JP3473009B2 - Seismic retrofit structure and construction method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a seismic strengthening structure for structures having piles and underground buried portions and a method for constructing the structure.

[0002]

2. Description of the Related Art Foundation types of structures are roughly classified into direct foundations, pile foundations, caisson foundations, etc., but when the ground strength near the surface is relatively small compared to the weight of the structure, In addition to adopting a pile foundation that drives piles up to a good-quality support layer, a structure is often provided with a certain underground buried portion.

Here, there are cases where the external seismic force used at the time of designing is insufficient and needs to be reviewed, but if there is no problem with the soundness of the pile, regardless of the problem with the pile itself. In many cases, the soundness of a structure can be maintained by seismically strengthening the structure, especially its underground buried part.
Then, at the time of earthquake-proof reinforcement, it is desirable to increase the strength without increasing the weight of the structure as much as possible, and for example, reinforcement by winding a carbon fiber sheet is effective.

[0004]

However, the above-mentioned seismic retrofitting method has a problem that the service of the facility must be interrupted during the construction period and that the seismic retrofitting itself is costly. .

On the other hand, with respect to the newly constructed structure, the above-mentioned problems in service of the facility do not occur, but it is still costly to increase the strength while suppressing the weight of the structure. New seismic retrofitting measures to replace seismic retrofitting were desired.

The present invention has been made in consideration of the above-mentioned circumstances, and provides a seismic retrofit structure for a structure which is excellent in economical efficiency without interrupting the service of the facility during the construction period, and a construction method thereof. The purpose is to do.

[0007]

In order to achieve the above object, the earthquake-proof reinforcing structure according to the present invention forms a hollow space between an underground buried portion of a structure and a surrounding ground, as described in claim 1. In addition, the hollow space is provided with a relative displacement absorption region filled with a predetermined cushioning material, and an elastic net is horizontally stretched in the hollow space. The elastic net is flooded during an earthquake. By supporting the buoyancy of the cushioning material by groundwater, the cushioning material is prevented from rising.

Further, in the seismic reinforcement structure according to the present invention, a tensile member is tied to the elastic net and the lower end of the tensile member is fixed in the ground.

Further, as described in claim 3, the earthquake-proof reinforcing structure according to the present invention forms a hollow space between the underground buried portion of the structure and the surrounding ground, and a predetermined cushioning material in the hollow space. A relative displacement absorbing region formed by filling the basement with a concavo-convex member on each of the opposing side walls of the underground buried portion and the earth retaining wall of the surrounding ground, and by engaging the concavo-convex member with the cushioning material, an earthquake It is intended to support the buoyancy of the cushioning material due to the sometimes infiltrated groundwater and prevent the cushioning material from rising. In addition, as described in claim 4, the method for constructing a seismic strengthening structure according to the present invention, after forming a hollow space by digging around the underground outer wall of the structure,
A method for constructing a seismic strengthening structure for filling a relative displacement absorption region by filling the hollow space with a cushioning material, wherein a stretchable net supporting the buoyancy of the cushioning material due to groundwater flooded during an earthquake is provided in the hollow space. It is stretched horizontally to prevent the cushioning material from floating.

In the seismic reinforcement structure and the construction method thereof according to the present invention, the relative displacement absorption area provided between the underground buried portion of the structure and the surrounding ground is the relative displacement between the underground buried portion and the surrounding ground during an earthquake. Absorb displacement. Therefore, the earthquake input from the side at the time of an earthquake becomes small,
As a result, the seismic energy input to the entire structure is reduced, and the earth pressure from the surrounding ground does not act on the underground buried portion of the structure, so the member force of the underground buried portion of the structure is greatly reduced. In addition, since the surrounding ground does not constrain the underground buried part of the structure, the natural period of the structure becomes longer, and it is possible to expect a seismic isolation effect, which deviates from the dominant period of seismic waves.

On the other hand, the cushioning material filled in the relative displacement absorption region acts as a damping member that absorbs the vibration energy of the structure at the time of an earthquake, and promptly converges the vibration of the structure. And since such a cushioning material is configured so as not to float up in the hollow space, there is no concern that it will float up due to the water in the hollow space, especially the groundwater that has infiltrated from the surrounding ground at the time of an earthquake, and the energy absorption function described above , It is surely demonstrated even in the event of an earthquake.

The cushioning material is mainly intended to be easy to handle because of its light weight and excellent in energy absorbing ability, and concretely, foam such as styrene foam and urethane foam, rubber, asphalt, silicone and the like can be considered.

