JP6004860B2 - Seismic reinforcement method and structure for spherical tank - Google Patents

Description

  The present invention relates to a seismic reinforcement method and a seismic reinforcement structure for a spherical tank for storing petroleum, liquefied gas, and the like.

Many of the current spherical tanks were constructed with the old earthquake resistance standards of about 1960 to 1970, and there is concern that they cannot withstand long-period and large-scale earthquakes such as the Great East Japan Earthquake. In particular, for braces spanned between struts that support spherical tanks, it was found that repeated loads greater than expected at the time of design were applied to the intersections of braces during relatively large earthquakes. It is desirable to apply a seismic reinforcement method.
In order to meet such a demand, Patent Document 1 below proposes an earthquake-proof reinforcement method in which the entire outer periphery of an existing brace is covered with a cylindrical brace using a half steel pipe, and the cylindrical brace is integrally formed by welding. .

JP 2011-184056 A

The technique proposed in Patent Document 1 has a problem that sufficient seismic reinforcement for the brace, in particular, a reduction in horizontal resistance against buckling when a compressive load is applied to the brace is not considered. Buckling usually occurs with a compressive axial force that is about 1/3 to 2/3 of the tensile strength, and the failure accompanied by buckling suddenly loses the axial force holding capacity and causes a decrease in the yield strength. Since the absorption capacity is low, damage to the entire structure is likely to be serious.
In addition, even if the damage is limited to the buckling of the brace, a large residual plastic deformation remains in the center of the brace, so it is necessary to replace all damaged braces after the earthquake. It was.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a seismic reinforcement method and a seismic reinforcement structure for a spherical tank capable of performing suitable reinforcement for braces, particularly suitable for buckling.

The present invention employs the following means in order to solve the above problems.
That is, the seismic reinforcement method for a spherical tank according to claim 1 is a spherical tank that seismically reinforces a cross brace composed of one brace and another brace crossing each other, which are spanned by a column supporting a spherical shell of the spherical tank. An anti-adhesion film forming step of forming an anti-adhesion film leaving an end in the length direction on the outer periphery of the cross brace, and an outer periphery of the cross brace between the cross brace. A steel pipe covering step in which a gap is formed between the vertical steel pipes by welding or bolting, and the adhesion preventing film formed on the outer periphery of the cross brace and the vertical split are covered with a vertical steel pipe with a gap therebetween. the concrete or mortar into the gap between the steel pipe joint portion is joined by welding or bolts of the steel pipe, such as concrete filling factory to fill the lower end of the steel pipe In the steel pipe covering step, in the steel pipe covering step, a steel pipe portion covering the one brace and a steel pipe portion covering the other brace are joined to each other at a portion corresponding to an intersecting portion of the brace. It is characterized by.

  Thereby, since the cross brace is restrained in bending deformation by the steel pipe and concrete or mortar, it is stably plasticized without buckling when subjected to a compressive load. In this way, the seismically reinforced cross brace can function as a vibration damper during an earthquake because the cross brace is stably plasticized, so that it is possible to realize seismic reinforcement of the spherical tank by a simple method. it can.

In the seismic reinforcement method for a spherical tank according to claim 3 , in the steel pipe coating step, the joining part of the steel pipe part covering the one brace and the steel pipe part covering the other brace is composed of four half-cut steel pipes. It is characterized by being constructed using two halved intersecting blocks in which the butt ends in the lengthwise direction of each other are joined in advance with the central openings directed in the same direction.

  A bisected cross block in which the butt ends in the length direction of each of the four half steel pipes are joined in advance in a state where their central openings are directed in the same direction is manufactured in advance in a factory or the like. In the field, the intersecting portion of the steel pipe can be easily manufactured by simply joining the butted portions of the half intersecting blocks with welding or bolts. Thereby, the work efficiency at the site can be improved and the construction time can be shortened by minimizing the site work.

The seismic reinforcement method for a spherical tank according to claim 4 is characterized in that, in the steel pipe covering step, a joining portion between a steel pipe portion covering the one brace and a steel pipe portion covering the other brace is a vertical portion covering the one brace. The split steel pipe part is constructed by using two vertically crossed steel pipe members in which a part of the vertically split steel pipe part covering the other braces is previously joined.

