JP7079726B2 - How to dismantle the support - Google Patents

Description

The present invention relates to a method of dismantling a support work.

When constructing a structure such as a pier in a water area, a temporary deadline such as a steel pipe sheet pile is placed in the shape of a cylinder to close the water area, and the ground inside it is excavated underwater to a predetermined depth and dried up. May be built.

A support work will be installed inside the well cylinder with the temporary deadline to resist the surrounding water pressure. Patent Document 1 describes an example in which a large opening is formed in a well tube by using a truss-shaped support, which facilitates the construction of piers and the like.

The support work is removed according to the construction of the structure, but since the support work is in a state where the axial force is acting from the steel pipe sheet pile, after unloading the axial force for work safety. It is desirable to remove the support work at.

As a method of unloading the axial force, for example, there is a method in which a jack is preliminarily charged in the support and the jack is contracted when the support is removed (for example, Patent Document 2).

Patent No. 6200550 Japanese Unexamined Patent Publication No. 2018-112035

However, there are cases where it is not possible to prepare the jack for support due to problems such as corrosion of the jack and the action of forces other than the axial force when the jack is installed. Especially in the above-mentioned construction in the water area, it is difficult to put a jack in the support work.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for dismantling a support work capable of unloading an axial force without using a jack.

In the present invention for solving the above-mentioned problems, in a support work, a part of a cross section of a horizontal steel material on which an axial force , which is an axial compressive force, acts is cut out and removed, and the steel material is buckled and deformed. After that, it is a dismantling method of the support work, which is characterized by removing the support work.

In the present invention, the steel material of the support work is cut out to cause a cross-sectional defect, thereby forcibly causing buckling of the steel material due to the axial force, thereby removing the axial force and removing the support work. Therefore, when the support is dismantled, it is not deformed unexpectedly due to the axial force, and the support can be safely dismantled. The notch of the steel material can be easily made by using a general-purpose gas cutting device, and it is not necessary to put a jack in the support work. It is also possible to visually check the unloading status in the buckled state.

It is desirable to measure the strain value of the steel material that is distorted by the axial force with a strain gauge attached in advance to the support work, and use the strain value to set the notch portion for the steel material to be buckled.
In the present invention, by measuring the strain of the steel material due to the axial force with a strain gauge and setting the notch portion using this, the notch portion of the steel material can be set according to the axial force actually acting. , It is possible to work while ensuring the safety of workers.

It is desirable that the notch portion is set so that the cross section of the steel material portion to be buckled and the length in the axial force acting direction satisfy the buckling formula. The buckling type is, for example, Euler's buckling type.
Specifically, the notch portion of the steel material is set so that the cross section and length of the steel material portion to be buckled satisfy a predetermined buckling formula. As a result, the steel portion can be suitably buckled. As the buckling type, for example, Euler's buckling type can be used.

It is desirable that the support work is provided inside the partition wall forming the closed area in the plane. The partition wall is, for example, a temporary deadline that closes the water area.
In the present invention, since a jack is not required for the support work, a large number of steel materials required for the support work in the partition wall can be easily installed. In addition, there is no problem in installing support works in the water area, and it is possible to significantly shorten the construction period as a whole.

For example, the steel material to be buckled is an abdomen having a vertical member, and the vertical member is buckled and deformed to the opposite side of the partition wall by the notch of the abdomen.
By buckling the abdomen as described above, the safety of the worker during buckling is improved.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method of dismantling a support work capable of unloading an axial force without using a jack.

The figure explaining the temporary deadline of a water area. The figure which shows the support work unit 10. The figure which shows the position of the strain meter 20. The figure which shows the steel material part a to buckle. The figure explaining the unloading of a box beam 16. The figure explaining the unloading of the flint 15. The figure explaining the unloading of the flint 15. The figure explaining the unloading of the abdomen 11. The figure explaining the dismantling of a support unit 10. The figure explaining the unloading of the flint 15.

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

In the method of dismantling a support according to an embodiment of the present invention, a temporary cutoff body such as a steel pipe sheet pile is used as a partition wall, a temporary cutoff is performed in a water area, a support work unit is installed inside the temporary cutoff body, and then a structure is formed inside the temporary cutoff body. An example of dismantling a support unit when constructing is described.

