JP2015218497A - Seismic strengthening structure and seismic strengthening method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seismic strengthening structure capable of being constructed even on a job site where a work space or an installation space is relatively narrow and capable of sufficiently increasing strength of a structure to be seismically strengthened, and a construction method for constructing the seismic strengthening structure.SOLUTION: A seismic strengthening structure according to the present invention includes: an anchor that is provided in such a manner as to protrude from a construction surface of a structure to be seismically strengthened; one or more precast forms that are made of mortar cured material with ultra-high strength and provided in such a manner as to cover the construction surface; and the mortar cured material with ultra-high strength that is filled into a space formed of the construction surface and an inner surface of the precast form.

Description

  The present invention relates to a seismic reinforcement structure and a seismic reinforcement method.

  Various seismic reinforcement techniques have been developed so far. For example, Patent Documents 1 and 2 below describe a method for improving the seismic strength of existing buildings.

JP 2009-249851 A JP 2005-155139 A

  By the way, there is not always enough work space or installation space for the seismic reinforcement structure at the site where the seismic reinforcement method is carried out, especially for seismic reinforcement work of existing structures (columns, beams, etc.) There are often space constraints.

  The present invention provides a seismic reinforcement structure that can be constructed even in a site where the work space or the installation space is relatively narrow, and can sufficiently improve the strength of the structure to be seismically strengthened, and a method for constructing the same. The purpose is to provide.

  The seismic reinforcement structure according to the present invention includes one or a plurality of anchors provided so as to protrude from the construction surface of the structure to be seismically strengthened and a cured product of ultra-high strength mortar so as to cover the construction surface. And a cured product of ultrahigh strength mortar filled in a space formed by the construction surface and the inner surface of the precast mold.

  According to the above-mentioned seismic reinforcement structure, while adopting ultra-high strength mortar as a filling material, it can be used as part of the seismic reinforcement structure without removing the precast formwork (made of ultra-high strength mortar) after curing it. By remaining, even if it is thin thickness (for example, about 100-300 mm), the intensity | strength of the structure of seismic reinforcement object can fully be improved. Here, the “thickness” of the seismic reinforcement structure means the distance from the construction surface to the outer surface of the precast formwork.

  In order to construct the seismic reinforced structure, a precast formwork manufactured at a factory or the like may be carried to the site and used. For this reason, it is possible to minimize the installation work of the formwork at the site, and it is possible to construct the seismic reinforcement structure even at a site where the work space is relatively narrow. Further, as described above, since the thickness of the seismic reinforcing structure can be sufficiently reduced, the seismic reinforcing structure can be installed even in a relatively narrow installation space.

As an example of the ultra high strength mortar constituting the precast mold and the filler, there is a mortar composition containing cement, silica fume, water, a water reducing agent, an antifoaming agent, and fine aggregate. It is preferable that the cement are those containing less than 2.7 wt% of _{C 3} S and from 40.0 to 75.0% by weight and _{C 3} A.

  The cured product of ultra high strength mortar constituting the precast form may contain organic fibers. Precast molds containing organic fibers have advantages such as excellent handling properties during transportation (hard to break) and excellent fire resistance (hard to explode). On the other hand, the cured product of ultra-high strength mortar that is a filler may not contain organic fibers from the viewpoint of excellent fluidity at the time of casting and high compressive strength after curing.

  In the present invention, the reinforcing bars may be arranged in a space formed by the construction surface and the inner surface of the precast formwork. Moreover, you may embed a shear reinforcement bar with a reinforcing bar in the hardened | cured material of ultra high intensity | strength mortar. Further, roughened irregularities may be provided on the inner surface of the precast mold frame in contact with the ultrahigh strength mortar for the purpose of improving the integrity with the ultrahigh strength mortar. When building a seismic reinforcement structure using multiple precast forms, from the viewpoint of achieving higher strength, it is used for reinforcement in the cured product of ultra-high-strength mortar so as to straddle the joints between adjacent precast forms. You may embed a plate or a wire mesh rebar. Or you may integrate a some precast formwork with the steel wire to which the prestress was given.

