JP4138426B2 - Steel tower basic structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is applied to construction and the like for strengthening a steel tower corresponding to an increase in capacity of a power transmission tower, etc., and is formed in a plurality of corners of an existing steel tower bottom panel and embedded in a foundation. The present invention relates to a steel tower foundation structure for reinforcing a steel foundation rising member.
[0002]
[Prior art]
Usually, power is supplied from a power station in a remote area to a place where power is demanded by a transmission line extending between many steel towers. Although it is necessary to increase the capacity of the transmission line in response to the increase in power demand, in recent years it has become difficult to secure a site for the power transmission route due to the concentration of houses and various facilities in the vicinity of the power demand area. It has become to. Therefore, the increase in power in the vicinity of the power demand area is dealt with by increasing the capacity of existing transmission lines. In order to increase the capacity of the existing transmission lines, it is necessary to rebuild the power transmission tower. Conventionally, the rebuilding work has been carried out by a raising method, a wrapping method or the like.
[0003]
Such an increase in capacity of the existing tower may cause the foundation of the existing tower to be unable to bear the increased foundation stress, but in that case, concrete is cast around the existing foundation to surround the existing foundation. I was reinforcing my body. However, to reinforce such an existing foundation, it is necessary for the reinforcement to be able to exert its proof stress integrally with the existing foundation. After roughening, new concrete was fixed. Furthermore, it is necessary to expose the reinforcing bar embedded in the foundation body, and to join the reinforcing bar to the reinforcing bar by welding or the like, and to place new concrete. A lot of time was spent inviting high costs.
[0004]
Therefore, although not intended for rebuilding work, a technique for reducing the stress burden on the foundation pile by dispersing the foundation stress of the foundation body has been proposed (for example, see Patent Document 1 below). This proposed technique will be briefly described with reference to FIG. 5. When a pile foundation is used for the foundation of a tower-shaped steel structure, as described in paragraph 12 of the publication, a plurality of pile foundations 103 are square in plan view. Alternatively, the pile foundation 103 is driven into a circular shape, and the steel foundation 104 that connects all the pile foundations 103 is joined by welding, bolts, or the like, with the horizontal level of the top being matched. As described in the latter half of the paragraph 14 of the gazette, the foundation rising material 101 of the tower-shaped steel structure is directly welded to the steel material 104 that is secured to the horizontal and joined to the pile foundation 103. This facilitates the adjustment of the foundation rising material 101 after construction and facilitates the omission and adjustment of the work process to obtain the cost reduction merit.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-47669 (paragraph 12, paragraph 14 and FIGS. 2 and 3)
[0006]
[Problems to be solved by the invention]
However, in the conventional example, although the basic stress of the foundation rising material 101 of the tower-shaped steel structure can be properly distributed to the plurality of pile foundations 103 via the horizontal steel material 104, a plurality of The top of the pile foundation 103 must be driven into the ground in a square or circular shape with the horizontal level aligned, and the steel 104 formed integrally with the top of the pile foundation 103 at the horizontal level. The horizontal level must be maintained even after joining and welding with bolts, and the foundation rising material 101 must be arranged at the center position of the foundation pile. The positions of the steel material 104, the foundation rising material 101, and the pile foundation 103 It cannot be denied that it is difficult to maintain the relationship properly, and it is difficult to say that the position holding function is sufficient. Moreover, since the foundation stress applied to the foundation rising material 101 is transmitted to the plurality of pile foundations 103 through the steel material 104, the steel material 104 must be formed as a single unit according to the quantity of the pile foundation 103, and the shape is The steel material 104 is complicated and heavy, which increases the cost and makes it difficult to transport to the work site.
[0007]
Therefore, the present invention solves the problems of the conventional foundation structure, reduces the suspension work of the existing foundation concrete, eliminates the need for reinforcing bar joints, etc., and loads most foundation stresses on the new foundation. An object is to provide a foundation structure of a steel tower that can be reduced in weight and can be easily transported.
[0008]
[Means for Solving the Problems]
For this reason, the present invention reinforces the foundation rising member of the angle irons embedded in the foundation body and the columnar concrete placed on the foundation body and disposed at a plurality of corners of the lowermost panel of the existing tower. In the foundation structure of the steel tower, pile foundations were installed on both sides of the foundation on the plane perpendicular to the center line of the existing tower, and the upper ends of the column concrete on the foundation were removed and exposed. A reinforcing member is provided between the base rising member and the base rising member. Further, the present invention provides a gusset plate to be abutted and joined to each flange of the basic rising member at a joint portion of the reinforcing member with the basic rising member, and both ends of the reinforcing member are bonded to the bonding plate. It is characterized by being joined to the pile foundation by, for example. Further, the invention is characterized in that the reinforcing member is divided into two parts with a gusset plate portion as a boundary. Further, the present invention is characterized in that an L-shaped hardware is interposed on the joint surface between the gusset plate and the basic rising member, and these are used as means for solving the problems.