That is, in the present embodiment, as shown in FIG. 1A, a steel pipe sheet pile 4 which is a temporary cutoff body is driven into the ground 2 at the bottom of the water to form a closed region on a flat surface, and the water area to be constructed is closed. The internal ground 2 is excavated underwater. After that, the inside of the steel pipe sheet pile 4 is dried up, and a paving stone layer 71, a batholith concrete 72, and a top slab concrete 73 are constructed at the bottom of the excavation. The steel pipe sheet pile 4 is provided in the shape of a well as shown in FIG. 1 (b). FIG. 1B shows a horizontal cross section taken along the line AA of FIG. 1A.

As the support unit 10, the truss support 1 whose plane is shown in FIG. 1 (b) is used. The truss support 1 has a substantially square-shaped annular plane along the inner circumference of the well cylinder made of the steel pipe sheet pile 4, and a large-area opening is formed in the central portion.

The truss support 1 has a truss structure in which a vertical girder 12 and a horizontal girder 13 are combined in a grid pattern inside the abdomen 11 on the outer peripheral portion, and a diagonal member 14 is provided in the grid. Further, a box beam 16 is provided so as to bridge the inside of the opening, and flints 15 are also provided at the four corners of the opening. These members are made of steel, and for example, H-shaped steel is used for the raised portion 11, the girders 12, 13, the slanted member 14, and the flint 15. A square steel pipe is used for the box beam 16.

In the present embodiment, as shown in FIG. 2, a two-stage truss support 1 is vertically connected by a truss structure having a plurality of vertical members 17 and diagonal members 18, and is used as a support unit 10. The diagonal members 18 are arranged in a substantially X shape between adjacent vertical members 17. The support unit 10 is assembled and manufactured in advance on the ground, on the water, or the like. Shaped steel such as H-shaped steel is used for the vertical material 17 and the diagonal material 18.

As shown in FIG. 1A, in the present embodiment, the support units 10 are arranged in two upper and lower stages, and the upper and lower truss support units 1 of each support unit 10 are made of steel pipes by a support mechanism (not shown) such as a bracket. It is supported by the sheet pile 4 and the like. Further, between each truss support 1 and the steel pipe sheet pile 4, filling is performed by a filling material (not shown) such as concrete.

The lower support unit 10 is dismantled after the top slab concrete 73 is constructed. However, since pressure such as water pressure is transmitted from the steel pipe sheet pile 4 to the support unit 10, an axial force (particularly compressive force) acts on each steel material of the truss support 1, and if the truss is dismantled as it is, the truss There is a risk in terms of safety because the support work 1 is unexpectedly deformed due to the axial force.

Therefore, in the present embodiment, as shown in FIG. 3, a strain gauge 20 is attached to the truss support 1 in advance, and the strain value of the steel material strained by the axial force is measured. Then, by using this strain value, the notch portion of the steel material is set according to the axial force, and then a part of the cross section of the steel material of the truss support 1 is cut out and removed. As a result, the steel material is forcibly buckled and deformed to unload the axial force. The "cross section" means a cross section orthogonal to the axial force acting direction. In the present embodiment, the axial force acting direction is the longitudinal direction (axial direction) of the steel material, and the cross section is a cross section orthogonal to the longitudinal direction of the steel material.

As the strain meter 20, a measuring device provided with a strain gauge and a data logger can be used, but the strain meter 20 is not particularly limited as long as the strain of the steel material can be measured. The strain gauge 20 is cured by a tent or the like so that strain measurement can be reliably performed regardless of the weather.

In the present embodiment, the notch portion of the steel material (the notch portion b and the like in FIG. 5A, which will be described later) is set by using the strain value measured by each strain gauge 20 after the dry-up. However, since the strain value of the strain gauge 20 changes depending on the progress of buckling work, fluctuations in the tide level, etc., in the present embodiment, the measurement is continuously performed by the strain gauge 20 even after the dry-up to the casting of the top slab concrete 73. If necessary, the setting of the notch is changed according to the measurement result, and the real-time measurement result is reflected in the buckling work of the steel material.

In addition, in order to ensure the safety of buckling work, the steel part to be buckled is basically a steel material that avoids the vicinity of the joint point between steel materials that are subject to tension, bending, or shear so as not to cause sudden buckling. Set in the center of. FIG. 4a shows this steel material portion.

As can be seen from FIG. 4, not all steel materials are subject to buckling in this embodiment, and the steel material portion a to be buckled is, in principle, symmetrical with respect to the center point o of the truss support work 1. Set to position. However, as an exception, the box beam 16 is set at a position where the steel portion a to be buckled is near the end and is symmetrical with respect to the center line m of the plane of the truss support 1.

