JP7012934B2 - Construction method of leg seismic reinforcement - Google Patents

Description

The present invention is for reinforcing an existing steel structure having braces between columns, such as a support structure for a spherical tank for storing compressed gas, liquefied gas, etc., for the purpose of improving earthquake resistance. It relates to a method and members for its construction.

As shown in FIG. 8, the spherical shell 2 of the existing spherical tank 1 is supported by the support column 3 and the foundation 4, and the horizontal vibration of the spherical tank is suppressed between the support columns 3 to increase the support strength. Is provided with braces 5 crossed in an X shape.
Specifically, a steel pipe composed of an upper support 3a connected to the spherical shell 2 and a lower support 3b fixed to the foundation 4 is used for the support 3, and a steel bar tie rod brace or a steel pipe is used for the brace 5. A pipe brace made of wood is used, but the brace 5 in the illustrated example shows the case of the pipe brace 5a.
In a part of the existing spherical tank 1 having such a brace structure, a large-scale earthquake causes a case where the joint portion between the support column 3 and the place 5 buckles, and the strength of the portion is improved. There is a need to make it.
The structure having the brace 5 between the columns 3 is not limited to the spherical tank 1, and is widely used in steel structures.

As an invention of the prior art, for example, there is an invention of Patent Document 1 “Spherical tank support member reinforcing method and reinforcing support member”. The present invention discloses a method in which a hole for injecting a coagulant such as mortar is formed in the lower portion of an existing spherical tank column, and the mortar is filled and solidified in the column to reinforce it.

Further, there is an invention of Patent Document 2 “Method for reinforcing an existing spherical tank having a steel pipe brace”. The present invention discloses a method in which each column of a spherical tank is provided with an opening for injecting and filling mortar, and the mortar is partially filled and reinforced by using a filling inside the column and the brace. ing.

Furthermore, there is an invention of Patent Document 3 “Spherical tank support and / or brace reinforcement construction method” by the present applicant. In the present invention, the intermediate portion of the lower strut of the existing spherical tank is removed, and then a reinforcing disk is installed inside the hollow of the upper brace joint and the lower brace joint located above and below, and then a new reinforcing intermediate is installed. Disclosed is a method of reinforcing the support and / or brace of a spherical tank in which the support is installed.

Japanese Unexamined Patent Publication No. 53-24623 Japanese Unexamined Patent Publication No. 2016-216904 JP-A-2015-193397

In an existing steel structure having braces 5 between columns 3 such as a spherical tank 1, if there is no reinforcing member inside the hollow of the columns 3 at the brace 5 joint, the joint between the columns 3 and the brace 5 will be formed during an earthquake. A large compressive force was applied, and there was a risk that the support column 3 would be damaged.
As a method of seismic retrofitting of the legs of the support column 3 or the brace 5, there is a method of replacing the entire member thickness of the support column 3 or the brace 5 with a member having a larger diameter than before or a member having a larger diameter. However, in order to replace the support column 3 or the brace 5 with a new member, a large-scale construction work is required in which the existing support column 3 is cut while being supported by a solid support and a new support column 3 is installed, which requires a long construction period. There was a problem that a large construction cost was required.
There is also a method of making a hole in the support column, filling the entire inside of the steel pipe with fluidized mortar or the like, and solidifying the support column to increase the strength of the support column. However, from the results of the strength analysis, when there is a problem only in the strength of the joint portion between the support column 3 and the brace 5, there is a problem that the above-mentioned reinforcement method causes excessive reinforcement and excessive cost. In some cases, the load on the foundation 4 increases due to the increase in weight, and the foundation 4 needs to be further reinforced.
Therefore, it is possible to partially add a reinforcing member to the inside of the existing pillar 3 steel pipe having a brace 5 between the pillars 3 for seismic retrofitting, and it is easy to construct without using a large-scale support work. There has been a demand for a method of constructing seismic retrofitting of legs that can be used.