[0009]
Embodiment
Hereinafter, the basic structure of the steel tower of this invention is demonstrated based on drawing. 1 to 4 show one embodiment of the foundation structure of the steel tower of the present invention. FIG. 1 (A) is a plan view of the foundation part including the bottom panel of the existing steel tower, and FIG. 1 (B) is a diagram. 1 (A) is an enlarged view of a portion A, FIG. 2 is a front view of the basic structure shown in the arrow B of FIG. 1 (B), and FIG. 3 is a plan view of the arrow C in FIG. ) Is a front view of the test specimen of the foundation structure portion, and FIG. 4B is a bending moment diagram of the reinforcing member in FIG. As shown in FIG. 1, the basic structure of the present invention is a tower for reinforcing a foundation rising member 3 made of angle iron, which is disposed at a plurality of corners of an existing tower bottom panel 1 and embedded in a foundation 2. In the foundation structure, the surface of the foundation 2 is perpendicular to the center line L of the existing tower (in the illustrated example, the diagonal direction of the existing tower bottom panel 1; the line connecting the foundation rising member 3 and the center O of the tower). The pile foundations 5A and 5B are installed on both sides, and the reinforcing members 6 (between the pile foundations 5A and 5B and the foundation rising member 3 exposed by removing the upper end portion of the columnar concrete 4 on the foundation body 2 are provided. The illustrated example is characterized in that 6A and 6B) divided into two are provided.
[0010]
This will be described in detail below. As shown in FIG. 1 (A), the existing steel tower is composed of angle risers 3, 3... Of angle irons disposed in a plurality of corners of the lowermost panel 1 indicated by broken lines and embedded in the foundation 2. It is constructed to extend upward (the front side in the drawing). In the example shown in the figure, the existing tower bottom panel 1 is a square quadrangle, but this does not preclude a triangular or polygonal shape. In that case, the cross-sectional shape of the angle steel in the foundation rising member 3 corresponds to the shape of the existing tower bottom panel 1. For example, in the illustrated example, the angle is 90 °, but in the case of a triangular steel tower, the angle of the angle steel in the foundation rising member 3 is 60 °, and in the case of a hexagon, the angle is 120 °. Corresponding to
[0011]
About the foundation part located in each corner of the existing steel tower bottom panel 1, as shown in FIG. 1 (B), which is an enlarged view of part A in FIG. 1 (A), referring to FIG. The lower part of the foundation rising member 3 is embedded in the columnar concrete 4 installed on the concrete foundation 2. The column concrete 4 is on the side of the center O (FIG. 1 (A)) of the tower so as to match the inclination of the foundation rising member 3 inclined according to the cross-sectional area of the tower that gradually decreases toward the top of the tower. It is formed in an inclined quadrangular pyramid that faces the surface. As shown in FIG. 1, pile foundations 5 </ b> A and 5 </ b> B are provided on both sides of a concrete foundation 2 so as not to interfere with the existing foundation across the foundation 2 on both sides of the surface perpendicular to the center line L of the existing tower. It is cast and buried in the ground. Thereafter, as shown in FIG. 2, the upper end portion 4 </ b> A of the columnar concrete 4 is dismantled and removed at the work site by the hanging work.
[0012]
Next, the pile foundations 5A and 5B and the foundation rising member 3 exposed by removing the concrete portion are passed and connected by the first reinforcing member 6A and the second reinforcing member 6B. As shown in FIGS. 2 and 3, the reinforcing member 6 is made of a steel material such as an H-shaped steel in which a top plate 6U and a bottom plate 6D arranged in parallel are connected by a web plate 6M, and both ends thereof are web plates 6M. Is connected to the connection plates 9A and 9B fixed to the upper ends of the pile foundations 5A and 5B. Gusset plates 7 are installed at the joint portions of the reinforcing members 6A and 6B with the foundation rising member 3 so as to be adapted to the first flange 3A and the second flange 3B of the foundation rising member 3. In the present embodiment, the gusset plates each having a length larger than the vertical width of the reinforcing members are formed at the opposing ends of the reinforcing members 6A and 6B cut at 45 ° with respect to the H-shaped steel web plate 6M. 7A and 7B are fixed.