Further, in the present embodiment, the strain value is not measured for all the steel materials to be buckled, and the same axial force as the axial force acting on another steel material acts on the steel material to be buckled. If so, the strain value measured with another steel material may be used to set the notch portion of the steel material to be buckled.

For example, the strain gauge 20 is not attached to the box beam 16 on the left side of FIG. 4, but when the box beam 16 is buckled, it is measured by the strain gauge 20 attached to the box beam 16 on the right side of FIG. The strain value is used to set the notch. Similarly, the strain meter 20 is not attached to the firing 15 of FIG. 4, but when the firing 15 is buckled, the strain value measured by the strain meter 20 attached to the diagonal member 14 is used in the notch portion. Used for setting.

In the truss support work 1, since the axial force acting on the inner steel material is smaller than that of the outer steel material, buckling is performed in order from the inner steel material to the outer steel material. Therefore, in the present embodiment, the box beam 16, the flint 15, the cutting beams 12, 13 and the slanted lumber 14 are buckled in this order, and the abdominal raising 11 is buckled.

Further, regarding the axial force acting on the steel material of the truss support 1 above and below the lower support unit 10 after the top slab concrete 73 is placed, the deformation of the steel pipe sheet pile 4 is restrained by the top slab concrete 73. It is considered that the axial force acting on the steel material of the lower truss support 1 is smaller than that of the steel material of the upper truss support 1. Therefore, in the present embodiment, the buckling of the steel material of the lower truss support 1 is performed first, and the buckling of the steel material of the upper truss support 1 is performed later.

5 (a) and 5 (b) show the perspective view of the box beam 16 on the left side and the cross section of the steel material portion a to be buckled on the right side of the box beam 16. In the present embodiment, when the box beam 16 shown in FIG. 5A is buckled, the notch portion b shown by the dotted line is notched, and as shown in FIG. 5B, the length along the axial force acting direction is long. Over the range of L, the side surface of the steel material and a part of the upper surface and the lower surface are removed. Then, as shown in FIG. 5C, the remaining upper surface and lower surface of the steel material portion a are bent and deformed up and down due to the axial force acting on the steel material of the box beam 16.

The notch portion b is set according to the axial force acting on the steel material of the box beam 16. More specifically, the cross section of the steel material portion a and the length L in the axial force acting direction are set so as to satisfy a predetermined buckling formula with respect to the axial force.

In this embodiment, Euler's buckling formula represented by the following formula (1) or (2) is used as the buckling formula.
σ = n × π ² × E / {L ² / (I / A)}… (1)
P = n × π ² × E × I / L ² … (2)

In the equations (1) and (2), n is the terminal coefficient, P (N) is the axial force acting on the steel material, σ (N / mm ^ 2) is the stress degree of the steel material with respect to the axial force, and E (N / mm). ^ 2) is the Young's modulus determined by the material of the steel material, L (mm) is the length of the steel material part a to be buckled, I (mm ^ 4) is the cross-sectional secondary moment of the cross section of the steel material part a, A ( mm ^ 2) is the cross-sectional area of the cross section of the steel part a.

Here, both the axial force P and the stress degree σ can be obtained by using the strain value. Further, the terminal coefficient n is a value corresponding to the boundary condition at both ends of the steel material portion a at the time of buckling. If the steel material portion a buckles in the pin state at both ends, n = 1 and the steel material portion a is fixed at both ends. If buckling is performed in this state, n = 4. In this embodiment, for example, n = 4.

As described above, in the present embodiment, the strain value measured by the strain gauge 20 is used to obtain the axial force (or the degree of stress with respect to the axial force) of the steel material so that the above-mentioned buckling-type relationship of Euler is established. The cross section and length L of the steel material portion a to be buckled are set. For example, when the cross section of the steel material portion a is determined by the construction procedure, the site environment, the work content, etc., the length L of the steel material portion a is set so that the buckling formula of the Euler described above is established.

As a result, the buckling of the steel material portion a is gradually progressed ductilely, and the steel material can be safely buckled. When buckling does not proceed, the steel material may be further cut out as shown by the dotted line c in FIG. 5D, and the length L of the steel material portion a may be extended to promote buckling.

In the present embodiment, after buckling the box beam 16 of the lower truss support 1, both ends of the box beam 16 are cut, and the box beam 16 is lifted and removed by a crane or the like. After that, the box beam 16 of the upper truss support 1 is buckled, cut, and removed in the same manner.