The invention of "Spherical tank support member reinforcement method and reinforcement support member" of Patent Document 1 is a method of seismically reinforcing the support of a spherical tank without partially cutting and removing the support of the existing spherical tank. It is a method of providing a hole in the column and filling the entire column with a coagulant such as mortar to retrofit the entire column, and does not relate to a method of partially reinforcing only the brace joint of the column.

The invention of Patent Document 2 "Method for reinforcing an existing spherical tank having a steel pipe brace" is a method for seismically reinforcing the support of a spherical tank without partially cutting and removing the support of the existing spherical tank. It is related to the method of partially filling and reinforcing the mortar while using the filling inside the column and the brace by providing an opening in the column, and the method of partially adding the reinforcing member to the inside of the steel pipe of the column. do not have.

The invention of Patent Document 3 "Reinforcing Construction Method for Spherical Tank Struts and / or Brace" relates to a method of seismically reinforcing by partially installing a reinforcing disk inside the hollow of the strut of the brace joint of the existing spherical tank. However, it relates to a reinforcement construction method in which an existing column is partially cut and removed and replaced with a new column. An insertion hole is provided in the column, a bag is inserted inside the column, and the bag is inserted. It is not related to the reinforcing method of filling the filler material.

The present invention has been made in view of the problems of the prior art as described above, and the purpose of the present invention is to provide rigidity and strength against horizontal vibration due to an earthquake in an existing steel structure having braces between columns. In order to improve durability and safety, it is possible to partially reinforce only the brace joint of the existing strut without cutting and removing the existing strut. Is to provide.

The method for constructing the leg seismic reinforcement according to the invention of claim 1 is the upper brace joint of the upper part of the support and the above-mentioned in the existing structure in which a plurality of adjacent columns are connected by braces intersecting each other in an X shape. It is a method of seismic reinforcement of the legs that reinforces each of the lower brace joints at the lower part of the column, and is an opening step that opens an insertion hole near the upper brace joint at the upper part of the column and the lower brace joint at the lower part of the column, and a bag. The insertion step of inserting the bag body formed into a shape into the hollow inside of the support column from the insertion hole, and the support member from the openings provided at the front side and the back side of the support column in the axial direction of the support column. The bag is inserted in the orthogonal direction, the bag is placed on the support member, and the bag is fixed inside the support column, and the filler injection hose attached to the hose injection port on the upper part of the bag is used to insert the bag. The inside of the body is filled with a filler, the bag is expanded so as to fit inside the support, and the filling step for closing the hose injection port and the insertion hole of the support are used. It is characterized by having a restoration step for attaching a closing member.

In the method of constructing the leg seismic reinforcement according to claim 2, the bag body is formed of a breathable net bag, a bag body support plate is attached to the tip end portion of the bag body, and the bag body is placed on the support member. However, the filler is filled in a fluid state when the inside of the bag is filled, and is cured inside the bag after the inside of the bag is filled .

The method for constructing leg seismic retrofitting according to claim 3 has a mechanism for releasing air inside the strut when the inside of the strut becomes high pressure in the restoration step of attaching the closing member to the insertion hole of the strut. It is characterized by mounting a member .

The method for performing seismic retrofitting of legs according to claim 4 is characterized in that the closing member has a thermal fuse that blows when the temperature reaches 100 ° C. or higher as a mechanism for discharging air inside the support column.

