JP2022038083A - Explosive fracture prevention structure - Google Patents

Abstract

To provide an explosive fracture prevention structure which can be simply and inexpensively configured, and can efficiently dissipate coagulated water and water vapor that is generated inside concrete due to residual moisture in the concrete or high temperature in firing.SOLUTION: An explosive fracture prevention structure has paths 3 for dissipating coagulated water and water vapor generated inside concrete due to residual moisture in a concrete column 1 or high temperature in firing to the outside. The path 3 is formed by mutually communicating a parallel direction path 31 in a direction parallel to a heating surface of the concrete column 1 and an orthogonal direction path 32 in a direction orthogonal to the heating surface in a direction crossing the parallel direction path 31.SELECTED DRAWING: Figure 1

Description

The present invention relates to an explosion prevention structure.

When the concrete member is exposed to a high temperature due to a fire or the like, the water remaining inside the concrete member and the condensed water that has fallen off from the hardened cement evaporate to become water vapor. When the concrete member has a dense structure such as high-strength concrete, it becomes difficult to dissipate the evaporated water vapor, and the pressure of the expanded water vapor may cause a part of the concrete member to peel off (explode). be.
As a measure against the explosion of concrete, the concrete structure may be fire-resistant coated, but it is necessary to perform the covering work after the construction of the concrete member, which increases the cost and labor and hinders the shortening of the construction period.
As another anti-explosion work, for example, Patent Document 1 describes a method in which organic fibers are contained in concrete and a void is formed for water vapor to dissipate by melting the organic fibers due to high heat such as in a fire. Is disclosed.
Further, Patent Document 2 discloses an explosion countermeasure structure in which a resin linear body braided in a net shape is embedded in a surface layer portion of concrete. In this anti-explosion structure, the striatum melts in the event of a fire to form a water vapor vent.
Further, in Patent Document 3, the concrete member is formed by embedding a thin tube having a large number of small holes as a separator so as to penetrate the inside and outside of the concrete member, thereby ensuring a ventilation path for water vapor in the event of a fire. The method is disclosed.

In the explosion countermeasure method of Patent Document 1, the fluidity of fresh concrete is lowered by mixing fibers, so that the workability is lowered. In addition, when a large amount of fiber is mixed, it takes time and effort to knead concrete. Further, since the strength is lowered due to the mixing of fibers, the higher the strength of the concrete, the higher the rate of high reduction due to the mixing of fibers tends to be.
In the explosion countermeasure method of Patent Document 2, a void is formed by melting the net-like linear body, but since the void does not face the outer surface, water vapor cannot be discharged to the outside.
In the explosion countermeasure method of Patent Document 3, although an exhaust pipe for steam is provided, a means for moving steam in a direction parallel to the heating surface (surface) of the concrete member is not provided. Therefore, there is a possibility that some parts of the concrete member cannot dissipate water vapor.

Japanese Patent Application Laid-Open No. 2003-306366 Japanese Unexamined Patent Publication No. 07-252902 Japanese Unexamined Patent Publication No. 07-252900

The present invention can be easily and inexpensively constructed, and efficiently removes condensed water that has fallen off from the hardened cement due to residual moisture inside the concrete and high temperature such as in a fire, or water vapor generated by evaporation thereof. The challenge is to propose an explosion prevention structure that can be dissipated to the outside.