  The present invention provides the following seismic reinforcement method. That is, the seismic reinforcement method according to the present invention includes (A) a step of providing an anchor so as to protrude from a construction surface of a structure to be seismic reinforcement, and (B) a cured product of ultra high strength mortar so as to cover the construction surface. A step of providing one or a plurality of precast molds, (C) a step of filling a space formed by the construction surface and the inner surface of the precast molds, and (D) filling the space. Curing the ultra-high strength mortar.

  The seismic reinforcement method may further include a step of arranging reinforcing bars on the construction surface, and this step may be performed before the step (C) or may be performed before the step (B). The seismic reinforcement method may further include a step of integrating a plurality of precast molds with a prestressed steel material.

  In the above-mentioned seismic reinforcement method, not all the molds need to be precast molds, and for places where the precast molds cannot be arranged, for example, wooden molds may be assembled on site. In other words, the seismic reinforcement method may further include a step of assembling and installing the formwork at a location where the precast formwork is not arranged on the construction surface.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a site where a work space or an installation space is comparatively narrow, it can be constructed, and a seismic reinforcement structure that can sufficiently improve the strength of a structure to be seismic reinforcement and a structure for constructing the same Construction methods are provided.

It is a perspective view which shows typically the internal structure of the earthquake-proof reinforcement structure which concerns on 1st Embodiment of this invention. It is sectional drawing in the II-II line of FIG. (A)-(c) is a front view which shows typically the process of constructing | assembling the earthquake-proof reinforcement structure which concerns on 1st Embodiment. (A) is a front view which shows typically the earthquake-proof reinforcement structure which concerns on 2nd Embodiment, (b) is sectional drawing which shows the structure of the hole for letting a steel wire pass. It is a front view which shows typically the internal structure of the earthquake-proof reinforcement structure which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the variation of a precast formwork. It is a perspective view which shows the precast formwork which has a convex part and a recessed part. It is a front view which shows the seismic reinforcement structure which has the reinforcement plate embed | buried so that the joint of the adjacent precast formwork may be straddled. It is a perspective view which shows the precast formwork which has a recessed part in an inner surface.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and a duplicate description is omitted.

<First Embodiment>
(Seismic reinforcement structure)
FIG. 1 is a perspective view schematically showing the internal structure of the seismic reinforcing structure according to the present embodiment. The seismic reinforcement structure 10 shown in the figure is for seismic reinforcement at a location where the existing RC column 1 and the existing RC beam 2 intersect (a structure to be seismically strengthened). The seismic reinforcement structure 10 includes a plurality of anchors 12 provided so as to protrude from the construction surface F, a plurality of precast molds 15 provided so as to cover the construction surface F, and the inner surfaces of the construction surface F and the precast mold 15 And a cured product 18 of ultra-high strength mortar filled in a space S (see FIG. 2) formed by 15a. Each configuration will be described below.

  The anchor 12 is for integrating the structure (existing RC pillar 1 and existing RC beam 2) to be seismically reinforced and the hardened material 18 of ultra high strength mortar. That is, the anchor 12 plays a role of transmitting seismic energy applied to the structure to be seismically reinforced to the seismic reinforced structure 10. For example, various types of anchor bolts can be used as the anchor 12. Note that FIG. 2 illustrates the anchor 12 embedded in the cured product 18 having a super-strength mortar as a whole, but the anchor has a tip (not shown) provided in the precast mold 15 on its outer surface 15b. It may be protruding. In this case, for example, the anchor may have a function of fixing the precast mold 15 to the construction surface F by allowing a nut to be attached to the tip of the anchor.

