JPH0336974B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an aqueduct bridge in which a plurality of cast pipes mainly manufactured by a centrifugal force casting method are connected, and in particular, the present invention relates to an aqueduct bridge in which a plurality of cast pipes manufactured by a centrifugal force casting method are connected. This invention relates to aqueduct bridges connected via flexible joints.

[Conventional technology and its problems] Aqueduct bridges in which multiple cast pipes are connected via flexible joints that can be bent are superior to aqueduct bridges made of steel pipes, which are made entirely of one pipe and have no joints. It has many features.
That is, since the joint can be deformed to some extent, it is extremely resistant to earth movements and ground fluctuations, and has excellent corrosion resistance, allowing for stable installation over a long period of time.

However, long water pipe bridges cannot be realized with cast pipes that have flexible joints. Aqueduct bridges that connect cast pipes are limited to three connections, with two ends fixed to anchors and one cast pipe connected between them, but aqueduct bridges that connect four or more cast pipes have been put into practical use. It has not been. This is because, for example, in an aqueduct bridge that connects four or more cast pipes, even if the two cast pipes at both ends are fixed to the anchors, the two middle cast pipes are not supported by the anchors, and the center joint is It falls and cannot stand on its own due to its own weight and the weight of the water passing inside.

Therefore, with conventional cast pipes, it is not possible to construct an aqueduct bridge that can stand on its own by connecting four or more pipes;
All constructed from steel pipes. However, aqueduct bridges made of steel pipes have the disadvantage that they are not flexible, and because they are connected by welding on site, welding work is time-consuming.
Post-processing to prevent corrosion of the welded part takes more time, and furthermore, the welded part is subjected to X-ray inspection, which requires advanced and dangerous work, and the overall construction cost is extremely high. Ta.

The present invention provides an aqueduct bridge using cast pipes that allows long aqueduct bridges, which could not be realized with conventional technology, to be constructed easily and easily at low cost without losing the characteristic of cast pipes having flexible joints. is to provide.

Another important object of the present invention is to provide an aqueduct bridge using cast pipes that can be stably used for a long period of time without worrying that the corrosion resistance of the connecting parts will deteriorate due to welding.

[Means for solving conventional problems] In an aqueduct bridge using cast pipes, a plurality of cast pipes are connected. At the connecting portion, the end portion is inserted into an adjacent cast pipe, the amount of insertion is limited by a stopper, and the plurality of cast pipes are connected via a flexible joint. At least the upper outer periphery of the casting tube is tensioned with a tension material to prevent the casting tube from falling.

[Operations and Effects] As shown in FIG. 2, one end of the cast pipe is inserted through and connected to the adjacent cast pipe T, so that the joint portion has flexibility to allow some bending. On the other hand, as shown in FIG. 3, steel pipes K whose entire circumferences are connected via flanges, or steel pipes which are connected by welding, have joints that cannot be bent and do not have flexibility. Cast pipes are characterized by flexibility in their joints, but this characteristic makes it impossible to create long water pipe bridges.

The present invention effectively utilizes the flexibility of the joint to realize a long water pipe bridge with a simple structure.

That is, as shown by the chain line in FIG. 4, the cast pipe T has the flexibility to be bent at the joint, so by tensioning the upper side with the tension material 3 as shown in FIG. , B are pulled upward. Since joints C and D are fixed to anchors, they will not fall, and a self-supporting water pipe bridge can be constructed using five cast pipes.

By the way, a downward force acts on joints A and B,
When under tension with the upper tendon, a compressive force acts on the lower contact surfaces of joints C and D, but this compressive force is applied to the open end of the inserted cast pipe and the adjacent cast pipe that it comes into contact with. It is supported by a stopper formed by a step.

The bending angles of joints C and D can be adjusted by adjusting the tension of the tendons. Furthermore, five cast pipes connected through joints tensioned with tendons, all of which have flexibility, are connected to construct a self-supporting aqueduct bridge. Therefore, even if the cast pipes on both sides that are fixed to the anchors move somewhat relative to each other, because the joint is flexible, the displacement will be absorbed by the joint and will not be applied to any part of the water pipe bridge. No load is applied. For this reason, the water pipe bridge of the present invention is connected by a flexible joint and does not lose the advantage of using cast pipes. Furthermore, since it can be constructed simply by simply inserting one end and then tensioning it with tension material without connecting it by welding or the like on-site, the overall construction cost can be significantly reduced. Furthermore, the combination of the use of highly corrosion-resistant cast pipes and the flexibility of the joints, especially the fact that the tension material does not impede the flexibility of the joints, allows for stable use over long periods of time. , realizing characteristics that are particularly important for aqueduct bridges.

