JP2557135B2 - How to repair concrete structures after a fire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a cylindrical reinforcing iron plate surrounding the outer peripheral side of a concrete skeleton such as a pillar or a beam and restraining the same, and the opposing reinforcing iron plate. The present invention relates to a method for repairing a concrete structure after a fire, which has a splicing core member that is bridged between the inner peripheral surfaces and joined to each other and embedded in a concrete skeleton.

<< Prior Art >> In recent years, as shown in FIG. 2, concrete such as columns 2 or beams of the concrete structure has been dealt with in order to meet the demand for higher yield strength accompanying the increase in the height and size of the concrete structure. A tubular reinforcing iron plate 6 for surrounding and restraining the body 4 is provided in close contact with the outer peripheral side of the body 4, and the tubular reinforcing iron plate 6 is hung between the opposing inner circumferential surfaces inside the tubular reinforcing iron plate 6. A splicing core member 8 which is passed over and whose end is joined to the inner peripheral surface.
And place the joint core member 8 into the concrete skeleton 4
A technique of embedding it inside is known. Here, in the illustrated example, the joining core member 8 is formed by combining flat iron plates in a cross shape (Japanese Utility Model Publication No. 2-51618, etc.).

<< Problems to be Solved by the Invention >> By the way, there is provided a concrete structure in which the outer peripheral side of the concrete skeleton 4 of the pillar 2 (or a beam or the like) is surrounded by the tubular reinforcing iron plate 6 and constrained as described above. When a fire occurs, as shown in FIG. 3, not only the tubular reinforcing iron plate 6 is thermally deformed and a gap 9 is formed between the reinforcing iron plate 6 and the concrete skeleton 4, but also the reinforcing iron plate 6 is burned. Since it is annealed and the strength of itself is reduced, it becomes impossible to sufficiently restrain the concrete skeleton 4 from the outer peripheral side of the tubular reinforcing iron plate 6 after that, and the proof stress of the column 2 is reduced. There was a problem of being lost.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a reinforcing iron plate surrounding and restraining a concrete skeleton such as a pillar or a beam on the outer peripheral side of the concrete skeleton, and for cylindrical reinforcement. A concrete structure with a splicing core member embedded inside a concrete frame and hung between the inner peripheral surfaces of the reinforcing iron plate facing each other and the ends of which are joined to the inner peripheral surface of the concrete structure It is to provide a repair method after a fire.

<< Means for Solving the Problem >> The present invention relates to a tubular reinforcing iron plate surrounding the outer peripheral side of a concrete skeleton such as a pillar or a beam to constrain it, and between the inner peripheral surfaces of the reinforcing iron plate facing each other. When a concrete structure having a splicing core member that is bridged over and joined at the end and is embedded in the concrete skeleton suffers a fire, when repairing it, heat is applied by the fire. A step of removing the deformed tubular reinforcing iron plate at the joint with the joint plate leaving a joining margin, and joining the joining margin to newly enclose the outer peripheral side of the concrete skeleton A step of providing an iron plate and a step of injecting a filler into a gap defined between the new reinforcing iron plate and the concrete frame are sequentially performed.

<< Working >> A cylindrical reinforcing iron plate that surrounds and restrains the outer peripheral side of the concrete frame and the end part that is bridged between the opposing inner peripheral surfaces of the reinforcing iron plate and the end is joined, When a concrete structure having a splicing insert member embedded therein suffers a fire, the tubular reinforcing iron plate is annealed to reduce its strength and cause thermal deformation, resulting in a concrete skeleton. A gap is created between the two and the outer peripheral side of the concrete frame cannot be effectively restrained. on the other hand,
Since the splicing core member embedded in the concrete body is protected by the concrete body having a large heat requirement, it does not suffer much damage.

Therefore, in repairing this, a tubular reinforcing iron plate that has undergone thermal deformation is cut off with a joint margin left at the joint with the neutrons, and this is jointed to this joint margin and attached to the outer peripheral side of the concrete frame. A new reinforcing iron plate surrounding the cylinder is provided, and after that, the gap defined between the newly formed cylindrical reinforcing iron plate and the concrete frame is filled with a filler such as mortar for repair. By doing so, it is possible to effectively use the splicing core member that has not been significantly damaged and sufficiently restrain the outer peripheral side of the concrete skeleton such as columns and beams with the newly provided tubular reinforcing iron plate. It is possible to restore the proof stress of the column or beam to a desired value or more.

<Example> An example of a method for repairing a concrete structure after a fire according to the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 2, the repair method of the present invention includes a tubular reinforcing iron plate 6 surrounding the outer peripheral side of a concrete skeleton 4 such as a pillar 2 or a beam to restrain the concrete skeleton 4, and the reinforcing iron plate 6 Repair when a conventionally known concrete structure having a splice between the inner peripheral surfaces facing each other and having end portions joined to each other and having a splicing insert member 8 embedded in the concrete skeleton 4 suffers a fire. Is assumed.

When the concrete structure suffers a fire, as described above, the tubular reinforcing iron plate 6 is not only annealed but its strength is lowered, but also it is thermally deformed and the space between the concrete structure 4 and After that, a large damage such as a gap 9 is generated, and the outer peripheral side of the concrete skeleton 4 cannot be sufficiently restrained after that, and the proof stress of the column 2 and the like is reduced (see FIG. 3).