As shown in FIGS. 1 and 2, a reinforcing bar 13 and a shear reinforcing bar 14 are arranged in advance on the construction surface F, and are embedded in a cured product 18 of ultrahigh strength mortar. Both the reinforcing bar 13 and the shear reinforcing bar 14 are preferably high in strength. Specifically, the yield point of the steel material used as the reinforcing bar 13 and the shear reinforcing bar 14 is preferably 390 N / mm ² or more, more preferably 490 to 1275 N / mm ² , and further preferably 685 to 1275 N / mm. ² . The tensile strength of the steel is preferably 560N / mm ² or more, more preferably 620~1500N / mm ^2, more preferably from 800~1500N / mm ^2. In this specification, “yield point” and “tensile strength” mean values measured according to the method described in JIS Z2241-2011.

The precast mold 15 is manufactured at a factory, for example, and is carried to the site. The shape and size of the precast mold 15 may be appropriately set according to the construction surface F. For example, the distance (thickness) from the inner surface to the outer surface of the precast mold 15 is from the viewpoint of workability and durability. What is necessary is just to be about 15 mm-50 mm. From the viewpoint of earthquake resistance and cost, the compressive strength of the cured product of the ultrahigh strength mortar constituting the precast mold 15 is preferably 80 to 200 N / mm ² , more preferably 100 to 200 N / mm ² , More preferably, it is 150-200 N / mm < ² >. As used herein, “compressive strength” refers to JIS A1108-2006 “Concrete” prepared by preparing a cylindrical specimen having a diameter of 5 cm and a height of 10 cm according to JIS A1132-2014 “How to make a specimen for concrete strength test”. Means a value measured on the age of 28 days according to the “compressive strength test method”.

  As an example of an ultra-high strength mortar constituting the precast mold 15, a mortar composition produced by adding fine aggregate to a paste composition containing cement, silica fume, water, water reducing agent, antifoaming agent and organic fiber Is mentioned. The precast form 15 may be manufactured at a factory or the like instead of at the site, and is therefore a thermosetting type that can obtain a predetermined strength by being cured by standard heat curing (for example, steam curing at about 90 ° C.). Although it may be present, the precast mold 15 does not require standard heat curing in order to obtain a composition and physical properties that are as similar as possible to a cured product 18 of ultra-high strength mortar that can be cured in situ to obtain a predetermined strength. A mold mortar composition may be employed.

Mineral composition of the cement is _{C 3} S content is 40.0 to 75.0 wt%, _{C 3} A content is less than 2.7 wt%. The amount of C ₃ S in the cement is preferably 45.0 to 73.0% by mass, more preferably 48.0 to 70.0% by mass, and still more preferably 50.0 to 68.0% by mass. The amount of C ₃ A is preferably less than 2.3% by mass, more preferably less than 2.1% by mass, and even more preferably less than 1.9% by mass. If the amount of C ₃ S is less than 40.0% by mass, the compressive strength tends to be low, and if it exceeds 75.0% by mass, the cement itself tends to be difficult to fire. Further, when the amount of C ₃ A is 2.7% by mass or more, the fluidity tends to be insufficient. In addition, the lower limit of the amount of C ₃ A is not particularly limited, but is about 0.1% by mass.

The C ₂ S amount of the cement is preferably 9.5 to 40.0% by mass, more preferably 10.0 to 35.0% by mass, and further preferably 12.0 to 30.0% by mass. . The amount of C ₄ AF is preferably 9.0 to 18.0% by mass, more preferably 10.0 to 15.0% by mass, and still more preferably 11.0 to 15.0% by mass. If it is the range of the mineral composition of such a cement, it will become easy to ensure the high fluidity | liquidity of a mortar composition, and the high compressive strength of the hardened | cured material.

  As for the cement particle size, the upper limit of the sieve residue of 45 μm is 25.0% by mass, preferably 20.0% by mass, more preferably 18.0% by mass, and further preferably 15.0% by mass. It is. The lower limit of the 45 μm sieve residue is 0.0% by mass, preferably 1.0% by mass, more preferably 2.0% by mass, and even more preferably 3.0% by mass. If the particle size of the cement is within this range, high compressive strength can be secured, and the slurry prepared using this cement has an appropriate viscosity, so that sufficient dispersibility can be obtained even if organic fibers described later are added. It can be secured.