The method for constructing the leg seismic reinforcement according to the invention of claim 1 is the upper brace joint of the upper part of the support and the above-mentioned in the existing structure in which a plurality of adjacent columns are connected by braces intersecting each other in an X shape. It is a method of seismic reinforcement of the legs that reinforces each of the lower brace joints at the lower part of the column, and is an opening step that opens an insertion hole near the upper brace joint at the upper part of the column and the lower brace joint at the lower part of the column, and a bag. The insertion step of inserting the bag body formed into a shape into the hollow inside of the support column from the insertion hole, and the support member from the openings provided at the front side and the back side of the support column in the axial direction of the support column. The bag is inserted in the orthogonal direction, the bag is placed on the support member, and the bag is fixed inside the support column, and the filler injection hose attached to the hose injection port on the upper part of the bag is used to insert the bag. The inside of the body is filled with a filler, the bag is expanded so as to fit inside the support, and the filling step for closing the hose injection port and the insertion hole of the support are used. Since it has a recovery step to install the closing member,
It is a simple construction that cuts and separates a part of the support of the existing steel structure, opens an insertion hole in the existing support, inserts the bag body, and fills the bag body with the filler without installing a new support. It is possible to partially reinforce the stanchions.
Since it is a method of seismic reinforcement of the legs that partially opens the insertion holes in the columns, the openings are not crushed by the load of the superstructure such as the tank body, and the filling material is filled inside the bag body. By inflating the bag body and fitting it into the hollow inside of the support column, it is possible to safely reinforce the bag body. A bag filled with a filler is installed so that it fits inside the hollow interiors of the upper brace joints and lower brace joints located above and below the column, and efficiency is applied only to the parts where a large compressive force acts due to seismic motion. Can be reinforced. That is, it is possible to prevent damage to the lower strut when an existing steel structure such as a spherical tank vibrates horizontally due to an earthquake and a large compressive force is applied to the vicinity of the brace joint of the strut. In addition, since it is a construction method in which the bag body is inserted into the support column in a deflated state and then filled with a filler to reinforce it, the size of the insertion hole can be reduced, and it can be installed easily and safely. can.
The amount of welds can be reduced without cutting and separating part of the stanchions of the existing steel structure and without bolting, and the filler can be easily filled in place where reinforcement is needed inside the stanchions. It is possible to fix the welded bag body.

In the method of constructing the leg seismic reinforcement according to claim 2, the bag body is formed of a breathable net bag, a bag body support plate is attached to the tip end portion of the bag body, and the bag body is placed on the support member. However, since the filler is filled in a fluid state when the inside of the bag is filled, and is cured inside the bag after the inside of the bag is filled .
It is possible to develop compressive strength by expanding the bag body by the internal pressure at the time of filling the filler, bringing the bag body into close contact with the inner wall surface of the hollow part of the column, and naturally curing the filler inside. There is, and it is possible to surely reinforce the part where a large compressive force acts. Further, since a curable filler is used, it is easy to fill the inside of the bag with a hose at the time of filling, and since it naturally cures after filling the inside of the bag, it is possible to surely counteract the compressive force.

The method for constructing leg seismic retrofitting according to claim 3 has a mechanism for releasing air inside the column when the inside of the column becomes high pressure in the restoration step of attaching the closing member to the insertion hole of the column. Since the member is attached , the temperature of the air in the upper space blocked by the bag body filled with the filler inside the column rises due to a fire or the like, and when the pressure becomes high, the air can escape. It is possible to prevent the columns from being damaged by internal pressure, improving safety.

The method for constructing the leg seismic retrofit according to claim 4 has a thermal fuse that blows when the temperature reaches 100 ° C. or higher as a mechanism for discharging the air inside the column.
It is possible to easily install a thermal fuse without separately drilling holes in the columns.

It is a front view for demonstrating the structure of the spherical tank 1 constructed by the construction method of the leg seismic retrofit according to this invention. It is a front view which shows the opening step which opens the insertion hole 8 in the vicinity of the brace joint portion 3b1 of the support column 3 of the existing spherical tank 1. It is a perspective view which shows the insertion step which inserts a support member 9 into the hollow inside of a support | column 3. It is sectional drawing which shows the fixing step which puts the bag body 6 on the support member 9. It is sectional drawing which shows the filling step which fills the filler 12 in the bag body 6. It is sectional drawing which shows the state which took out the hose 15 from the bag body 6 after filling the bag body 6, and closed the filler injection port of the upper part of a bag body 6 with a fixing material 11. It is sectional drawing which shows the restoration step which attaches the closing member 14 to the insertion hole 8 of the support post 3. It is a front view which shows the spherical tank 1 provided with the conventional general brace 5.

