JP6755655B2 - Seismic reinforcement method for existing tubular walls made of reinforced concrete - Google Patents

Description

The present invention relates to a seismic reinforcement method for an existing tubular wall made of reinforced concrete.

Walls made of reinforced concrete are often used as the walls of building structures. Various methods for seismically reinforcing such a reinforced concrete wall are generally used.

For example, Patent Document 1 discloses a structure 30 in which a concrete wall is seismically reinforced as shown in FIG. In the present structure 30, the existing concrete wall 31 has a filling layer 32 made of a filler such as mortar, a reinforcing steel plate 33 fixed to the concrete wall 31 with a horizontal anchor via the filling layer 32, and a reinforcing steel plate 33. It is reinforced by a structure of an exterior layer 34 formed by applying a finishing agent to the outside of the reinforcing steel plate 33.

Further, Non-Patent Document 1 describes "reinforcement by additional striking of an existing seismic wall" in which an existing reinforced concrete wall is seismically reinforced by additional striking of concrete. FIG. 4 shows this type of reinforcement method. FIG. 4A is a side sectional view of an existing reinforced concrete wall 40. In this example, the existing reinforced concrete wall 40 includes a concrete 41 and a grid-like bar arrangement 42 composed of vertical bars 42a and horizontal bars 42b.

First, as shown in FIG. 4B, the surface 43 of the existing reinforced concrete wall 40 is partially roughened. Further, a shear connector, an anchor 44, or the like is provided on the roughened surface 43.

After that, as shown in FIG. 4 (c), a new grid-like reinforcing bar 45 composed of vertical bars 45a and horizontal bars 45b was placed on the roughened surface 43 and bound to the anchor 44. After the formwork is installed so that the surface 43 and the formwork sandwich the reinforcing bars 45, concrete 46 is additionally struck between the surface 43 and the formwork.

Such reinforcement methods are often used for general building structures. The top, bottom, left, and right of the wall of a general building structure are surrounded by peripheral frames such as columns and beams. The new bar arrangement 45 installed at the portion where the concrete 46 is additionally struck is fixed to the peripheral frame via a post-construction anchor (not shown). As described above, the wall formed by the additional striking of the concrete 46 by the anchor 44, the post-construction anchor, and the like is integrated with the existing wall 40 and the peripheral frame.

The thickness of the reinforced concrete 46 is generally equal to or greater than the thickness of the existing reinforced concrete wall 40.

Japanese Unexamined Patent Publication No. 2001-329699

Japan Building Disaster Prevention Association "Earthquake-Resistant Repair Design Guidelines for Existing Reinforced Concrete Buildings / Explanation", 2001 Revised Edition, pp. 93-97

In the existing reinforced concrete wall reinforcement structures and methods described in Patent Document 1 and Non-Patent Document 1, the seismic strength is increased by the additional striking of the wall, while the weight of the wall is also increased by the additional striking. Only increase. In the case of a general building structure, the top, bottom, left and right of the wall are surrounded by peripheral frames as described above, and the increased weight is applied to the peripheral frame by fixing the reinforced part to the peripheral frame with an anchor or the like. It is also possible to bear the burden. Therefore, since the increase in seismic strength exceeds the weight of the wall, that is, the increase in required seismic strength, it is possible to sufficiently improve the seismic resistance even with the conventional structure and method as described above. However, for a wall such as a tubular wall 50 made of reinforced concrete having an internal space 51 as shown in FIG. 5 which is not surrounded by a peripheral frame such as a column or a beam and therefore only supports its own weight. Therefore, even if the conventional reinforcement by additional striking is applied, there is a problem that the increase in seismic strength and the weight of the wall, that is, the increase in required seismic strength cancel each other out, and as a result, it is difficult to obtain the effect of seismic reinforcement.