The brane specific surface area of the cement is preferably 2500 to 4800 cm ² / g, more preferably 2800 to 4000 cm ² / g, still more preferably 3000 to 3600 cm ² / g, and particularly preferably 3200 to 3500 cm ² / g. When the brane specific surface area of the cement is less than 2500 cm ² / g, the strength of the mortar composition tends to be low, and when it exceeds 4800 cm ² / g, the fluidity at the low water cement ratio tends to be lowered.

  In manufacturing the cement, it is not necessary to perform an operation different from that of normal cement. The cement is changed according to the target mineral composition such as limestone, silica, slag, coal ash, construction generated soil, blast furnace dust, etc., fired in the actual kiln, gypsum added to the obtained clinker And can be manufactured by pulverizing to a predetermined particle size. A general NSP kiln, SP kiln, or the like can be used for the kiln to be fired, and a general pulverizer such as a ball mill can be used for pulverization. Moreover, 2 or more types of cement can also be mixed as needed.

The silica fume is a by-product obtained by collecting dust in exhaust gas generated when producing metal silicon, ferrosilicon, electrofused zirconia, etc., and the main component is an amorphous substance that dissolves in an alkaline solution. SiO ₂ . The average particle size of silica fume is preferably 0.05 to 2.0 μm, more preferably 0.10 to 1.5 μm, still more preferably 0.18 to 0.28 μm, and particularly preferably 0.20 to 0.28 μm. is there. By using such silica fume, it becomes easy to ensure high fluidity of the mortar composition and high compressive strength of the cured product.

  In the mortar composition, the silica fume is preferably 3 to 30% by mass, more preferably 5 to 20% by mass, still more preferably 10 to 18% by mass, and particularly preferably 10 to 10% by mass, based on the total amount of cement and silica fume. Contains 15% by mass. The silica fume is preferably contained in an amount of 3 to 30% by mass, more preferably 5 to 20% by mass, and further preferably 10 to 18% by mass based on the total amount of cement, silica fume and fine aggregate.

The amount of water added is preferably 10 to 25 parts by mass, more preferably 12 to 20 parts by mass, and still more preferably 13 to 18 parts by mass with respect to 100 parts by mass of the total amount of cement and silica fume. Unit water content of the mortar composition is preferably 180~280kg / ^{m 3,} more preferably 200~270kg / ^{m 3,} more preferably a 210~260kg / ^{m 3.}

  As the water reducing agent, lignin-based, naphthalenesulfonic acid-based, aminosulfonic acid-based, polycarboxylic acid-based water reducing agents, high-performance water reducing agents, high-performance AE water reducing agents, and the like can be used. From the viewpoint of ensuring fluidity at a low water cement ratio, it is preferable to use a polycarboxylic acid-based water reducing agent, a high-performance water reducing agent or a high-performance AE water reducing agent as the water reducing agent, and a polycarboxylic acid-based high-performance water reducing agent. It is more preferable to use The mortar composition is preferably 0.5 to 6.0 parts by mass, more preferably 1.0 to 4.0 parts by mass, and still more preferably 100 parts by mass of the total amount of cement and silica fume. It contains 1.8 to 3.0 parts by mass, particularly preferably 2.0 to 3.0 parts by mass.

  Examples of antifoaming agents include special nonionic compounding surfactants, polyalkylene derivatives, hydrophobic silica, and polyethers. In this case, the antifoaming agent is preferably 0.01 to 2.0 parts by weight, more preferably 0.02 to 1.5 parts by weight, and still more preferably 0.000 parts by weight with respect to 100 parts by weight of the total amount of cement and silica fume. Including 03 to 1.0 parts by mass.