In the present invention for solving the above problems, the water content in the concrete member (residual water content and condensed water that has fallen off from the hardened cement due to high temperature such as in a fire, or water vapor generated by evaporation of the residual water content and condensed water, etc. ) Is an explosion prevention structure having a path for dissipating. In the path, a parallel path parallel to the surface (heating surface) of the concrete member and an orthogonal path orthogonal to the surface (heating surface) communicate with each other.
In such an explosion prevention structure, the path for dissipating the residual water in the concrete member extends in the direction parallel to the surface of the concrete member and in the direction orthogonal to the surface, so that the concrete member is exposed to high temperature. Even if it is done, water vapor is likely to dissipate. Further, even when the water vapor in the concrete member evaporates to generate water vapor, the water vapor can be dissipated by the above-mentioned path. Since the plurality of paths extend in the directions parallel to and orthogonal to the heating surface of the concrete member, water (condensed water and water vapor) can be dissipated from substantially the entire area of the concrete member. Here, in the present specification, the "direction parallel to the heating surface" includes "substantially parallel" and also includes the case where the surface is slightly inclined with respect to the heating surface. Similarly, the "direction orthogonal to the heated surface" includes "approximately orthogonal" and does not necessarily have to be 90 ° with respect to the heated surface.

When the concrete member has a polygonal cross section, it is desirable that at least the parallel direction path is added to the main bar arranged along the corner portion of the concrete member. Further, it is desirable that the orthogonal path is provided on the joint surface, joint portion or joint portion of the concrete member. Further, it is desirable that the route is a single pipe material bound to the reinforcing bar of the concrete member or a plurality of bundled pipe materials. By doing so, it is possible to perform the route installation work in parallel with the bar arrangement work at the time of construction, so that the workability is excellent.

According to the explosion prevention structure of the present invention, it is possible to construct it easily and inexpensively, and it is possible to dissipate the condensed water and water vapor generated inside the concrete due to the residual moisture in the concrete or the high temperature such as in the event of a fire. Will be.

It is sectional drawing of the concrete member provided with the explosive prevention structure which concerns on this embodiment. It is a cross-sectional view of a concrete member. It is sectional drawing which shows the explosive prevention structure which concerns on other forms.

In this embodiment, an explosion prevention structure for suppressing an explosion that occurs when a concrete member is exposed to a high temperature such as in a fire will be described. The explosion-prevention structure of the present embodiment is made of concrete in order to dissipate residual water in the concrete member and condensed water that has fallen off from the hardened cement due to a high temperature history such as a fire, or water vapor generated by evaporation of those waters. It consists of a path 3 formed inside the member. As shown in FIGS. 1 and 2, the concrete member of the present embodiment is a concrete pillar 1 having a rectangular cross section.
The concrete pillar 1 of the present embodiment is formed to a predetermined height by placing concrete in a plurality of times. Therefore, the concrete column 1 has the joint surface 11 at a predetermined pitch. The composition of the concrete constituting the concrete pillar 1 is appropriately determined. Further, organic fibers and metal fibers may be mixed in the concrete as needed.

Reinforcing bars 2 are arranged on the concrete columns 1. The reinforcing bar 2 of the present embodiment includes a main reinforcing bar 21 and a reinforcing bar (band bar) 22.
The main bars 21 are arranged along the axial direction of the concrete columns 1. In the present embodiment, one main bar 21 is arranged at each corner of the concrete column 1 and two main bars 21 are arranged at equal intervals between the main bars 21 arranged at the corners. That is, 12 main bars 21 are arranged at equal intervals in the circumferential direction of the concrete column 1.
The reinforcing bars 22 are arranged so as to surround a plurality of (12) main bars 21. The reinforcing bar 22 secures a cover having a predetermined thickness from the surface of the concrete column 1. The reinforcing bar 22 of the present embodiment has a rectangular shape in a plan view, and is arranged so as to be orthogonal to the main bar 21. A plurality of reinforcing bars 22 are arranged at equal intervals with respect to the axial direction (height direction) of the concrete column 1. The configuration of the reinforcing bars 2 is not limited, and the number, pitch, and the like may be appropriately determined, and shear reinforcing bars may be arranged as needed.