In the present embodiment, the buckling of the firing 15 is continuously performed. 6 (a) and 6 (b) show the perspective view of the flint 15 on the left side and the cross section of the steel material portion a to be buckled on the flint 15 on the right side. The flint 15 is formed by arranging H-shaped steels in an I shape as shown in FIG. 6A. In this case, the flange of the H-shaped steel is a horizontal member arranged in the substantially horizontal direction, and the web is a vertical member arranged in the substantially vertical direction.

The buckling method of the flint 15 is basically the same as described above. That is, the notch portion b so that the cross section of the steel material portion a to be buckled and the length L in the axial force acting direction satisfy the buckling formula of Euler with respect to the axial force acting on the steel material of the flint 15. And cut out the steel material of flint 15. As described above, the axial force (or the degree of stress with respect to the axial force) acting on the steel material of the flint 15 can be obtained by using the strain value measured for the diagonal member 14.

In the present embodiment, when buckling the flint 15 shown in FIG. 6 (a), as shown in FIG. 6 (b), the upper and lower parts of the steel material are raised and lowered over a range of length L along the axial force acting direction. Cut out the flange and remove it. Then, as shown in FIG. 6 (c), the remaining web of the steel material portion a is bent and deformed laterally due to the axial force acting on the steel material of the flint 15. For the deformed web, the edge is cut by cutting the central part in the axial force acting direction in the vertical direction, but it may be left as it is.

It should be noted that the notch of the steel material can be improved in safety by gradually increasing the notch portion b so that the steel material portion a finally has the cross section and the length L set above. can.

For example, as shown in FIG. 7A, the outer portions of the upper and lower flanges are cut out first, and then the cuts d are made in the inner portions of the upper and lower flanges. After that, the inner portion of the flange is cut out as shown by the dotted line e so as to widen the width of the notch d in a triangular shape, and finally the inner portion is cut out in a quadrangular shape like the outer portion (see FIG. 6 (b)). ).

The outside refers to the steel pipe sheet pile 4 side, and corresponds to the upper right side in the left figure of FIG. 7A and the right side in the right figure. On the other hand, the inside means the opposite side, and corresponds to the lower left side in the left figure of FIG. 7 (a) and the left side in the right figure. This also applies to FIGS. 7 (b) and 8 (a) to 8 (d), which will be described later.

Further, the specific notch order is not particularly limited, and for example, as shown in FIG. 7B, the lower flange may be cut out first, and then the upper flange may be cut out.

After buckling the flint 15 of the lower truss support 1 in this way, both ends of the flint 15 are cut, and the flint 15 is lifted and removed by a crane or the like. After that, the buckling, cutting, and removal of the flint 15 of the upper truss support 1 are subsequently performed in the same manner.

In the present embodiment, after the box beam 16 and the flint 15 are removed, the cutting beams 12, 13 and the slant 14 of the truss support 1 are buckled. The same H-shaped steel as in FIG. 6A is also used for the girders 12, 13 and the slanted lumber 14, and buckling can be performed by the same method as described above.

The abdomen of the truss support 1 and the buckling of the abdomen 11 are performed last. 8 (a) to 8 (d) show the perspective view of the abdomen 11 on the left side and the cross section of the steel material portion a to buckle the abdomen 11 on the right side. The abdomen 11 is formed by arranging H-shaped steels in an H shape as shown in FIG. 8 (a). In this case, the flange of the H-shaped steel is a vertical member arranged in the substantially vertical direction, and the web is a horizontal member arranged in the substantially horizontal direction.

The buckling method of the abdomen 11 is basically the same as described above, and the cross section of the steel part a to be buckled and the length L in the axial force acting direction are the steel materials of the abdomen 11. The notch portion b is set so as to satisfy Euler's buckling formula with respect to the axial force acting on the abdomen, and the steel material of the abdomen 11 is cut out. Here, in consideration of safety in particular, the inner flange (hereinafter referred to as the inner flange) is bent and deformed inward, and this will be described below.

That is, here, first, as shown in FIGS. 8 (b) and 8 (c), the web of the steel material of the raised portion 11 and the outer flange (hereinafter referred to as the outer flange) are sequentially cut out and removed. The notch range of the web and the outer flange at this time is determined so that the web on both sides of the notch portion b and the outer flange do not collide with each other during buckling shown in FIG. 8 (e) described later.