The mortar composition (ultra-high strength mortar) for producing the precast mold 15 includes organic fibers as described above. Examples of the organic fiber include polypropylene fiber, polyethylene fiber, and vinylon fiber. The fineness of the organic fiber is preferably 1.0 to 20 dtex, more preferably 1.5 to 15 dtex, and still more preferably 2.0 to 4.0 dtex. The tensile strength of the organic fiber is preferably 1 to 6 cN / dtex, more preferably 1.5 to 5 cN / dtex, and still more preferably 2 to 4 cN / dtex. The elongation of the organic fiber is preferably 400% or less, more preferably 300% or less, and still more preferably 50 to 200%. The fiber length of the organic fiber is preferably 3 to 30 mm, more preferably 4 to 20 mm, and still more preferably 5 to 15 mm. The density of the organic fiber is preferably 0.8 to 1.5 g / cm ³ , more preferably 0.8 to 1.3 g / cm ³ , and still more preferably 0.85 to 0.95 g / cm ³ . The aspect ratio (fiber length / fiber diameter) of the organic fiber is preferably 200 to 900, more preferably 300 to 800, and still more preferably 400 to 700. By using the organic fiber satisfying these conditions, high fire resistance can be sufficiently secured in addition to high fluidity of the mortar composition and high toughness, high compressive strength and high tensile strength of the cured product. In addition, it is possible to suppress a defect with respect to some impact, such as a corner defect of the precast mold 15.

  The addition amount of the organic fiber is preferably 0.05 to 3% by volume, more preferably 0.1 to 2% by volume, and still more preferably 0.3 to 1% by volume with respect to the mortar composition not containing the organic fiber. %. If the amount of organic fiber added is less than 0.05% by volume, sufficient fire explosion resistance and impact resistance may not be obtained. If it exceeds 3% by volume, mixing into the mortar composition may be difficult. is there.

  The fine aggregate is not particularly limited, but river sand, land sand, sea sand, crushed sand, quartz sand, limestone fine aggregate, blast furnace slag fine aggregate, ferronickel slag fine aggregate, copper slag fine aggregate, electric furnace oxidation Slag fine aggregate etc. can be used. The fine aggregate preferably contains 15 to 85% by mass, more preferably 20 to 70% by mass, and further preferably 25 to 45% by mass of a particle group having a particle size of 0.15 mm or less. The fine aggregate preferably contains 3 to 20% by mass, more preferably 5 to 15% by mass of a particle group having a particle size of 0.075 mm or less.

  When the particle group having a particle size of 0.15 mm or less contained in the fine aggregate is less than 15% by mass, the viscosity of the mortar composition may be insufficient and material separation may occur. If the fine aggregate contains particles with a particle size of 0.15 mm or less exceeding 85% by mass, the amount of fine particles is too high and the viscosity becomes high, and it is necessary to increase the water-cement ratio in order to obtain a predetermined fluidity. Therefore, there is a risk of reducing the strength. In addition, although the preparation method of a fine particle part is not specifically limited, For example, it can prepare by mixing the fine aggregate from which 2 or more types of particle sizes differ.

The amount of fine aggregate in the mortar composition is preferably 400 to 1000 kg / m ³ , more preferably 430 to 850 kg / m ³ , and still more preferably 500 to 750 kg / m ³ .

The mortar composition may further contain an inorganic fine powder. As the inorganic fine powder, fine powder such as limestone powder, quartzite powder, crushed stone powder, and slag powder can be used. The inorganic fine powder is a fine powder obtained by pulverizing or classifying limestone powder, quartzite powder, crushed stone powder, slag powder or the like until the Blaine specific surface area is 2500 cm ² / g or more, and can improve the fluidity of the mortar composition. Be expected. Preferably Blaine specific surface area of the powder inorganic fine powder is 3000~5000cm ² / g, more preferably 3200~4500cm ² / g, more preferably in a 3400~4300cm ² / g, 3600~4300cm ² / G is particularly preferable.