  Since it is constructed using two vertically-intersecting steel pipe members in which part of the vertically-separated steel pipe part covering the other brace is pre-joined to the vertically-separated steel pipe part covering one brace, at the site, By simply welding the butt portion, the crossing portion of the steel pipe can be manufactured. Thereby, the work efficiency at the site can be improved and the construction time can be shortened by minimizing the site work.

The method for seismic reinforcement of a spherical tank according to claim 2 , wherein the seismic reinforcement of a spherical tank is provided for seismic reinforcement of a cross brace composed of one brace and another brace crossing each other on a support supporting the spherical shell of the spherical tank. A method of reinforcing, wherein an adhesion preventing film forming step of forming an adhesion preventing film while leaving an end portion in a length direction on an outer periphery of the cross brace, and a gap between the outer periphery of the cross brace and the cross brace. A steel pipe covering step of opening and covering with a vertically divided steel pipe and joining the butted portions of the ends of the vertically divided steel pipes by welding or bolts; and the adhesion preventing film formed on the outer periphery of the cross brace and the vertically divided steel pipe A concrete filling process in which concrete or mortar is filled in a gap between a welded part or a steel pipe joined by bolts, and the steel pipe coating work In the steel pipe, the a steel pipe portion covering the steel pipe portion covering one brace the other brace is joined together at the portion corresponding to the intersection of the brace, in the anti-adhesion film forming step, the cross The adhesion preventing film is not formed at the intersection of the braces.

  The crossing portion of the cross brace is deformed very little in both cases of compression and tension as compared with the end side of the brace extending therefrom. Therefore, there is no need to prevent the axial force of the brace in this part from being transmitted to the steel pipe or concrete. The strength does not change whether or not an adhesion preventing film is formed at the intersecting portion of the intersecting brace. As a result, it is possible to reduce the cost and shorten the construction period without lowering the seismic strength by not forming the adhesion preventing film on the intersecting portion of the intersecting brace.

The spherical tank seismic reinforcement structure according to claim 5 is a spherical tank in which a cross brace composed of one brace and another brace crossing each other on a column supporting the spherical shell of the spherical tank is seismically reinforced. An anti-seismic reinforcing structure, wherein an adhesion preventing film is formed on the outer periphery of the cross brace leaving an end in the length direction, and the steel pipe covers the outer periphery of the cross brace with a gap between the cross brace. And a concrete or mortar filled in a gap between the adhesion preventing film formed on the outer periphery of the cross brace and the steel pipe, and the steel pipe includes a steel pipe portion covering the one brace and the other brace. a steel pipe portion covering is joined together at the portion corresponding to the intersection of the brace, the intersection of the cross-braces, characterized in that not the anti-adhesion film is formed
In this case, the same effect as that of the invention described in claim 2 can be obtained.

  According to the first aspect of the present invention, since the cross brace is plasticized stably, it functions as a vibration damper at the time of an earthquake, so that the seismic reinforcement of the spherical tank can be realized by a simple method.

In addition, since the cross braces are plasticized stably, the design seismic force of the entire tank can be reduced by functioning as a vibration damper during an earthquake. Accordingly, the design seismic force of the columns, foundations, piles, and joints other than the braces is reduced, and the seismic reinforcement of the other members becomes unnecessary only by the seismic reinforcement of the cross braces.
Furthermore, since the steel pipes covering the cross braces are joined to each other at the part corresponding to the cross part of the braces, that is, usually the central part in the longitudinal direction of the steel pipes, the outer circumference of the existing brace is individually connected with the steel pipe and concrete or mortar. Compared to the case of covering independently, high-strength seismic reinforcement can be performed.

According to the third aspect of the present invention, the work efficiency at the site can be improved and the construction time can be shortened by reducing the field work as much as possible.

According to the invention described in claim 4 , as in the invention described in claim 2, the work efficiency at the site can be improved and the construction time can be shortened by reducing the field work as much as possible.

According to invention of Claim 2 , cost reduction and shortening of a construction period can be aimed at, without reducing seismic strength.
According to the invention described in claim 5, the same effect as that of the invention described in claim 2 is obtained.