Further, in a wall such as the above-mentioned tubular wall 50, as described above, since it is not surrounded by peripheral frames such as columns and beams, the existing skeleton is provided with reinforcing bars added in the conventional reinforcement by additional striking. Cannot be effectively fixed. Even under such factors, it is difficult for the conventional structure and method to obtain the effect of seismic reinforcement on a wall such as the above-mentioned tubular wall 50.

Further, a wall such as the tubular wall 50 may be used in a nuclear power plant to store a nuclear reactor in an internal space 51 and prevent radiation emitted by the nuclear reactor from leaking to the outside. In order to further enhance the radiation shielding property of such a tubular wall 50, a roof slab made of reinforced concrete may be newly constructed on the upper part of the tubular wall 50 to block the internal space 51. The higher the height from the ground, the greater the acceleration of the seismic force acting on the structure. Therefore, when a roof slab is installed, the increased self-weight increases the seismic force acting on the legs of the tubular wall 50. .. When the seismic reinforcement associated with the installation of the roof slab is performed by the conventional method as described above, in addition to the weight of the roof slab, the weight of the reinforced portion of the wall is further added to the tubular wall 50. In addition, the center of gravity of the entire structure will be higher than before construction due to the installation of roof slabs and the reinforcement of additional walls. Due to these factors, there is an increased risk of damage or collapse of the tubular wall 50 or a fall due to the legs of the tubular wall 50 being lifted during an earthquake.

Further, when power generation equipment such as a nuclear reactor and a reactor containment vessel is installed in the internal space 51 of the tubular wall 50, the temperature of the internal space 51 becomes higher than that of the outside air. Due to the temperature difference between the inside and outside of the tubular wall 50, a temperature gradient is generated in the skeleton of the tubular wall 50, but the tubular wall 50 has a cross-sectional shape closed in the circumferential direction, so that deformation is restrained, resulting in Therefore, a temperature stress as shown in FIG. 6 is generated inside the frame of the tubular wall 50 according to the coefficient of linear expansion of concrete. According to FIG. 6, except for the vicinity of the legs of the tubular wall 50, compressive stress is applied to the inner surface side of the tubular wall 50 having a high temperature in both the circumferential direction and the radial direction of the tubular wall 50, and the outer surface side having a low temperature. A tensile stress is generated in. On the other hand, in the vicinity of the legs of the tubular wall 50, a tensile stress is generated on the inner surface side and a compressive stress is generated on the outer surface side with respect to the radial axis because the foundation is highly fixed. In the reinforcement method for a general building as described above, the seismic performance in a state where such temperature stress is constantly acting cannot be effectively improved.

An object of the present invention is to provide a method for reinforcing an existing tubular wall made of reinforced concrete, which can effectively enhance earthquake resistance.

The present invention employs the following means in order to solve the above problems. That is, the present invention is a method for reinforcing an existing tubular wall made of reinforced concrete having an internal space that is open upward, and the existing concrete on the outer surface of the existing tubular wall is deeper than the existing reinforcing bar. Chipping, removing the existing reinforcing bar, arranging a new outer reinforcing bar having a larger amount of reinforcing bar and / or higher strength than the existing reinforcing bar at the portion where the existing concrete is scraped, said. Provided are methods for reinforcing an existing tubular wall made of reinforced concrete, including placing new outer concrete on top of the new outer reinforcing bar to form a tubular wall reinforcing structure.
According to the above configuration, after the existing concrete on the outer surface of the existing tubular wall is scraped deeper than the existing reinforcing bar and the existing reinforcing bar is removed, the amount of reinforcing bar is larger and / or the strength is higher than that of the existing reinforcing bar. By arranging high, new outer rebar, the tubular wall can be reinforced while reducing the weight increase. This makes it possible to effectively prevent damage, collapse, and overturning of the tubular wall reinforcing structure during an earthquake, and to improve earthquake resistance.
Further, according to the above configuration, in the portion to be reinforced, the outer surface thereof is in a state where the concrete is scraped over the entire surface and the surface is roughened. That is, compared to the conventional method, the area of the roughened surface and the degree of unevenness are larger, and the adhesion strength of the joint surface is higher. Therefore, the number of anchors installed per unit area and the diameter of the anchors can be reduced. It is possible. As a result, the construction cost can be further reduced.