[0013]
Preferably, the components are reduced in weight for transportation, and as shown in FIG. 3, the reinforcing member 6 is divided into two parts with a gusset plate portion 7 as a boundary, and the first of the basic rising members 3 is formed. And the first and second gusset plates 7A and 7B attached and joined to the outside of the second flanges 3A and 3B, respectively, are installed at the opposing inner ends of the first and second reinforcing members 6A and 6B. is there. However, since the reinforcing member itself configured as an H-shaped steel beam member is lightweight, the reinforcing member 6 is formed as an integral structure extending between the pile foundations 5A and 5B, and corresponds to the foundation rising member 3 of the reinforcing member 6. A portion can be cut into an L shape, and a gusset plate 7 made of L-shaped steel can be fixed to the cut portion.
[0014]
The organic back-up of the top plate 6U, the web plate 6M, and the bottom plate 6D in the reinforcing member 6 that is an H-shaped steel ensures that the positions of the gusset plates 7A and 7B are maintained and their shapes are maintained. However, an L-shaped hardware 8 is attached to the inside of each flange 3A, 3B of the foundation rising member 3 in order to prevent flattening of the foundation rising member 3 made of angle steel. Further, triangular reinforcing plates 10, 10... Are interposed for reinforcing the position of the gusset plate 7 relative to the reinforcing member 6. Then, by integrally joining these L-shaped hardware 8, the foundation rising member 3 and the gusset plate 7 with bolts or the like penetrating the new pile foundation 5 and the reinforcing member 6 to the existing foundation rising member 3. Can be built.
[0015]
FIG. 4 is a test body and a test result diagram of the stress test of the foundation structure portion. In the foundation structure having the above-described configuration, the existing foundation rising member 3 is separated from the existing foundation body 2, and the newly installed reinforcing member is completely removed. This is a test of whether or not stress can be borne. As shown in FIG. 4A, the foundation rising member 3 is separated from the existing foundation body 2 so that the foundation stress is not transmitted from the foundation rising member 3 to the existing foundation body 2. Gusset plates 7A and 7B at opposite ends of the reinforcing members 6A and 6B are attached and joined to the outside of the flanges 3A and 3B, respectively, and L-shaped hardware 8 is placed inside the flanges 3A and 3B of the base rising member 3. Are connected together by bolts. The other end of the reinforcing members 6A, 6B is connected to the pile foundations 5A, 5B to form a test body.
[0016]
210 kN was loaded as the tensile force on the basic rising member 3 in the test body. FIG. 4B shows a bending moment distribution diagram of the reinforcing member 6. The horizontal axis represents the reinforcing member length direction position with the joint portion of the basic rising member 3 as the origin, and the vertical axis represents the bending moment. The solid line indicates the calculated value of the simple support beam assuming that the joint between the foundation rising member 3 and the reinforcing member 6 is rigid, and the ● mark indicates the experimental value. From these bending moment distributions, it is understood that the calculated values and the experimental values correspond well, and the joints between the flanges 3A, 3B of the foundation rising member 3 and the reinforcing member 6 are bolted and integrated. It was proved that the stress can be transmitted reliably. Moreover, the strength calculation which made the length of pile foundation 5A, 5B the simple support beam is employ | adopted, and it can evaluate to a safe side. It should be noted that, as in the test example, all of the foundation stress acting on the foundation rising member 3 is borne by the pile foundations 5A and 5B via the reinforcement members 6A and 6B, as well as the existing foundation and the new reinforcement member. It is also possible to obtain a share rate of the basic stress so that a part of the basic stress is also borne by the existing foundation.
[0017]
As mentioned above, although each embodiment of the present invention has been described, within the scope of the gist of the present invention, the shapes and types of the existing foundation bodies and the number thereof (that is, the planar shape of the bottom panel of the existing tower), the existing tower Form of capacity increase, shape of foundation rising member including angle of angle of angle cross section, shape of foundation body including columnar concrete part, embedding form of foundation rising member in the foundation body, adjacent foundation rising members Steel tower shape, type, pile foundation shape, type and its installation form on the ground, column concrete removal form, shape of reinforcing members including split type (preferred) H-shaped steel is adopted, but a predetermined reinforcing structure as a beam such as a channel shape or a square pipe shape can be adopted), the shape and form of the gusset plate and its installation form on the reinforcing member, the pile of the reinforcing member Basics Bonding form of the shape of the L-shaped fittings, in form and additionally provided form or the like into the foundation rising member can be selected as appropriate.