The structure for preventing the cushioning material from being lifted up is arbitrary and various structures are possible.
A configuration in which an elastic net is stretched horizontally in the hollow space is possible. According to this structure, the buoyancy of the cushioning material is supported by the stretchable net, and the cushioning material is prevented from rising. The stretchable net may be stretched only on the top of the cushioning material, but if it is stretched in several steps, for example, the buoyancy of the cushioning material can be dispersed and supported. The reliability of time increases. The elastic net is
Since the structure expands and contracts due to the relative displacement during the earthquake between the underground buried part and the surrounding ground, there is no hindrance to the function as the relative displacement absorption region.

As another example of the structure for preventing the cushioning material from floating, a construction in which the cushioning material is fixed to an underground buried portion or the surrounding ground is conceivable. In addition, the method of fixing is adhesion with adhesive, fixing with anchor bolts,
It may be appropriately selected from friction or engagement with the surrounding ground or the underground buried portion of the structure.

The surrounding ground referred to in the present invention includes an earth retaining wall and a ground stabilization material constructed to prevent the ground from collapsing.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an earthquake-proof reinforcing structure and a method of constructing the same according to the present invention will be described below with reference to the accompanying drawings. It should be noted that parts and the like which are substantially the same as those of the conventional technique are designated by the same reference numerals and the description thereof is omitted.

FIG. 1 shows a seismic retrofit structure for a structure according to this embodiment. As can be seen in the figure, the structure for earthquake-proof reinforcement of the present embodiment forms a hollow space 8 such as a dry area between the underground buried portion 2 of the structure 1 and the surrounding ground 3, and The space is provided with a relative displacement absorbing region 4 which is filled with a predetermined buffer material 5 so as to absorb the relative displacement between the underground buried portion 2 and the surrounding ground 3 during an earthquake.

The cushioning material 5 is made of a foam material such as styrofoam or urethane foam which is easy to handle because of its light weight and has excellent energy absorbing ability. Such cushioning material 5
In order to enhance the energy absorption effect, it is preferable to use one having a size variation of, for example, several cm to several tens cm square.

On the other hand, stretchable nets 6a, 6b, 6c are horizontally stretched in the hollow space 8 of the relative displacement absorption region 4 to prevent the cushioning material 5 from rising. The elastic nets 6a, 6b, 6c may be connected to the underground buried portion 2 of the structure 1 and the side walls of the surrounding ground 3, but since they reliably support a large buoyancy acting in the vicinity of the middle, As shown in the figure, it is preferable that the tension member 7 is tied to each of the elastic nets 6a, 6b, 6c and the lower end thereof is fixed in the ground. Further, the size of the mesh of the elastic nets 6a, 6b, 6c is made sufficiently smaller than the size of the cushioning material 5.

In constructing the structure for earthquake-proof reinforcement of the structure according to the present embodiment, the hollow space 8 is formed by digging around the underground outer wall of the structure 1, and then the cushioning material 5 is provided in the hollow space.
To construct the relative displacement absorption region 4.

In the seismic reinforcement structure and the construction method thereof according to the present embodiment, the relative displacement absorption region 4 provided between the underground buried portion 2 of the structure 1 and the surrounding ground 3 is the underground buried portion 2 at the time of earthquake. And the relative displacement between the surrounding ground 3 is absorbed. Therefore, the earthquake input from the surrounding ground 3 on the side at the time of an earthquake becomes small, the seismic energy input to the entire structure 1 decreases correspondingly, and the surrounding ground 3
Since the earth pressure from no longer acts on the underground buried portion 2 of the structure 1, the member force of the underground buried portion 2 of the structure 1 is significantly reduced. In addition, the surrounding ground 3 is the underground buried portion 2 of the structure 1.
Therefore, the natural period of the structure 1 becomes longer and deviates from the dominant period of seismic waves, so to speak, a seismic isolation effect can be expected.

On the other hand, the cushioning material 5 filled in the relative displacement absorption region 4 acts as a damping member that absorbs the vibration energy of the structure 1 at the time of an earthquake, and promptly converges the shaking of the structure 1. The cushioning material 5 is prevented from rising in the hollow space by the elastic nets 6a, 6b, 6c.