The structure of the spherical tank to which the seismic reinforcement method of the spherical tank of the embodiment of the present invention is applied is shown, (a) is a schematic side view showing the structure before the earthquake resistance reinforcement of the spherical tank, and (b) is the earthquake resistance reinforcement of the spherical tank. It is a schematic side view which shows the subsequent structure. It is an enlarged side view which shows the principal part of the seismic reinforcement structure of the spherical tank of embodiment of this invention. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is a side view explaining the adhesion prevention film formation process of the seismic reinforcement method of the spherical tank of the embodiment of the present invention. It is the side view which carried out the cross section partially explaining the steel pipe coating process of the seismic reinforcement method of the spherical tank of embodiment of this invention. It is a perspective view explaining the vertically divided steel pipe used in the steel pipe coating process of the seismic reinforcement method of the spherical tank of the embodiment of the present invention, and a half crossing block. It is a perspective view explaining the vertically divided steel pipe and the vertically divided steel pipe member used in the steel pipe covering step of the seismic reinforcing method for the spherical tank according to the embodiment of the present invention. It is a figure which shows the effect | action of the seismic reinforcement structure of the spherical tank of embodiment of this invention. It is a figure which shows the specific structure of the brace represented by FIG. 8, (a) is a side view of the existing brace, (b) is a side view of the prior art brace introduced by background art, (c) is this book It is a side view of the brace which concerns on invention. It is a figure which shows the characteristic of the brace used with the earthquake-proof reinforcement structure of the spherical tank of embodiment of this invention. It shows for the comparison with the seismic reinforcement structure of the spherical tank of this invention, Comprising: (a) is a compression tension characteristic of a general tie rod brace, (b) is a compression tension characteristic of a general steel pipe brace. . It is a figure which shows the relationship between an attenuation constant and a response magnification correction coefficient. It is a schematic side view which shows the other example of the seismic reinforcement structure of the spherical tank of this invention. The further another example of the seismic reinforcement structure of the spherical tank of this invention is shown, (a) is a schematic side view, (b) is sectional drawing which follows the (a) BB line.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1A and 1B show a structure of a spherical tank to which a seismic reinforcement method for a spherical tank according to an embodiment of the present invention is applied. FIG. 1A is a schematic side view showing a structure of a spherical tank before the earthquake resistance reinforcement, and FIG. It is a schematic side view which shows the structure after earthquake-proof reinforcement of. FIG. 2 is an enlarged side view showing the main part of the seismic reinforcement structure for the spherical tank according to the embodiment of the present invention, and FIG. 3 is a sectional view taken along the line III-III in FIG.

  As shown in FIG. 1A, a spherical tank 1 that stores oil and liquefied gas is supported inside a spherical tank 1 before seismic reinforcement by a column 3. The column 3 is erected vertically on the foundation 4. An X-shaped cross brace 5 that connects the upper end portion and the lower end portion of the support columns 3 is disposed between the adjacent support columns 3.

That is, the cross brace 5 includes one brace 5A that connects the upper end of one strut 3 and the lower end of another strut 3, and the lower end of the one strut 3 and the upper end of the other strut And the other brace 5B connecting the two. The cross braces 5 may or may not be joined at the center of each brace 5A, 5B. Further, when the braces 5A and 5B are not joined, they are disposed in the vicinity of the poles even if the central portions thereof are in contact or not in contact.
Further, the braces 5A and 5B are made of a rod-like or pipe-like steel material so as to withstand a tensile / compressive load. Further, the cross-sectional shape of the braces 5A and 5B is not limited to a circular shape or a ring shape, but may be a square shape or an elliptical shape, and may be an H shape or an I shape.

The seismic reinforcement according to the present invention is applied to such an existing spherical tank support structure. Seismic reinforcement is performed on the cross brace 5 as shown in FIG.
That is, the structure after the seismic reinforcement is performed is that the adhesion preventing film 10 formed by leaving the end of the length direction on the outer periphery of the cross brace 5 and the outer periphery of the cross brace 5 between the cross brace 5. The steel pipe 11 is covered with a gap, and the concrete 12 or mortar filled in the gap between the steel pipe 11 and the adhesion preventing film 10 formed on the outer periphery of the cross brace 5 is provided.

  The adhesion preventing film 10 is formed, for example, as an adhesion preventing material made of a viscoelastic material whose main component is a sheet-like rubber. Examples of materials other than the sheet-like rubber include viscoelastic plastic, natural rubber, polyisoprene. Polybutadiene, styrene butadiene rubber, ethylene propylene rubber, polychloroprene, polyisobutylene, asphalt, paint, and mixtures thereof can be used.