An embodiment of the construction method of the leg seismic retrofitting according to the present invention will be described with reference to FIGS. 1 to 8. The present invention is not limited to the following embodiments. It goes without saying that the following components can be omitted or added, and embodiments such as the shape of the components can be changed without departing from the gist of the present invention. In addition, the figure shows an outline, and only a part is drawn and the detailed structure is omitted.

FIG. 1 is a front explanatory view showing an example of the structure of a spherical tank 1 constructed by the construction method of leg seismic retrofitting according to the present invention, in which a spherical shell 2 is supported on a foundation 4 by a plurality of columns 3. , It is a structure connected by a brace 5 provided so as to be inclined and crossed in an X shape between the columns 3.
The brace 5 in FIG. 1 shows the case of a pipe brace 5a of a cylindrical steel pipe.
The support column 3 has a structure including an upper support column 3a connected to the spherical shell 2 and a lower support column 3b to which the brace 5 is fixed.
Reference numeral 6 is a bag body 6 provided inside the cylindrical hollow of each of the upper part and the lower part of the support column 3. The bag body 6 is internally filled with a filler 12 to increase rigidity and to prevent damage due to compression of the cylindrical portion. It is a member.
The bag body 6 is made of a flexible and breathable material. As the bag body 6, for example, a mesh bag made of resin such as nylon, tetron, or vinylon, which has a minute air outlet, can be used. It is also possible to use a high-strength fiber sheet such as a carbon fiber sheet or an aramid fiber sheet.
Further, a bag body support plate 6a is attached to the tip end portion of the bag body 6 and placed on the support member 9 so as not to fall downward.
The filler 12 is a cured material that is fluidly filled when the inside of the bag 6 is filled and is cured inside the bag 6 after the inside of the bag 6 is filled. For example, mortar, concrete, fiber reinforced concrete mixed with reinforced fibers, and the like.

By using a hardening material for the filler 12, the bag 6 is expanded by the internal pressure at the time of filling the filler 12, the bag 6 is brought into close contact with the inner wall surface of the hollow portion of the support column 3, and the inside is filled. By naturally curing the material 12, the portion on which a large compressive force acts can be reliably reinforced.
Further, by using the curable filler 12, it is easy to fill the inside of the bag 6 with the hose 15 at the time of filling, and after filling the inside of the bag 6, it is naturally cured to surely counter the compressive force. It is possible.

2 to 7 are views showing an example of a step of inserting the bag body 6 and the filler 12 into the hollow inside the brace joint portion 3b1 of the support column 3 of the existing spherical tank 1 and restoring the support column 3. be. Although FIGS. 2 to 7 show a method of constructing the brace joint portion 3b1 at the upper part of the lower strut 3b, the same procedure is used for the brace joint portion 3b2 at the lower part of the lower strut 3b. FIG. 2 is a front view of the upper part of the upper column 3a and the lower column 3b, FIG. 3 is a perspective view showing the upper part of the lower column 3b partially cut out, and FIGS. It is a cross-sectional view.
FIG. 2 shows a step of opening an insertion hole 8 in the vicinity of the brace joint portion 3b1 of the support column 3. The insertion hole 8 of FIGS. 2 to 7 is not limited to the round hole of FIG. 2, and is opened in a shape that facilitates the insertion of the bag body 6 in the contracted state. The insertion hole 8 is opened by a drill, gas cutting, or the like.
The insertion hole 8 opened in the support column 3 has a size that allows the bag body 6 in a contracted state to be inserted.
Further, at the time of opening the insertion hole 8, an opening 10 for inserting a support member 9 for fixing the bag body 6 inside the support column 3 is provided in the support column 3 with a drill or the like.

FIG. 3 is a perspective view showing an insertion step of inserting the support member 9 into the hollow inside of the support column 3.
As shown in FIG. 3, two openings 10 are provided on the front side and the back side of the support column 3 so that the flat plate-shaped support member 9 can be inserted.
Various shapes can be adopted for the support member 9 and the opening 10.