Furthermore, although a long aqueduct bridge is formed on a somewhat high arch at the center, the aqueduct bridge of the present invention can also adjust the radius of curvature of the arch by changing the tension of the tendons.

[Preferred Embodiment] An embodiment of the present invention will be described below based on the drawings.

The aqueduct bridge shown in Fig. 1 consists of 5 centrifugally cast ductile cast iron pipes 1a, 1b, 1c, 1d, and 1e.
The cast iron pipes 1a and 1e at both ends are buried and fixed in anchors 2, and the middle cast iron pipe 1
To prevent joints A and B of b and 1d from falling, the flanges 4 of joints C and D are tensioned with tension members 3 extending along the cast iron pipes.

As shown in Figure 5, a joint for cast iron pipes is formed so that the inner diameter of the end is slightly larger than the outer diameter of the inserted forged pipe so that the ends of adjacent cast iron pipes can be inserted and connected to the required depth. ing.

In the strained cast iron pipe, when section A is about to fall in FIG. 4, the lower side of joint C is compressed and the upper side is expanded. The upper extension is tensioned by tendons, and the lower compression is stopped by a cast iron pipe stopper. The stopper limits the amount of insertion of the cast iron pipe, and the stopper of the cast iron pipe shown in Figs. Determine the insertion position by placing the open end of the

In the water pipe bridge joint shown in FIG. 5, an annular liner 6 is interposed between the open end of the inserted cast iron pipe and the stepped portion 5 against which the pipe is pressed.

The liner 6 is made of a metal that does not deform when pressed against the open end of the cast iron pipe under tension, for example, the same material as the cast iron pipe or a metal stronger than this. For those with an annular liner, the open end 7 of the cast iron pipe hits the stepped part 5 through the liner 6, so even if the stepped part is formed in a somewhat tapered shape, the inserted cast iron pipe can be easily inserted, as shown in Fig. 5. The open end 7 can come into contact with the liner 6 with almost its front surface in surface contact, thereby reducing the local overload of the contact pressing area during tension and preventing damage.

As shown in FIG. 6, the liner 7 is thick at the top and thinner toward the bottom, so that the front surface of the open end 7 of the cast iron pipe can come into surface contact with the liner 6 with the joint slightly bent.

However, the present invention does not limit the stopper to a structure with a liner; for example, a structure may be adopted in which the liner is omitted and the open end of the inserted cast iron pipe directly collides with the inner surface of the adjacent cast iron pipe. As shown in FIG. 7, annular grooves 8 and 9 are provided on opposing surfaces of the inserted cast iron pipe, and a lock ring 10 is fitted into the grooves 8 and 9, and the lock ring 10 and the grooves 8 and 9 are used to create a stopper. It is also possible to adopt a structure that limits the insertion depth of the cast iron pipe.

As shown in FIG. 5, a rubber ring 12 is press-fitted into the gap between the two cast iron pipes using a push ring 11 to close the gap watertightly.

The press ring 11 has an L-shaped cross section in the radial direction, and is fastened to the flange 4 of the cast iron pipe via bolts 13 and nuts 14, and the rubber ring 12 is pushed into the gap between the two forged pipes.

A stainless steel rod, a stainless steel wire, a rolled prestressed steel rod or a prestressed steel wire made of an alloy containing carbon, manganese, silicon, and vanadium can be used as the tendon material.

The stainless steel rod and wire are made of SUS304 stainless steel, and the rolled PC steel rod has a diameter of 26 to 32 mm and contains 0.7% carbon, 1.5% manganese, and 0.7%.
Silicon St835/1030, St1080/1230 to which 0.3% vanadium is added, etc. can be used.

As the PC steel wire, a steel wire made of a heat-treated alloy or drawn from a hot-rolled wire can be used. For the former steel wire, hot-rolled alloy steel wire containing 0.5% carbon, 1.6% silicon, 0.6% manganese, and 0.4% chromium can be heat-treated in multiple stages to make it strong. In addition, the latter steel wire has 0.8% carbon,
The steel wire used is made of rolled wire containing 0.2% silicon and 0.7% manganese, which has been drawn repeatedly.

As shown in FIGS. 1 and 6, the tension material 3 is
The end is inserted into the flange 4, and a nut 17 is tightened into the male threaded portion of the insertion end to tension the flange 4 of the joint. In the tension member having this structure, the tension force of the tension member 3 can be adjusted by adjusting the amount of tightening of the nut 17.

When the tension member is not connected to the flange 4, as shown in FIG. 7, the collar 16 is fixed to the outer periphery of the cast iron pipe,
A tensioning material 3 is inserted into this collar 16 to tension it.