  The steel pipe 11 is not limited to a ring shape in cross section, and may have other shapes. For example, when the braces 5A and 5B have an H-shaped section or an I-shaped one, a square pipe may be used. In the steel pipe 11, a steel pipe portion 11A covering one brace 5A and a steel pipe portion 11B covering another brace 5B are joined to each other at a portion corresponding to an intersecting portion of the braces, for example, a central portion of the steel pipe portions. .

Next, the seismic reinforcement method for the spherical tank will be described.
4 and 5 are views for explaining the seismic reinforcement method for the spherical tank 1 according to the embodiment of the present invention. FIG. 4 is a side view for explaining an adhesion preventing film forming step, and FIG. 5 is a steel pipe covering step. It is the side view which cut a part to explain. FIG. 6 is a perspective view for explaining a longitudinally divided steel pipe and a half intersecting block used in the steel pipe covering step of the spherical tank seismic reinforcement method of the embodiment of the present invention, and FIG. 7 is a perspective view of the spherical tank of the embodiment of the present invention. It is a perspective view explaining the vertically split steel pipe and the vertically crossed steel pipe member used in the steel pipe covering step of the seismic reinforcement method.

In order to seismically reinforce the spherical tank 1, first, as shown in FIG. 4, the adhesion preventing film 10 is formed on the outer periphery of the intersecting brace 5 while leaving both ends of the braces 5 </ b> A and 5 </ b> B in the length direction. Film formation step). Specifically, when the material of the adhesion preventing film 10 is liquid, the materials are applied to the outer circumferences of the braces 5A and 5B, or when the material of the adhesion preventing film 10 is previously formed in a cloth shape. Forms the adhesion preventing film 10 by winding these materials around the outer periphery of the braces 5A and 5B.
The adhesion preventing film 10 is not formed on the intersecting portion 5C of the intersecting brace 5.

Next, the outer periphery of the cross brace 5 is covered with the vertically split steel pipe 13 with a gap S between the cross brace 5 and the abutting portion between the ends of the vertically split steel pipes 13, that is, FIGS. 6 and 7. As shown, the outer periphery of the intersection part of the cross brace 5 and the part where the adhesion preventing film 10 is formed is welded by the steel pipe 11 by welding the abutting part 13a at the circumferential end part and the abutting part 13b at the axial end part, respectively. Cover (steel pipe coating process).
In FIG. 6, the vertically divided steel pipe 2 is divided into two in the length direction of the brace. However, when the brace is long, the vertically divided steel pipe 2 is divided into three or more in the length direction. May be.

  Here, the portions corresponding to the intersecting portions of the braces of the steel pipe 11 are joined to each other at the central portions of both the steel pipe portions 11A and 11B as described above. And a method using a cross steel pipe member 16 shown in FIG. 7 can be considered.

The construction method shown in FIG. 6 is constructed by using two half-intersecting blocks 14A and 14B. In the half-intersecting block 14A (14B), the four half-steel pipes 15 are opened in the center of each other. The butt ends in the length direction of each other are joined with the portion 15a oriented in the same direction. By welding the butt portions of these half-split cross blocks 14A and 14B in the field, the joint portions of the central portions of both steel pipe portions 11A and 11B can be easily formed.
Then, one end portion 13 b in the axial direction of the longitudinally divided steel pipe 13 is welded to each of the four joining end portions of the cross block 14.

The construction method shown in FIG. 7 is constructed by using two vertically-intersecting steel pipe members 16A and 16B, and the vertically-intersecting steel pipe member 16A (16B) is attached to the half-separated steel pipe portion 17 covering one brace 5A. The intersection part 13c which is a part of the half steel pipe part 13 covering the other braces is cut off and joined in advance so as to have a predetermined intersection angle. By welding the butted portions of these vertically split steel pipe members 16A and 16B in the field, a steel pipe 11A covering one brace is formed, and at the same time, the central parts of both steel pipe parts 11A and 11B are joined together. Can be formed.
Then, one end portion 13 b in the axial direction of the vertically split steel pipe 13 is welded to the two joining end portions of the cross steel pipe member 16.

Next, concrete 12 or mortar is filled in the gap S between the adhesion preventing film 10 formed on the outer periphery of the intersecting brace 5 and the steel pipe 11 where the butted portion of the vertically split steel pipe is welded (concrete filling process). .
In this case, as a filling method of concrete or the like, concrete or the like may be injected in a state where a certain amount of pressure is applied from the lower end of the steel pipe 11. Moreover, the edge part of the steel pipe 11 is obstruct | occluded with a cover body as needed, and concrete etc. with which it filled are prevented from leaking out. The lid is removed when the concrete is cured.