  The mixture of fine aggregate and inorganic fine powder preferably contains 40 to 80% by mass, more preferably 45 to 80% by mass, and even more preferably 50 to 75% by mass of a particle group having a particle size of 0.15 mm or less. The mixture preferably contains 30 to 80% by mass, more preferably 35 to 70% by mass, and further preferably 40 to 65% by mass of a particle group having a particle size of 0.075 mm or less. If the particle group having a particle size of 0.075 mm or less contained in the inorganic fine powder is less than 30% by mass, the mortar composition may have insufficient viscosity and may cause material separation.

The mixture of fine aggregate and inorganic fine powder preferably contains 10 to 60 parts by mass of fine aggregate and 10 to 60 parts by mass of inorganic fine powder with respect to 100 parts by mass of the total amount of cement and silica fume. More preferably, the material contains 15-30 parts by mass, the inorganic fine powder 15-30 parts by mass, the fine aggregate 20-30 parts by mass, and the inorganic fine powder 20-30 parts by mass. The unit amount of the mixture of fine aggregate and inorganic fine powder per 1 m ^{3 of} the mortar composition is preferably 140 to 980 kg / m ³ , more preferably 300 to 900 kg / m ³ , still more preferably 600 to 900 kg / m. ³ .

  The mortar composition may contain at least one kind of expansion material, shrinkage reducing agent, setting accelerator, setting retarder, thickener, glass fiber, re-emulsified resin powder, polymer emulsion, and the like, as necessary. .

  The method for producing the mortar composition is not particularly limited, but some or all of materials other than water, water reducing agent and organic fiber are mixed in advance, and then water and water reducing agent are added and put in a mixer. It is preferable to manufacture by kneading. The fiber material is preferably added to the mixer after the mortar is produced and further kneaded. The mixer used for kneading the mortar composition is not particularly limited, and a mortar mixer, a biaxial forced kneading mixer, a pan-type mixer, a grout mixer, and the like can be used.

  The cured product 18 of ultra high strength mortar is filled in a space S formed by the construction surface F and the inner surface 15a of the precast mold 15 (see FIG. 2). The hardened | cured material 18 does not need to contain an organic fiber from a viewpoint of the outstanding fluidity | liquidity at the time of casting, and the high compressive strength after hardening. In addition, as above-mentioned, it is preferable that the mortar composition for the hardened | cured material 18 is a normal temperature curing type so that it does not need to perform a standard heat curing process on the spot.

The ultra-high strength mortar for the cured product 18 can be the same as the ultra-high strength mortar for producing the precast mold 15 except that it does not contain organic fibers. The compressive strength of the cured product 18 of ultra-high strength mortar is preferably 80 to 200 N / mm ² , more preferably 100 to 200 N / mm ² , and still more preferably 150 to 200 N from the viewpoint of earthquake resistance and cost. / Mm ² .

  As described above, by adopting the precast mold 15 having a high compressive strength and the cured product 18 of the super high strength mortar, a sufficiently excellent seismic strength can be achieved even if the thickness of the seismic reinforcing structure 10 is reduced. . Therefore, the thickness of the seismic reinforcement structure 10, in other words, the thickness of the precast mold 15 (the length from the facing surface 15c facing the construction surface F of the precast mold 15 to the outer surface 15b) is preferably 100 to 300 mm. More preferably, it can be 150-200 mm. Therefore, the seismic reinforcement structure 10 according to the present embodiment can be constructed even in a site where the work space or the installation space is relatively narrow, and can sufficiently improve the strength of the structure to be seismic reinforcement.

(Seismic reinforcement method)
Next, the seismic reinforcement construction method for constructing the seismic reinforcement structure 10 will be described. The seismic reinforcement method according to this embodiment includes the following steps.
-The process of providing the anchor 12 so that it may protrude from the construction surface F (process (A)).
-The process of arrange | positioning the reinforcing bar 13 and the shear reinforcement 14 on the construction surface F.
-The process of providing the several precast formwork 15 so that the construction surface F may be covered ((B) process).
A step of filling the space S with the ultra high strength mortar 18a (step (C)).
A step of curing the ultrahigh strength mortar 18a filled in the space S to obtain a cured product 18 (step (D)).