Then, as shown in FIG. 8D, the connection portion of the web with the inner flange is cut out so as to be widened from the notch range of the web in the axial force acting direction, and the steel material portion a is provided within the range of the length L. Separate the inner flange of the web from the web. Then, as shown in FIG. 8 (e), the inner flange of the steel material portion a can be bent and deformed inward by the axial force acting on the steel material of the abdominal upset 11. For the deformed inner flange, the edge is cut by cutting the central portion in the axial force acting direction in the vertical direction, but the deformed inner flange may be left as it is.

On the other hand, although it is possible to bend and deform the web of the abdomen 11 in the vertical direction, in the support unit 10, there is no wide space between the webs of the abdomen 11 of the upper and lower truss support 1. Therefore, when the web is bent and deformed, there is a risk that it will be difficult for the worker who is between the webs of the upper and lower truss supporters 1 to rise up and 11 to retreat.

However, in the present embodiment, since the work shown in FIG. 8D can be performed by the worker who is upset and is inside the inner flange of 11, and there is a wide space inside the inner flange, the inner flange is used. Workers can easily evacuate when bending and deforming inward. Moreover, since the cross section of the flange is large, buckling does not proceed rapidly. Further, when buckling does not proceed at the stage where the steel material is cut out as shown in FIG. 8D, it is necessary to extend the length L by additional cutting, but in this embodiment as well, the steel material is cut without danger. It is possible to extend the length L.

After buckling the girders 12, 13, diagonal members 14, and abdomen 11 for the truss support 1 below the support unit 10 by the above procedure, the truss support 1 above is also cut in the same manner. Buckling of 12, 13, diagonal lumber 14, and abdomen 11 is performed. As a result, the cutting beams 12, 13, the diagonal members 14, and the abdominal raising 11 of the supporting support unit 10 are unloaded, and then, in the present embodiment, the steel materials (cutting) of the supporting support unit 10 except for the box beam 16 and the flint 15. The beams 12, 13, the slanted lumber 14, the raised abdomen 11, and the vertical lumber 17 and the slanted lumber 18) are cut and removed.

For cutting these steel materials, the cut steel material is either linear or truss-shaped (triangular) only in the plane or in the vertical plane so that the cut steel material can pass through the opening of the upper support unit 10 without any problem. It is performed so as to have a shape). Regarding the lower support unit 10, the steel material is separated into small pieces in this way, and the cut steel material is sequentially carried upward through the opening of the upper support unit 10 using a crane or the like.

When removing the steel material, in order to prevent the filling material from falling, the filling material is supported on the steel pipe sheet pile 4 side with a support material (not shown) using a steel rod and a turnbuckle, and the support unit 10 is removed. When is completed, remove the filling material.

FIG. 9A shows a state in which the lower support unit 10 is removed. In the present embodiment, a reinforced concrete pier 74 is constructed on the top slab concrete 73 as shown in FIG. 9B. The circumference of the pier 74 is backfilled with earth and sand. The pier 74 is constructed inside the opening of the upper support unit 10.

The upper support unit 10 is dismantled at an appropriate time after the lower support unit 10 is dismantled. Here, as shown in FIG. 9B, it is assumed that the inside of the well cylinder made of the steel pipe sheet pile 4 is backfilled with earth and sand and then dismantled.

The upper support unit 10 can be dismantled in the same manner as described above, and the box beam 16 and the flint 15 are buckled, cut, and removed, and then the remaining steel material is buckled, cut, and removed.

The specific buckling, cutting, and removal methods of each steel material may be the same as described above, but may be slightly different. For example, in the upper support unit 10, the steel material of the upper truss support 1 can be buckled first, and the steel material of the lower truss support 1 can be buckled afterwards. In addition, for example, for the H-section steel of flint 15, as shown in FIG. 10, it is also possible to first cut out the upper flange and then cut out the lower flange to buckle the web.

Further, the remaining steel materials (cutting beams 12, 13, diagonal members 14, abdominal raising 11, and the vertical members 17 and diagonal members 18) other than the box beam 16 and the flint 15 of the upper support unit 10 are cut. When removing it, unlike the previous one, there is no obstacle on the upper support unit 10, so it is possible to disassemble it. For example, it is possible to bring the cut steel material into a state having a truss shape both in the plane and in the vertical plane, and sequentially carry it upward by using a crane or the like.

By the above procedure, the upper and lower support units 10 in the steel pipe sheet pile 4 are removed as shown in FIG. 9 (c).