The tension material 3 tensions the cast iron pipe in order to prevent the cast iron pipe from sagging at the joint due to its own weight and passing water. Therefore, the tension material 3 tensions the upper outer periphery of the cast iron pipe. In order for the tension material to most effectively prevent the joint from sagging, it is best to tension the top of the cast iron pipe. However, even if the tension material tensions the top and bottom center of the cast iron pipe on both sides, it is possible to prevent the cast iron pipe from sagging. Therefore, in this specification, the "upper part" where the tension member tensions the upper part of the cast iron pipe means the upper and lower center of the cast iron pipe or the upper part thereof.

Furthermore, as shown in FIG. 8, the entire circumference of the cast iron pipe can be tensioned with tensioning material 3. In this case, the cast iron pipe joint can prevent bending in both the vertical and horizontal directions.
Particularly stable connection.

The present invention is characterized by tensioning a plurality of cast iron pipes with a tension material, but does not specify the state of tension.

Aqueduct bridges 1a, 1b, 1c, 1d shown in Figure 9,
In 1e, one end of the tendon 3 is fixed to the anchor 18, and the other end is fixed to the flanges 4 of the joints A and B through the through holes of the flanges 4 of the joints C and D.

Furthermore, in the aqueduct bridge shown in FIG.
I'm nervous.

Furthermore, in the aqueduct bridge of FIG. 11, joints C and A and joints A and B are tensioned with separate tension members 3, and in the aqueduct bridge of FIG. is tensioned with one tension material 3.

As shown in Fig. 13, an aqueduct bridge tensioned with tendons can be prevented from condensation by covering its outer periphery with a heat insulating material 19 such as synthetic resin foam to isolate the tendons from the outside. Bridge insulation and cast pipe corrosion can be prevented.

Furthermore, as shown in FIG.
8, the water pipe bridge is formed into an arch with the stopper of the joint in contact, i.e., the cast pipe is held together to form an arch-like shape as a whole. As shown in the plan view of the figure, the flange 4 is tensioned with a plurality of tension members 3 to prevent the cast iron pipe from moving and rotating in the direction of the arrow. In this case, the tension material 3 only needs to prevent the rotation of the aqueduct bridge, so the tension force can be weakened.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of the aqueduct bridge of the present invention, FIG. 2 is a cross-sectional view showing how two cast pipes are connected, FIG. 3 is a side view showing how steel pipes are connected, and FIG.
The figure is a schematic side view showing a flexible state of the joint of a cast pipe, FIGS. 5 and 6 are cross-sectional views showing the joint, FIG. 7 is a cross-sectional view showing an example of a tensioned state, and FIG. Cross-sectional view showing the connecting part of tendons, No. 9
12 to 12 are schematic sectional views showing other embodiments of the water pipe bridge of the present invention, FIG. 13 is a sectional view showing a joint covered with a heat insulating material, and FIG. 14 is an arch-shaped overall shape. FIG. 15 is a schematic side view showing another embodiment of the aqueduct bridge of the present invention, and FIG. 15 is a plan view showing the tensioned portion of the tendon material of the aqueduct bridge shown in FIG. 14. 1a, 1b, 1c, 1d, 1e...cast iron pipe, 2
...Anchor, 3...Tension material, 4...Flange,
5...Step part, 6...Liner, 7...Open end,
8, 9...groove, 10...lock ring, 11...
Push ring, 12... Rubber ring, 13... Bolt, 14...
...nut, 15...flange, 16...tsuba, 17
...Natsuto, 18...Anchor, 19...Insulation.

Claims (1)

[Scope of Claims] 1. In an aqueduct bridge consisting of a plurality of connected cast pipes whose ends are inserted into adjacent cast pipes and whose insertion amount is limited by a stopper, at least the upper outer periphery of the cast pipe is An aqueduct bridge using a cast pipe characterized by being tensioned with tendons extending along the pipe. 2. An aqueduct bridge using a cast pipe according to claim 1, wherein the end of the tendon is connected to a flange of the cast pipe. 3. An aqueduct bridge using a cast pipe according to claim 1, wherein both ends of the tendons are connected to flanges of the cast pipe adjacent to each other to anchoring members fixed to the surface of the cast pipe. 4. An aqueduct bridge using a cast pipe according to claim 1, wherein the tendons are stainless steel rods. 5. An aqueduct bridge using a cast pipe according to claim 1, wherein the tendons are stainless steel wires. 6 Claim 1 in which the tendon material is a PC steel wire
Aqueduct bridge using cast pipes as described in Section 1. 7 Claim 1 in which the tendon material is a PC steel bar
Aqueduct bridge using cast pipes as described in Section 1.