Next, the operation of the seismic reinforcement structure for the spherical tank constructed as described above will be described.
FIG. 8 is a diagram showing the action of the seismic reinforcement structure of the spherical tank according to the embodiment of the present invention, in which the vertical axis represents compressive force and the horizontal axis represents axial contraction (strain). In this figure, (a) is the characteristic of the brace before the seismic reinforcement, (b) is the characteristic of the brace after the conventional seismic reinforcement described in the background art in which the outer periphery of the brace is covered with a steel pipe, and (c) is the present invention. The characteristics of the brace after seismic reinforcement are shown. The specific configuration of these braces is shown in FIG.

  As shown in FIG. 8A, the brace before the seismic reinforcement is buckled and broken with a relatively small compressive force when an axial compressive force is applied, as indicated by a in FIG. In addition, as shown in FIG. 8B, in the case of the brace after the conventional seismic reinforcement described in the background art, when an axial compressive force is applied, buckling occurs and breaks with a relatively high compressive force. Therefore, the plastic deformation region does not appear. On the other hand, as shown in FIG. 8 (c), in the brace after seismic reinforcement of the present invention, when an axial compressive force is applied, it is first elastically deformed, and the periphery is constrained by a steel pipe and concrete or mortar. Therefore, without causing buckling, compression plastic deformation that shrinks in the axial direction with a certain compressive force thereafter occurs. That is, it can be seen that in the brace after the seismic reinforcement of the present invention, the deformation in the direction perpendicular to the axial direction of the brace is restrained by the steel pipe 11 and the concrete 12, and the plasticity is stably plasticized without buckling. In addition, the cross section of the brace that has undergone compression plastic deformation due to the influence of the Poisson's ratio becomes slightly larger. It does not bear the axial force.

FIG. 10 is a diagram showing the restoring force characteristics of the seismically reinforced brace used in the seismic reinforcing structure of the spherical tank according to the embodiment of the present invention. The vertical axis represents axial force / yield axial force ratio, and the horizontal axis represents axial strain.
As can be seen from this figure, in the brace after seismic reinforcement of the present invention, there is no difference in rigidity and no difference in yield strength between the compression side and the tension side. As a result, a stable spindle-shaped hysteresis characteristic similar to that on the tension side can be obtained on the compression side, and this enables tensile yielding and compression without buckling even for earthquakes that generate unexpected axial forces. By repeatedly surrendering, it exhibits a so-called damping effect that absorbs seismic energy in a stable state.

  As described above, such a characteristic is that the deformation in the direction perpendicular to the axial direction of the brace is restrained by the steel pipe 11 and the concrete 12, and the buckling of the brace is prevented. This is because the prevention film 10 prevents the concrete from adhering to the brace, and the brace rigidity and tensile strength are the same as before the seismic reinforcement, and only the buckling strength is equal to the tensile strength.

FIG. 11 shows a comparison with the seismic reinforcement structure of the spherical tank of the present invention, where (a) is a compression-tensile characteristic of a general tie rod brace, and (b) is a compression of a general steel pipe brace. Tensile properties. In this figure, the upper side of the vertical axis is the tensile axial force, the lower side of the vertical axis is the compression axial force, the right side of the horizontal axis is the amount of deformation along the axis, and the left side of the horizontal axis is the deformation of the shrinkage along the axis. Each amount is taken.
In FIG. 11, it is shown that the larger the area surrounded by the compressive tensile properties, the higher the energy absorption performance against earthquakes, that is, the damping performance (damping constant). 11 (a) and 11 (b), it can be seen that the brace buckles early when compressed, and the energy absorption performance against the compressive force / tensile force repeatedly generated during an earthquake is low.
On the other hand, in the seismic reinforcing structure of the spherical tank of the present invention, as shown in FIG.

FIG. 12 shows the relationship between the attenuation constant and the response magnification correction coefficient. FIG. 12 shows that the response magnification correction coefficient is small because there is an effect of reducing the seismic force when the attenuation performance (attenuation constant) is high. That is, increasing the damping constant indicates that the seismic force of the entire building can be reduced.
Therefore, reducing the seismic force of the entire building leads to a reduction in the member size of not only the brace but also the entire structure such as the columns, foundations, piles, and joints, which is economically advantageous.