FIG. 4 is a cross-sectional view showing a fixing step in which the bag body 6 is placed on the support member 9.
The hose 15 is inserted until the tip of the hose reaches the bottom surface of the bag body 6, and the bag body 6 is inserted into the insertion hole 8 opened in the support column 3.

FIG. 5 is a cross-sectional view showing a filling step of filling the inside of the bag body 6 with the filler 12.
Using a pump (not shown), a hose 15 is used to inject a fluid filler 12 into the bag 6, the bag 6 is inflated, and the internal pressure of the filler 12 causes the bag 6 to be placed on the support column 3. Adhere to the inner wall surface of the hollow part.

FIG. 6 is a cross-sectional view showing a state in which the bag body 6 is filled with the filler 12, the hose 15 is pulled out from the bag body 6, and the filler injection port on the upper portion of the bag body 6 is closed by the fixing material 11.
The hose 15 is pulled up in accordance with the injection of the filler 12, the hose 15 is pulled out, and then the filler injection port of the bag body 6 is closed by the fixing material 11.
In this case, the fixing material 11 is preferably one whose tightening can be adjusted by opening and closing a screw such as a hose band, and can close the filler injection port of the bag body 6.

In this way, the amount of welding can be reduced without cutting and separating a part of the column 3 of the existing steel structure and without bolting, and the internal reinforcement of the column 3 is required at a predetermined position. It is possible to easily fix the bag body 6 filled with the filler 12.

FIG. 7 is a cross-sectional view showing a restoration step in which the closing member 14 is attached to the insertion hole 8 of the support column 3. (A) is an example of filling the inside of the bag body 6 with the filler 12, and (b) is an example of filling the inside of the bag body 6 with air 13 instead of filling the inside of the bag body 6, and then filling the upper part of the bag body 6 with the filler 12 An example of another reinforcement method for filling is shown.
The closing member 14 is a plate material or the like whose length, width, and thickness are the same as the length, width, and depth of the insertion hole 8. After the insertion hole 8 and the closing member 14 are grooved for welding, the closing member 14 is fitted into the opening of the insertion hole 8 and the outer peripheral edge of the closing member 14 is welded to form a vertical insertion hole. It is preferable to close the opening of No. 8 and restore the support column 3 to its original state.
Alternatively, the closing member 14 may be used as a backing plate or the like, and may be fixed to the outer surface of the column 3 by welding so that the insertion hole 8 is completely closed with a dimension larger than the length and width of the insertion hole 8.
Further, when the insertion hole 8 is closed, the opening 10 is also closed.
In FIG. 7, the opening 10 is closed with the support member 9 left inside the support column 3, but the support member 9 may be removed from the support column 3 to close the opening portion 10.

For example, at the lower part of the lower support column 3b of the spherical tank 1, when the temperature of the air inside the support column 3 or the support column 3 rises due to a fire or the like and the inside of the support column 3 becomes high pressure due to the expansion of the air, the internal pressure thereof A thermal fuse is provided to blow out air when the temperature reaches a predetermined temperature or higher so that the support column 3 is not damaged. However, the upper space is provided by the bag body 6 filled with the filler 12 installed inside the support column 3. The part will be cut off, increasing the risk of damage to the upper part of the column 3 in the event of a fire.
Therefore, by attaching a closing member 14 having a mechanism for discharging the air inside the support column 3, the temperature of the air in the upper space blocked by the bag body 6 filled with the filler 12 inside the support column 3 becomes a fire. Since the air can be released when the pressure rises due to an internal pressure or the like and the pressure becomes high, it is possible to prevent the support column 3 from being damaged by the internal pressure, and the safety is improved.
As a mechanism for discharging the air inside the support column 3, when a temperature fuse 14a or the like that blows when the temperature reaches a predetermined temperature (for example, 100 ° C.) or higher is attached, it can be attached using the insertion hole 8 and the support column is separately provided. It can be easily installed without drilling holes in 3.
Further, the closing member 14 may be provided with a hole for releasing air, or the insertion hole 8 itself may be used as a mechanism for discharging the air inside the support column 3 without providing the closing member 14.