As described above, according to the seismic strengthening structure and its construction method according to the present embodiment, the relative displacement between the underground buried portion 2 and the surrounding ground 3 at the time of an earthquake is absorbed by the relative displacement absorption region 4. The shock absorbing material 5 filled in the relative displacement absorption region 4 is intended to reduce the earthquake input by
Since the vibration energy of the structure 1 is absorbed by the structure 1, the seismic performance of the structure 1 can be improved without increasing the structural cross-section of the structure 1 itself or reinforcing the structure with a carbon fiber sheet or the like as in the conventional case. Can be improved.

Therefore, even if the design external force is reviewed, it can be easily dealt with whether it is a design surface or a construction surface, and the service of the structure 1 is suspended to construct the relative displacement absorption region 4. There is no need.

FIG. 2 is a graph showing the results of a dynamic response analysis carried out to confirm the working effects of the seismic reinforcement structure and its construction method according to the present embodiment, in which the relative deformation absorption region 4 is provided. Therefore, it can be seen that the horizontal earth pressure acting on the structure 1 during an earthquake can be significantly reduced.

Further, since the inside of the structure 1 is not reinforced against earthquakes, it is possible to reduce the cost required for the aseismic reinforcement, and especially when the structure 1 is a new structure, it can be carried out in parallel with the foundation work. Since the relative displacement absorption region 4 can be constructed by using the above, a significant cost reduction can be achieved.

Further, according to the seismic reinforcement structure and the construction method thereof according to the present embodiment, since the stretchable nets 6a, 6b, 6c are horizontally stretched in the hollow space 8 of the relative displacement absorption region 4, it is possible to prevent the occurrence of an earthquake. Even if groundwater infiltrates into the hollow space and the buffer material 5 receives buoyancy due to the groundwater, the buoyancy is supported by the elastic nets 6a, 6b, 6c,
Can be prevented from rising.

Therefore, there is no concern that the buffer material 5 will be lifted by the groundwater that has entered from the surrounding ground 3 at the time of an earthquake, and the above-mentioned energy absorbing function can be surely exhibited even at the time of an earthquake. The elastic nets 6a, 6b, 6
By properly setting the size of the mesh of c, it is possible to reuse the packaging waste material and the like having different sizes and shapes as the cushioning material 5.

Further, according to the seismic reinforcement structure and the construction method thereof according to the present embodiment, the elastic nets 6a, 6b, 6c are provided.
Since it is stretched in three stages, the buoyancy of the cushioning material 5 can be dispersedly supported, and the reliability at the time of an earthquake is enhanced.

In the present embodiment, the boundary between the relative displacement absorption region 4 and the surrounding ground 3 is set to the vertical plane, but it is not necessary to set it to the vertical plane. For example, as shown in FIG.
A hollow space 8 is formed between the slope 32 formed on the inner wall of the structure 1 and the underground buried portion 2 (underground outer wall) of the structure 1, and the hollow space is filled with a cushioning material 5, which is used as a relative displacement absorption region 33. Good.

Although not particularly mentioned in the present embodiment, when the surrounding ground is soft, there is a concern that the ground will collapse toward the relative displacement absorption region side during an earthquake. In such a case, as shown in FIG. 4 (a), an earth retaining wall 41 made of a continuous underground wall, a steel plate, a steel pipe sheet pile, or the like is provided on the peripheral ground 3 on the side facing the relative displacement absorption area 4, As shown in (b) of the figure, the ground stabilization material 42 made of shotcrete or the like is formed on the slope of the surrounding ground 3 on the side facing the relative displacement absorption area 33.
Should be provided.

According to this structure, not only the surrounding ground 3 is not collapsed to the relative displacement absorption area side at the time of an earthquake but also excessive earth pressure is prevented from being generated on the cushioning material 5, and the relative displacement as described above is prevented. By providing the displacement area, it is possible to reliably and long-term obtain the effect of reducing the earthquake input.

Further, in the present embodiment, the lifting of the cushioning material 5 is prevented by the elastic nets 6a, 6b, 6c, but instead of this construction, as shown in FIG. 5 (a),
Underground buried part 2 of structure 1 and earth retaining wall 41 of surrounding ground 3
The uneven member 51 may be attached to each of the opposing side walls of the above, and the uneven member and the cushioning member 52 may be engaged with each other to prevent floating due to groundwater. Further, as shown in FIG. 2B, an adhesive 53 is applied in advance to each of the opposing side walls of the underground buried portion 2 of the structure 1 and the earth retaining wall 41 of the surrounding ground 3, and then the cushioning material 52 is adhered. By doing so, floating up due to groundwater may be prevented. It is conceivable that the cushioning material 52 used in such a configuration is made of an in-situ foam type foam.