In the present embodiment, the same number of paths 3 as the main bar 21 are provided in the concrete column 1 with respect to the cross section of the concrete column 1. The path 3 is a parallel path 31 in a direction parallel to the heating surface (surface) of the concrete column 1 (extending in the vertical direction) and a heating surface along the direction intersecting the parallel path 31 (extending in the horizontal direction). It is provided with an orthogonal direction path 32 orthogonal to the above. The parallel direction path 31 and the orthogonal direction path 32 are continuous (communication) with each other. In the present embodiment, the path 3 is formed by a wire rod that melts with the heat of hydration of cement. The wire rod is arranged at the position of the parallel direction path 31 and the orthogonal direction path 32. As the resin (resin fiber) constituting the path 3 (wire), a material that melts or shrinks at a relatively low temperature (for example, 60 to 80 ° C.) is desirable, and for example, polyvinyl chloride, acrylic resin, polyethylene, or the like can be used. Is.
The parallel path 31 is bound to the reinforcing bar 2 in a state of being arranged along the outside of the main bar 21. The orthogonal path 32 is formed by bending a wire rod at the end of the parallel path 31. The end of the orthogonal path 32 (the end of the path 3) faces the surface of the concrete column 1. The orthogonal path 32 of the present embodiment is provided along the joint surface 11 of the concrete column 1. That is, the path 3 is arranged between the upper and lower joint surfaces 11 and 11 of the concrete pillar 1 and has a U-shaped side view.

The wire rod constituting the path 3 is arranged together with the reinforcing bar arrangement of the reinforcing bar 2. That is, before placing concrete, when arranging the reinforcing bars 2, the wire rods constituting the path 3 are bound to the reinforcing bars 2. At this time, the orthogonal path 32 is formed by bending the lower end of the wire rod outward on the upper surface of the joint surface 11. Further, the upper end of the wire rod is projected upward from the position of the upper surface (joint surface 11) of the concrete to be newly placed, or is bent outward at the position of the new joint surface 11. Subsequently, when concrete is placed, the wire rod is melted by the heat of hydration of the cement, so that the concrete pillar (concrete member) has a path 3 (hole) for the movement of water vapor (moisture) inside. 1 is constructed. By using a material that melts at a temperature as low as the heat of hydration as the material constituting the path 3, it becomes possible to dissipate condensed water and water vapor from the initial stage at the time of a fire.

In the explosion prevention structure of the present embodiment, since the path 3 for dissipating condensed water and water vapor to the outside is formed in the concrete pillar 1, the water remaining in the concrete pillar 1 can be discharged. .. That is, the path 3 functions as a flow path for the residual moisture in the concrete pillar 1 to move even when the concrete pillar 1 is not exposed to high heat due to a fire or the like. Further, when the concrete pillar 1 is exposed to a high temperature due to a fire or the like and condensed water and water vapor are generated inside, the water can be dissipated to the outside through the path 3. As a result, it is possible to prevent the surface of the concrete from peeling off (exploding) due to the pressure of the water vapor generated by the evaporation of the water in the concrete pillar 1. Therefore, even if it is a dense concrete member, it is possible to suppress the generation of water vapor pressure inside and effectively dissipate water.

Moisture (condensed water and water vapor) taken into the path 3 passes through the path 3 and is discharged to the outside of the concrete pillar 1 from the tip of the orthogonal path 32. Since the plurality of paths 3 extend in the direction parallel to the heating surface of the concrete pillar 1 and in the direction orthogonal to the heating surface, moisture can be dissipated from substantially the entire area of the concrete pillar 1.
Since the path 3 is connected to the outside in a state where a certain volume is secured, the water generated inside the concrete (residual water and condensed water generated by a high temperature history such as a fire) can be discharged even in a liquid state. Therefore, the absolute amount of water that can be discharged is larger than that of the conventional explosion prevention method that discharges only gas, which is more effective.
Further, since the route 3 installation work can be performed in parallel with the bar arrangement work at the time of construction, the workability is excellent. Since the explosion of concrete can be effectively suppressed by the path 3 formed along the reinforcing bar 2, it is not necessary to generate concrete with a special composition for the purpose of suppressing the explosion. As described above, according to the explosion prevention structure of the present embodiment, the manufacturing cost of concrete can be suppressed, and further, the labor for kneading the concrete having a special composition can be omitted, so that the cost is higher than that of the conventional one. It is possible to reduce the cost and shorten the construction period.