The method of performing seismic retrofitting of legs shown in the present invention has the following effects.
A part of the support column 3 of the existing steel structure is cut and separated, and the bag body 6 is inserted by opening an insertion hole 8 in the existing support column 3 without attaching a new support column 3, and the filler 12 is put in the bag body 6. It is possible to partially reinforce the column 3 with a simple filling operation.
Since the leg seismic reinforcement method is to partially open the insertion hole 8 in the support column 3, the opening is not crushed by the load of the superstructure such as the tank body, and the filling material is inside the bag body 6. It is possible to safely reinforce the bag body 6 by filling the bag body 6 and inflating the bag body 6 to fit the inside of the hollow of the support column 3.
A bag body 6 filled with a filler 12 is installed so as to fit into the hollow interiors of the upper brace joints 3b1 and the lower brace joints 3b2 located above and below the support column 3, and a large compressive force acts due to the seismic motion. Only the part to be reinforced can be efficiently reinforced. That is, it is possible to prevent damage to the lower column 3b when an existing steel structure such as a spherical tank 1 vibrates horizontally due to an earthquake and a large compressive force is applied to the vicinity of the brace joints 3b1 and 3b2 of the column 3. ..
Further, since the method is a method in which the bag body 6 is inserted into the support column 3 in a deflated state and then filled with the filler 12 to reinforce the bag body 6, the size of the insertion hole 8 can be reduced, and it is easy and safe. Can be constructed.

The construction method of leg seismic retrofitting according to the present invention can be applied not only to improve the seismic resistance of an existing spherical tank but also to improve the seismic resistance of a new spherical tank. In addition, it can be widely applied to supporting works and scaffolding of various structures having braces between columns.

1 Spherical tank
2 Spherical shell
3 props
3a Upper support
3b lower support
3b1 upper brace joint
3b2 lower brace joint
4 Basics
5 brace
5a pipe brace 6 bag
6a Bag body support plate
7 Gusset board
8 (Insert bag 6) Insertion hole 9 Support member 10 (Insert support member 9) Opening 11 Fixing material 12 Filling material 13 Air 14 Closing device 14a Temperature fuse 15 (for filling material 12 injection) Hose

Claims (4)

In the existing structure in which a plurality of adjacent columns are connected by braces intersecting each other in an X shape, the leg seismic reinforcement for reinforcing each of the upper brace joint at the upper part of the column and the lower brace joint at the lower part of the column. The method is an opening step for opening an insertion hole in the vicinity of the upper brace joint at the upper part of the support and the lower brace joint at the lower part of the support, and a bag-shaped body is hollowed out from the insertion hole to the support. The support member is inserted through the insertion step to be inserted inside and the openings provided at the front side and the back side of the support column in the direction orthogonal to the axial direction of the support column, and the bag body is placed on the support member. The filling material is filled inside the bag body from the fixing step of placing and fixing the inside of the support column and the filler injection hose attached to the hose injection port on the upper part of the bag body. A leg characterized by comprising a filling step of inflating the bag body so as to fit inside the support column and closing the hose injection port, and a restoration step of attaching a closing member to the insertion hole of the support column. Construction method of partial seismic reinforcement. The bag body is formed of a breathable net bag, a bag body support plate is attached to the tip of the bag body, and the bag body is placed on the support member, and the filler is inside the bag body. The method for applying seismic reinforcement of legs according to claim 1 , wherein the bag is filled in a fluid state at the time of filling and then hardened inside the bag after being filled inside the bag . The leg according to claim 1 , wherein in the restoration step of attaching the closing member to the insertion hole of the column, a closing member having a mechanism for releasing the air inside the column when the inside of the column becomes high pressure is attached . Construction method of seismic retrofitting. The method for applying seismic retrofitting of legs according to claim 3 , wherein the closing member has a thermal fuse that blows when the temperature reaches 100 ° C. or higher as a mechanism for discharging air inside the column.

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