JPS6044471B2 - Joint structure of old and new concrete structure - Google Patents

Description

[Detailed Description of the Invention] When adding a concrete structure part, especially a wall, in the renovation of an existing concrete structure, one method of joining the existing part and the added part is to insert a hole into a hole drilled in the existing part. There is a method of installing a set of embedded bolts, known by trade names such as Anchor, and pouring concrete for the extension to transfer shear force between the existing part and the extension.

However, if a force exceeding a certain level is applied to the embedded bolt set, it is likely that the machined part will break, and in order to transmit the shearing force, it is necessary to process the embedded bolt set as much as the currently commonly used embedded bolt set. is not required. However, since special metal fittings that have been processed are used, the installation cost is relatively high, and the conventional method using an embedded bolt set has various drawbacks. The present invention was proposed in order to eliminate such defects, and the present invention has been proposed in order to eliminate such defects. The steel rod is inserted into the existing steel rod insertion hole so that a gap exists between it and the inner wall surface of the insertion hole, and a part of the steel rod protrudes into the new structure, and the steel rod is inserted into the existing steel rod insertion hole. This relates to a joint structure between old and new concrete structures, which is characterized by being straddled over a new concrete structure.

In the present invention, as described above, a steel rod such as a steel bar or a steel pipe is drilled at the joint surface of an existing concrete structure consisting of an open frame to a new concrete structure consisting of a concrete wall to be added within the same structure. A steel rod is inserted into the insertion hole so that a part thereof protrudes into the extension part, and then concrete for the extension part is poured, and the old and new concrete parts are joined together through the steel rod. Unlike conventional embedded bolt sets, the steel rod does not have any machined parts such as threaded parts or wedge insertion parts, and the presence of such machined parts can cause local stress concentration and rupture. It is difficult and highly reliable to perform construction, and as mentioned above, the steel rod used in the present invention does not have any processed parts as described above, so the material cost is low and it can be used in existing construction. The insertion work into the steel rod insertion hole provided in the concrete structure is extremely easy, making it possible to save labor costs and shorten the construction period.

Furthermore, according to the present invention, since a gap is provided between the steel rod and the insertion hole, the rigidity of both the old and new concrete structures can be adjusted by adjusting the size of the gap between the two. The present invention has many advantages, such as improved performance. The present invention will be described below with reference to the illustrated embodiments.

As shown in Figure 1, after drilling a steel rod insertion hole 1 in the joint surface of the existing concrete structure A, a steel rod 2 made of a steel bar or steel pipe is partially added to the insertion hole 1. Then, concrete is poured on the joint surface of the structure A to construct the concrete structure B of the extension, and the steel is inserted over both structures A and B. A rod 2 is buried, and the two structural parts A and B are integrally joined via the steel rod 2. As the steel rod 2, a deformed steel bar may be used in addition to a general steel bar and a steel pipe. FIG. 2 shows another embodiment of the present invention, in which an L-shaped bent portion 2α is formed at the tip of the steel rod 2 to more firmly connect the structural portions A and B. .

Further, the structural parts A and B may be in close contact with each other as shown in FIGS. 1 and 2, or may not be in close contact with each other as shown in FIG. 3. Further, the steel rod 2 and its insertion hole 1 may be perpendicular to the joint surface of the structure 5 A as in each of the above embodiments, or may be oblique as shown in FIG. . Furthermore, even if the steel rod 2 is tightly fitted into the steel rod insertion hole 1 of the structural part A (see FIG. 5), the cement page. Even if they come into close contact through the striker 3, etc. (see Figure 6)
Alternatively, a gap may be left between both 1 and 2.

(See Figure 7) Figure 8 shows an example of adding a new reinforced concrete wall within an existing reinforced concrete open frame. A steel rod 2 is inserted into the rod insertion hole 1, a part of which is connected to the pillars a1 and ? 2, and concrete is poured into the space between each of the columns α1 and beams α2, and a reinforced concrete wall C is constructed which is integrated with the columns α1 and beams α2 via the steel rods 2. It is.

In addition, the inserted steel rod 2 at the bottom of the beam α2 is connected to the reinforced concrete wall C.
In order to prevent the steel rod from falling before pouring, install the steel rod 2.
It is preferable to tie them to the reinforcing bars of the wall C, or to hammer in a copper rod 2 having a diameter that fits tightly into the steel rod insertion hole 1.

Although the present invention has been described above with reference to embodiments, the present invention is of course limited to such embodiments, but is not limited to such embodiments, and the design can be modified in various ways without departing from the spirit of the invention. However, it is better to create a gap between the tip of the inserted steel rod and the existing part to prevent the steel rod from being pushed by the expansion of the poured concrete and causing cracks in the existing part.

[Brief explanation of drawings]

Figures 1 to 7 are longitudinal cross-sectional views showing respective examples of joint structures for old and new concrete structures according to the present invention, and Figure 8 is a diagram showing the present invention in which a reinforced concrete wall is added to an existing reinforced concrete open frame. FIG. 3 is a front view showing an example applied to a case. A: Existing concrete structure, B:
... Concrete structure of the extension part, 1... Steel rod insertion hole, 2... Steel rod.

Claims (1)

[Claims] 1. Insert a steel rod into a steel rod insertion hole drilled at the joint surface of an existing open frame concrete structure with a new concrete structure consisting of a concrete wall that will be added to the same structure, and between it and the inner wall surface of the insertion hole. A new and old concrete structure, characterized in that the steel rod is inserted so that a gap exists in the new structure and a part thereof protrudes into the new structure, and the steel rod is straddled over the existing and new concrete structure. joint structure.