Chipping of the existing concrete and removal of the existing reinforcing bar were carried out over the entire circumference of the existing tubular wall, the new outer reinforcing bar included a horizontal bar, and the horizontal bar was the existing concrete in which the existing concrete was scraped. Reinforcing bars may be continuously arranged over the entire circumference of the tubular wall.
According to the above configuration, the lateral bars of the new outer reinforcing bars can be improved in seismic resistance without fixing to the existing skeleton, so that the seismic resistance can be effectively improved even without a peripheral frame. it can.
In addition, since the outside of the existing tubular wall is reinforced by arranging reinforcing bars that can withstand tensile stress over the entire circumference, the reinforcing bars are generated in a state where the temperature inside the tubular wall is higher than the temperature outside. It acts as a tag that restrains the expansion of the tubular wall in the circumferential direction due to the above-mentioned temperature stress, and thereby it is possible to prevent cracks in the concrete that occur on the outer surface of the tubular wall reinforcing structure.

The existing concrete is scraped and the existing reinforcing bar is removed from the upper outer surface of the existing tubular wall, and the new outer reinforcing bar includes the outer vertical bar and is below the existing tubular wall. A new inner vertical bar is arranged on the inner surface, and inner concrete is struck on it, and the lower end of the outer vertical bar and the upper end of the inner vertical bar overlap in the vertical direction. That may be further included.
According to the above configuration, since the lower end of the outer vertical streaks and the upper end of the inner vertical streaks are provided with a reinforcing section in which they overlap in the vertical direction, the outer shavings on the upper part of the tubular wall are provided. It is possible to continuously reinforce from the post-strike reinforcement portion to the inner additional striking reinforcement portion at the bottom of the tubular wall, and it is possible to effectively improve seismic resistance even without a peripheral frame.
Further, regarding the above-mentioned temperature stress generated when the temperature inside the tubular wall is higher than the outside temperature, the amount of reinforcing bars on the outer reinforcing bar on which the tensile stress acts is large on the upper side of the tubular wall, and / Alternatively, it is reinforced so as to have high strength, and further, in the lower side of the tubular wall, for example, in the vicinity of the legs, the inner concrete is additionally struck and the inner reinforcing bars are additionally arranged. As a result, at each part of the tubular wall, reinforcing bars effective for tensile resistance can be arranged on the tensile stress side of the bending moment acting, and reinforcement against temperature stress can be effectively performed.
In addition, the weight of the lower side of the tubular wall is increased and heavier due to the striking reinforcement, so that the weight of the upper side of the tubular wall is relatively lighter than the weight of the lower side, and the weight distribution between the upper side and the lower side is changed. Therefore, it is possible to further reduce the seismic response of the tubular wall reinforcing structure, increase the resistance to the lifting of the foundation and pulling it out from the foundation at the time of an earthquake, and prevent the fall. Furthermore, when the roof slab is installed on the upper part of the tubular wall, the shear force acting on the legs of the tubular wall reinforcement structure also increases due to the weight increase due to the installation of the roof slab. It is also possible to increase the horizontal shear strength of the legs of the wall reinforcement structure.

According to the present invention, it is possible to provide a method for reinforcing an existing tubular wall made of reinforced concrete, which can effectively enhance earthquake resistance.

In a preferred manner, it is possible to reduce the cost of construction.

It is a partially enlarged view which shows the reinforcement method of the existing tubular wall made of reinforced concrete shown as the embodiment of this invention. Of the reinforced structure reinforced by the method of reinforcing the existing tubular wall made of reinforced concrete shown as the embodiment of the present invention, (a) is a perspective view, and (b) is a part of FIG. 2 (a) omitted. ´Cross section. It is sectional drawing of the conventional reinforcement structure. It is a partially enlarged view which shows the conventional reinforcement method. It is a perspective view of the tubular wall to be reinforced in the method of reinforcing an existing tubular wall made of reinforced concrete shown as the embodiment of the present invention. It is a temperature stress distribution diagram of a tubular wall when a nuclear reactor is installed in the internal space.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 5 is a perspective view of the existing tubular wall 50 to be reinforced in the method for reinforcing the existing tubular wall made of reinforced concrete shown as the embodiment of the present invention.