As described above, in the present embodiment, the steel material of the truss support 1 is cut out to cause a cross-sectional defect, thereby forcibly causing buckling of the steel material due to the axial force, thereby unloading the axial force and supporting the truss. Remove work 1. Therefore, when the truss support 1 is dismantled, it is not deformed unexpectedly due to the axial force, and the truss support 1 can be safely dismantled. The notch of the steel material can be easily made by using a general-purpose gas cutting device, and it is not necessary to put a jack in the truss support 1. It is also possible to visually check the unloading status in the buckled state.

Further, in the present embodiment, the strain of the steel material due to the axial force is measured by the strain gauge 20, and the notch portion b is set using this, so that the notch of the steel material is cut according to the axial force actually acting. Part b can be set, and it is possible to ensure the safety of workers and perform work.

Specifically, the notch portion b of the steel material is set so that the cross section and the length L of the steel material portion a to be buckled satisfy Euler's buckling formula (see equations (1) and (2)). do. Thereby, the steel material portion a can be suitably buckled.

Further, in the present embodiment, since the truss support 1 does not require a jack, a large number of steel materials required for the support in the steel pipe sheet pile 4 can be easily installed. In addition, there is no problem in installing the truss support work 1 even in the water area, and the construction period of the entire construction can be significantly shortened.

Further, in the present embodiment, by buckling the vertical member (inner flange) of the abdomen 11 inward by the procedure shown in FIG. 7, it is easy to secure the evacuation space for the worker, and the worker at the time of buckling Improves safety.

However, the present invention is not limited to this. For example, the steel pipe sheet pile 4 may form a closed region on a flat surface, and is not limited to a steel pipe sheet pile 4 that closes a water area in a well-shaped manner. For example, the water area may be closed in a cylindrical shape. In this case, the plane of the truss support 1 may be an annular plane having a substantially circumferential shape. Further, instead of the steel pipe sheet pile 4, a steel sheet pile or other member may be used as a temporary cutoff body.

Further, in the present embodiment, a support unit 10 in which two upper and lower truss support 1s are connected by a truss structure is used, but the present invention is not limited to this. For example, it is possible to connect three or more stages of truss support works 1 up and down by a truss structure, and dismantling can be performed by the same method as described above. In addition, one or a plurality of stages of truss support works 1 may be arranged independently (without being connected).

Further, although the present embodiment has described the case where the water area is closed by the steel pipe sheet pile 4, it can also be applied to the case where the construction area on land is closed by the steel pipe sheet pile 4 or other partition walls. Further, this embodiment can be applied to support works other than the above-mentioned truss support work 1, and the steel material used for the support work is not limited to H-shaped steel and square steel pipe.

Further, the buckling type for setting the cross section and the length L of the steel material portion a to be buckled is not limited to the buckling type of Euler shown in the formulas (1) and (2). Other known buckling formulas can also be used.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modified or modified examples within the scope of the technical idea disclosed in the present application, and these also naturally belong to the technical scope of the present invention. Understood.

1: Truss support 2: Ground 4: Steel pipe sheet pile 10: Support unit 11: Raised 12, 13: Cut beam 14, 18: Oblique material 15: Fire 16: Box beam 17: Vertical material 20: Strain meter a : Steel part (trying to buckle) b: Notch

Claims (7)

It is characterized by cutting out a part of the cross section of the horizontal steel material on which the axial force , which is the compressive force in the axial direction, acts, buckling and deforming the steel material, and then removing the support work. How to dismantle the support work. The first aspect of claim 1, wherein the strain value of the steel material distorted by the axial force is measured by a strain gauge preliminarily attached to the support work, and the notch portion is set for the steel material to be buckled by using the strain value. How to dismantle the support work. The method for dismantling a support according to claim 2, wherein the cutout portion is set so that the cross section of the steel material portion to be buckled and the length in the axial force acting direction satisfy the buckling formula. .. The method for dismantling a support work according to claim 3, wherein the buckling type is a buckling type of an oiler. The method for dismantling a support according to any one of claims 1 to 4, wherein the support is provided inside a partition wall forming a closed region in a plane. The method for dismantling a support work according to claim 5, wherein the partition wall is a temporary deadline that closes the water area. The steel material to be buckled is an uplifted material with a vertical member.
The method for dismantling a support work according to claim 5 or 6, wherein the vertical member is buckled and deformed to the opposite side of the partition wall by the notch of the abdomen.

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