[0018]
【The invention's effect】
As described above in detail, according to the present invention, a foundation steel disposed at a plurality of corners of the bottom panel of an existing steel tower and an angle steel embedded in columnar concrete installed on the foundation body. In the foundation structure of a steel tower for reinforcing the foundation rising members, pile foundations are installed on both sides of the foundation on a plane orthogonal to the center line of the existing tower, and the pile foundation and the column concrete on the foundation By installing a reinforcing member between the foundation rising member exposed by removing the upper end of the foundation, it is possible to install a new pile foundation without reinforcement and interference with the existing foundation body, All or most of the foundation stress applied to the existing foundation rising member can be equally applied to the pile foundations on both sides of the existing foundation body via the reinforcing member.
[0019]
In addition, a gusset plate that is abutted against and joined to each flange of the foundation rising member is installed at a joint portion of the reinforcing member with the foundation rising member, and both ends of the reinforcing member are connected to each other by a bonding plate or the like. When joined to a pile foundation, proper positioning when joining with a wide contact surface and holding of the proper position after joining are made effective by joining the foundation rising member to each flange with a gusset plate. In addition, it is easy to attach the reinforcing member to the pile foundation. Further, when the reinforcing member is divided into two parts with the gusset plate portion as a boundary, the constituent members are shortened and reduced in weight, and are easily transported and excellent in workability.
[0020]
Furthermore, when an L-shaped hardware is interposed on the joint surface between the gusset plate and the foundation rising member, the existing foundation rising is accompanied by an increase in capacity of the steel tower due to the presence of the strong L-shaped hardware. Even if a force to flatten the chevron cross-section of the member is applied, it is possible to effectively suppress those forces.
Thus, according to the present invention, it is possible to reduce the lifting work of existing foundation concrete, eliminate the need for reinforcing bar joints, etc., and reduce the weight of components while allowing most of the foundation stress to be borne by the newly installed foundation. It is possible to provide a foundation structure of a steel tower that can be easily transported.
[Brief description of the drawings]
FIG. 1 shows an embodiment of a steel tower having a foundation structure of a steel tower according to the present invention. FIG. 1 (A) is a plan view of a foundation including the lowest panel of an existing steel tower, and FIG. 1 (B) is a diagram. It is the A section enlarged view of 1 (A).
FIG. 2 is a view showing a basic structure in a front view as viewed in the direction of arrow B in FIG. 1 (B).
3 is a plan view taken along arrow C in FIG.
4A is a front view of a test body of a foundation structure portion, and FIG. 4B is a bending moment diagram of a reinforcing member in FIG. 4A.
FIG. 5 is an explanatory view showing a conventional basic structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Existing steel tower bottom panel 2 ... Base body 3 ... Base rising member 3A ... 1st flange 3B ... 2nd flange 4 ... Column concrete 4A ..... Upper end portion 4B ... Lower end portion 5A ... First pile foundation 5B ... Second pile foundation 6 ... Reinforcement member 6A ... First reinforcement member 6B ... ··· Second reinforcing member 6U ··· Top plate 6M ··· Web plate 6D ··· Bottom plate 7 ··· Gusset plate 7A · · · First gusset plate 7B · · · Second Gusset plate 8 ... L-shaped hardware 9A ... First joint plate 9B ... Second joint plate 10 ... Reinforcement plate L ... Center line O ... Center of tower

Claims (4)

In the foundation structure of the steel tower for reinforcing the foundation rising member of the angled steel embedded in the foundation body and the columnar concrete installed on the foundation body arranged at a plurality of corners of the bottom panel of the existing steel tower, Pile foundations are installed on both sides of the foundation on the plane perpendicular to the center line of the existing tower, and the upper part of the column concrete on the foundation is removed and exposed between the foundation rising members. A steel tower foundation structure characterized in that a reinforcing member is handed over.   A gusset plate that is abutted and joined to each flange of the foundation rising member is installed at a joint portion of the reinforcing member with the foundation rising member, and both ends of the reinforcing member are connected to the pile foundation by a joining plate or the like. The steel tower foundation structure according to claim 1, wherein the steel tower foundation structure is joined to the steel tower.   The steel tower foundation structure according to claim 2, wherein the reinforcing member is divided into two parts with a gusset plate portion as a boundary.   The foundation structure of the steel tower according to claim 2 or 3, wherein an L-shaped metal fitting is interposed on a joint surface between the gusset plate and the foundation rising member.

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