The existing tubular wall 50 is a cylindrical reinforced concrete wall, and has an internal space 51 that is open upward. The existing tubular wall 50 includes an outer surface 52, which is a surface facing the outside air, and an inner surface 53, which is a surface facing the internal space 51. Such an existing tubular wall 50 may be used as a blocking wall for storing a nuclear reactor in an internal space 51 and blocking radiation from the nuclear reactor, for example, in a nuclear power plant. In this case, the existing tubular wall 50 has, for example, a height of about 50 m and a thickness of about 1 m.

Basically, such an existing tubular wall 50 is sufficient to have enough strength to support its own weight, and therefore, in many cases, it does not have a peripheral frame of a beam or a column.

FIG. 1A is a partially enlarged view of a cross section of the existing tubular wall 50.

The surface on the right side of the existing tubular wall 50 shown in FIG. 1A in the direction of the paper surface is the outer surface 52, and the surface on the left side is the inner surface 53. The existing tubular wall 50 includes an existing concrete 54 and an inner reinforcing bar 55 and an outer reinforcing bar 56 arranged inside the existing concrete 54. The inner reinforcing bar 55 is a lattice-shaped reinforcing bar composed of vertical reinforcing bars 55a and horizontal reinforcing bars 55b, and is installed closer to the inner surface 53 in the thickness direction of the existing tubular wall 50. The outer reinforcing bar 56 is a lattice-shaped reinforcing bar composed of vertical reinforcing bars 56a and horizontal reinforcing bars 56b, and is installed closer to the outer surface 52 in the thickness direction of the existing tubular wall 50.

Next, a method of constructing the reinforcing structure 1 of the existing tubular wall made of reinforced concrete will be described.

First, FIGS. 1 (b) and 1 (c) are drawn with respect to the upper side of the existing tubular wall 50, that is, the outer surface 52 in a range of more than half the height of the existing tubular wall 50 from the upper end of the existing tubular wall 50. It is used to carry out the post-scratch reinforcement described below.

In the chipping post-casting reinforcement, as shown in FIG. 1B, the existing concrete 54 on the outer surface 52 of the existing tubular wall 50 is chipped deeper than the existing outer reinforcing bar 56, and the outer reinforcing bar 56 is removed. The chipping of the existing concrete 54 and the removal of the existing outer reinforcing bar 56 are carried out over the entire circumference of the existing tubular wall 50. On the outer surface of the scraped surface 2 of the portion where the existing concrete 54 is scraped, unevenness is formed on the entire surface due to the scraping of the existing concrete 54.

The existing concrete 54 is deeper than the existing outer reinforcing bar 56, preferably less than half the thickness of the existing tubular wall 50.

Then, a post-construction anchor 3 is installed on the chipping surface 2 so that one end thereof is buried in the existing concrete 54 left by the chipping. The other end of the post-construction anchor 3 is short and vertically bent to form a hook 3a, and the post-installation anchor 3 is installed so that the hook 3a faces upward.