  FIG. 3A shows a state in which a plurality of anchors 12 are provided on the construction surface F and the reinforcing bars 13 and the shear reinforcing bars 14 are arranged. In order to fix the reinforcing bar 13 to the construction surface F, for example, an anchor (not shown) for fixing the reinforcing bars may be provided on the construction surface F.

  FIG. 3B shows a state in which a plurality of precast molds 15 are provided so as to cover the construction surface F. In order to fix the precast form 15 to the construction surface F, for example, a support or a separator (not shown) may be used. In order to prevent the ultra-high strength mortar 18a from leaking from the joint between the construction surface F and the opposing surface 15c of the precast mold 15 and between the adjacent precast molds 15, a sealing process is applied to these locations. Just give it. When the sealing process is performed firmly, the construction surface F and the facing surface 15c do not have to be in contact with each other, and there may be a gap between the construction surface F and the facing surface 15c.

  FIG. 3C schematically shows a state in which the operation of filling the space S with the ultra-high strength mortar 18a is performed. After filling with the ultra high strength mortar 18a, the super high strength mortar 18a becomes the cured product 18 preferably by curing for 3 to 7 days (typically about 3 days). The seismic reinforcement structure 10 is constructed on the construction surface F through these steps.

Second Embodiment
In the said 1st Embodiment, although the case where the reinforcing bar 13 and the shear reinforcement 14 were arrange | positioned in the space S was illustrated, the PC steel wire to which the prestress was given instead of this structure or with this structure was given. A configuration may be adopted in which a plurality of precast molds 15 are integrated. In this case, as shown in FIG. 4, each precast formwork is provided with a plurality of holes 15d formed by using a sheath tube 16 that communicates a plurality of precast molds 15 in the horizontal direction and the vertical direction. Prestress is applied through line 17. In addition, what is necessary is just to fill the inside of the sheath pipe | tube 16 with grout after installing the PC steel wire 17 and giving prestress to this.

<Third Embodiment>
In 1st Embodiment and 2nd Embodiment, although the case where the precast formwork 15 was used and the formwork was not assembled on the spot was illustrated, depending on the situation of the spot, the precast formwork 15 and the formwork assembled on the spot are used. You may use together. For example, as shown in FIG. 5, when the existing RC beam 3 further extends in a direction orthogonal to the existing RC column 1 and the existing RC beam 2, For example, the wooden formwork 15A may be assembled at the site, while the precast formwork 15 may be disposed on the outside thereof. By using together the precast formwork 15 and the formwork 15A assembled on site, it is possible to flexibly cope with the situation at the site.

  As shown in FIG. 5, a high-tension metal panel plate P1 is disposed at a position facing the upper surface 3a of the existing RC beam 3 having a rectangular cross-sectional shape, and the remaining three surfaces 3a and 3b of the existing RC beam 3 are disposed. , 3c is also provided with a high-tension metal panel plate P2 having three surfaces facing each other. The panel plate P1 and the panel plate P2 are fixed by bolts B and nuts N arranged so as to penetrate the existing slab 4. The end portions of the reinforcing bars 13 are welded to the panel plates P1 and P2, and the reinforcing bars 13 extend in the horizontal and vertical directions therefrom.

  The first to third embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. For example, in order to increase the strength of the seismic reinforcement structure, the following measures may be taken.

  As shown in FIG. 6, in addition to passing the steel wire 17 through the hole 15d of the precast mold 15, the shear reinforcement 14 may be appropriately disposed in the precast mold 15 itself. FIG. 6 is a cross-sectional view showing variations of these arrangements. Further, from the viewpoint of improving the integrity of adjacent precast molds 15, as shown in FIG. 7, one precast mold 15 is provided with a protrusion 15 e, and the other precast mold 15 is provided with a recess 15 f, You may make it these fit. Alternatively, as shown in FIG. 8, a reinforcing plate 19 and a wire mesh reinforcing bar (not shown) are embedded in a cured product 18 of ultra-high strength mortar so as to straddle the joints between adjacent precast molds 15. Also good. As the reinforcing plate 19, a metal plate such as an iron plate, a carbon fiber plate, or the like can be employed. As shown in FIG. 9, a plurality of recesses 15 g may be provided on the inner surface 15 a of the precast mold 15. By providing the recess 15g, further integration with the cured product 18 can be achieved, and the precast mold 15 can be reduced in weight.