  Furthermore, even if a conventional spherical tank that did not satisfy the newly established earthquake resistance standards, the seismic load generated on structures other than braces can be reduced by applying the spherical tank seismic reinforcement method of the present invention. Is done. Specifically, increasing the damping constant of the entire structure not only reduces the design load of the brace, but also reduces the seismic force generated in the entire spherical tank structure. Seismic force generated in all members such as piles and joints can be reduced. Thereby, even if the existing spherical tank does not satisfy the seismic standard, the seismic standard can be satisfied by applying the present invention.

Conventional seismic reinforcement is generally reinforced by increasing the cross-section of the brace, and if the strength of the brace increases, a greater load is generated on the members other than the brace. Often reinforcement is required.
On the other hand, the present invention only prevents buckling without increasing the cross section of the conventional brace, so that the compressive strength increases to the same level as the tensile strength, but the tensile strength does not increase as shown in FIG. Energy absorption performance with a large history area can be obtained. This energy absorption performance can reduce the vibration of the earthquake, and the maximum axial force of the brace does not increase from before the reinforcement, so that the load that can be generated on the pillars, foundations, piles and joints other than the brace Therefore, members other than the brace need not be reinforced.

In addition, in the brace subjected to the seismic reinforcement method for the spherical tank of the present invention, the steel pipes 11A and 11B covering the existing brace are joined to each other at a portion corresponding to the intersecting portion of the brace 5, and therefore the steel pipe 11A. , 11B can be mutually enhanced. For this reason, compared with the case where the outer periphery of the existing brace is individually and independently covered with a steel pipe and concrete or mortar, high-strength seismic reinforcement can be performed.
In other words, when it is sufficient to obtain equivalent seismic strength, the steel pipe 11 covering the existing braces can be reduced in diameter and thinned.

  Furthermore, according to the seismic reinforcement method of the spherical tank of the present invention, in the steel pipe covering step, the joining portion of the steel pipe portion covering one brace and the steel pipe portion covering the other brace is divided into half-crossed blocks 14A and 14B. Or two longitudinally split steel pipe members 16A and 16B. Therefore, at the site, it is only necessary to weld the butt portions of the half intersecting blocks 14A and 14B, or The center joint portion of the steel pipe 11 can be manufactured simply by welding the butted portions of the split steel pipe members 16A and 16B. As a result, it is possible to improve on-site work efficiency and shorten construction time by minimizing on-site work.

The seismic reinforcement method or seismic reinforcement structure of the spherical tank of the present invention is not limited to the above-described embodiment described with reference to the drawings, and various modifications are conceivable within the technical scope thereof.
For example, as shown in FIG. 13, the object of seismic reinforcement is not limited to the cross brace, and the pillar 3 is prevented from buckling and being damaged by performing the same seismic reinforcement on the pillar 3 as well. You can also.
Further, in the above embodiment, the case where the seismic reinforcement is performed by the additional work for the support structure of the existing spherical tank has been described as an example. However, the present invention is not limited to this, and the present invention is not limited to this. It can also be applied to.
For example, as shown in FIG. 14, the present invention can also be applied to a case where a newly installed cross brace 21 in which flat plate braces 21A and 21B having a rectangular cross section are combined is subjected to earthquake resistance reinforcement. In this case, as the steel pipe 22, a steel pipe having a ring-shaped cross section is used in FIG. 14B, but is not limited to this, and the cross-sectional square shape or the rectangular cross-section shape is matched to the cross-sectional shape of the brace. A square steel pipe may be used.

Moreover, in the said embodiment, although the steel pipe 11 which covers the outer periphery of the cross brace 5 is constructed using the vertical halved steel pipe along the axis, it is not limited to this. It is also possible to construct using a three-part steel pipe.
Moreover, in the said embodiment, although the edge part of the cross brace 5 is not reinforced, the reinforcement for buckling prevention is performed only in the intermediate part of the cross brace 5, However, it is not restricted to this, As needed, a brace is You may reinforce the junction part to a support | pillar.