Further, as shown in FIG. 1 (c), a new outer reinforcing bar 4 having a grid pattern having vertical bars (outer vertical bars) 4a and horizontal bars 4b is arranged on the chipping surface 2. The new outer reinforcing bar 4 is a reinforcing bar having a larger amount of reinforcing bars and / or higher strength than the existing outer reinforcing bars 56 that have been removed. That is, the pitch between the reinforcing bars is narrower than that of the existing outer reinforcing bars 56, and the thickness of the reinforcing bars is thicker than that of the existing outer reinforcing bars 56. The vertical bars 4a of the new outer reinforcing bars 4 are arranged so as to extend above the existing tubular wall 50, that is, from the upper end of the existing tubular wall 50 to a range of more than half the height of the existing tubular wall 50. .. The horizontal reinforcing bars 4b of the new outer reinforcing bars 4 are arranged so as to be continuous on the chipping surface 2 over the entire circumference of the existing tubular wall 50. A new outer reinforcing bar 4 is arranged so that a part of the horizontal reinforcing bars 4b is placed on the post-construction anchor 3 and is in contact with the inner surface of the hook 3a, and the post-construction anchor 3 and the new outer side are arranged. Reinforcing bars 4 are tied together.

Then, after the formwork is installed so that the chipping surface 2 and the formwork sandwich the new outer reinforcing bar 4, a new outer concrete 5 is placed between the chipping surface 2 and the formwork. After placing the outer concrete 5, the outer concrete 5 is cured and demolded.

Next, additional striking reinforcement is performed on the lower side of the existing tubular wall 50, that is, the inner surface 53 in the range from the lower end of the existing tubular wall 50 to at least half the height of the existing tubular wall 50. That is, inside the lower side of the existing tubular wall 50, the inner surface 53 is formed without deep chipping of the existing concrete 54 and removal of the existing inner reinforcing bar 55 as shown in FIG. 1 (b). Add new reinforcing bars and concrete on top.

Specifically, first, a new grid-like inner vertical streak having vertical streaks and horizontal streaks is arranged on the inner surface 53. The vertical bars of the new inner reinforcing bars are arranged so as to extend from the lower side of the existing tubular wall 50, that is, from the lower end of the existing tubular wall 50 to a range of more than half the height of the existing tubular wall 50. .. As a result, the upper end of the vertical bar of the new inner reinforcing bar is higher than the lower end of the vertical bar 4a of the new outer reinforcing bar 4 installed on the upper side of the existing tubular wall 50, and the lower end and the upper end of each of them are higher. It overlaps in the vertical direction.

Then, after installing the formwork so as to surround the new inner reinforcing bar, a new inner concrete is placed between the inner surface 53 and the formwork, and the mold is removed after curing.

2A and 2B show a perspective view of an existing tubular wall 50 made of reinforced concrete in which the existing tubular wall 50 shown in FIG. 5 is reinforced by the method as described above. FIG. 2A is a cross-sectional view taken along the line AA ′ in which a part of FIG. 2A is omitted. FIG. 2A shows a building structure in which a roof slab 10 is erected and an internal space 51 is closed with respect to a reinforcing structure 1 in which an existing tubular wall 50 is reinforced by a method as described above.

The reinforcing structure 1 includes an existing portion 11, an outer chipping post-strike reinforcing portion 12, and an inner additional striking reinforcing portion 13.

The existing portion 11 is formed by removing a part of the structure of the existing tubular wall 50. Specifically, in the existing portion 11, the existing concrete 54 on the outer surface 52 is deeper than the existing outer reinforcing bar 56 on the upper side of the existing tubular wall 50, as shown in FIG. 1 (b), which is desirable. It is formed by chipping to a depth of less than half the thickness of the existing tubular wall 50 and removing the existing outer reinforcing bar 56.

The outer squeezing post-casting reinforcing portion 12 is formed on the upper side of the existing tubular wall 50 at a portion where the existing concrete 54 is squeezed and the existing outer reinforcing bar 56 is removed.

As shown in FIG. 1C, the outer chipping post-casting reinforcing portion 12 includes a new outer reinforcing bar 4 and a new outer concrete 5. As described above, the new outer reinforcing bar 4 is formed so that the amount of reinforcing bars is larger and / or the strength is higher than that of the existing outer reinforcing bars 56 that have been removed. That is, the pitch between the reinforcing bars is narrower than that of the existing outer reinforcing bars 56, and the thickness of the reinforcing bars is thicker than that of the existing outer reinforcing bars 56.