Therefore, in the present invention, the concrete structure damaged by the fire is repaired as described later.

That is, first, as shown in FIG. 1 (I), a step of cutting and removing the reinforcing iron plate 6 that has been thermally deformed is performed. At this time, the reinforcing iron plate 6 is cut off by fusing or the like, leaving a joint margin 10 at the joint portion with the splicing core member 8 embedded in the concrete skeleton 4.

Next, as shown in FIG. 1 (II), a tubular reinforcing iron plate 12 newly surrounding the outer side of the concrete skeleton 4 exposed by removing the thermally deformed reinforcing iron plate 6 is removed. Perform the process of providing. At this time, as the newly provided tubular reinforcing iron plate 12, four iron plates 12a bent at right angles are used. Each of the iron plates 12a is welded at its both end portions to the joining margin 10, and is formed into a rectangular tubular shape so as to surround the outer peripheral side of the concrete skeleton 4, and the new reinforcing iron plate 12 and the concrete skeleton are formed. A gap 14 is defined between the two.

Next, as shown in FIG. 1 (III), a filler 16 such as mortar is pressed into a gap 14 defined between the new rectangular tubular reinforcing iron plate 12 and the concrete skeleton 4. Perform the process of injecting and filling by the above.

That is, if the concrete structure is repaired after the fire as described above, the splicing core member 8 which is protected by the concrete skeleton 4 having a large heat requirement at the time of the fire and is not much damaged is effectively used. With the newly provided tubular reinforcing iron plate 12, the outer peripheral side of the concrete skeleton 4 of the pillar 2 can be sufficiently firmly restrained, and thus the proof stress of the pillar 2 beam can be restored to a desired value or more.

In the illustrated embodiment, a seaming core member 8 formed by combining iron plates in a cross shape is used, and each end of the seaming core member 8 is formed into a rectangular cylindrical tubular reinforcing iron plate 12. Although the one joined to the inner peripheral surface of the side is shown as an example, the present invention is not limited to this and is also applicable to a concrete structure using a rod material as the splicing core member 8.

Moreover, although the column 2 having a rectangular cross-section is illustrated in the illustrated embodiment, the present invention may be applied to a column having a circular cross-section and the like, and is not limited to the column and may be applied to a beam. It is a theory.

<Effect> As described in detail in the above examples, according to the method for repairing a concrete structure after a fire according to the present invention, a tubular reinforcing iron plate having a thermal deformation is used as a splicing core member. A new reinforcing iron plate is cut off at the joint to leave a joint margin, and is joined to this joint margin on the outer peripheral side of the concrete skeleton to enclose it in a cylindrical shape, and after this, the newly formed cylindrical reinforcement is reinforced. Since the space defined between the steel plate and the concrete structure is filled with a filler such as mortar for repair, a splicing core that is protected by the concrete structure that has a large heat requirement during a fire and is not damaged. By effectively using the member, it is possible to sufficiently firmly restrain the outer peripheral side of the concrete skeleton such as columns and beams with the newly provided tubular reinforcing iron plate,
Therefore, the proof stress of the column or beam can be restored to a desired value or more.

[Brief description of drawings]

FIG. 1 shows an embodiment in which the repairing method according to the present invention is applied to a pillar, and FIG. 1 (I) is a transverse cross-sectional view showing a step of cutting a thermally deformed tubular reinforcing iron plate, Figure (II)
Is a cross-sectional view showing the process of removing a heat-deformed reinforcing iron plate, and then providing a new reinforcing iron plate on the outer peripheral side of the concrete structure. The same figure (III) shows a concrete structure with a new reinforcing iron plate. FIG. 2 is a cross-sectional view showing a step of filling a filler in between, and FIG. 2 shows a concrete structure to be subjected to the repairing method of the present invention. The outer peripheral side of the concrete skeleton is surrounded by a cylinder to be restrained. FIG. 3 is a cross-sectional view of a known pillar provided with a reinforcing iron plate, and FIG. 3 is a cross-sectional view showing a state of the pillar shown in FIG. 2 after suffering a fire. 2 …… Pillar 4 …… Concrete skeleton 6 …… Reinforcing iron plate 8 …… Splice core member 10 …… Joining cost 12 …… New reinforcing iron plate 14 …… Between new reinforcing iron plate and concrete skeleton Gap defined 16 ... Filler

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Masae Sakanishi 4-640 Shimoseido, Kiyose-shi, Tokyo Inside Obayashi Technical Research Institute Co., Ltd. (56) References Mitsuihei 2-51618 (JP, U)

Claims (1)

(57) [Claims] 1. A cylindrical reinforcing iron plate surrounding the outer peripheral side of a concrete structure such as a pillar or a beam for restraining the same, and an end portion of the reinforcing iron plate which is hung between the inner peripheral surfaces facing each other. In a method for repairing a concrete structure having a splicing core member that is joined and embedded in the concrete skeleton after the fire, the tubular reinforcing iron plate thermally deformed by the fire is the splicing core. A step of cutting away the joint margin at the joint part with the member, a step of joining to the joint margin and newly providing a cylindrical reinforcing iron plate surrounding the outer peripheral side of the concrete skeleton, and this new reinforcing iron plate A method for repairing a concrete structure after a fire, which comprises sequentially performing a step of injecting a filler into a gap defined between the concrete structure and the concrete structure, and