JPS5830882Y2 - Hanging bars for large concrete structures - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a reinforcing steel for large concrete structures such as concrete caissons and concrete wells.

One method of constructing concrete caissons for breakwaters, bridge piers, etc. is to first manufacture the concrete caisson on land, then transport it by sea using purging techniques, and then install it at a predetermined location.

In the case of this construction method, a metal bar for lifting and moving the caisson by a crane ship or the like is embedded in the concrete wall of the caisson.

Conventionally, three types of gold wire have been used: Types A, B, and C listed below, but each of these has advantages and disadvantages, and cannot necessarily be said to be a rational gold wire.

Type A is shown in Figure 4, and requires a hook because it uses round steel, and the metal part that protrudes from the concrete surface is made by bending the center of this round steel at a specific curvature, making the whole round. Made only of steel.

Therefore, in this type A, the amount of steel used is large.

Also, since the adhesion strength of concrete is low, there is no advantage to using high-tensile steel.

Also, due to its structure, cracks tend to occur on the concrete surface when it is suspended.

Type B is shown in Figure 5. A fixing plate is attached to the tip of a metal bar made of round steel, and the head of the round steel has a ring-shaped metal part forged to improve the adhesion and fixation of the round steel. The structure is supported by the bearing force of the plate.

Note that high tensile strength steel is used for the round steel.

Type B has the drawback that processing costs are high because heat treatment and forging are performed in processing the metal part.

Type C is shown in Fig. 6, and is made of deformed steel bar (using high-strength steel) with high adhesion, and weighs less than half (about 0.42 times) that of Type A.

Type C does not require a fixing plate, but the metal part is processed into a ring shape like type B, so it has the same drawback as high processing costs.

In addition, in Type C, the upper part of the concrete is easily broken due to the wedge action of the deformed steel bar, so an unbond part is provided in that part.

The present invention aims to eliminate the above-mentioned drawbacks of the conventional type, and provides a metal reinforcement whose hanging portion can be used repeatedly as an improved type of metal reinforcement of the type C mentioned above.

The metal reinforcing bars for large concrete structures according to the present invention will be explained below based on the drawings.

In the figure, 1 is a deformed threaded steel bar, and 2 is a metal part that is joined by a coupler 3.

The deformed straight steel bar 1 has a threaded surface over its entire length, and is made of high-strength steel.

As shown in FIG. 2 or 3, this deformed steel bar 1 is embedded and fixed in concrete, such as a caisson 4, in advance.

The metal part 2 is manufactured by forging or machine cutting a ring integrally attached to the head of a steel bar having a threaded joint similar to that of the irregular shaped threaded steel bar 1, and when lifting a concrete structure, the irregular shaped threaded steel bar is 1, and a wire rope 7 from a crane ship or the like is hung on this ring to hang it.

The coupler 3 has a female thread formed to match the shape of the thread at the joint end of the deformed steel bar 1 and the metal part 2, and is threaded so that it can be screwed therewith. transfer of stress takes place.

Generally, when deformed steel bars are used as reinforcing bars, an unbonded part is provided in a section from the concrete surface that is more than 6 times the diameter of the reinforcing bars, and when embedding the reinforcing bars of the present invention, Type C Similarly, it is necessary to cover it with a sheath such as vinyl chloride pipe 5.

The location of the coupler is due to construction and structural constraints of the concrete caisson 4, and may be at the lower end of the unbond as shown in Figure 2 or on the upper surface of the concrete as shown in Figure 3. It will be decided accordingly.

In addition, in actual construction, the weight of the concrete caisson is approximately 1,000 to 3,000, and the diameter is D76 mm.
10 to 32 metal bars with a design load of 140 tons are required, and the embedded length is approximately 40 D (3 m to 4 m).

The present invention has the above-mentioned structure, and has excellent fixing strength due to the irregularly shaped threaded steel bar embedded in the concrete.It is also very economical because the expensive metal parts that are difficult to process can be removed after construction and can be used over and over again. .

Also, if the coupler is exposed on the top of the concrete, it can be used repeatedly.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of application of the metal reinforcement of the present invention, Figs. 2 and 3 are sectional views showing the fixing mechanism of the metal reinforcement, and Figs. 4, 5, and 6 show a conventional example. FIG. 1... Deformed steel bar, 2... Metal part, 3
...Coupler, 4...Caisson, 5.
...vinyl chloride pipe (unbonded part), 6.
...Round steel, 7...Wire rope.

Claims (1)

[Scope of utility model registration request] A deformed steel bar with thread-like irregularities formed on its surface over its entire length, a metal part with a ring integrally formed on the head of the steel bar having a joint of the same shape, and a joint end of these deformed steel bars. and a coupler that can be screwed onto the joint end of the metal part, the irregularly shaped steel bar is embedded and fixed in a concrete structure, and a sheath is attached near the surface of the concrete structure to connect the unbonded part. A metal reinforcement for large concrete structures characterized by being formed.