Moreover, as a representative of existing braces, there are a steel pipe brace and a tie rod brace, and the steel pipe brace welds the intersecting portion, but the intersecting portion of the tie rod brace is in contact with each other and is not welded. The present invention can be applied to either type.
In the case of a tie rod brace, an anti-adhesion material is installed around the same as a steel pipe brace, and it is restrained by a steel pipe and concrete or mortar to prevent buckling against compressive force. Large energy absorption performance can be obtained.

1 Spherical tank 2 Spherical shell 3 Prop 4 Foundation 5 Cross brace 5
5A One brace 5B Other brace 5C Cross brace crossing part 10 Adhesion prevention film 11 Steel pipe 11A Steel pipe part 11B covering one brace Steel pipe part 12 covering another brace Concrete or mortar 14 Cross steel blocks 14A, 14B Crossing block 16 Crossing steel pipe member 16A, 16B Vertically crossing steel pipe member S Clearance

Claims (5)

An anti-seismic reinforcement method for a spherical tank that seismically reinforces a cross brace composed of one brace crossing each other and another brace spanned on a support column that supports the spherical shell of the spherical tank,
An anti-adhesion film forming step of forming an anti-adhesion film leaving an end in the length direction on the outer periphery of the cross brace;
A steel pipe covering step of covering the outer periphery of the cross brace with a vertically split steel pipe with a gap between the cross braces and joining the butted portions of the ends of the vertically split steel pipes by welding or bolts;
Concrete in which concrete or mortar is filled from the lower end of the steel pipe into the gap between the adhesion preventing film formed on the outer periphery of the cross brace and the steel pipe in which the joining portion of the longitudinal steel pipe is joined by welding or bolts, etc. A filling process,
In the steel pipe covering step, the steel pipe is characterized in that a steel pipe portion covering the one brace and a steel pipe portion covering the other brace are joined to each other at a portion corresponding to an intersecting portion of the brace. Seismic reinforcement method for spherical tanks. An anti-seismic reinforcement method for a spherical tank that seismically reinforces a cross brace composed of one brace crossing each other and another brace spanned on a support column that supports the spherical shell of the spherical tank,
An anti-adhesion film forming step of forming an anti-adhesion film leaving an end in the length direction on the outer periphery of the cross brace;
A steel pipe covering step of covering the outer periphery of the cross brace with a vertically split steel pipe with a gap between the cross braces and joining the butted portions of the ends of the vertically split steel pipes by welding or bolts;
A step of filling concrete or mortar with concrete or mortar in the gap between the adhesion preventing film formed on the outer periphery of the cross brace and the steel pipe in which the joining portion of the vertically split steel pipe is joined by welding or bolts, and
In the steel pipe covering step, the steel pipe is joined to a steel pipe part covering the one brace and a steel pipe part covering the other brace at a part corresponding to an intersecting part of the brace,
An anti-seismic reinforcing method for a spherical tank , wherein, in the adhesion preventing film forming step, the adhesion preventing film is not formed at the intersection of the intersecting braces. In the steel pipe covering step, the joining portion of the steel pipe part covering the one brace and the steel pipe part covering the other brace is in a state in which the four half steel pipes face each other in the same direction. 3. The method for seismic reinforcement of a spherical tank according to claim 1 or 2 , wherein the construction is carried out using two halved intersection blocks obtained by joining the butt ends in the longitudinal direction in advance. In the steel pipe coating step, the joining portion of the steel pipe portion covering the one brace and the steel pipe portion covering the other brace is a vertically divided steel pipe portion covering the other brace on the vertically divided steel pipe portion covering the one brace. The method for seismic reinforcement of a spherical tank according to claim 1 or 2 , wherein the construction is performed using two vertically-intersecting steel pipe members, part of which is joined in advance. An anti-seismic reinforcement structure for a spherical tank in which a cross brace composed of one brace crossing each other and a brace crossing a support supporting the spherical shell of the spherical tank is seismically reinforced,
An adhesion preventing film formed on the outer periphery of the cross brace leaving an end in the length direction;
A steel pipe covering the outer periphery of the cross brace with a gap between the cross brace;
Concrete or mortar filled in a gap between the adhesion preventing film formed on the outer periphery of the cross brace and the steel pipe,
In the steel pipe, a steel pipe portion covering the one brace and a steel pipe portion covering the other brace are joined to each other at a portion corresponding to a crossing portion of the brace ,
An anti- seismic reinforcement structure for a spherical tank, wherein the adhesion preventing film is not formed at an intersection of the intersection brace .

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