Further, as shown in FIG. 6, the cushioning material 62 filled in the hollow space 8 is fixed by a fixing member 61 such as a stud bolt, an anchor bolt, and a reinforcing bar to the underground buried portion 2 of the structure 1 and the surrounding ground 3. You may make it prevent from floating by groundwater by connecting with the earth retaining wall 41 of each. Buffer material 62 used in such a configuration
For example, a plate-shaped foam material used as an embankment material can be diverted.

[0035]

As described above, according to the seismic retrofit structure and the method for constructing the same according to the present invention, the structural cross section of the structure itself can be increased or seismic retrofitted with a carbon fiber sheet or the like as in the prior art. Without increasing the seismic performance of the structure. Therefore, even if the external design force is reviewed, it can be easily dealt with whether it is a design surface or a construction surface, and it is not necessary to suspend the service of the structure to construct the relative displacement absorption region. Further, even if groundwater is submerged in the hollow space at the time of an earthquake and the cushioning material receives buoyancy due to the groundwater, the buoyancy can be supported by the stretchable net and the cushioning material can be reliably prevented from rising. By properly setting the size of the mesh of the stretchable net, it is possible to reuse packaging waste materials having different sizes and shapes as cushioning materials. In addition, even if groundwater is flooded into the hollow space during an earthquake and the cushioning material receives buoyancy due to the groundwater, the cushioning material is attached to the surrounding ground or structure underground by using existing fixing means such as engagement, adhesion, and fixing. By fixing to the embedded portion, buoyancy acting on the cushioning material can be transmitted to the surrounding ground or the like, and the floating can be surely prevented.

[0036]

[0037]

[0038]

[Brief description of drawings]

1A and 1B are diagrams of a structure for earthquake-proof reinforcement of a structure according to the present embodiment, where FIG. 1A is a vertical sectional view and FIG. 1B is a horizontal sectional view taken along the line AA.

FIG. 2 is a graph showing a result of an analysis performed to confirm a function and effect of the seismic strengthening structure for a structure according to the present embodiment.

FIG. 3 is a vertical cross-sectional view of a seismic retrofit structure for a structure according to a modification.

FIG. 4 is a vertical cross-sectional view of a seismic strengthening structure for a structure according to another modification.

FIG. 5 is a detailed vertical sectional view of a seismic retrofit structure for a structure according to another modification.

FIG. 6 is a detailed vertical sectional view of a seismic retrofit structure for a structure according to another modification.

[Explanation of symbols]

1 structure 2 underground part 3 surrounding ground 4, 33 Relative displacement absorption area 5, 52, 62 cushioning material 6a, 6b, 6c Stretchable net 8 hollow space 41 Earth retaining wall 42 Ground stabilization material 51 Concavo-convex member (fixing means) 53 Adhesive (fixing means) 61 fixing member (fixing means)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-177061 (JP, A) JP-A-9-125414 (JP, A) JP-A-6-173288 (JP, A) JP-A-2- 140319 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) E02D 27/34 E02D 27/48

Claims (4)

(57) [Claims] 1. A relative displacement absorption region formed by forming a hollow space between an underground buried portion of a structure and a surrounding ground, and providing a relative displacement absorbing region in which the hollow space is filled with a predetermined cushioning material. The stretchable net is stretched horizontally,
The elastic net is adapted to support the buoyancy of the cushioning material due to groundwater inundated during an earthquake and prevent the cushioning material from being lifted up. 2. The seismic reinforcement structure according to claim 1, wherein a tensile member is tied to the elastic net, and a lower end of the tensile member is fixed in the ground. 3. A relative displacement absorption region formed by forming a hollow space between an underground buried portion of a structure and a surrounding ground, and providing a relative displacement absorbing region in which the hollow space is filled with a predetermined cushioning material. An uneven member is attached to each of the opposing side walls of the earth retaining wall of the peripheral ground, and the uneven member and the cushioning material are engaged with each other to support the buoyancy of the cushioning material due to the groundwater inundated during an earthquake. A seismic strengthening structure characterized by preventing it from rising. 4. A method for constructing a seismic retrofit structure in which a hollow space is formed by digging around the underground outer wall of a structure and then a cushioning material is filled in the hollow space to construct a relative displacement absorption region, which is a method for constructing a seismic reinforcement structure during an earthquake. A method for constructing a seismic strengthening structure, characterized in that an elastic net that supports the buoyancy of the cushioning material due to flooded groundwater is horizontally stretched in the hollow space to prevent the cushioning material from rising.