Chipping of the existing concrete 54 and removal of the existing outer reinforcing bar 56 on the upper side of the existing tubular wall 50 are carried out over the entire circumference of the existing tubular wall 50, and as a result, the outer shaving post-casting reinforcing portion 12 Is formed over the entire upper circumference of the reinforcing structure 1 as shown in FIG. 2A. The horizontal reinforcing bars 4b of the new outer reinforcing bars 4 in the outer reinforcing portion 12 are arranged so as to be continuous over the entire circumference of the existing portion 11 in which the existing concrete 54 has been chipped.

As shown in FIG. 1 (c), the new outer concrete 5 is cast so as to bury the new outer reinforcing bar 4.

Further, as shown in FIG. 1 (c), the post-construction anchor 3 is installed so as to fasten the existing portion 11 and the outer chipping post-strike reinforcing portion 12. The new outer reinforcing bar 4 is fixed to the existing portion 11 by being placed on the post-construction anchor 3 provided with the hook 3a and bound.

As shown in FIG. 2B, the inner additional striking reinforcing portion 13 is provided on the lower side of the existing portion 11, that is, in the range from the lower end of the existing portion 11 to at least half the height of the existing portion 11. It is formed on the inner surface of the existing tubular wall 50, that is, on the inner surface 53 of the existing tubular wall 50. The inner additional striking reinforcing portion 13 is different from the outer striking post-strike reinforcing portion 12, and with its installation, the existing concrete 54 is deeply chipped and formed on the inner surface 53 without removing the existing inner reinforcing bar 55. Has been done.

The inner reinforced portion 13 is provided with a new inner vertical bar (not shown) and a new inner concrete. The new inner rebar is arranged on the inner surface 53. The inner additional striking reinforcing portion 13 is manufactured by additional striking the inner concrete on the new inner reinforcing bar.

As shown in FIG. 2B, the lower end of the outer chipping post-strike reinforcing portion 12 is located at a height lower than the upper end of the inner additional striking reinforcing portion 13. As a result, the vertical reinforcing bars 4a of the new outer reinforcing bars 4 arranged in the outer squeezing post-strike reinforcing portion 12 and the vertical reinforcing bars of the new inner reinforcing bars arranged in the inner additional striking reinforcing portion 13 The streaks are installed so that their lower ends and upper ends overlap in the vertical direction.

The leg portion 13a, which is the lower end of the inner additional striking reinforcing portion 13, is formed in a tapered shape so that the wall thickness gradually increases from the upper side toward the lower side in contact with the foundation.

Next, the action and effect of the reinforcing structure 1 will be described.

In the reinforcing structure 1 as described above, as shown in FIG. 1, in the outer squeezing post-casting reinforcing portion 12 on the upper side of the reinforcing structure 1, the existing concrete 54 of the outer surface 52 of the existing tubular wall 50 is placed on the existing outer side. After the existing outer reinforcing bar 56 is removed by scraping deeper than the reinforcing bar 56, a new outer reinforcing bar 4 is arranged. The new outer reinforcing bar 4 has a larger amount of reinforcing bars and / or higher strength than the existing outer reinforcing bars 56.

In some cases, the thickness of the wall on the upper side of the reinforcing structure 1 after the chipping post-strike reinforcement is performed can be made thinner than the existing tubular wall 50. As a result, reinforcement that reduces the increase in weight becomes possible, and it is possible to effectively prevent breakage, collapse, and overturning of the tubular wall during an earthquake and improve earthquake resistance.

Further, in the inner additional striking reinforcing portion 13 on the lower side of the reinforcing structure 1, the lower inner surface 53 of the existing tubular wall 50 scoops concrete deeply like the outer striking post-casting reinforcing portion 12 and is existing. It is formed by installing a new inner vertical bar and a new inner concrete on the inner surface 53 without removing the reinforcing bar. In this way, the weight of the lower side of the reinforcing structure 1 is increased and becomes heavier by the striking reinforcement, so that the weight of the upper side of the reinforcing structure 1 is relatively lighter than the weight of the lower side, and the height of the center of gravity is lowered. Since the weight distribution on the upper and lower sides has been changed so as to be, the seismic response of the reinforcing structure 1 is further reduced, and the resistance to the floating of the foundation and the pulling out from the foundation during an earthquake is increased to prevent the fall. can do.

