culvert without applying axial force directly to the hinge, and the divided parts can be joined to each other along the arch axis. Because of this structure, the arch shape is reliably determined during assembly, which has the effect of making the construction easier and more accurate.

It should be noted that the shape of the arch culvert is not limited to the semicircular shape of the embodiment, but it goes without saying that the present invention can be applied to various arches such as a horseshoe shape and a parabolic shape.

[Brief explanation of the drawing]

Fig. 1 is a front view showing one embodiment of an arch culvert according to the present invention, Fig. 2 is a plan view thereof, Fig. 3 is a perspective view showing its main parts, and Fig. 4 is a front view showing its reinforcement structure. Figure 5 is a plan view, Figures 6 and 7 are explanatory diagrams for mechanical analysis,
Figure 8a is a moment diagram of the left half of the arch, Figure 8b
The figures are also shear force diagrams, FIG. 8c is a similarly axial force diagram, and FIGS. 9 and 10 are explanatory diagrams for performing mechanical analysis in other embodiments. DESCRIPTION OF SYMBOLS 10... Arch culvert body, 11... Arch culvert alone, 12... Top, 14, 15... Divided portion, 16... Connecting hole, 17... Connecting shaft, 20... Foundation, 23... Cushion mat.

Claims (1)

[Claims] 1. An arch culvert made of reinforced concrete that is installed as a hinge model on a foundation is divided at the top, and the divided parts are hinged at positions offset from the arch axis, and the divided parts are connected to the arch axis. A prefabricated hinge arch culvert constructed to be able to be joined to each other along the 2. The prefabricated hinge arch culvert according to claim 1, characterized in that a cushion mat is interposed between the divided portions that are joined to each other along the arch axis.