  In the said embodiment, although the case where the earthquake-proof reinforcement was performed with respect to the existing RC beam and the existing RC column was illustrated, the structure of earthquake-proof reinforcement object is not limited to these, Even if it targets structures, such as a steel frame reinforced concrete structure Good. Depending on the shape and size of the object of seismic reinforcement, a plurality of precast molds may not be used, and the seismic reinforcement structure may be constructed with one precast mold.

DESCRIPTION OF SYMBOLS 1 ... Existing RC pillar (structure subject to seismic reinforcement), 2 ... Existing RC beam (structure subject to seismic reinforcement), 4 ... Existing slab, 10 ... Seismic reinforcement structure, 12 ... Anchor, 13 ... Rebar, 14 ... Shear reinforcement, 15 ... Precast formwork, 15A ... Formwork, 15a ... Inner surface, 15b ... Outer surface, 15c ... Opposite surface, 15d ... Hole, 17 ... Steel wire, 18 ... Hardened material of ultra high strength mortar, 19 ... Reinforcement Plate, F ... construction surface.

Claims (12)

An anchor provided so as to protrude from the construction surface of the structure subject to seismic reinforcement;
One or a plurality of precast molds made of a cured product of ultra-high strength mortar and provided to cover the construction surface;
A cured product of ultra-high strength mortar filled in the space formed by the construction surface and the inner surface of the precast formwork;
Seismic reinforcement structure comprising   The earthquake-proof reinforcement structure of Claim 1 further equipped with the reinforcing bar arrange | positioned in the space formed by the said construction surface and the inner surface of the said precast formwork.   The earthquake-proof reinforcement structure of Claim 1 or 2 whose distance from the said construction surface to the outer surface of the said precast formwork is 100-300 mm.   The seismic reinforcement structure according to any one of claims 1 to 3, wherein the cured product of the ultra-high-strength mortar constituting the precast formwork includes organic fibers.   The seismic reinforcement structure according to any one of claims 1 to 4, wherein the precast formwork has an embedded shear reinforcement. Comprising the plurality of precast forms,
The reinforcing plate or the wire netting rebar embedded in the cured product of the ultra-high strength mortar so as to straddle the joint between the adjacent precast formwork, 6. Seismic reinforcement structure. Comprising the plurality of precast forms,
The seismic reinforcement structure according to any one of claims 1 to 6, wherein the plurality of precast molds are integrated by a prestressed steel material. The ultra-high strength mortar is a mortar composition containing cement, silica fume, water, a water reducing agent, an antifoaming agent, and fine aggregate.
The cement, _{C 3} S contains less than 2.7% by weight 40.0 to 75.0% by weight and _{C 3} A and seismic reinforcement structure according to any one of claims 1 to 6. (A) a step of providing an anchor so as to protrude from the construction surface of the structure to be seismically reinforced;
(B) providing one or a plurality of precast molds made of a cured product of ultra-high strength mortar so as to cover the construction surface;
(C) filling the space formed by the construction surface and the inner surface of the precast formwork with ultrahigh strength mortar;
(D) curing the ultra-high strength mortar filled in the space;
Seismic reinforcement construction method equipped with.   The earthquake-proof reinforcement method of Claim 9 further equipped with the process of arrange | positioning a reinforcing bar on the said construction surface.   The seismic reinforcement method according to claim 9 or 10, further comprising a step of integrating the plurality of precast molds with a prestressed steel material.   The earthquake-proof reinforcement method as described in any one of Claims 9-11 further equipped with the process which assembles and installs a formwork in the location which does not arrange | position the said precast formwork in the said construction surface.

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