Further, the leg portion 13a, which is the lower end of the inner reinforced striking portion 13, is formed in a tapered shape so that the wall thickness gradually increases from the upper side toward the lower side in contact with the foundation. As a result, it is possible to more effectively prevent falls and improve earthquake resistance.

Further, as described above, the reinforcing structure 1 has a lower center of gravity than the existing tubular wall 50. Therefore, it is possible to install the roof slab 10 without impairing the earthquake resistance. Further, the horizontal shear rigidity of the inner reinforcement portion 13 is increased by the additional reinforcement, and in the seismic response analysis, the natural period of the entire structure in which the roof slab 10 is installed is reinforced without the roof slab 10. Seismic resistance can be further effectively improved by keeping the natural period of the existing tubular wall 50 equivalent to that of the previous existing tubular wall 50 and by setting the response displacement at the top of the reinforcing structure 1 to the same level as before the reinforcement.

Further, regarding the above-mentioned temperature stress that occurs when the temperature of the internal space 51 is higher than the outside temperature, in the above-mentioned reinforcing structure 1, on the upper side of the reinforcing structure 1, a new outer reinforcing bar 4 on which tensile stress acts. It is reinforced so that the amount of reinforcing bars is large and / or the strength is high, and further, on the lower side of the reinforcing structure 1, the inner concrete is additionally struck and the inner reinforcing bars are additionally arranged. As a result, at each portion of the reinforcing structure 1, reinforcing bars having an effect on tensile resistance can be arranged on the tensile stress side of the bending moment acting, and reinforcement against temperature stress can be effectively performed.

Further, in the outer striking post-casting reinforcing portion 12, the horizontal reinforcing bars 4b of the new outer reinforcing bars 4 are arranged so as to be continuous over the entire circumference of the existing portion 11 where the existing concrete has been chipped. As a result, the seismic resistance can be improved without fixing the horizontal reinforcing bar 4b of the new outer reinforcing bar 4 to the existing skeleton. Further, a new vertical reinforcing bar 4a of the outer reinforcing bar 4 arranged in the outer squeezing post-strike reinforcing portion 12, and a new vertical reinforcing bar of the inner reinforcing bar arranged in the inner additional striking reinforcing portion 13. Is installed so that the lower end and the upper end of each of them overlap in the vertical direction. Therefore, from the outer shaving post-striking reinforcing portion 12 on the upper side of the reinforcing structure 1, the inward additional striking on the lower side of the reinforcing structure 1 The reinforcing portion 13 can be continuously reinforced. Due to these factors, seismic resistance can be effectively improved even without a peripheral frame.

Further, the horizontal reinforcing bar 4b of the new outer reinforcing bar 4 acts as a tag that restrains the expansion of the reinforcing structure 1 in the circumferential direction due to the above-mentioned temperature stress, which occurs when the temperature of the internal space 51 is higher than the external temperature. However, this makes it possible to prevent cracks in the concrete that occur on the outer surface of the reinforcing structure 1.

Further, in order to thicken the lower wall of the existing tubular wall 50 by additional striking reinforcement, when a nuclear reactor is installed in the internal space 51, it is in the activity area of the worker who works outside the tubular wall. It is possible to further improve the shielding property of radiation near a certain surface of the earth.

Further, in the method shown in FIG. 4, the surface of the wall 40 is partially roughened, whereas according to the reinforcing structure 1 as described above, the outer shaving post-strike reinforcing portion 12 is used. The part to be reinforced is in a state where the concrete is scraped over the entire surface and the eyes are roughened. That is, as compared with the conventional method, the area of the roughened surface and the degree of unevenness are larger, and the adhesion strength of the joint surface is higher. Therefore, the number of anchors 3 installed per unit area on the chipping surface 2 and the anchors 3 are increased. It is possible to reduce the diameter of. As a result, the construction cost can be further reduced.