Although the embodiments according to the present invention have been described above, the present invention is not limited to the above-described embodiments, and each of the above-mentioned components can be appropriately changed without departing from the spirit of the present invention.
In the above embodiment, the case where the explosion prevention structure is formed with respect to the concrete pillar 1 has been described, but the concrete member to which the explosion prevention structure of the present invention can be applied is not limited to the concrete pillar 1, and for example, concrete. It can be applied to all concrete members such as lining concrete for walls and tunnels. Further, the concrete member may be a precast member (segment) 12 as shown in FIG. When the precast member 12 is used as the concrete member, it is desirable that the orthogonal path 32 of the path 3 is provided at the joint portion 13 (or joint) of the precast member 12.
In the above embodiment, the path 3 (parallel direction path 31) is arranged along each main bar, but the arrangement of the path 3 is not limited. For example, when the concrete column (concrete member) 1 has a polygonal cross section, the parallel direction path 31 may be added only to the main bar 21 arranged along the corner portion of the concrete column 1. Further, the route 3 may be arranged in a larger number than the number of the main bars 21. Further, the path 3 does not need to be bound to the reinforcing bar 2, and may be bound to, for example, a spacer, or may be separately held by a holding member or the like.

In the above embodiment, the case where the path 3 is composed of a wire rod made of a resin that melts at a low temperature has been described, but the material constituting the path 3 is not limited. For example, it may be formed of a pipe material having a plurality of holes formed therein. The pipe material constituting the path 3 may be a metal pipe or a resin pipe. If a large number of holes are formed in the pipe material constituting the path 3, it is possible to take in the water vapor generated in the concrete column 1 into the pipe. Further, the path 3 may be formed by bundling a plurality of pipe materials.
Further, for example, it may be formed of a pipe material that shrinks due to the heat of hydration of concrete. If a hole (gap) is formed in the portion adhering to the concrete due to the shrinkage of the pipe material, the water generated in the concrete pillar 1 can be taken into the hole (gap) and discharged.
Further, the orthogonal path 32 may be provided so as to cross the concrete member. In this way, the water (condensed water and water vapor) in the central part of the concrete can also be dissipated. At this time, if the parallel direction path 31 is also formed in the central portion of the concrete member, the water can be dissipated more efficiently.
In the above embodiment, the case where the path 3 is formed by arranging the wire rod to be melted by the heat of hydration has been described, but when the precast member or the like is steam-cured, the wire rod melted by the heat at the time of curing is performed. May be disposed.
Further, the parallel direction path 31 may include a case where it is substantially parallel to the surface of the concrete pillar (concrete member) 1 and may be slightly inclined with respect to the surface of the concrete pillar 1. Further, the orthogonal path 32 may be substantially orthogonal to the surface of the concrete pillar (concrete member) 1, and does not necessarily have to be 90 ° with respect to the surface.

1 Concrete pillar (concrete member)
11 Joint surface 2 Reinforcing bar 21 Main bar 22 Reinforcing bar 3 Path 31 Parallel path 32 Orthogonal path

Claims (4)

An explosion-prevention structure that has a path for dissipating water in the concrete member.
The path is an explosion prevention structure characterized in that a parallel path parallel to the surface of the concrete member and an orthogonal path orthogonal to the surface are in communication with each other. The first aspect of the present invention, wherein when the concrete member has a polygonal cross section, the parallel direction path is attached to a main bar arranged along at least a corner portion of the concrete member. Explosion prevention structure. The explosion prevention structure according to claim 1 or 2, wherein the orthogonal path is provided on a joint surface, a joint portion, or a joint portion of the concrete member. The explosion prevention according to any one of claims 1 to 3, wherein the route is a single pipe material bound to a reinforcing bar of the concrete member or a plurality of bundled pipe materials. Construction.

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