In the above embodiment, the horizontal reinforcing bars 4b of the new outer reinforcing bars 4 of the outer squeezing post-casting reinforcing portion 12 are arranged so as to be continuous over the entire circumference of the existing portion 11 where the existing concrete has been squeezed. Although it is reinforced, the horizontal reinforcing bar 4b does not have to be one continuous reinforcing bar over the entire circumference, and for example, a plurality of reinforcing bars may be joined by a lap joint or the like.

Further, in the above embodiment, the existing tubular wall 50 is cylindrical, but this shape may be a shape in which the cross-sectional shape in the horizontal direction is closed, and therefore, a quadrangle, a hexagon, an octagon, or the like. It may be a polygon.

Further, in the above embodiment, when the reinforcing structure 1 is constructed, the outer shaving post-strike reinforcing portion 12 is constructed in front of the inner reinforced striking reinforcing portion 13, but the present invention is not limited to this. For example, the inner additional striking reinforcing portion 13 may be constructed in front of the outer chipping post-strike reinforcing portion 12, or may be constructed at the same time.

The preferred embodiments of the present invention have been described in detail above, but those having ordinary knowledge in the art will understand that various modifications and equal embodiments are possible from now on. ..

Therefore, the scope of rights of the present invention is not limited to this, and various modifications and improvements of those skilled in the art using the basic concept of the present invention described in the claims are also included in the present invention.

1 Reinforced structure of existing tubular wall made of reinforced concrete 2 Chipping surface 3 Post-construction anchor 4 New outer reinforcing bar 4a Vertical bar (outer vertical bar)
4b Horizontal bar 5 New outer concrete 10 Roof slab 11 Existing part 12 Outer chipping post-casting reinforcement 13 Inner additional reinforcement 50 Existing tubular wall 51 Interior space 52 Exterior surface 53 Inner surface 54 Existing concrete 55 Existing inner reinforcing bar 56 Existing outer rebar

Claims (3)

This is a seismic reinforcement method for existing tubular walls made of reinforced concrete that have an internal space.
After the existing concrete on the outer surface of the existing tubular wall is scraped deeper than the existing reinforcing bar and the existing reinforcing bar is removed , the post-construction anchor is embedded in the existing concrete left by the scraping at one end. To install in
Arranging new outer reinforcing bars having a larger amount of reinforcing bars and / or higher strength than the existing reinforcing bars at the portion where the existing concrete is scraped.
Placing new outer concrete on the new outer rebar to form a tubular wall reinforcement structure,
Including
The chipping of the existing concrete and the removal of the existing reinforcing bar were carried out over the entire circumference of the existing tubular wall.
A method for seismic reinforcement of an existing tubular wall made of reinforced concrete, wherein the new outer reinforcing bar includes a horizontal reinforcing bar, and a part of the horizontal reinforcing bar is placed on the post-construction anchor . The other end of the post-construction anchor on the opposite side to the one end is bent upward to form a hook.
A part of the horizontal bar is placed on the existing concrete side of the hook.
The seismic reinforcement method for an existing tubular wall made of reinforced concrete according to claim 1, further comprising. The existing concrete was scraped and the existing reinforcing bar was removed from the upper outer surface of the existing tubular wall, and the new outer reinforcing bar included the outer vertical reinforcing bar.
A new inner vertical bar is arranged on the lower inner surface of the existing tubular wall, and inner concrete is additionally struck on the new inner vertical bar, so that the lower end of the outer vertical bar and the upper end of the inner vertical bar are formed. , Overlapping in the vertical direction,
The seismic reinforcement method for an existing tubular wall made of reinforced concrete according to claim 1 or 2 , further comprising.

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